protection and control

protection and control presentation page contents presentation 1 grounding systems 3 short-circuit currents lexicon generalities Merlin Gerin 9 discrimination 15 electrical system protection 21 transformer protection 29 motor protection 35 AC generator protection 41 capacitor protection 47 sensors 53 I> overcurrent protection U< I <– directional overcurrent protection >f> I > N earth fault protection U> undervoltage protection over and underfrequency protection overvoltage protection Ii > negative sequence unbalance protection P <–– real reverse power protection I thermal overload protection Q <–– reactive reverse power protection ∆I differential protection I > U voltage restrained overcurrent protection Protection devices continuously monitor the electrical status of system units and cause them to be de-energized (e.g. tripped by a circuit breaker) when they are the site of a disturbance: short-circuit, insulation fault... The objectives are: to contribute to protecting people against electrical hazards, to prevent equipment damage (the power produced by a three-phase short-circuit on a MV busbar can melt up to 50 kg of copper within 1 second, the temperature at the centre of the arc can exceed 10,000°C), to limit thermal, dielectric and mechanical stress on equipment, to maintain stability and service continuity in the system, to protect adjacent installations (for example, by reducing induced voltage in adjacent circuits). In order to attain these objectives, a protection system should have the following features: speed, discrimination, reliability. U N > neutral voltage displacement protection Buchholz Protection, however, has its limits: faults have to actually occur in order for it to take effect. Protection cannot therefore prevent disturbances; it can only limit their duration. Furthermore, the choice of a protection system is often a technical and economic compromise between the availability and safety of the electrical power supply. The choice of a protective device is not the result of isolated study, but rather one of the most important steps in the design of the electrical system. Based on an analysis of the behaviour of electrical equipment (motors, transformers...) during faults and the phenomena produced, this guide is intended to facilitate your choice of the most suitable protective devices. protection guide 1 2 protection guide Merlin Gerin grounding systems introduction The choice of MV and HV grounding systems has long been a topic of heated controversy due to the impossibility of finding a single compromise for the various types of electrical systems. Experience acquired today enables a pertinent choice to be made according to the specific constraints of each system. five grounding sytems Neutral potential can be grounded using five methods that differ according to the kind (capacitive, resistive, inductive) and value (zero to infinity) of the Zn impedance connection made between the neutral and earth: Zn = ∞ ungrounded, no deliberate connection, Zn is a resistance with a fairly high value, Zn is a reactance with a generally low value, Zn is a reactance designed to compensate for the system capacity, Zn = 0 - the neutral is directly grounded. difficulties and selection criteria The selection criteria involve many aspects: technical characteristics (system function, overvoltage, fault current, etc...), operation (service continuity, maintenance), safety, cost (investment and operating expenses), local and national customs. In particular, there are two major technical considerations which are, in fact, contradictory: Reducing the level of overvoltage Overvoltage is of several origins: lightning overvoltage, which all overhead systems are exposed to, up to the user supply point, internal system overvoltage caused by operations and certain critical situations (resonance), overvoltage resulting from an earth fault itself and its clearance. Reducing earth fault current (If). Fault current that is too high produces a whole series of consequences: damage caused by the arc at the fault point; particularly the melting of magnetic circuits in rotary machines, thermal withstand of cable shields, size and cost of earthing resistance, induction into adjacent telecommunication systems, danger for people created by raised frame potential. Merlin Gerin Unfortunately, optimizing one of these requirements is automatically to the disadvantage of the other. Two typical grounding methods accentuate this contrast: the ungrounded neutral system, which eliminates the flow of earth fault current through the neutral but causes the most overvoltage, the directly grounded neutral system, which reduces overvoltage to a minimum, but causes high fault current. An intermediate solution is therefore often chosen: the impedance grounded neutral system. protection guide 3 grounding systems (cont.) ungrounded Id 4 protection guide In this type of system, a phase-to-earth fault only produces a weak current through the phase-to-earth capacity of the fault-free phases. It can be shown that Id = 3 CωV c V being the simple voltage, c C the phase-to-earth capacity of a phase, c ω the frequency of the system (ω = 2πf). The Id current can remain for a long time, in principle, without causing any damage since it does not exceed a few amperes (approximately 2 A per km for a 6 kV singlepole cable, with a 150 mm2 cross-section, PRC insulated, with a capacity of 0.63 µF/km). Action does not need to be taken to clear this 1st fault, making this solution advantageous in terms of maintaining service continuity. However, this brings about the following consquences: c if not cleared, the insulation fault must be signalled by a permanent insulation monitor, c subsequent fault tracking requires device made all the more complex by the fact that it is automatic, for quick identification of the faulty feeder, and also maintenance personnel qualified to operate it, c if the 1st fault is not cleared, a second fault occurring on another phase will cause a real two-phase short circuit through the earth, which will be cleared by the phase protections. Advantage The basic advantage is service continuity since the very weak fault current prevents automatic tripping. Drawbacks The failure to eliminate overvoltage through the earth can be a major handicap if overvoltage is high. Also, when one phase is earthed, the others are at delta voltage (U = V.e) in relation to the earth increasing the probability of a 2nd fault. Insulation costs are therefore higher since the delta voltage may remain between the phase and earth for a long period as there is no automatic tripping. A maintenance department with the equipment to quickly track the 1st insulation fault is also required. Applications This solution is often used for industrial systems (≤ 15 kV) requiring service continuity. Merlin Gerin resistance grounding I > N N Rn I > N Id Rn accessible neutral non accessible neutral Protections The detection of weak fault current Id requires protections other than overcurrent phase relays. These “earth fault" protections detect fault current: c directly in the neutral earthing connection 1 , c or within the system by measuring the vectorial sum of the 3 currents using: v 3 CTs feeding the phase overcurrent protections 2 , v a core balance CT - (accurate solution - to be used preferably) 3 . I > N 1 2 3 I > N I > N Merlin Gerin In this type of system, a resistive impedance limits earth fault current Id, while still allowing proper evacuation of overvoltage. Protections must however intervene automatically to clear the first fault. In systems that feed rotating machines, the resistance is calculated so as to obtain an Id current of 15 to 50 A. This weak current must however be Id ≥ 2 Ic (Ic : total capacitive current in the system) in order to reduce operation overvoltage and to enable simple detection. Distribution systems use higher ratings (100 to 1000 A) that are easier to detect and allow evacuation of lightning overvoltage. Advantages This system is a good compromise between weak fault current and good overvoltage evacuation. The protection devices are fairly simple and discriminating and the current is limited. Drawbacks c no service continuity; earth faults must be cleared as soon as they occur, c the higher the voltage and level of current limitation, the higher the cost of the earthing resistance. Applications Public and industrial MV distribution systems. Earthing resistance If the neutral is accessible (star-connected transformer), the earthing resistance is inserted between the neutral and earth. When the neutral is not accessible or when determined by the discrimination study, an artificial neutral point is established (zero sequence generator) using a coil or a special transformer with a very low zero sequence reactance. The relay is set according to the fault current Id that is calculated leaving out the zero sequence impedance of the source and of the connection in relation to impedance Rn and taking the following 2 rules into account: c setting > 1.3 times system capacitive current downstream from the protection, c setting at approximately 20 % of maximum earth fault current. Also, if 3 CTs are used for detection, the setting must not be less than 10% of the CT rating to take into consideration the uncertainty linked to: v assymmetry of transient currents, v differences in performance level. protection guide 5 grounding systems (cont.) reactance grounding For system voltage above 40 kV, it is preferable to use reactance rather than a resistance because of the difficulties arising from heat emission in the event of a fault. compensation reactance grounding This system is used to compensate for capacitive current in the system. Fault current is the sum of the currents which flow through the following circuits: c reactance grounding, c fault-free phase capacitance with respect to earth. The currents may compensate for each other since: c one is inductive (in the grounding), c the other one is capacitive (in the fault-free phase capacitances). They are therefore opposite in phase. L N Advantage The system reduces fault current, even if the phase-to-earth capacitance is high. Id direct grounding 6 protection guide Drawback The cost of reactance grounding may be high due to the need to modify the reactance value in order to adapt compensation. Protection Fault detection is based on the active component of the residual current. The fault causes residual currents to flow throughout the system, but the faulty circuit is the only one through which resistive residual current flows. In addition, the protective devices take into account repetitive self-extinguishing faults (recurring faults). When the earthing reactance and system capacitance are compensated (3Ln Cw2 =1) v fault current is minimal, v it is resistive current, v faults are self-extinguishing. The compensation reactance is called an extinction coil or Petersen coil. When the neutral is directly grounded without any coupling impedance, fault current Id between the phase and earth is practically a phase-to-neutral short-circuit, with a high value. This system, ideal for overvoltage evacuation, involves all the drawbacks and hazards of strong earth fault current. There is no continuity of service, but there are no specific protections: the regular phase overcurrent protections clear the fault. Applications c this type of system is not used in European overhead or underground MV systems, but is prevalent in North American distribution systems. In these (overhead) systems, other features come into play to justify the choice: v the existence of a distributed neutral conductor, v 3 ph or 2 ph/N or ph/N distribution, v use of the neutral conductor as a protective conductor with systematic earthing of each electrical cable pole. c this type of system may be used when the short-circuit power of the source is low. Merlin Gerin Merlin Gerin protection guide 7 8 protection guide Merlin Gerin short-circuit currents introduction A short circuit is one of the major incidents affecting electrical systems. The consequences are often serious, if not dramatic: c a short circuit disturbs the system environment around the fault point by causing a sudden drop in voltage, c it requires a part of the system (often a large part) to be disconnected through the operation of the protection devices, c all equipment and connections (cables, lines) subjected to a short circuit undergo strong mechanical stress (electrodynamic forces) which can cause breaks, and thermal stress which can melt conductors and destroy insulation, c at the fault point, there is often a high power electrical arc, causing very heavy damage that can quickly spread all around. Although short circuits are less and less likely to occur in modern well-designed, welloperating installations, the serious consequences they can cause are an incentive to implement all possible means to swiftly detect and attenuate them. The short circuit value at different points in the system is essential data in defining the cables, busbars and all breaking and protection devices as well as their settings. definitions Short-circuit current at a given point in the system is expressed as the rms value Isc (in kA) of its AC component. The maximum instantaneous value that short-circuit current can reach is the peak value Ip of the first half cycle. This peak value can be much higher than √2.Isc because of the damped DC component that can be superimposed on the AC component.This random DC component depends on the instantaneous value of voltage at the start of the shortcircuit and on the system characteristics. Short-circuit power is defined by the formula Ssc = eUn . Isc (in MVA). This theoretical value has no physical reality; it is a practical conventional value comparable to an apparent power rating. current DC component iρ 2 2 Icc Merlin Gerin time protection guide 9 short-circuit currents (cont.) The Isc value of three-phase short circuit current at a point F within the system is: U Isc = e Zsc phase-to-phase shortcircuit Isc Zsc U Zsc U Zsc F in which U refers to the phase-to-phase voltage at point F before the fault occurs and Zcc is the equivalent upstream system impedance as seen from the fault point. c in theory, this is a simple calculation; in practice, it is complicated due to the difficulty of calculating Zsc, an impedance equivalent to all the unitary impedances of series- and parallel-connnected units located upstream from the fault. These impedances are themselves the quadratic sum of reactances and resistances. F F There may not be a single source of voltage, but rather several sources in parallel, in particular, synchronous and asynchronous motors, reacting like generators upon the occurrence of short circuits. Three-phase short circuit current is generally the strongest current that can flow in the system. Two-phase short circuit current is always weaker (by a ratio of e/2, i.e. approximately 87%). 2-phase Isc = U 2 Zsc Zsc = VR2 + X2 Calculations can be made much simpler by knowing the short-circuit power Ssc at the point that joins the distribution system. Knowing Ssc at this point, the equivalent Za impedance upstream from this point can be calculated using the formula: Za = phase-to-earth short circuit current (single-phase) 1 N 2 Zn The value of this current depends on Zn impedance between the neutral and earth.This impedance can be virtually nil if the neutral is directly grounded (in series with the earthing connection resistance) or, on the contrary, almost infinite if the neutral is ungrounded (in parallel with the system's phase to earth capacitance). Calculation of this unbalanced short-circuit current requires the use of the symmetrical components method. This method replaces the real system by superimposing 3 systems: positive Z1 , negative Z2 , zero sequence Z0 The value of the phase-to-earth fault current Io is: I0 = 3 Io Ue Z1 + Z2 + Z0 + 3 Zn This calculation is required for systems in which the neutral is earthed by a Zn impedance. It is used to determine the setting of the "earth fault" protection devices which are to intervene to break the earth fault current. In practice : I0 z 10 protection guide U2 U , Isc = e Za Ssc U e Zn Merlin Gerin short circuit currents at generator terminals It is more complicated to calculate shortcircuit current at a synchronous generator's terminals than at the terminals of a transformer connected to the system. This is because the internal impedance of the machine cannot be considered constant after the start of the fault. It increases progressively and the current becomes weaker, passing through three characteristic stages: subtransient: (approx. 0.01 to 0.1 sec). Short-circuit current (rms value of the AC component) is high: 5 to 10 times permanent rated current. transient: (between 0.1 and 1 sec). Shortcircuit current drops to between 2 and 6 times rated current. continuous: Short-circuit current drops to between 0.5 and 2 times rated current. current subtransient phenomena The given values depend on the power rating of the machine, its excitation mode and, for continuous current, on the value of the exciting current, therefore on the machine's load at the time of the fault. Also, the zero sequence impedance of the AC generators is generally 2 to 3 times lower than their positive sequence impedance. Phase-to-earth short circuitcurrent is therefore stronger than threephase current. By way of comparison, the three-phase short-circuit current at a transformer's terminals ranges between 6 and 20 times rated current depending on the power rating. It can be concluded that short-circuits at generator terminals are difficult to assess, and that their low, decreasing value makes protection setting difficult. transient continuous i1 t i2 t i3 t fault occurs calculation of short-circuit currents Merlin Gerin 3 short circuit currents at generator terminal The rules for calculating short-circuit currents in industrial installations are presented in IEC standard 909 issued in 1988. The calculation of short-circuit currents at various points in a system can quickly turn into an arduous task when the installation is a complicated one. The use of specialized software enables these calculations to be performed faster. protection guide 11 short-circuit currents (cont.) equipment behaviour during short-circuits There are 2 types of system equipment, the type that intervenes and the type that does not intervene at the time of a fault. Passive equipment This category comprises all equipment which, due to its function, must have the capacity to transport both normal current and short-circuit current without damage. This equipment includes cables, lines, busbars, disconnecting switches, switches, transformers, series reactances and capacitors, instrument transformers. For this equipment, the capacity to withstand a short-circuit without damage is defined in terms of: electrodynamic withstand (expressed in peak kA), characterizing mechanical resistance to electrodynamic stress. thermal withstand (expressed in rms kA for 1 to 5 seconds) characterizing maximum admitted overheating. Active equipment This category comprises the equipment designed to clear short circuit currents: circuit breakers and fuses. This property is expressed by the breaking capacity and if required, by the making capacity upon occurrence of a fault. breaking capacity This basic characteristic of a switching device is the maximum current (in rms kA) it is capable of breaking in the specific conditions defined by the standards, it generally refers to the rms value of the AC component of the short circuit current; sometimes, for certain switchgear, the rms value of the sum of the 2 components is specified: AC and DC; it is then "unbalanced current". The breaking capacity requires other data such as: voltage, R/X ratio of broken circuit, system natural frequency, number of breaks at maximum current, for example the cycle: B - M/B - M/B (B = breaking; M = making), status of the device after test. The breaking capacity appears to be a fairly complicated characteristic to define: it therefore comes as no surprise that the same device can be assigned different breaking capacities depending on the standard by which it is defined. making capacity upon occurrence of a short-circuit In general, this characteristic is implicitly defined by the breaking capacity: a device should have the capacity to "make" upon the occurrence of a short-circuit that it has the capacity to break. Sometimes making capacity needs to be higher, for example for AC generator circuit breakers. The making capacity is defined at peak kA since the 1st asymmetric peak is the most restrictive one from an electrodynamic point of view. short-circuit current presumed to be "broken" Some devices have the capacity to limit the current they are going to break. Their breaking capacity is defined as the maximum current presumed to be broken that would develop in the case of a full short circuit at the upstream terminals of the device. 12 protection guide Merlin Gerin Merlin Gerin protection guide 13 14 protection guide Merlin Gerin discrimination I> I> I> introduction Protections comprise a coherent whole in relation to the structure of the system and its grounding. They should be looked upon as a system based on the principle of discrimination which consists of isolating as quickly as possible the part of the system affected by the fault and only that part, leaving all the fault-free parts of the system energized. current discrimination Current discrimination is based on the fact that within a system, the further the fault is from the source, the weaker the fault current. Current-based protection is installed at the starting point of each section: its setting is set at a value lower than the minimum value of short-circuit current caused by a fault in the monitored section, and higher than the maximum value of the current caused by a fault located downstream (beyond the monitored area). Set in this way, each protection device operates only for faults located immediately downstream from it, and is not sensitive to faults beyond. In practice, it is difficult to define the settings for two cascading protection devices (and still ensure good discrimination) when there is no notable decrease in current between two adjacent areas (medium voltage system). However, for sections of lines separated by a transformer, this system can be used advantageously as it is simple, economical and quick (tripping with no delay). An example of the application is shown (fig.1). ISCA > Ir ≥ ISCB ISCB image at the transformer primary of the maximum short-circuit current on the secondary. I> A Icc I A B Icc ISCBB SCA (fig.1) example of current discrimination Various means can be implemented to ensure proper discrimination in electrical system protection: c current discrimination, c time discrimination, c discrimination by data exchange, referred to as logic discrimination, c discrimination by the use of directional protection devices, c discrimination by the use of differential protection devices. Ir I max. SCB Merlin Gerin I min. SCA I protection guide 15 discrimination (cont.) time discrimination time setting * 1,1s I> Time discrimination consists of setting different time delays for the current-based protection devices distributed throughout the system. The closer the relay is to the source, the longer the time delay. The fault shown in the diagram opposite is detected by all the protections (at A, B, C, and D). The time-delayed protection at D closes its contacts more quickly than the one installed at C, which is in turn faster to react than the one at B, etc. Once circuit breaker D has been tripped and the fault current has been cleared, protections A, B and C, which are no longer required, return to the stand-by position. A 0,8s I> B 0,5s I> C 0,2s I> D The difference in operation times ∆t between two successive protections is the discrimination interval. It takes into account: c circuit breaker breaking time Tc, c time delay tolerances dt, c time for the protection to return to stand-by: tr ∆t should therefore correspond to the relation: ∆t ≥ Tc + tr + 2dt. Considering present switchgear and relay performances, ∆t is assigned a value of 0.3 sec. This discrimination system has two advantages: c it provides its own back-up (granted, by eliminating a fault-free part of the installation), c it is simple. However, when there are a large number of cascading relays, since the protection located the furthest upstream has the longest time delay, the fault clearing time is prohibitive and incompatible with equipment short-circuit current withstand and external operating necessities (connection of a distributor to electrical system, for example). This principle is used in radial networks. phase to phase fault (*) IRA ≥ IRB ≥ IRC ≥ IRD IR: setting of overcurrent protection 16 protection guide Merlin Gerin I> I> I> application of time discrimination A IrA The time delays set for time discrimination are activated when the current exceeds the relay settings. The settings must be coherent. There are 2 types of time-delayed currentbased relays: cdefinite time relays, the time delay is constant regardless of the current, provided it is higher than the setting. IrA > IrB > IrC. , tA > tB > tC. t B IrB current setting not operating t time delayed operating C B A t A C IrC ∆t t B ∆t t C time delay I IrC (fig.1) definite time tripping curve IrB IccC IccB IccA I IrA cIDMT relays (fig. 2), the stronger the current, the shorter the time delay. If the settings are set to In, overload protection is ensured at the same time as short-circuit protection and setting coherency is guaranteed. InA > InB > InC IrA = InA IrB = InB IrC = InC The time delays are set for the discrimination interval ∆t of the maximum current detected by the upstream protection relay. t current setting not operating t C B A time delayed operating ∆t ∆t I (fig.2) IDMT tripping curve Merlin Gerin IrC IrB IrA IccC IccB IccA I protection guide 17 discrimination (cont.) logic selectivity I> I> This principle is used when short fault clearing time is required. Theexchange of logic data between successive protection devices eliminates the need for discrimination intervals. In a radial system, the protections located upstream from the fault point are activated; those downstream are not. The fault point and the circuit breaker to be controlled can therefore be located without any ambiguity. Each protection activated by a fault sends: a blocking input to the upstream stage (order to increase the upstream relay time delay), a tripping order to the related circuit breaker unless it has already received a blocking input from the downstream stage. Time-delayed tripping is provided for as back-up. Advantage Tripping time is no longer related to the location of the fault within the discrimination chain. R blocking input I> R I> R phase-to-phase fault logic selectivity system 18 protection guide Merlin Gerin I> I> I> directional discrimination In a looped system, in which faults are fed from both ends, it is necessary to use a protection system that is sensitive to the direction of the flow of fault current in order to locate and clear it. Example of the use of directional protections: D1 and D2 are equipped with instantaneous directional protections; H1 and H2 are equipped with time-delayed overcurrent protections. In the event of a fault at point 1 , only the protections on D1 (directional), H1 and H2 detect the fault. The protection on D2 does not detect it (because of the direction of its detection system). D1 breaks. The H2 protection de-energizes and H1 breaks. tH1 = tH2 tD1 = tD2 tH = tD + ∆t H2 H1 I> I> 1 A I I D1 D2 way of detection example of use of directional protections sélectivité par protection différentielle I protected equipment I' Rs ∆I high impedance differential protection diagram I protected equipment I' These protections compare the current at the ends of the monitored section of the system. Any difference in amplitude and phase between the currents indicates the presence of a fault. This is a selfdisciminating protection system as it only reacts to faults within the area it covers and is insensitive to any faults outside this area. The protected equipment can be: a motor, an AC generator, a transformer, or a connection (cable or line). This protection is used to : c detect fault currents lower than rated current c trip instantaneously since discimination is based on detection and not on time delays. There are two main principles: The high impedance protective device is series-connected with a stabilization resistor (1) in the differential circuit. The percentage-based differential protective device is connected separately to the I and I' current circuits. The difference between these currents I - I' is determined in the protective device and the protection stability (1) is obtained by a restraint related to the measurement of let-through current I + I' . 2 (1) The stability of the differential protective device is its capacity to remain dropped out when there are no faults within the zone being protected, even if a differential current is detected: v transformer magnetizing current, v line capacitive current, v error current due to saturation of the current sensors. ∆I percentage-based differential protection diagram Merlin Gerin protection guide 19 20 protection guide Merlin Gerin electrical system protection introduction Merlin Gerin Electrical system protection should: detect faults, cut off of the faulty parts of the electrical system, keeping the fault-free parts in operation. Protection systems are chosen according to the electrical system configuration (parallel operation of AC generators or transformers, loop or radial system,grounding system…). Protection against each of the following types of faults is to be considered: phase-to-phase faults, earth faults (protections related to electrical system grounding). This will be done by successively examining the following cases: a single incoming line, two incoming lines, a busbar, a loop. protection guide 21 electrical system protection (cont.) electrical system with a single incoming line phase-to-phase faults (fig. 1) I> t A A 2 The protection device at D detects faults 1 on the outgoing lines and is tripped following a time delay tD. The protection device at A detects the faults 2 on the busbars and is tripped following a time delay tA. It also acts as back-up in the event of a malfunction of protection D. Choose : IrA ≥ IrD and tA ≥ tD +∆t ∆t : discriminator interval (generally 0,3 s). D I> t D 1 (fig. 1) phase-to-earth faults H IN > 3 IN > A 2 D3 D2 IN > D1 IN > IN > 1 (fig. 2) resistive current 22 protection guide capacitive current Grounding by resistance on transformer (fig.2) Outgoing lines, the incoming line and the grounding connection are equipped with earth fault protection devices. These devices are necessarily different from multiphase fault protections as the fault currents are in a different range. Outgoing line protections are set selectively in relation to the incoming line protection, which is itself set selectively in relation to the protection equipping the grounding connection (respecting discrimination intervals). The fault current is fed back by the capacitances of the fault-free outgoing lines and the grounding resistance. All the faultfree outgoing line sensors detect capacitive current. So as to prevent inadvertent tripping, the protection device on each outgoing line is set at a setting higher than the outgoing line's own capacitive current. c fault at 1 : the D1 circuit breaker trips, actuated by the protection device linked to it, c fault at 2 : the A circuit breaker trips, actuated by the incoming line protection device, c fault at 3 : the protection device located on the neutral grounding connection causes circuit breaker H to trip at the transformer primary. Merlin Gerin Grounding by resistance on the busbar (fig.3) The outgoing and ingoing line protections are selectively set in relation to the protection equipping the grounding impedance. As in the previous case, the protection on each outgoing line is set at a setting higher than the outgoing line's own capacitive current. In the event of a fault on outgoing line 1 only the D1 outgoing line circuit breaker trips. In the event of fault on the busbar 2 , only the protection equipping the grounding connection detects the fault. It causes tripping by circuit breaker A. In the event of fault on the transformer secondary 3 , the incoming line protection detects the fault. It causes tripping by circuit breaker H. H 3 I IN > t rA A A IN > IrN tN 2 D2 Note: when circuit breaker A is open, the transformer secondary is ungrounded. D1 IN > IN > I rD t D 1 (fig. 3) permanent insulation monitoring UN > Ungrounded neutral (fig.4). A fault, regardless of its location, produces current which is fed back by the capacitance of the fault-free outgoing lines. in industrial system, this current is generally weak (a few amperes), allowing operations to carry on while the fault is being tracked. The fault is detected by a permanent insulation monitor (Vigilhom) or a neutral voltage displacement protection device. In the case of a system with high total capacitve current (tens of amperes), added measures are required to quickly clear the fault. Directional earth protection can be used to selectively trip the faulty outgoing line. (fig. 4) Merlin Gerin protection guide 23 electrical system protection (cont.) system with two incoming lines H1 H2 I> t I> t I t H T1 H T2 3 t I R I> t R t I> A A1 A A2 2 D1 phase-to-phase faults (fig.1) phase-to-earth faults (fig. 2) System with two transformer incomers or with two incoming lines The outgoing lines are equipped with phase overcurrent protections with a time delay of tD. The two incoming lines A1 and A2 are equipped with phase overcurrent protections selectively set with the outgoing lines, i.e. at a value of tA ≥ tD + ∆t. They are also equipped with directional protection devices with time delays set at tR < tA - ∆t. Therefore, a fault at 1 is cleared by the opening of D2 with a time delay of tD. A fault at 2 is cleared by the opening of A1 and A2 with a time delay of tA (the directional protections do not detect the fault). A fault at 3 is detected by the A1 directional protection which opens at time tR, allowing continued operation of the faultfree part of the system. The fault at 3 however is still fed by T1. At time tH ≥ tA + ∆t, H1 is actuated by the phase overcurrent protection with which it is equipped. System with two transformer incomers Grounding by resistance on the transformers. The outgoing lines are equipped with earth fault protection devices set at a setting higher than the corresponding capacitive current with a time delay of tD. The incomers (A1 and A2) are equipped with directional protections with a time delay of tR. The grounding connections are equipped with earth fault protections, the setting of which is higher than the settings of the incomer and outgoing line protections with a time delay of tN ≥ tD + ∆t. Therefore, a fault at 1 is cleared by the opening of D1. A fault at 2 is cleared by the opening of A1, A2, H1 and H2, triggered by the protections located on the grounding connections of the 2 transformers. A fault at 3 is detected by the A1 directional earth fault protection which opens at time tR, allowing continued operation of the fault-free part of the system. However, fault 3 is still fed up to time tN, the moment at which the protection located on the corresponding transformer's grounding connection triggers the opening of the H1 circuit breaker. D2 I> t D I> t D 1 H1 H2 detection way (fig. 1) IN > 3 IN t t N N IN > t IN R A1 t R A2 2 D1 D2 IN > tD D3 IN > tD IN > tD 1 detection way (fig. 2) 24 protection guide Merlin Gerin busbars ∆I In addition to the protections described earlier, a busbar can be equipped with a specific protection device, referred to as high impedance differential protection, the aim of which is to be sensitive, quick and selective. The differential protection (fig.1) takes the vectorial sum per phase of currents entering and leaving the busbar; whenever this sum is not equal to zero, it trips the busbar power supply circuit breakers. Logic discrimination (fig.2) applied to overcurrent protections provides a simple, simple solution for busbar protection . A fault at 1 is detected by the D1 protection which transmits a blocking input to the A protection. The D1 protection is tripped 0.6 sec. later A fault at 2 is detected only by the A protection which is tripped 0.1 sec. later. (fig. 3) I> t = 0,1 s I> t = 0,6 s I> t = 0,3 s A 2 D1 1 D2 (fig. 4) Merlin Gerin protection guide 25 electrical system protection (cont.) In a distribution system comprising substations fed in a loop, protection can be at the head of the loop or by sections: open loop closed loop Protection at the head of the loop (fig. 1) I> I> The loop is always open. The circuit breaker at the head of each loop is equipped with an overcurrent protection device. A fault in a cable joining up 2 substations causes the opening of one of the two circuit breakers at the head, depending on the position of the loop opening. Protection is often completed by an automation system which: c clears the fault with the power off by opening the devices located at the ends of the cable involved, after localisation of the faulty cable (by cable fault detector), c close the incomer circuit breaker that tripped, c closes the device which ensured the normal opening of the loop. (fig. 1) Loop section protection ∆I ∆I ∆I ∆I Each end of the cable is equipped with a circuit breaker, with severall protection solutions. c differential protection solution (fig. 2): each cable is equipped with a differential line protection device and each substation is equipped with a busbar differential protection device. This type of protection is very quick but expensive. Also, if the neutral is resistance grounded, the sensitivity of the differential protections must cover phase-toearth faults. This solution may be used in bolh open and closed loops. (fig. 2) 26 protection guide Merlin Gerin Loop section protection (cont.) I> Overcurrent protection and directional logic discrimination (fig. 3) The circuit breakers in the loop are fitted with overcurrent protection and directional protection devices. The principle of logic discrimination is also used to clear faults as quickly as possible. A fault in the loop activates: c all the protection devices when the loop is closed, c all the protection devices upstream from the fault when the loop is open. Each protection device sends a blocking input to one of the devices adjacent to it within the loop, according to the data transmitted by the directional protection device. Protection devices that do not receive a blocking input trip within a minimum amount of time regardless of the fault's position in the loop: c the fault is cleared by two circuit breakers, one on either side of the fault if the loop is closed, and all the switchboards remain energized, c the fault is cleared by the upstream circuit breaker if the loop is open. This solution is a full one since it protects the cables and switchboards. It is quick, discriminating and includes back-up protection. I> I I I I I I I I (fig. 3) I> t4 I> I> t5 t5 I> I t1 t3 I I> t2 t3 I I> t2 t4 I t1 Overcurrent and directional overcurrent protection (fig. 4) In the case of a loop limited to two substations, time discrimination can be used with overcurrent and directional overcurrent protection devices as shown in the diagram. A higher number of substations results in prohibitive time delays. The time gap between delays t1, t2… t5 is the discrimination interval ∆t. Long distance protection This solution is only useful for very long connections (several kilometers long). It is costly and very seldom used, in medium voltage. time gap between t1, t2,… t3 is ∆t discrimination interval detection way (fig. 4) Merlin Gerin protection guide 27 28 protection guide Merlin Gerin transformer protection introduction The transformer is a particularly important system component. It requires effective protection against all faults liable to damage it, whether of internal or external origin. The choice of a protection system is often based on technical and cost considerations related to the power rating. types of faults The main faults affecting transformers are: c overloads, c short-circuits, c frame faults An overload can result from an increase in the number of loads being fed simultaneously or from an increase in the power absorbed by one or more loads. It results in an overcurrrent of long duration causing a rise in temperature that is detrimental to the preservation of insulation and to the service life of the transformer. Short circuits can be inside or outside the transformer: c internal: faults occurring between winding conductors with different phases or faults in the same winding. The fault arc damages the transformer winding and can cause fire. In oil transformers, the arc causes the emission of decomposition gas. If the fault is a weak one, there is a slight gas emission and the accumulation of gas can become dangerous. A violent short circuit can cause major damage that can destroy the winding and also the tank frame by the spread of burning oil. c external: phase-to-phase faults in the downstream connections. The downstream short circuit current produces electrodynamic forces In the transformer that are liable to affect the windings mechanically and then develop in the form of internal faults. A frame fault is an internal fault. It can occur between the winding and the tank frame or between the winding and the magnetic core. It causes gas emission in oil transformers. Like internal short circuits, it can cause transformer damage and fire. The amplitude of the fault current depends on the upstream and downstream grounding systems, and also on the position of the fault within the winding. c in star connections (fig.1), the frame current varies between 0 and the maximum value depending on whether the fault is at the neutral or phase end of the winding. c in delta connections (fig.2), the frame current varies between 50 and 100% of the maximum value depending on whether the fault is in the middle or at the end of the winding. I I I max I max I max 2 0 100% (fig.1) 0 50% 100% (fig.2) fault current according to the winding fault position Merlin Gerin protection guide 29 transformer protection (cont.) Overloads Overcurrent of long duration is generally detected by a direct time or IDMT delayed overcurrent protection which is discriminating with respect to secondary protection. Thermal overload protection is used to monitor the temperature rise: overheating is determined by simulation of heat release as a function of the current and temperature lag of the transformer. protection devices I> ∆I I >> Tank frame faults c tank frame protection (fig.3): This instantaneous overcurrent protection device installed on the transformer frame earthing connection constitutes a simple, efficient solution for internal winding-toframe faults (provided its setting is suitable with grounding system used) the transformer tank has to be insulated from the ground. This form of protection is discriminating, being sensitive only to transformer frame faults. Another solution consists of using earth fault protection: c earth protection located on the upstream system for frame faults affecting the transformer primary. c earth fault protection located on the incoming line of the board being fed, if the neutral of the downstream system is earthed on the busbars (fig.4). These protections are disciminating: they are only sensitive to phase-to-earth faults located in the transformer or on the upstream and downstream connections. c restricted earth protection if the neutral of the downstream system is earthed at the transformer (fig.5). This is a high impedance differential protection system which detects the difference in residual currents measured at the grounding point and at the threephase transformer outlet. c neutral earth protection if the downstream system is earthed at the transformer (fig.6). (fig.2) (fig.1) I> I > N (fig.3) Short-circuits For oil transformers: c a Buchholz relay or DGPT gas pressure temperature detector that is sensitive to gas release or oil movement is used, causing respectively a short-circuit between turns of the same phase and a violent phase-tophase short-circuit. c differential transformer protection (fig.1) ensures rapid protection against phase-tophase faults. It is sensitive to fault currents in the range of 0.5 In and is used for important transformers. c an instantaneous overcurrent protection (fig.2) device linked to the circuit breaker located at the transformer primary ensures protection against violent short circuits. The current setting is set at a value higher than the current due to a short circuit on the secondary, thus ensuring current discrimination. c for low power transformers, a fuse is used for overcurrent protection. (fig.4) ∆I (fig.5) I > N (fig.6) 30 protection guide Merlin Gerin examples of transformer protection MV/LV MV/LV MV MV (1) I I> (2) I>> (2) I > (3) N I > N (3) (4) (4) I > N (5) (6) (6) LV LV high power low power (1) Thermal overload (2) Fuse or 2-setting overcurrent (3) Earth fault (4) Buchholz or DGPT (5) Tank earth leakage (6) LV circuit breaker MV/MV MV/MV I I> (1) I (2) I> II >> >> I > N I > (3) (5) low power ∆I N (7) (4) (4) N (2) I >> (3) I > (1) I > N (6) ∆I (8) high power (1) Thermal overload (2) Fuse or 2-setting overcurrent (3) Earth fault (4) Buchholz or DGPT (5) Tank earth leakage (6) Neutral earth protection (7) Transformer differential (8) Restricted earth fault protection Merlin Gerin protection guide 31 transformer protection (cont.) setting information type of fault overload short circuit earth fault 32 protection guide settings LV circuit breaker: In (for MV/LV transformer) thermal overload: time constant in the 10' range fuse: rating > 1.3 In, direct time overcurrent lower setting < 6 In; time delay ≥ 0.3 s (selective with downstream), upper setting > downstream Isc instantaneous, IDMT overcurrent IDMT lower setting (selective with downstream), high setting > downstream Isc, instantaneous, differential transformer, 25% to 50% of In. tank earth leakage setting > 20 A 100 ms time delay, earth fault current setting ≤ 20 % of maximum earth fault and ≥ 10% of CT rating if fed by 3 CTs, time delay 0.1 s if grounded within the system, time delay according to discrimination if grounded in the transformer, restricted earth fault protection setting approximately 10% of In when the 3 CT integrator assembly is used, neutral earth protection setting approximately 10% of maximum earth fault current. Merlin Gerin Merlin Gerin protection guide 33 34 protection guide Merlin Gerin motor protection introduction The motor constitutes an interface between the electrical and mechanical fields. It is found in an environment linked to the driven load, from which it is inseparable. Furthermore, the motor can be subjected to inner mechanical stress due to its moving parts. A single faulty motor may cause disturbance in a complete production process. types of faults Merlin Gerin Motors are affected by: faults related to the driven load power supply faults internal motor faults Faults related to the driven load overloads. Since the power called upon is greater than rated power, there is overcurrent in the motor and an increase in losses, causing a rise in temperature. too long, too frequent start-ups. Motor start-up creates substantial overcurrents which are only admissible since they are of short duration. If start-ups are too frequent or too long due to an insufficient gap between motor torque and load torque, the overheating that is inevitably produced becomes prohibitive. jamming. This refers to a sudden stop in rotation for any reason related to the driven mechanism. The motor absorbs the start-up current and stays jammed at zero speed. There is no more ventilation and overheating very quickly occurs. pump de-energizing. This causes motor idling which has no direct harmful effect. However, the pump itself quickly becomes damaged. reverse power. This type of fault occurs due to a voltage drop when a synchronous motor driven by the inertia of the load sends power back into the network. In particular, should the normal network power supply be released, the synchronous motor can maintain the voltage in an undesirable fashion and feed the other loads which are connected in parallel. Power supply faults drop in voltage. This reduces motor torque and speed: the slow-down causes increased current and losses. Abnormal overheating therefore occurs. unbalance. 3-phase power supply can be unbalanced because: the power source (transformer or AC generator) does not provide symmetrical 3-phase voltage, all the other consumers together do not constitute a symmetrical load, unbalancing the power supply network, the motor is fed on two phases due to fuse melting. Power supply unbalance produces reverse currrent causing very high losses and therefore quick rotor overheating. Modern motors have optimized characteristics which make them inappropriate for operation other than according to their rated characteristics. The motor is therefore a relatively fragile electrical load that needs to be carefully protected. Internal motor faults phase-to-phase short-circuits: these can vary in strength depending on the position of the fault within the coil; they cause serious damage. frame faults: fault current amplitude depends on the power supply network grounding system and on the fault's position within the coil. Phase-to-phase short-circuits and frame faults require motor rewinding, and frame faults can produce irreparable damage to the magnetic circuit. loss of synchronism.This fault involves synchronous motors losing their synchronism due to field loss: motor operation is asynchronous but the rotor undergoes considerable overheating since it is not designed for this. protection guide 35 motor protection (cont.) motor protection devices ∆I (fig.1) Overloads Overloads are monitored: c either by IDMT overcurrent protection, c or by thermal overload protection. Thermal overload involves overheating due to current. c or by a temperature probe. Excessive starting time and locked rotor The same function ensures both protections. This involves an instantaneous current relay set at a value lower than the start-up current, which is validated after a time delay beginning when the motor is turned on; this time delay is set at a value greater than or equal to the normal duration of start-up. Starts per hour The corresponding protection is sensitive to the number of starts taking place within a given interval of time or to the time between starts. Pump de-energizing Is detected by a direct time undercurrent protection device which is reset when the current is nil (when the motor stops). Reverse power Is detected by a directional real power protection device. Drops in voltage Are monitored by a time-delayed undervoltage protection device. The voltage setting and time delay are set for discrimination with the system's short-circuit protection devices and to tolerate normal voltage drops, for example during motor starts. This type of protection is often shared by several motors in the same switchboard. Unbalance Protection is ensured by IDMT or direct time negative sequence unbalance detection. Phase-to-phase short circuits Are detected by a time-delayed overcurrent protection device. The current setting is set higher than or equal to the start-up current and the time delay is very short; its purpose is to make the protection insensitive to the first peaks of making current. When the corresponding breaking device is a contactor, it is associated with fuses which ensure short-circuit protection. For large motors, a high impedance or percentage-based differential protection system is used (fig. 1). Through appropriate adaptation of the connections on the neutral side and by the use of summing current transformers, a simple overcurrent protection device ensures sensitive, stable detection of internal faults (fig.2). Frame faults This type of protection depends on the grounding system. Higher sensitivity is sought so as to limit damage to the magnetic circuit. Field loss (for synchronous motors). It is detected by a time-delayed max. reactive power protection device. ∆I (fig.2) 36 protection guide Merlin Gerin examples of protection I thermal overload Ii > unbalance I> overcurrent IN > Contactor-controlled or circuit breakercontrolled asynchronous motor Additional protection according to the type of load: c excessive starting time + locked rotor c starts per hour c undercurrent U< undervoltage earth fault M I thermal overload Ii > unbalance I> overcurrent IN > earth fault ∆I differential High power asynchronous motor Additional protections according to the type of load: c excessive starting time + locked rotor c starts per hour c undercurrent U< undervoltage M High power synchronous motor Additional protection according to the type of load: c excessive starting time + locked rotor c starts per hour c undercurrent I thermal overload Ii > unbalance I> overcurrent U< undervoltage IN > earth fault P <–– real reverse power ∆I differential Q <–– field loss M Merlin Gerin protection guide 37 motor protection (cont.) setting information type of fault overloads breaking unbalance and phase reversal short circuits stator frame excessive starting time locked rotor drop in voltage real reverse power field loss 38 protection guide settings thermal overload parameters should be adapted to fit the characteristics of the motor (time constant in the 10' range), IDMT overcurrent relay setting should allow starting. negative sequence unbalance setting between 0.3 and 0.4 In, time delay: approximately 0.6 sec. If the system can function with almost continuous unbalance, an IDMT characteristic is used: setting allowing 0.3 In during starting without tripping fuse rating > 1.3 In, allowing starting, direct time overcurrent setting ≥ 1.2 start-up current, time delay approximately 0.1 sec. differential: setting 10% to 20% of In resistance grounding The lowest setting compatible with the protected outgoing line's capacitive current is selected, setting between 10 and 20% of maximum earth fault current, time delay: 0.1 sec. approximately. setting approximately 2.5 In, time delay 1.1 x starting time. setting between 0.75 and 0.8 Un, time delay: approximately 1 sec. approximate settings setting 5% of Pn time delay 1 sec. approximate settings setting 30% of Sn time delay 1 sec. Merlin Gerin Merlin Gerin protection guide 39 40 protection guide Merlin Gerin AC generator protection introduction AC generator operation can be altered by both faults within the machine and by disturbances occurring in the electrical system to which it is connected. An AC generator protection system therefore has a dual objective: protecting the machine and protecting the system. types of faults Faults such as overloads, unbalance and internal phase-to-phase faults are the same type for AC generators as for motors. However, there are other types of faults that are characteristic of AC generators. When a short circuit occurs in a an electrical system close to an AC generator, the fault current looks like that shown in figure 1. The maximum short-circuit current value should be calculated taking into account the machine's substransient impedance X"d . The value of the current detected by a protection device, which is very slightly timedelayed (by about 100 milliseconds), should be calculated taking into account the machine's transient impedance X’d. The value of steady state short-circuit current should be calculated taking into account the synchronous impedance X. This current is weak, generally less than the AC generator's rated current. Internal phase-to-frame fault This is the same type of fault as for motors and its effects depend on the grounding systems adopted. A particularity in relation to motors, however, lies in the fact that AC generators can operate decoupled from the electrical system during the start-up and shutdown periods, and also when operating for testing or on stand-by. The grounding system may differ depending on whether the AC generator is coupled or decoupled and the protection devices should be suitable for both cases. current subtransient phenomena Field loss When an AC generator previously coupled with a system loses its field, it becomes desynchronized from the system. It then operates asynchronously, overspeeding slightly, and it absorbs reactive power. Motor-like operation When an AC generator is driven like a motor by the electrical power system to which it is connected and it applies mechanical energy to the shaft, this can cause wear and damage to the driving machine. Voltage and frequency variations Voltage and frequency variations during steady state operating are due to the malfunction of the related regulators. These variations create the following problems: too high a frequency causes abnormal motor overheating, too low a frequency causes motor power loss, variations in frequency cause variations in motor speed which can bring about mechanical damage, too high a voltage puts stress on all parts of the network, too low a voltage causes torque loss and an increase in current and motor overheating. transient continuous t fig.1 Merlin Gerin protection guide 41 AC generator protection (cont.) protection devices tripping current Ir 0,3 Ir U Un 0,3 Un (fig.2) Ir : setting current I> (A) A I > (B) (fig.3) AC generator connected to other power sources 42 protection guide Overloads The overload protection devices for AC generators are the same as for motors: c IDMT overcurrent, c thermal overload, c temperature probe. Unbalance Protection, like for motors, is ensured by IDMT or direct time negative sequence detection. External phase-to-phase short-circuits As the value of short-circuit current decreases over time to within the range of rated current, if not weaker, in steady state operation, a simple current detection device can be insufficient. This type of fault is effectively detected by a voltage restrained overcurrent detection device, the setting of which increases with the voltage (fig.2). Operation is delayed. Internal phase-to-phase short circuits c high impedance or percentage-based differential protection provides a sensitive, quick solution. c In certain cases, especially for an AC generator with a low power rating compared to the system to which it is connected , the following combination can be used for internal phase-to-phase short-circuit protection (fig.3): v instantaneous overcurrent protection (A), validated when the AC generator circuit breaker is opened, with current sensors located on the neutral side, with a setting lower than rated current, v instantaneous overcurrent protection (B), with current sensors located on the circuit breaker side, with a setting higher than AC generator short-circuit current. Stator frame fault c if the neutral is grounded at the AC generator neutral point, earth fault or restricted earth fault protection is used. c if the neutral is grounded within the system rather than at the AC generator neutral point, stator frame faults are detected by: v earth fault protection on the AC generator circuit breaker when the AC generator is coupled to the electrical system, v by an insulation monitoring device for ungrounded systems when the AC generator is uncoupled from the system. c If the neutral is ungrounded, protection against frame faults is ensured by an insulation monitoring device. This device operates either by detecting residual voltage or by injecting DC current between the neutral and earth. If this device exists in the system, it monitors the AC generator when it is coupled, but a special AC generator device, validated by the circuit breaker being in the open position, is needed to monitor insulation when the AC generator is uncoupled. Rotor frame faults When the exciting current circuit is accessible, frame faults are monitored by a permanent insulation monitor (Vigilohm). Field loss This type of fault is detected either by measuring the reactive power absorbed or by monitoring the excitation circuit if accessible, or else by measuring the impedance at the AC generator terminals. Motor-like operation This is detected by a relay that senses the real power absorbed by the AC generator. Voltage and frequency variations These are monitored respectively by an overvoltage-undervoltage protection device and an underfrequency device. These protection devices are time-delayed since the phenomena do not require instantaneous action and because the electrical system protections and voltage and speed controller must be allowed time to react. Merlin Gerin examples of applications Low power AC generator, uncoupled G IN > earth fault I thermal overload Ii > negative sequence unbalance I > U voltage restrained overcurrent IN > earth fault I thermal overload Ii > negative sequence unbalance I > U voltage restrained overcurrent Medium power AC generators G ∆I Merlin Gerin differential P <–– real reverse power Q <–– reactive reverse power >U> over and undervoltage >f> over and underfrequency protection guide 43 AC generator protection (cont.) examples of applications Medium power AC generator (grounded in electrical system) G I thermal overload Ii > negative sequence unbalance I > U voltage restrained overcurrent P <–– real reverse power Q <–– field loss >U> over and undervoltage >f> over and underfrequency UN > residual overvoltage I <–– IN directional current earth fault Medium power block generator thermal overload G ∆I 44 protection guide differential Ii > negative sequence unbalance I > U voltage restrained overcurrent P <–– real reverse power Q <–– field loss UN > residual overvoltage >U> over and undervoltage >f> over and underfrequency IN > earth fault Merlin Gerin setting information type of fault overloads unbalance external short-circuit internal short-circuit frame faults field loss motor operation voltage variation speed variation Merlin Gerin settings thermal overload to be adapted to rated characteristics (time constants in the 10' range)). max. neg. phase sequence component to be adapted to characteristics (if lack of data, setting 15% of In, IDMT). voltage restrained overcurrent setting 1.2 to 2 times In, time delay according to discrimination. high impedance differential threshold approximately 10% of In. neutral grounded in electrical system earth fault, setting 10% to 20% of maximum earth fault current, time delay: instantaneous or 0.1 sec. neutral grounded at AC generator neutral point earth fault setting approximately 10% In time delay according to discrimination ungrounded residual overvoltage setting approximately 30% of Vn reactive reverse power setting 30% of Sn, time delay of a few seconds. directional real power setting 1 to 20% of Pn, time delay ≥ 1 sec. over and undervoltage 0.8 Un < U < 1.1 Un, time delay: approximately a second. over and underfrequency 0.95 fn < f < 1.05 fn, time delay: a few seconds. protection guide 45 46 protection guide Merlin Gerin capacitor protection introduction Capacitor banks are used to compensate for reactive energy absorbed by electrical system loads, and sometimes to make up filters to reduce harmonic voltage. Their role is to improve the quality of the electrical system. They may be connected in star, delta and double star arrangements, depending on the level of voltage and the system load. A capacitor comes in the form of a case with insulating terminals on top. It comprises individual capacitances which have limited maximum permissible voltages (e.g. 2250 V) and are series-mounted in groups to obtain the required voltage withstand and parallel-mounted to obtained the desired power rating. There are two types of capacitors: those with no internal protection, those with internal protection: a fuse is combined with each individual capacitance. types of faults The main faults which are liable to affect capacitor banks are: overload, short-circuit, frame fault, capacitor component short-circuit. An overload is due to temporary or continuous overcurrent: continuous overcurrent linked to: raising of the power supply voltage, the flow of harmonic current due to the presence of non-linear loads such as static converters (rectifiers, variable speed drives), arc furnaces, etc., temporary overcurrent linked to the energizing of a capacitor bank step. Overloads result in overheating which has an adverse effect on dielectric withstand and leads to premature capacitor aging. A short-circuit is an internal or external fault between live conductors, phase-tophase or phase-to-neutral depending on whether the capacitors are delta or starconnected. The appearance of gas in the gas-tight chamber of the capacitor creates overpressure which may lead to the opening of the case and leakage of the dielectric. A frame fault is an internal fault between a live capacitor component and the frame created by the metal chamber. Similar to internal short-circuits, the appearance of gas in the gas-tight chamber of the capacitor creates overpressure which may lead to the opening of the case and leakage of the dielectric. groupe 1 groupe 2 V n-1 V groupe 3 groupe n (fig.1) Merlin Gerin V n-1 A capacitor component short-circuit is due to the flashover of an individual capacitance. with no internal protection: the parallelwired individual capacitances are shunted by the faulty unit: the capacitor impedance is modified the applied voltage is distributed to one less group in the series each group is submitted to greater stress, which may result in further, cascading flashovers, up to a full short-circuit. with internal protection: the melting of the related internal fuse eliminates the faulty individual capacitance: the capacitor remains fault-free, its impedance is modified accordingly. protection guide 47 capacitor protection (cont.) protection devices 48 protection guide Capacitors should not be energized unless they have been discharged. Re-energizing must be time-delayed in order to avoid transient overvoltage. A 10-minute time delay allows sufficient natural discharging. Fast discharging reactors may be used to reduce discharging time. Overloads Overcurrent of long duration due to the raising of the power supply voltage may be avoided by overvoltage protection that monitors the electrical system voltage. This type of protection may be assigned to the capacitor itself, but it is generally a type of overall electrical system protection. Given that the capacitor can generally accommodate a voltage of 110% of its rated voltage for 12 hours a day, this type of protection is not always necessary. Overcurrent of long duration due to the flow of harmonic current is detected by an overload protection of one the following types: thermal overload time-delayed overcurrent, provided it takes harmonic frequencies into account. The amplitude of overcurrent of short duration due to the energizing of capacitor bank steps is limited by series-mounting impulse reactors with each step. Short circuits Short-circuits are detected by a time-delayed overcurrent protection device. Current and time delay settings make it possible to operate with the maximum permissible load current and to close and switch steps. Frame faults Protection depends on the grounding system. If the neutral is grounded, a timedelayed earth fault protection device is used. Capacitor component short-circuits Detection is based on the change in impedance created by the short-circuiting of the component for capacitors with no internal protection by the elimination of the faulty individual capacitance for capacitors with internal fuses. When the capacitor bank is double starconnected, the unbalance created by the change in impedance in one of the stars causes current to flow in the connection between the netural points. This unbalance is detected by a sensitive overcurrent protection device. Merlin Gerin examples of capacitor bank protection Double star connected capacitor bank for reactive power compensation I> overcurrent IN earth fault U> I> overvoltage overcurrent Filter Merlin Gerin I thermal overload I> overcurrent IN > earth fault protection guide 49 capacitor protection (cont.) setting information type of fault overload short-circuit frame fault capacitor component short circuit 50 protection guide setting overvoltage setting ≤ 110 % Vn thermal overload setting ≤ 1.3 In or overcurrent setting ≤ 1.3 In direct time or IDMT time delay 10 sec overcurrent direct time setting approximately 10 In time delay approximately 0.1 sec earth fault direct time setting ≤ 20 % maximum earth fault current and ≥ 10 % CT rating if suppied by 3 CTs time delay approximately 0.1 sec overcurrent direct time setting < 1 ampere time delay approximately 1 sec Merlin Gerin Merlin Gerin protection guide 51 52 protection guide Merlin Gerin sensors introduction Protection or measuring devices require data on the electrical rating of the equipment to be protected. For technical, economic and safety reasons, this data cannot be obtained directly from the high voltage equipment power supply; the following intermediary devices are needed: voltage transformers (VT), current transformer (CT), core balance CTs to measure earth fault current. These devices fulfill the following functions: reduction of the value to be measured (e.g.1500/5 A), galvanic isolation, providing the power required for data processing and for protection operation itself. current transformers (CTs) The CTs are characterized by the following values (according to IEC 185 standards)*. CT voltage This is the operating voltage applied to the CT primary. Note that the primary is at the HV potential level and that one of the secondary terminals is generally earthed. As for other equipment, the following is also defined : maximum1 min. withstand voltage at standard frequency maximum impulse withstand voltage. e.g. for 24 kV rated voltage, the CT must withstand 50 kV voltage for 1 min at 50 Hz and 125 kV impulse voltage . Rated transformation ratio It is usually given as the transformation ratio between primary and secondary current I1/I2. Secondary current is generally 5 A or 1 A. Accuracy level It is defined by the composite error for the accuracy limit current. e.g. 5P10 means 5% error for 10 In 10P15 means 10% error for 15 In 5P and 10P are the standard accuracy classes. 5 In, 10 In, 15 In, 20 In are the standard accuracy limit currents. The accuracy limit factor is the ratio between the accuracy limit current and the rated current . Class X is another way of specifying CT characteristics based on "knee-point voltage" (fig.1, CT response in saturated state). Accuracy level power Secondary power at rated current for which the accuracy level is guaranteed. Expressed in VA, it indicates the power that the secondary can deliver for its rated current, while respecting the rated accuracy class. It represents the total consumption of the secondary circuit, i.e. the power consumed by all the connected devices as well as the connecting wires. If a CT is loaded at a power rating lower than its accuracy level power, its actual accuracy level is higher than the rated accuracy level. Likewise, a CT that is loaded too much loses accuracy. Admissible short time current Expressed in rms kA, the maximum current admissible for 1 second (Ith) (the secondary being short-circuited) represents CT thermal overcurrent withstand. The CT must have the capacity to withstand short-circuit current for the time required to clear it. If the clearing time t is other than 1 sec., the current the CT can withstand is Ith / Vt. Electrodynamic withstand expressed in peak kA is at least equal to 2.5 x Ith P1 I1 I2 S1 S2 P2 Merlin Gerin Normal values of rated currents: at the primary (in A) 10 - 12.5 - 15 - 20 - 25 - 30 - 40 50 - 60 - 75 and multiples or decimal submultiples. * Also to be taken into account are elements related to the type of assembly, characteristics of the site (e.g. temperature), system frequency, etc... protection guide 53 sensors (cont.) When subjected to very strong current, the CT becomes saturated, i.e. the secondary current is no longer proportional to the primary current. The current error which corresponds to the magnetization current becomes very high. CT response in saturated state P1 S1 I m V Knee-point voltage (fig.1) This is the point on the current transformer magnetization curve at which a 10% increase in voltage V requires a 50% increase in magnetization current Im. S2 P2 V knee point voltage (fig.1) conclusion on CTs sending current into an overcurrent type protection device specific "wide band" current sensors 54 protection guide +10% +50% Im For direct time overcurrent protections, if twice the setting current does does cause saturation, operation is ensured no matter how strong the fault. For IDMT overcurrent protections, saturation must not be reached for current values in the working part of the operation curve (a maximum of 20 times the setting current). These sensors, most often without magnetic circuits and therefore not subject to saturation. Linked to an electronic device, their response is linear. These CTs are used and supplied with the digital technology protection units. They only require knowledge of the primary rated current. Merlin Gerin earth fault protection sensors 3 CT summing integrator assembly (fig.3) This assembly is only used if it is impossible to use core balance CTs. Because of the CT summing error, the minimum setting for residual current is approximately 10% of In. Earth fault current can be detected in several ways. CT mounted on neutral point I > N N earth fault (fig.3) (fig.1) Differential measurement by core balance CT I1 N I2 I3 I > N (fig.2) differential protection sensors The CTs should be specified according to the operating principle of the protection system; refer to the instruction manual of the system being used. protected zone P1 P2 P2 P1 differential protection Merlin Gerin protection guide 55 sensors (cont.) voltage transformers Voltage transformers have the following characteristics (IEC186) (1) electrical system frequency generally 50 or 60Hz, system's highest primary voltage (secondary voltage is standardized 100, 100/ , 110, 110/ Volts), rated voltage factor VA power rating and accuracy class 3-transformer assembly (requires 1 insulated high voltage terminal per transformer) 2 transformer assembly ("V" assembly) (requires 2 insulated high voltage terminals per transformer) voltage ratio: Un 100 In ungrounded systems, all neutral phase VTs must be loaded enough to prevent the risk of ferromagnetic resonance. voltage ratio: Un/ 100/ 56 protection guide (1) also to be taken into account are elements related to the type of assembly, characteristics of the site (e.g. temperature...) etc... Merlin Gerin Protection and control RS 485 - Modbus network connection accessories instruction manual Contents page RS 485 network 2 2-wire bus topology 2 general characteristics 2 4-wire bus topology 3 communication interfaces 4 Merlin Gerin equipment 4 Sepam 2000 4 Sepam 1000+ communication interface module ACE 949 5 accessories 6 CCA 609 connection box 6 CCA 629 connection box 2 wire 6 CCA 600-2 9-pin connectors 7 CCA 602 cable 7 CCA 619 connector 2 wire 7 converters 8 ACE 909-2 RS 485 / RS 232 converter 8 ACE 919 RS 485 / RS 485 converter 10 wiring and commissioning 12 RS 485 network cable 12 connection of “master” station 13 ACE 909-2 or ACE 919 converters 13 connection of “slave” stations 2 wire RS 485 14 master station in RS 232 with ACE 909-2 14 master station in RS 232 with ACE 909 15 master station in RS 485 without converter 16 connection of “slave” stations Sepam 1000+ 2 wire RS 485 connection of “slave” stations 2 wire RS 485 with Sepam 1000 RS 485 network connection guide 17 + 18 connection of “slave” stations 4 wire RS 485 20 extension of the RS 485 network with ACE 919 in case of distributed power supply 21 setting and testing - commissioning 22 troubleshooting 23 1 RS 485 network Presentation General characteristics The Modbus communication network may be used to connect equipment to a central monitoring and control system on a local network in half duplex, master-slave mode. type of transmission asynchronous serial rate 300, 600, 1200, 2400, 4800, 9600, 19200, 38400 bauds (1) data formats 1 start, 8 bits, no parity, 1 stop 1 start, 8 bits, even parity, 1 stop 1 start, 8 bits, odd parity, 1 stop RS 485 electrical interface complies with EIA RS 485 standard The communication network is a LAN (Local Area Network). Transmission is of the serial type and all the stations are connected in parallel to a 2-wire / (4-wire) bus. The physical layer is of the RS 485 type in compliance with the EIA RS 485 standard. The RS 485 communication bus operates according to the principle of differential line voltage. There are 2 main wiring principles for this type of network: c 2-wire topology, c 4-wire topology. maximum distance 1300 m branch distance less than 3 m maximum number of stations on a line 32 (1) 300, 600 bauds not available with ACE 909-2. 300, 600, 1200, 2400 not available with Sepam 1000+. station 03 2-wire bus topology Two-wire cabling of the communication network makes it possible to use a single shielded pair, which means simple cabling. 5V RD - Each item of equipment connected to the network includes a transmitter and a receiver that are connected to the same cable. Since communication is half duplex, alternating and two-way, messages are conveyed in both directions on the same line from the master to the slaves and vice versa. TD + Rp L - (B/B') Rc Rc L + (A/A') Communication takes place alternately, with the transmitters taking turns on the line. Rp The master can be any station. 0V Connection of the stations (2-wire) The network comprises a single cable (a shielded, twisted pair). The various stations in the network are connected by linking both of the following: c all the outputs marked + (TD+, RD+) to the network + wire (marked L+), c all the outputs marked - (TD-, RD-) to the network wire (marked L-). station 01 station 02 station n (n ≤ 32) General architecture of an RS 485 network TD + TD – transmitters Impedance matching Two 150 Ω resistors (Rc) are required at each end to match line impedance. Each item of equipment, as well as each connector, connection box and interface, contains a 150 Ω resistor which can be used for this purpose. station n-1 RD + RD – (A) (B) (A') (B') receivers Polarization Polarization creates a continuous flow of current through the network, putting all the receivers in deactivated status until a transmitter is validated. The network is polarized by connecting the (L+) line to the 0 V and the (L-) line to the 5 V via two 470 Ω polarization resistors (RP). The network should only be polarized in one location on the line to avoid random transmission. It is recommended that the master’s power supplies and resistors be used. The ACE 909-2 and ACE 919 converters provide this polarization. Some Schneider equipment offers also this possibility. Please note Some equipment items do not comply with the RS 485 standard with respect to polarities as well as polarization and line impedance matching. When a mixture of equipment is being connected, make sure to check these points. 2 RS 485 network connection guide 4-wire bus topology For 4-wire connection of the communication network, 2 shielded pairs are used. With 4-wire connection, the “master station” is defined and then the two communication lines, a master to slaves “transmission” line and a slaves to master “receiving” line. Communication is alternating half duplex. Requests are sent from the master to the salves on the transmission line. Replies are sent from the slaves to the master on the receiving line. Connection of stations (4-wire) The different network are stations are connection by linking: c master station v RD+ inputs to the L+ “transmission” line, RD- inputs to the L- “transmission” line, v TD+ outputs to the L+ “receiving” line, TD- outputs to the L- “receiving” line. The connection of the master station is the opposite to that of the other stations: c master station v RD+ input to the L+ “receiving” line, RD- input to the L- “receiving” line, v TD+ output to the L+ “transmission” line, TD- output to the L- “transmission” line. 5V Rp L – (B/B’) receiving line (transmission from slaves to master) Rc Rc L + (A/A’) Rp 5V 0V Rp L – (B/B’) transmission line (transmission from master to slaves) Rc Rc L + (A/A’) TD – TD + RD – TD – RD + Rp TD + RD – RD + TD – TD – TD + RD – RD + TD + RD – TD – RD + TD + RD – RD + 0V slave station n° slave station n° master station (supervisor) slave station n° slave station n° RC = load resistor (150 ohms), Rp = polarization resistor (470 ohms) Impedance matching Four 150 Ohm resistors (Rc) are mandatory, one at each end, for impedance matching of both the transmission and receiving lines. RS 485 network connection guide Polarization (see 2-wire topology) It is necessary to polarize both the transmission and receiving lines. ACE 909-2 and ACE 919 converters are only used with the 2-wire topology. 3 Communication interfaces Schneider’s experience in the industrial world has shown that more than 50% of communication problems are linked to the commissioning of the network. Example of equipment concerned: Sepam 2000 This manual describes the accessories available and the different connection schemes that may be used for equipment fitted with a Modbus RS 485 physical link. CE40 red green indicators These accessories may be used to: c facilitate commissioning, c reduce risks linked to the environment (EMC), c reduce incorrect wiring (faulty welding...). communication connector (item 1B) Merlin Gerin equipment items which use the same type of RS 485 interface, connected to 9-pin Sub-D connectors, are identified in the connection schemes by the symbol MERLIN GERIN . B ACE 909-2 Rp + Rp – 0V 5V Rc RD + (A') RD – (B') TD + (A) TD – (B) A You wish to connect an equipment item 1 2 6 3 7 4 8 5 9 to a network: recommended module function Modbus slave equipment type repeater 4 2-wire network powered 2-wire network 4-wire network ACE 949 and CCA 612 cable powered 2-wire RS 485 CCA 609 and CCA 602 cable CCA 629 and CCA 602 cable not-powered 2-wire RS 485 CCA 609 and CCA 602 cable CCA 629 and CCA 602 cable 4-wire RS 485 Modbus master equipment example Sepam 1000 + Sepam 2000 DC 150 Vigilohm system CCA 609 and CCA 602 cable RS 232 ACE 909-2 2-wire RS 485 CCA 609 and master cable 2-wire RS 485 ACE 919 4-wire RS 485 CCA 609 and master cable 2-wire RS 485 / 2-wire RS 485 ACE 919 ACE 909-2 ACE 919 CCA 609 and master cable ACE 919 RS 485 network connection guide Sepam 1000+ communication interface module ACE 949 The network cable connections are made to terminals A and B situated on the module. The power supply for the RS 485 communication interfaces (ACE 949 opposite, items V- and V+) is provided via the network cable by a single accessory, ACE 909-2 (or ACE 919) which may be used to connect up to 20 units. The distributed power supply network is wired using a shielded cable that comprises 2 twisted pairs. Each module is equipped with a 3 meter long CCA 612 prefabricated cable connected to the C output of Sepam 1000+. green indicator line activity C RC B RC A 88 - +L L V- V+ - +L L V- 30 V+ 72 RS485 network A ACE 949 L- L+ V- V+ 1 2 3 4 B 4 3 2 1 C CCA 612 C Sepam 1000 + L- L+ V- V+ RS485 network RS 485 network connection guide 5 Accessories CCA 609 connection box Each equipment item may be connected to the network cable via a CCA 609 connection box mounted on a DIN rail (symmetrical or asymmetrical). The connection box can be used to tap onto the communication cable. validation of impedance matching on the end station only (strap 9-10) connection via CCA 602 connection cable The CCA 609 box is used for 4-wire topologies and/or in the case of polarization by a Sepam. It is replaced in other cases by the CCA 629 box. With this type of connection, it is possible to remove a station from the network without leaving any connectors “loose” It also facilitates the connection of new stations at a later date. c Mounting on symmetrical or asymmetrical DIN rail, c Dimensions: 83 mm (L) x 85 mm (H) “ 110 m (D) with CCA 602 connected, c Weight: 120 g. possibility of network polarization (in one location only) (straps 13-14 and 15-16) via a station 9 10 11 12 13 14 15 16 1 2 3 4 5 6 7 8 85 83 55 earthing terminal 2-wire configuration (straps 5-6 and 7-8) 2-wire RS 485 network connection terminal block: incoming: L + to 1 normal L – to 2 outgoing: L + to 3 normal L – to CCA 629 connection box 2 wire connection via CCA 602 connection cable Each equipment item may be connected to the network cable via a CCA 629 connection box mounted on a DIN rail (symmetrical or asymmetrical). The connection box can be used to tap onto the communication cable and provides continuity of the distributed power supply. validation of impedance matching on the end station only (strap 1-2) 1 2 This box is connected to 2-wire RS 485 networks only. With this type of connection, it is possible to remove a station from the network without leaving any connectors “loose” It also facilitates the connection of new stations at a later date. clamps for attachment and recovery of bus cable shielding (incoming/outgoing) C A B 1 2 3 4 1 2 3 4 85 c Mounting on symmetrical or asymmetrical DIN rail, c Dimensions: 83 mm (L) x 85 mm (H) x 110 m (D) with CCA 602 connected, c Weight: 120 g. RS 485 bus 83 CCA 609 or CCA 629 CCA 602 Sepam 2000 6 earthing terminal 55 clamps for attachment and recovery of bus cable shielding (incoming/outgoing) 2-wire RS 485 network connection terminal block: incoming: V + to 1 normal V – to 2 L + to 3 normal L – to 4 RS 485 network connection guide CCA 600-2 9-pin connectors 56,4 The CCA 600-2 accessory may be used to produce cables long enough for customized cabling systems: c connection of station to CCA 609, c connection of CCA 609 to ACE 909, c supplied with the ACE 909-2 / ACE 919. 16 44,5 36 CCA 602 cable The CCA 602 “cable” accessory is used to create branches of the RS 485 network from the CCA 609 connection box to each equipment item. It may also be used to connect the ACE 909 converter (master / central computer link). 1 1 6 2 6 2 7 3 7 3 8 4 8 4 9 5 9 5 This accessory comprises a 3-meter cable with a 9-pin sub-D connector with metallic cover at either end. CCA 619 connector 2 wire (CCA 629 alternative solution) Connection of the CCA 619 connector L + to + L – to – Presentation Each equipment item may be connected directly to the 2-wire RS 485 communication network only, using the CCA 619 connector. c dimensions: see diagram, c weight: 120 g. 23 - + bus RS 485 cable (2-wire) for chaining with another CCA 619 connector - + CCA 619 46 Sepam 2000 ground wire 70 Setting of the configuration microswitches termination resistor connected 2-wire cable (standard) 2 W POL line polarization 2W POL 50 POL POL no polarization not connected Normal RS 485 network connection guide Each line end 7 Converters ACE 909-2 RS 485 / RS 232 converter Connection connection to the RS 485 network with CCA 602 accessory or screw-on connector CCA 600-2 (supplied with the converter) Presentation The ACE 909 converter may only be used for 2-wire mode operation. Without requiring any flow control signals, after the parameters are set, the ACE 909-2 performs conversion, polarization and automatic dispatching of Modbus frames between the master and the stations by two-way alternating transmission (half-duplex with single pair). The ACE 909-2 converter also provides a 12 V supply for the distributed power supply of the Sepam 1000+ ACE 949 interfaces. MERLIN GERIN ACE 909-2 off on No polarization 1 2 No impédance -3 matching RpRp+ Rc SW1 master link limited to 10 m, connection by 2.5 mm screw terminal Rx = box receiving Tx = box transmission 0V = Rx/Tx common (do not earth) Rate SW2/1 SW2/2 SW2/3 SW2/4 SW2/5 1200 1 1 1 2400 0 1 1 4800 1 0 1 9600 0 0 1 19200 1 1 0 38400 0 1 0 parity 0 no parity 1 1 2 stop 0 1 stop 105 85 Rx Tx on/off 0 1 +V -V L+ L- 1 2 3 4 5 At the time of cabling, it is necessary to ensure that the L+ and L- lines are independent or insulated. The setting of the communication parameters should be the same as the setting of the Sepam 1000+s and the master communication. 3 7 9 5 Rx Tx 0V RS 232 RS 485 SW2 Vac ~ 220Vac 110Vac 0,1A Ph N Data displayed on the front of the device c On/Off: On (lit) / Off (extinguished), c Tx, Rx display of RS 232 transmission and receiving line activity. 105 65 47 selective switch for AC voltage 110 - 220 Vac for access to fuse, unlock by making a 1/4 turn connection of mains power supply by 2.5 mm screw terminal (reversible Ph/N) earthed via terminal (green-yellow wire) and metal case (connection on back of case). Weight: 460 g DIN rail mounting 8 RS 485 network connection guide Commissioning speed SW2 / 1 SW2 / 2 SW2 / 3 1200 1 1 1 2400 0 1 1 4800 1 0 1 9600 0 0 1 Please note: This operation must be performed before energizing the converter. 19200 1 1 0 38400 0 1 0 strap position function Parameter setting of transmission via SW2 Used to set the rate and format of asynchronous transmission. SW2 / 4 0 with parity 1 without parity Parameter setting of supply voltage The 110 Vac/220 Vac supply voltage is changed using a switch which may be accessed on the bottom of the box (fuse end). SW2 / 5 To change the parameter setting, the box must be de-energized (reset) in order for the new values to be processed. Parameter setting of line resistors via SW1 The SW1 microswitches are used to activate (or deactivate) the RS 485 network polarization and line impedance matching resistors. Box configuration when delivered c mains power supply 220 Vac. c 9600 baud rate, 8-bit format, with parity, 1 stop bit, c polarization and line impedance matching resistors activated, Electrical characteristics c mains power supply: 110 Vac / 220 Vac, ±10%, 47 to 63 Hz, c protection by 0.1 A time-delayed fuse (5 mm x 20 mm), c galvanic isolation 2000+ V rms, 50 Hz, 1 mn between: v mains input and interface internal power supply outputs, v mains input and mechanical frame, c galvanic isolation 1000 V rms, 50 Hz, 1 mn between RS 232 and RS 485 interfaces, c transmission delay < 100 ns. 0 2 stop 1 1 stop strap position function SW1 / 1 ON polarization at 0 V via Rp - 470 Ω SW1 / 2 ON polarization at 5 V via Rp + 470 Ω SW1 / 3 ON 150 Ω impedance matching resistor at end of RS 485 bus electromagnetic compatibility CEI 60255-5, 1.2 impulse wave / 50 microseconds 1 kV differential mode 3 kV common mode IEC 60255-22-1, 1 MHz damped oscill. wave 0.5 kV differential mode 1 kV common mode IEC 60255-22-4, 5 ns fast transients 4 kV with capacitive coupling in common mode 2 kV with direct coupling in common mode 1 kV with direct coupling in differential mode Mechanical characteristics c mounting on symmetrical/asymmetrical DIN rail, c dimensions: 105 mm (L) x 85 mm (H) x 47 mm (D), c weight: 460 g, c ambient operating temperature: -5 °C to +55 °C. RS 485 network connection guide 9 Converters (cont’d) ACE 919 RS 485 / RS 485 converter Connection connection to the RS 485 network with CCA 602 accessory (see example of application) or screw-on connector CCA 600-2 (supplied with the converter) Presentation The ACE 919 converter is used to connect a master / central computer equipped with an RS 485 type serial port as a standard feature to the stations cabled in an RS 485 bus type network, and to adapt the system for operation in 2-wire mode. MERLIN GERIN Without requiring any flow control signals, the ACE 919 converter performs network polarization. The ACE 919 converter also provides a 12 V supply for the distributed power supply of the Sepam 1000+ ACE 949 interfaces. Data displayed on the front of the device c On/Off: On (lit) / Off (extinguished). RS 485 link L+ + line L- - line shielding ACE 919 CC off on No polarization RpRp+ Rc 1 2 No impédance -3 matching SW1 105 85 on/off +V -V L+ L- L+ L- 3 7 9 5 RS 485 RS 485 Vdc = 0,2A +Vc 0V 105 65 47 for access to fuse, unlock by making a1/4 turn connection of DC power supply by 2.5 mm screw terminal earthed via terminal (green-yellow wire) and metal case (connection on back of case). Weight: 460 g DIN rail mounting connection to the RS 485 network with CCA 602 accessory (see example of application) or screw-on connector CCA 600-2 (supplied with the converter) RS 485 link L+ + line L- - line shielding MERLIN GERIN ACE 919 CA off on RpRp+ Rc 1 2 No impédance -3 No polarization matching SW1 105 85 on/off +V -V L+ L3 7 9 5 L+ LRS 485 RS 485 Vac ~ 220Vac 110Vac 0,1AT Ph N 105 65 47 for access to fuse, unlock by making a1/4 turn Weight: 460 g connection of mains power supply by 2.5 mm screw terminal (reversible Ph/N) earthed via terminal (green-yellow wire) and metal case (connection on back of case). DIN rail mounting 10 RS 485 network connection guide Commissioning AC or DC power supply ACE 919 DC 24-48 Vdc, ACE 919 AC 110-220 Vac. strap position function SW1 / 1 ON polarization at 0V via Rp - 470 Ω SW1 / 2 ON polarization at 5V via Rp + 470 Ω SW1 / 3 ON 150 Ω impedance matching resistor at end of RS 485 bus Parameter setting of supply voltage For ACE 919 CA the 110 Vac/220 Vac supply voltage is changed using a switch which may be accessed on the bottom of the box (fuse end). Please note: This operation must be performed before energizing the converter. Parameter setting of line resistors via SW1 The SW1 microswitches are used to activate (or deactivate) the RS 485 network polarization and line impedance matching resistors. Box configuration when delivered c mains power supply 220 Vac or 48 Vdc. c 9600 baud rate, 8-bit format, with parity, 1 stop bit, Electrical characteristics c mains power supply: 110 Vac / 220 Vac + 10%, 47 to 63 Hz, c protection by 0.1 A time-delayed fuse (5 mm x 20 mm), c galvanic isolation 2000+ V rms, 50 Hz, 1 mn between: v mains input and interface internal power supply outputs, v mains input and mechanical frame, DC power supply c 24 / 48 Vdc + 20% electromagnetic compatibility IEC 60255-5, 1.2 impulse wave / 50 microseconds 1 kV differential mode 3 kV common mode IEC 60255-22-1, 1 MHz damped oscill. wave 0.5 kV differential mode 1 kV common mode IEC 60255-22-4, 5 ns fast transients 4 kV with capacitive coupling in common mode 2 kV with direct coupling in common mode 1 kV with direct coupling in differential mode Mechanical characteristics c mounting on symmetrical/asymmetrical DIN rail, c dimensions: 105 mm (L) x 85 mm (H) x 47 mm (D), c weight: about 400 g, c ambient operating temperature: -5 °C to +55 °C. RS 485 network connection guide 11 Wiring and commissioning RS 485 network cable Wiring precautions The characteristics of the cable recommended for connecting the CCA… type connection boxes or ACE type RS 485 interfaces are as follows: c twisted pair with tinned copper braid shielding, coverage: > 65%, c characteristic impedance: 120 Ω, c gauge: AWG 24, c resistance per unit length: < 100 Ω / km, c capacitance between conductors: < 60 pF / m, c conductor and shielding: < 100 pF / m. For the sake of both the safety of people and efficient combating against the effects of interference, the cabling of systems which comprise digital links must comply with a set of basic rules aimed at establishing an equipotential-bonded, meshed and earthed network. The total network cable length should not be greater than 1300 meters except limitation due to distributed power supply. Examples of compatible cables: c supplier: BELDEN, reference: 9841 (1 pair) or 9842 (2 pairs), c supplier: FILOTEX, reference: FMA-2PS. 12 Special care must be taken when making connections between buildings with earthing that is not interconnected. For details and useful recommendations, please refer to the Telemecanique document TSX DG GND F entitled “Grounding cabling guide”. All the accessories make it possible to ensure the continuity of the cable shielding and regular grounding. It is therefore necessary to ensure that: c the 2 connectors at the ends of the CCA 602 branching cable are plugged in correctly and locked by the 2 screws specially provided, c the clamps are tightened onto the metallic shielding braid on each CCA 609, CCA 619, CCA 629 and ACE 949 connection box, c each CCA connection box is grounded (earthed) by a 2.5 mm2 diameter greenyellow wire or a short braid (< 10 cm) via the terminal specially provided, c the metal case of the ACE 909 or ACE 919 converter is grounded (earthed) by a green-yellow mains power supply connector wire and an eye lug on the back of the case. RS 485 network connection guide Connection of “master” station ACE 909-2 or ACE 919 converters Modicon BM 85 in RS 485 BM85 R/D A 3 to L+ R/T B Gnd In the wiring examples shown, the master is situated at the end of the network, which is generally the case. 2 to L- 1 RS 485 serial port With a master situated in the middle of the network, it is necessary to remove the impedance matching resistors from the master stations and install them at the end of the line. L –L+ ACE 919 V+ V– L+ L– 3 7 9 5 V+ V– L+ L– L –L+ (1) RC RP AC/DC supply Modicon BM 85 in RS 2432 BM85 RxD 2 to Tx TxD 3 to Rx GND 5 to 0V 4-6 strap 7-8 RS 232 serial port 2 3 5 RxTx Ov ACE 909-2 3 7 9 5 V+ V– L+ L– V+ V– L+ L– (1) RC RP 110 / 220 Vac supply APPLICOM board in RS 485 BX4010 RC 4 to L+ T- 3 to L+ T+ 2 to L- RS 485 serial port L- L+ V+ V– ACE 919 L+ L– RC RP L- L+ 3 7 9 5 V+ V– L+ L– (1) AC/DC supply RC impedance matching resistor to be installed if at end of line RP polarization of deactivated line (1) RS 485 network connection guide distributed power supply output to be used for the connection of Sepam 1000+. 13 Connection of “slave” stations 2 wire RS 485 Master station in RS 232 with ACE 909-2 CCA 629 and CCA 629 RS 232 serial port MERLIN GERIN MERLIN GERIN MERLIN GERIN ACE 909-2 ACE 909-2 ACE 909-2 CCA 602 CCA 602 CCA 602 (1) 2 3 5 RxTx Ov ACE 909-2 V+ V– L+ L– 3 7 9 5 1 2 1 2 1 2 CCA 629 1 2 3 4 4 3 2 1 CCA 629 1 2 3 4 4 3 2 81 CCA 629 1 2 3 4 4 3 2 1 L+ L– L+ L– L+ L– RC RP (1) strap 1-2 impedance matching resistor at end of line 110 / 220 Vac supply CCA 609 and CCA 602 RS 232 serial port MERLIN GERIN MERLIN GERIN MERLIN GERIN ACE 909-2 ACE 909-2 ACE 909-2 CCA 602 CCA 602 CCA 602 (2) 2 3 5 RxTx Ov ACE 909-2 V+ V– L+ L– 3 7 9 5 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 (1) L + L– L+ L– (1) 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 (1) L+ L– RC RP (1) 2-wire configuration strap 5-6 and 7-8 (2) strap 9-10 impedance matching resistor at end of line 110 / 220 Vac supply CCA 619 RS 232 serial port 2 3 5 RxTx Ov ACE 909-2 V+ V– L+ L– 3 7 9 5 MERLIN GERIN MERLIN GERIN MERLIN GERIN MERLIN GERIN ACE 909-2 ACE 909-2 ACE 909-2 ACE 909-2 CCA 619 + – + – CCA 619 + – + – CCA 619 + – + – CCA 619 + – + – L+ L– L+ L– L+ L– L+ L– RC RP 110 / 220 Vac supply 2W POL POL 14 2W POL POL RS 485 network connection guide Master station in RS 232 with ACE 909 CCA 602 and CCA 629 RS 232 serial port MERLIN GERIN MERLIN GERIN MERLIN GERIN ACE 909-2 ACE 909-2 ACE 909-2 2 3 5 CCA 602 CCA 602 CCA 602 (1) RxTx Ov CCA 602 ACE 909 1 2 CCA 629 (or CCA 609) 1 2 3 4 4 3 2 1 1 2 1 2 1 2 CCA 629 1 2 3 4 4 3 2 1 CCA 629 1 2 3 4 4 3 2 81 CCA 629 1 2 3 4 4 3 2 1 L+ L– assembly to be installed for EMC protection of master (CCA 609 or CCA 629) interface RC RP 110 / 220 Vac supply L+ L– L+ L– (1) strap 1-2 impedance matching resistor at end of line CCA 602 and CCA 609 RS 232 serial port MERLIN GERIN MERLIN GERIN MERLIN GERIN ACE 909-2 ACE 909-2 ACE 909-2 2 3 5 CCA 602 CCA 602 CCA 602 (2) RxTx Ov CCA 602 ACE 909 1 2 CCA 629 (or CCA 609) 1 2 3 4 4 3 2 1 L+ L– assembly to be installed for EMC protection of master (CCA 609 or CCA 629) interface RC RP 110 / 220 Vac supply 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 (1) L + L– (1) 9 10 11 12 13 14 1516 CCA 609 1 2 3 4 5 6 7 8 (1) L+ L– (1) 2-wire configuration strap 5-6 and 7-8 (2) strap 9-10 impedance matching resistor at end of line CCA 619 RS 232 serial port 2 3 5 RxTx Ov CCA 602 ACE 909 RC RP 110 / 220 Vac supply MERLIN GERIN MERLIN GERIN MERLIN GERIN ACE 909-2 ACE 909-2 ACE 909-2 ACE 909-2 CCA 619 + – + – CCA 619 + – + – CCA 619 + – + – CCA 619 + – + – 1 2 CCA 629 (or CCA 609) 1 2 3 4 4 3 2 1 L+ L– assembly to be installed for EMC protection of master (CCA 609 or CCA 629) interface 2W L+ L– POL POL RS 485 network connection guide MERLIN GERIN L+ L– L+ L– 2W POL POL 15 Connection of “slave” stations 2 wire RS 485 (cont’d) Master station in RS 485 without converter CCA 602 and CCA 629 MERLIN GERIN MERLIN GERIN MERLIN GERIN ACE 909-2 ACE 909-2 ACE 909-2 RS 485 serial port L– CCA 602 CCA 602 CCA 602 (1) L+ 1 2 CCA 629 (or CCA 609) 1 2 3 4 4 3 2 1 L+ L– 1 2 1 2 1 2 CCA 629 1 2 3 4 4 3 2 1 CCA 629 1 2 3 4 4 3 2 81 CCA 629 1 2 3 4 4 3 2 1 L+ L– L+ L– L+ L– assembly to be installed for EMC protection of master (CCA 609 or CCA 629) interface (1) strap 9-10 impedance matching resistor at end of line CCA 602 and CCA 609 MERLIN GERIN MERLIN GERIN MERLIN GERIN ACE 909-2 ACE 909-2 ACE 909-2 RS 485 serial port L– CCA 602 CCA 602 CCA 602 (2) L+ 1 2 1 2 3 4 L+ L– 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 CCA 629 (or CCA 609) 4 3 2 1 L+ L– assembly to be installed for EMC protection of master (CCA 609 or CCA 629) interface 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 (1) L + L– (1) 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 (1) L+ L– (1) 2-wire configuration strap 5-6 and 7-8 (2) strap 9-10 impedance matching resistor at end of line CCA 619 RS 485 serial port L– L+ MERLIN GERIN MERLIN GERIN MERLIN GERIN MERLIN GERIN ACE 909-2 ACE 909-2 ACE 909-2 ACE 909-2 CCA 619 + – + – CCA 619 + – + – CCA 619 + – + – CCA 619 + – + – 1 2 CCA 629 (or CCA 609) 1 2 3 4 4 3 2 1 L+ L– L+ L– L+ L– L+ L– L+ L– assembly to be installed for EMC protection of master (CCA 609 or CCA 629) interface 2W POL POL 16 2W POL POL RS 485 network connection guide Connection of “slave” stations Sepam 1000+ 2 wire RS 485 Sepam 1000+ needs distributed power supply for ACE 949 interface Master station in RS 232 with ACE 909-2 Sepam 1000+ Sepam 1000+ Sepam 1000+ CCA 612 CCA 612 CCA 612 RS 232 serial port ACE 949 1 2 3 4 4 3 2 1 2 3 5 RxTx Ov ACE 909-2 V+ V– L+ L– 3 7 9 5 V+ V– L+ L– V+ V– L+ L– RC ACE 949 1 2 3 4 4 3 2 1 ACE 949 1 2 3 4 4 3 2 1 V+ V– L+ L– RC RP max 250 m 110 / 220 Vac supply RC impedance matching resistor to be installed if at end of line RP polarization of deactivated line Master station in RS 485 with ACE 919 Sepam 1000+ Sepam 1000+ Sepam 1000+ CCA 612 CCA 612 CCA 612 RS 485 serial port ACE 949 1 2 3 4 4 3 2 1 L –L+ L –L+ ACE 919 V+ V– L+ L– 3 7 9 5 V+ V– L+ L– RC ACE 949 1 2 3 4 4 3 2 1 ACE 949 1 2 3 4 4 3 2 1 V+ V– L+ L– V+ V– L+ L– RC RP AC/DC 24 - 48 DC 110 / 220 Vac supply max 250 m RC impedance matching resistor to be installed if at end of line RP polarization of deactivated line RS 485 network connection guide 17 Connection of “slave” stations 2 wire RS 485 with Sepam 1000+ Sepam 1000+ needs distributed power supply for ACE 949 interface Master station in RS 232 with ACE 909-2 Extension of an existing network with CCA 629 MERLIN GERIN Sepam 1000+ CCA 602 CCA 612 CCA 602 CCA 612 (2) 1 2 1 2 ACE 949 1 2 3 4 4 3 2 1 2 3 5 ACE 909-2 ACE 909-2 (1) RS 232 serial port RxTx Ov MERLIN GERIN Sepam 1000+ ACE 909-2 V+ V– L+ L– 3 7 9 5 L+ L– V+ V– L+ L– V+ V– L+ L– V+ V– L+ L– CCA 629 1 2 3 4 4 3 2 1 ACE 949 1 2 3 4 4 3 2 1 CCA 629 1 2 3 4 4 3 2 1 without distributed power supply RC RP max 250 m 110 / 220 Vac supply (2) strap 1-2 impedance matching resistor at end of line (1) use of CCA 629 for continuity of distributed power supply RC impedance matching resistor to be installed if at end of line RP polarization of deactivated line Extension of an existing network with CCA 609 MERLIN GERIN Sepam 1000+ CCA 602 CCA 612 MERLIN GERIN Sepam 1000+ ACE 909-2 ACE 909-2 CCA 602 CCA 612 (2) (1) RS 232 serial port 9 10 11 12 13 14 1516 CCA 609 1 2 3 4 5 6 7 8 1 2 ACE 949 1 2 3 4 4 3 2 1 2 3 5 ACE 949 1 2 3 4 4 3 2 1 CCA 629 1 2 3 4 4 3 2 1 (3) RxTx Ov ACE 909-2 V+ V– L+ L– 3 7 9 5 V+ V– L+ L– V+ V– L+ L– V+ V– L+ L– RC RP L+ L– without distributed power supply max 250 m 110 / 220 Vac supply (1) use of CCA 629 for continuity of distributed power supply (2) strap 9-10 impedance matching resistor at end of line (3) strap 5-6 and 7-8 for 2-wire RS 485 RC impedance matching resistor to be installed if at end of line RP polarization of deactivated line 18 RS 485 network connection guide Master station in RS 232 with ACE 919 Extension of an existing network with CCA 629 MERLIN GERIN Sepam 1000+ CCA 602 CCA 612 CCA 602 CCA 612 (2) 1 2 1 2 ACE 949 1 2 3 4 4 3 2 1 L –L+ ACE 919 ACE 909-2 (1) RS 485 serial port L –L+ MERLIN GERIN Sepam 1000+ ACE 909-2 V+ V– L+ L– 3 7 9 5 V+ V– L+ L– V+ V– L+ L– CCA 629 1 2 3 4 4 3 2 1 ACE 949 1 2 3 4 4 3 2 1 CCA 629 1 2 3 4 4 3 2 1 L+ L– V+ V– L+ L– without distributed power supply RC RP max 250 m AC/DC 24 - 48 DC 110 / 220 Vac supply (2) strap 1-2 impedance matching resistor at end of line (1) use of CCA 629 for continuity of distributed power supply RC impedance matching resistor to be installed if at end of line RP polarization of deactivated line Extension of an existing network with CCA 609 MERLIN GERIN Sepam 1000+ CCA 602 CCA 612 MERLIN GERIN Sepam 1000+ ACE 909-2 ACE 909-2 CCA 602 CCA 612 (2) (1) RS 485 serial port 1 2 ACE 949 1 2 3 4 4 3 2 1 L –L+ ACE 949 1 2 3 4 4 3 2 1 CCA 629 1 2 3 4 4 3 2 1 9 10 11 12 13 14 1516 CCA 609 1 2 3 4 5 6 7 8 (3) L –L+ ACE 919 V+ V– L+ L– 3 7 9 5 V+ V– L+ L– V+ V– L+ L– V+ V– L+ L– L+ L– without distributed power supply RC RP max 250 m AC/DC 24 - 48 DC 110 / 220 Vac supply (1) use of CCA 629 for continuity of distributed power supply (2) strap 9-10 impedance matching resistor at end of line (3) strap 5-6 and 7-8 for 2-wire RS 485 RC résistance d’adaptation en extrémité de ligne RP polarisation de la ligne au repos RS 485 network connection guide 19 Connection of “slave” stations 4 wire RS 485 Master station at one end of line polarization of lines, load resistors at end of lines, transmission (optional), receiving master station (supervisor) MERLIN GERIN MERLIN GERIN MERLIN GERIN ACE 909-2 ACE 909-2 ACE 909-2 CCA 602 CCA 602 CCA 602 (1) 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 RD + TD + TD – RD – (2) TD + TD – RD + RD – 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 TD + TD – RD + RD – (2) 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 (2) TD + TD – RD + RD – (1) strap 9-10 and 11-12 impedance matching resistor at end of both lines (2) removal of strap 5-6 and 7-8 in 2-wire mode Master station at the middle of line polarization of lines, transmission (optional), receiving master station (supervisor) TD + TD – RD + RD – 8 4 9 5 (*) pins on CCA 609 9-pin Sub-D connector TD + TD – RD + RD – MERLIN GERIN master strand * ACE 909-2 CCA 602 MERLIN GERIN MERLIN GERIN ACE 909-2 ACE 909-2 CCA 602 CCA 602 (1) (1) 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 TD + TD – RD + RD – 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 TD + TD – RD + RD – 9 10 11 12 13 14 15 16 CCA 609 1 2 3 4 5 6 7 8 TD + TD – RD + RD – (1) strap 9-10 and 11-12 impedance matching resistor at end of both lines 20 RS 485 network connection guide Extension of the RS 485 network with ACE 919 in case of distributed power supply RS 232 serial port 2 3 5 max 250 m RxTx Ov ACE 909-2 V+ V– L+ L– 3 7 9 5 RC RP MERLIN GERIN Sepam 1000+ ACE 909-2 110 / 220 Vac supply 1 2 ACE 949 1 2 3 4 4 3 2 1 V+ V– L+ L– CCA 629 1 2 3 4 4 3 2 1 L+ L– L- L+ max 250 m L- L+ ACE 919 V+ V– L+ L– 3 7 9 5 MERLIN GERIN Sepam 1000+ ACE 909-2 AC/DC supply 1 2 CCA 629 1 2 3 4 4 3 2 1 V+ V– L+ L– ACE 949 1 2 3 4 4 3 2 1 V+ V– L+ L– L- L+ max 250 m L- L+ ACE 919 V+ V– L+ L– 3 7 9 5 Sepam 1000+ Sepam 1000+ AC/DC supply ACE 949 1 2 3 4 4 3 2 1 V+ V– L+ L– RC ACE 949 1 2 3 4 4 3 2 1 V+ V– L+ L– RC RC load impedance matching resistor to be installed if at end or beginning of line RP RP polarization of deactivated line RS 485 network connection guide 21 Setting and testing Commissioning Setting of communication parameters selection transmission rate adjustable from 300 to 38,400 bauds on converters on equipment Before Modbus communication equipment is put into service, parameters need to be set. slave n° assigned adjustable from 1 to 255 to equipment parity: no parity, even parity, odd parity on converters on equipment 22 line polarization 1 location only (master) line impedance matching at end of line on converters on equipment RS 485 network connection guide Troubleshooting Operating problems In case of problems, it is advisable to connect the devices to the RS 485 network one by one. The green lamp indicates that there is traffic on the line. Make sure that the master sends frames to the equipment concerned and to the RS 232 – RS 485 / RS 485 – RS 485 converter, if there is one. Points to be checked Check: c the wiring to the CCA 612 connectors, the CCA 602 branching cables and the RS 485 network cable, c the wiring of the ACE convecters, c the wiring to each ECA 609 / CCA 629 / CCA 619 connection box, c the wiring of the ACE 949 interface, c the distributed voltage V+, V- (12 V), c the polarization is in one location only, c the impedance matching is set up at the ends and only at the ends of the RS 485 network, c the cable used is the one advised, c the ACE converters used are correctly connected and parameterized, c the L+ or L- lines are not earthed, c the earthing of all the cable shielding, c the earthing of all the converters, interfaces and connection boxes. Use an oscilloscope to check the forum of the signals: c transmit voltage v level 0 +1.5 V to +5 V v level 1 -1.5 V to -5 V c reception voltage threshold v level 0 > +0.2 V v level 1 < -0.2 V RS 485 network connection guide 23 Protection and control Sepam range Sepam 2000 Sepam 1000 Diagnosis guide Sepam 2000 diagnosis guide Contents page Sepam 2000 diagnosis guide 2 Sepam 2000 appendix 13 Sepam 1000 diagnosis guide 14 Sepam 1000 appendix 19 c the symptoms column describes the fault observed, together with the possible consequences. c the possible causes column describes what could have caused the fault. c the remedies column describes the tests to be performed or operations to be carried out to correct the situation (they are not necessarily given opposite the causes discussed). All indicators off Symptoms Possibles causes Remedies c all the indicators and the display unit are off, c the TSM 2001 terminal is not communicating, the screen is blank. c the Sepam 2000 is not being supplied with power, c the device has been switched on rapidly several times in a row, causing internal tripping of the CE40 power supply. c check the voltage on the power supply connector, c disconnect the power supply for a few minutes, c if the fault persists, change the Sepam 2000 power supply board. The CE40 board is fitted with an internal fuse; never replace it (since other power supply components are damaged when the fuse blows). 2 Guide de diagnostic “maintenance” message and red indicator on Symptoms Possible causes Remedies c Sepam displays the maintenance message, c the red indicator is on, c the TSM 2001 pocket terminal is not operational, c the Sepam 2000 is not working; the watchdog has dropped out. The parameters have been altered. There may be several causes for the alteration: c the memory cartridge has been inadvertently plugged in or pulled with the power on. c Sepam 2000 self-testing has detected an internal fault which prevents it fromcarrying out its functions. c replace the customer cartridge by the TSM 2005 final testing cartridge and read the internal fault using the TSM 2001 (see TSM 2005 manual, chapter on reading internal faults). without the TSM 2005 c to locate the fault, replace the cartrige by another one (made for use in the same model). If the fault disappears, it came from the cartridge: reprogram it with LOGIPAM using the reprogram settings option, c if necessary, replace the faulty cartridge, c if the fault persists, replace the power supply card, c if the fault persists, replace Sepam 2000. Before re-energizing the Sepam, check the complete parameter setting of the Sepam: c status, c protection settings, c control logic parameters: bistables, time delays... “maintenance” message and red indicator off Symptoms Possible causes Remedies c Sepam displays the maintenance message, c the red indicator is off, c the TSM 2001 pocket terminal is operational, c Sepam 2000 is working, c the maintenance message disappears when a key on the front of the device is pressed, but comes back again after a few seconds. c the microswitches are in a prohibited setting, c Sepam 2000 internal self-testing has detected an internal fault which does not prevent Sepam 2000 from momentarily performing its functions. c check the setting of the microswitches on the ECM (or ECA) and 3U+Vo boards (installation manual), c for S25 and S35 Sepam, an error code can be read with the pocket terminal in the About Sepam menu, SFT 2800 heading; it appears in line 4 of the screen, on the right : v code 0400: change the ECM (ECA) board (slot 2), v code 1000: change the 3U+Vo board, v code 0800: change the additional ECM (ECA) board (slot 3), v codes 2000, 8000: change the RTD boards, v other codes or if the fault persists: replace Sepam 2000. With TSM 2005 c replace the customer cartridge by the TSM 2005 final testing cartridge and read the internal fault using the TSM 2001 (see TSM 2005 manual, chapter on reading internal faults). Guide de diagnostic 3 Sepam 2000 diagnosis guide (cont’d) “CARTRIDGE” message Symptoms Possible causes Remedies c Sepam displays the cartridge message, c the red indicator is on. c the TSM 2001 pocket terminal is not working, c Sepam 2000 is not working; the watchdog relay has dropped out. c the cartridge does not match the Sepam model, c boards needed for Sepam 2000 operation are missing, c the boards have been switched around, c 2 different ECM boards are pluged in Sepam. c ensure that the cartridge has not been mixed up with another Sepam 2000 cartridge, c check the number of ESTOR I/O boards. It should be greater than or equal to the number of boards needed for the control logic program, c check that the cartridge is installed in the correct model of Sepam: the Sepam model in which the cartridge should be inserted appears in line 1 of the label on the front of the cartridge. Example : a cartridge labeled S25 LX M01 should be inserted in a model 2025 LX Sepam, c the Sepam model appears in the label stuck to its side. Check that the boards present in the rear compartment of that model comply with the board position table in the appendix, c check that ECM boards have the same sérial number (03143179 or 3122288). With TSM 2005 c replace the customer cartridge by the TSM 2005 final testing cartridge and read the internal fault using the TSM 2001 (see TSM 2005 manual, chapter on reading internal faults). “M.CARTRIDGE” message and red indicator on Symptoms Possible causes Remedies c Sepam displays the M.CARTRIDGE message, c the red indicator is off, c the TSM 2001 pocket terminal is not working , c the Sepam 2000 is not working; the watchdog has dropped out. c cartridge memory fault, with possible altered parameters. c replace the cartridge. Before re-energizing the Sepam, check the complete parameter setting of the Sepam: c status, c protection settings, c control logic parameters: bistables, time delays... “M.CARTRIDGE” message and red indicator off Symptoms Possible causes Remedies c Sepam displays the M.CARTRIDGE message, c the red indicator is off, c the TSM 2001 pocket terminal is working, c the Sepam 2000 is working, c the M.CARTRIDGE message disappears when a key on the front of the device is pressed, but comes backagain after a few seconds. c incorrect status setting, c the maximum number of cartridge memory entries has been reached c check whether the STATUS menu parameters are blinking. Blinking parameters should be reprogrammed, c for S25 and S35 Sepam, an error code is read using the pocket terminal in the About Sepam menu, item SFT 2800; it appears in line 4 of the screen, on the right: v code 0040 : replace the cartridge. 4 Guide de diagnostic Everything off except for green and red indicators Symptoms Possibles causes Remedies c the green on indicator is on, c the red inidicator is off, c the TSM 2001 pocket terminal is not communicating, its screen is blank, c the 3 indicators I on, O off, trip and the display unit are off, c the blinking cursor is displayed on the TSM 2001 pocket terminal but the terminal is not working. c the cartridge is missing, c there may be a programming fault in the cartridge, c the control logic part is not programmed, c power supply board fault. c check for the cartridge behind the shutter, c replace the cartridge by a cartridge that is presumed to be a good one (intended for the same model of Sepam 2000). If the fault disappears, the fault came from the cartridge: replace or reprogram it, c if the fault persists, change the Sepam 2000 power supply board, c if the fault persists, change Sepam 2000. Symptoms Possible causes Remedies c a line of dashs is displayed: --------------, c this message may appear in normal operating conditions. c pressing a key on the front which is not used (e.g. V/Hz key on a Sepam which does not contain voltage measurement functions), c pressing the alarm key (to display the stored messages) when no messages have been stored, c when stored messages are being read (after the user has pressed the alarm key), the dashs appear to indicate the end of the list of messages (they appear after the oldest message). c none. This is not a fault. Display of dashs The TSM 2001 display is blank Symptoms Possible causes Remedies c the TSM 2001 pocket terminal screen is dark, or blank except for the blinking cursor, c the green on indicator is on, c lthe red indicator is off, c the Sepam 2000 display unit is working and the keys on the front are operational. c the TSM 2001 pocket terminal display unit contrast adjustment has been modified, c the pocket terminal is out of order. c turn the dial on the right-hand side of the TSM 2001 pocket terminal, c test the pocket terminal on another Sepam 2000 to determine whether the fault comes from the terminal or Sepam 2000. If the fault is located in Sepam 2000, replace it. Guide de diagnostic 5 Sepam 2000 diagnosis guide (cont’d) The current measurements are false Symptoms Possible causes Remedies c the difference between the expected measurement and the measurement indicated by Sepam 2000 may be between 10% and 500%, c the green on indicator is on, c the red indicator is off, c the display unit is lit up, c the TSM 2001 pocket terminal is working normally. c the microswitches on the back of the ECM (or ECA) board are not set correctly, c one of the parameters in the status menu is not set correctly. c check the setting of the microswitches on the ECM (or ECA) board; refer to installation manual, c check that the In setting (status menu, phase CT heading) matches the rating of the CTs or CSP sensors being used; refer to use/commissioning manual, c check that the network frequency has been selected correctly (50 or 60 Hz, status menu). With TSM 2005 c use the TSM 2005 to test the ECM or ECA current boards (see TSM 2005 manual, chapter on testing ECM or ECA boards). The residual current measurement is false Symptoms Possible causes Remedies c reading < 50% of injected current. cthe core balance CT is not compatible. c replace the core balance CT by a CSH, c check that the core balance CT is wired to the core balance CT input and not to the CT input. I2 current measurement does not appear Symptoms Possible causes Remedies c the I2 measurement is missing. It does not appear on the display or on the TSM 2001 pocket terminal, c the phase 1 and 3 currents are correct. c the number of phase CTs selected in the status menu is 2 instead of 3. If this is the case, Sepam is unaware of the presence of the phase 2 CT. c check the number of CTs indicated in the status menu, phase CT heading. Set it to 3. One of the 3 phase current measurements is zero Symptoms Possible causes Remedies c one of the measurements indicates a value of zero or close to zero, c the other 2 phase current measurements are working normally. The indications are the same on the display and on the TSM 2001 pocket terminal, c the green on indicator is on c the red indicator is off, c the display unit is lit up, c the TSM 2001 pocket terminal is working normally. c there are only 2 CTs in the cubicle, c one CT is not wired, c the ECM (or ECA) current input board is faulty, c the current measured is less than 1.5% of In. c Sepam connected to a 1A/5A CT: ensure that there is current in the CT secondary circuit which reaches the CCA 660 or CCA 650 connector, c replace the ECM board, c Sepam connected to a CSP sensor: momentarily reverse the connections (BNC connector) on the ECA board: if the fault disappears, the problem is an external one; if the fault persists, replace the ECA board. With TSM 2005 c use the TSM 2005 to test the ECM or ECA current boards (see TSM 2005 manual, chapter on testing ECM or ECA boards). 6 Guide de diagnostic The voltage measurements are false Symptoms Possible causes Remedies c the difference between the expected measurement and the measurement indicated by Sepam 2000 may be between 10% and 500%, c the protections do not trip at the expected setting, c the green on indicator is on, c the red indicator is off, c the display unit is lit up, c the TSM 2001 pocket terminal is working normally. c the microswitches on the back of the 3U+Vo board are not set correctly, c one of the parameters in the status menu is not set correctly. c check the setting of the microswitches on the 3U+Vo board; refer to installation manual, c check that the Unp and Uns settings (status menu, phase VT heading) match the VTs being used; refer to use/ commissioning manual, c check that the network frequency has been selected correctly (50 or 60 Hz, status menu). With TSM 2005 c use the TSM 2005 to test the 3U+Vo boards (see TSM 2005 manual, chapter on testing 3U+Vo boards). One or two phase voltage measurements do not appear Symptoms Possible causes Remedies c the U13 (and U32) measurement is missing. It does not appear on the display or on the TSM 2001 pocket terminal, c the other voltages are correct. c the phase VTs selected in the status menu are U21(and U32). If this is the case, Sepam is unaware of the presence of the other VTs. c check the number of VTs indicated in the status menu, phase VT heading. Set it to 3. A voltage measurement is zero Symptoms Possible causes Remedies c one of the phase-to-phase voltage measurements indicates a value of zero or close to zero. The indications are the same on the display and on the TSM 2001 pocket terminal, c the green on indicator is on, c the red indicator is off, c the display unit is lit up, c the TSM 2001 pocket terminal is working normally. c there are only one or two VTs in the cubicle, c the 3U+Vo voltage input board is faulty, c the voltage measured is less than 1.5% of Un. c ensure that the wiring to Sepam 2000 is correct, c replace the 3u+Vo board. Guide de diagnostic With TSM 2005 c use the TSM 2005 to test the 3U+Vo voltage boards (see TSM 2005 manual, chapter on testing 3U+Vo voltage boards). 7 Sepam 2000 diagnosis guide (cont’d) The power measurements and accumulated energy readings are false Symptoms Possible causes Remedies c the power indicated may be totally false or almost zero, c the power factor indicated may be a deviant value, c otherwise, the current and voltage measurements are correct. c inversion of CT wiring to Sepam 2000 current inputs if the frequency is correct, c inversion of VT cabling to Sepam voltage inputs if the frequency is displayed by dashs. c check the wiring. Comply with the given order of phases. The current measurement is zero and the accumulated energy increments Symptoms Possible causes Remedies c the accumulated energy increments for a displayed current of zero. c the load is low and the current is less than 1.5% of In (e.g. no-load transformer). c normal operation. The frequency measurement is not displayed or is given as dashs Symptoms Possible causes Remedies c no display of frequency measurement, c otherwise, the current and voltage measurements are correct, c the power indicated and the power factor are correct. c inversion of VT wiring to Sepam 2000 voltage inputs, c direction of phase rotation is incorrect, c the frequency is not measured if voltage U21 < 40%, c the frequency is outside the tolerance range 45 < F < 55 for 50 Hz 55 < F < 65 for 60 Hz. c check the wiring. Comply with the given order of phases. 8 Guide de diagnostic A protection does not trip at the expected set point Symptoms Possible causes Remedies c one or more protections do not trip at the expected set points. c the causes may be same as when the current or voltage measurements are false; microswitches or status parameter set incorrectly, c a protection set point is outside the range accepted by Sepam 2000 after a modification of In, Ib, Unp or Uns, c the control logic omits the protection (see control logic operation further on), c the protection is set to 999. c check the setting of the microswitches on the 3U+Vo and the ECM (or ECA) boards; refer to installation manual, c check that the frequency, Unp and Uns settings (status menu, phase VT heading) match the VTs being used; refer to use/commissioning manual, c check that the In setting (status menu, CT ratio) matches the rating of the CTs or CSP sensors used. See user commissioning manual; c using the TSM 2001 pocket terminal, review the list of protections (protections menu) and check that none of them is blinking. If that is the case, reset it. Generally speaking, it is recommended to set all the parameters in the status menu before setting the protections, c check the control logic. Symptoms Possible causes Remedies c the display unit indicates connector, c pressing key A (for example) makes the message disappear momentarily, c the green on indicator is on, c the red indicator is off, c the display unit is lit up, c the TSM 2001 pocket terminal is working normally. c detection of unplugged connector. c check that all connectors are plugged into rear of device, c check that the detection of plugged connectors bridge (marked DPC) is present on terminals 5 and 6 of the 6-pin connectors; terminals 7 and 8 on the 8-pin connectors and terminals 20 and 21 on the 21-pin connectors. N.B. The BNC, power supply and communication connectors are not equipped with the plugged connector detection system. “connector” message A logic input generates a fault in cabling outside Sepam Symptoms Possible causes Remedies c the logic input is working normally but it creates interference in the outside circuit (e.g. monitoring of tripping circuit continuity), c the green on indicator is on, c the red indicator is off, c the display unit is lit up, c the TSM 2001 pocket terminal is working normally. c wiring error on the connector of the related board, c the ESB or ESTOR board is faulty. c check wiring, c replace the faulty ESB or ESTOR board. Guide de diagnostic 9 Sepam 2000 diagnosis guide (cont’d) The standard control logic does not operate as expected Symptoms Possible causes Remedies c the standard control logic does not operate as expected, c case in which Sepam 2000 is equipped with standard control logic. The standard control logic is recognized by the presence of the CAT label which is read on the TSM 2001 pocket terminal, in the About Sepam menu, program logic heading, c the green on indicator is on, c the red indicator is off, c the display unit is lit up, c the TSM 2001 pocket terminal is working normally. c the control logic time delays are not set correctly, c the Kp parameters, set via the pocket terminal, are not set correctly. They mainly define the control logic operating modes according to the type of switchgear, c fault in wiring outside Sepam 2000, c ESB or ESTOR board faulty. c if Sepam 2000 is equipped with the standard control logic, refer to the use/commissioning manual. Check: v control logic time delay settings, v Kp parameters (control logic contacts set with the TSM 2001 pocket terminal). c control logic with undervoltage release: check the open order input I13 wiring (normally set to 1), c generator control logic: check the emergency shutdown input I22 wiring (normally set to 1). With TSM 2005 c use the TSM 2005 to test the ESB or ESTOR logic input/output boards (see TSM 2005 manual, chapter on testing ESB and ESTOR boards). Without TSM 2005 c in case of doubt regarding the operation of a logic input, check that there is voltage on the input, and set it to 1; to do so check the input status (1 or 0) using the TSM 2001 pocket terminal (program logic menu, logic input heading). In the event of a discrepancy, change the faulty board, c when in doubt regarding the operation of a relay output, check that the relay is activated when Sepam sets the output to 1; to do so check the input status (1 or 0) using the TSM 2001 pocket terminal (program logic menu, logic input heading). In the event of a discrepancy, change the faulty board. Control logic does not operate as expected Symptoms Possible causes Remedies c the control logic does not operate as expected, c case in which Sepam 2000 is equipped with customized control logic, c the green on indicator is on, c the red indicator is off, c the display unit is lit up, c lthe TSM 2001 pocket terminal is working normally. c error in the control logic program, c time delays or Kp internal bits incorrectly set, c defect in cabling outside Sepam 2000, c faulty ESB or ESTOR board. c if there is no CAT label, it is essential to obtain the customized control logic program in order analyze it and detect the source of the fault, c when in doubt regarding the operation of logic outputs, refer to the paragraph above. 10 Guide de diagnostic The red communication indicator stays on Symptoms Possible causes Remedies c the red communication indicator is on, c this indicator (communication watchdog) is located on the back of Sepam 2000, near the communication inlet, on the CE40 power supply board. It is normal for it to light up for a few seconds when the power is switched on. When the device is operating normally, it should be off, c this indicator may light up even if the remote monitoring and control system is not operating or is not connected. c Sepam 2000 communication coupler blockage, c communication coupler failure. c change the communication kit (2 boards). The green Jbus indicator does not blink Symptoms Possible causes Remedies c the green communication indicator does not blink, c the green indicator is located on the back of Sepam 2000, near the communication inlet, on the CE40 power supply board. If the remote monitoring and control system is connected, the indicator should blink to indicate that there is electrical activity in the line. If it does not blink, it means that the Sepam communication input is electrically deactivated, c the red coupler indicator is off, c the rest of Sepam 2000 is working normally. c the remote monitoring and control system is not in service or is not sending messages throught the line, c the line is cut, c the L+ and L- network wires are reversed, c polarization or impedance matching of the RS 485 line are incorrect. c refer to Jbus communication documents and check the following: v check the direction of line cabling to terminals 1 to 4 of all the CCA609 units in the network, v check that the line has been polarized. This should be at one point only. v check that line impedance has been matched at both ends. Guide de diagnostic With TSM 2005 c use the TSM 2005 and a PC to test the communication system (refer to communication kit manual. 11 Sepam 2000 diagnosis guide (cont’d) The Jbus communication CPT2 diagnosis counter increments Symptoms Possible causes Remedies c the CPT2 counter increments, c the counter is accessed via the TSM 2001 pocket terminal, status menu, communication heading. It counts the errors in the communication frames. When the device is operating normally, it should not increment, c the green coupler indicator is blinking (so the line is not cut). The red coupler indicator is off, c the rest of Sepam 2000 is working normally. c one of the communication parameters has not been set correctly: rate or parity, c impedance matching and/or communication network polarization are incorrect, c there is noise on the line c use the TSM 2001 pocket terminal to set the communication rate and parity in accordance with the remote monitoring and control system (status menu, communication heading), c if this is not sufficient, check polarization and line impedance matching (see Jbus communication manual), c check that the CCA 609 clamps are tightened onto the cable shielding and not onto the insulating material. The clamps earth the cable shielding, c check the earthing of the CCA 609 (greenyellow wire), c check that the CCA 602 cable connecting Sepam and the CCA 609 unit is plugged in and locked at both ends. It contributes to shielding continuity, c check that the communication network does not cross through zones with high levels of electrical pollution. N.B. The frames which contain errors are detected by Sepam 2000 which does not process them. Overall Sepam/remote monitoring and control system operation is not generally affected and the number of frames with errors remains limited (a few). With TSM 2005 c use the TSM 2005 and a PC to test the communication system (refer to communication KIT manual). The JBUS communication CPT9 diagnosis counter does not increment Symptoms Possible causes Remedies c the CPT9 counter does not increment, c the counter is accessed via the TSM 2001 pocket terminal, status menu, communication heading. It counts the errors in the communication frames. When the device is operating normally, it should not increment, c the green coupler indicator is blinking (so the line is not cut). The red coupler indicator is off, c the rest of Sepam 2000 is working normally. c the remote monitoring and control system never addresses this Sepam, c one of the communication parameters is not set correctly: rate, slave number or parity, c communication network impedance matching or polarization is incorrect. c use the TSM 2001 pocket terminal to set the communication speed, salve number and parity in accordance with the remote monitoring and control system (status menu, communication heading), c if this is not suficient, check polarization and impedance matching (see Jbus communication manual). 12 Guide de diagnostic Sepam 2000 appendix Table of rear compartment board positions c The table below indicates the position of the boards in the rear compartment according to the different Sepam 2000 models. c If the board poisitions are not complied with, Sepam 2000 will not start up and will display maintenance or cartridge. slot 8 7 6 5 4 3 2 1 CE40 S26 or S25 models ESTOR(2) LS (2)(4) ESB SONDE ECM(1) (4) ESB 3U+Vo ECM(1) CE40 ESTOR LT ESTOR ESTOR LX ESTOR(2)(4) ESTOR(4) ESB nothing ECM(1) CE40 XT ESTOR(2) ESTOR ESB 3U+Vo nothing CE40 S36 or S35 models KR ESTOR(3) ESTOR(2) ESTOR ESB nothing ECM ECM(1) CE40 KZ SONDE ESTOR(2) ESTOR ESB nothing ECM ECM(1) CE40 YR ESTOR(3) ESTOR(2) ESTOR ESB nothing nothing ECM(1) CE40 ZR ESTOR (3) (2) ESTOR ESB nothing SONDE ECM(1) CE40 LR ESTOR(3) ESTOR(2) ESTOR ESB 3U+Vo ECM ECM(1) CE40 LS SONDE ESTOR(2) ESTOR ESB 3U+Vo ECM ECM(1) CE40 SR ESTOR(3) ESTOR(2) ESTOR ESB 3U+Vo SONDE ECM(1) CE40 (2) ESTOR ESB 3U+Vo SONDE ECM(1) CE40 ESTOR SS SONDE ESTOR XR ESTOR(3) ESTOR(2) ESTOR ESB 3U+Vo nothing ECM(1) CE40 TR ESTOR(3) ESTOR(2) ESTOR ESB 3U+Vo 3U+Vo ECM(1) CE40 CR (3) ESTOR ESTOR (2) ESTOR ESB nothing ECMD ECMD CE40 CC(5) ESTOR(3) ESTOR(2) ESTOR ESB ECMD ECMD ECMD CE40 TS(5) SONDE ESTOR(2) ESTOR ESB 3U+Vo 3U+Vo ECM(1) CE40 Notes (1) or ECA for CSP sensor, (2) the ESTOR 2 board may be installed, depending on the application, (3) option for the ESTOR board, (4) For SX1 and SX2 applications the ESTOR boards are not installed in Sepam, (5) available with S36 only. Functions of rear compartment boards c CE40 Power supply: 3 versions available: 24/30 VDC, 48/127 VDC and 220/250 VDC. c INT RS 485 : Communication interface. It is located behind the metal plate on the power supply board. c ECM Current inputs for 1 A or 5 A seonsor and CSH core balance CT input for residual current measurement. Sepam TC type. c ECA current inputs for CSP sensor or CSH core balance CT input for residual current measurement. This board in installed in place of the ECM board for Sepam 2000 CS type. Guide de diagnostic 9644 c 3U+Vo: voltage inputs and residual voltage input, c SONDE: 6 PT100 RTD inputs, c ESB: 2 logic inputs, 2 output relays and watchdog relay 3 versions available: 24/30 VDC, 48/127 VDC and 220/250 VDC, c ESTOR: 8 logic inputs and 4 output relays 3 versions available: 24/30 VDC, 48/127 VDC and 220/250 VDC. 13 Sepam 1000 diagnosis guide All indicators off Symptoms Possible causes Remedies c all the indicators and the display unit are off. c the Sepam 1000 is not being supplied with power. c check the voltage on the power supply connector, c if the fault persists, change the Sepam 1000 AS' power supply board. The AS' board is fitted with an internal fuse; never replace it (since other power supply components are damaged when the fuse blows). Everything off except for green and red indicators Symptoms Possible causes Remedies c c c c c the self-tests have detected an internal fault, c power supply board fault. c change the Sepam AS' power supply board, c if the fault persists, replace the Sepam 1000. the green on indicator is on, the red indicator is on, the trip indicator and display unit are off, the watchdog has dropped out. display of the “check settings” message Symptoms Possible causes Remedies c the display unit shows the message: check settings, c the values of some parameters are blinking, c the protections are working normally. c Sepam 1000 has detected a parameter setting faults (outside range, incompatible settings, set point modified after a change of In, etc.). c switch to parameter setting mode and change the settings of all the parameters which are blinking on the display unit. The -, + and enter keys are disabled Symptoms Possible causes Remedies c the -, + and enter keys are disabled. c Sepam is not in parameter setting mode. c switch to parameter setting mode by pressing for a second on the P key on the back of Sepam. Display of the “fault” message Symptoms Possible causes Remedies c internal fault. c internal fault. c replace Sepam. 14 Guide de diagnostic The current measurements are false Symptoms Possible causes Remedies c the difference between the expected measurement and the measurement indicated by Sepam 1000 may be between 10% and 500%, c the green on indicator is on, c the red indicator is off, c the display unit is working. c the microswitches on the back of the EM (or EA) board are not set correctly, c one of the parameters in the status loop is not set correctly. c check the setting of the microswitches on the EM (or EA) board; refer to installation manual, c check that the In setting (status loop) matches the rating of the CTs or CSP sensors being used; refer to use/ commissioning manual, c check that the network frequency has been selected correctly (50 or 60 Hz, status loop). One of the phase current measurements is zero Symptoms Possible causes Remedies c a measurement indicates a value of zero or close to zero, c the 2 other phase current measurements are working normally, c the green on indicator is on, c the red indicator is off, c the display unit is working. c there are only 2 CTs in the cubicle, c one CT is not wired, c the EM (or EA) current input board is faulty. c Sepam connected to a 1A/5A CT: ensure that there is current in the CT secondary circuit which reaches the CCA 660 or CCA 650 connector, c replace the EM board, c Sepam connected to a CSP sensor: momentarily reverse the connections (BNC connector) on the EA board: if the fault disappears, the problem is an external one; if the fault persists, replace the EA board. The voltage measurements are false Symptoms Possible causes Remedies c the difference between the expected measurement and the measurement indicated by Sepam 1000 may be between 10% and 500%, c the protections do not trip at the expected setting, c the green on indicator is on, c the red indicator is off, c the display unit is working. c the microswitches on the back of the ET board are not set correctly, c one of the parameters in the status loop is not set correctly. c check the setting of the microswitches on the ET board; refer to installation manual, c check that the Unp and Uns settings (status loop) match the VTs being used; refer to use/commissioning manual, c check that the network frequency has been selected correctly (50 or 60 Hz, status loop). Guide de diagnostic 15 Sepam 1000 diagnosis guide (cont’d) The U32 and U13 phase voltage measurements do not appear Symptoms Possible causes Remedies c the U32 and U13 measurements are missing, c the U21 voltage measurement is correct. c the VT's parameter in the status loop is set to U21, in which case Sepam is unaware of the value of the other voltage measurements. c check the VT's parameter (status loop). Set it to U21U32. A voltage measurement channel indicates zero Symptoms Possible causes Remedies c one of the phase-to-phase voltage measurements indicates a value of zero or close to zero, c the green on indicator is on, c the red indicator is off, c the display unit is working. c there are only one or two VTs in the cubicle or not all the VTs are cabled, c the ET voltage input board is faulty. c ensure that the VT secondaries are wired to Sepam 1000, c replace the ET board. 16 Guide de diagnostic A protection does not trip at the expected set point Symptoms Possible causes Remedies c one or more protections do not trip at the expected set points. c the causes may be same as when the current or voltage measurements are false; microswitches or status parameter set incorrectly, c a protection set point is outside the range accepted by Sepam 1000 after a modification of In, Ib, Unp or Uns, c case of residual current protection: core balance CT connection error (2 A , 30 A rating or CT). c check the setting of the microswitches on the ET and the EM (or EA) boards; refer to installation manual, c check that the Unp and Uns settings (status loop) match the VTs being used, c check that the In setting (status loop) matches the rating of the CTs or CSP sensors being used; refer to use/commissioning manual, c check that the network frequency setting has been selected correctly (50 or 60 Hz, status loop), c review the list of parameters and check that none of them are blinking. If that is the case, set the parameters again. Generally speaking, it is recommended to set all the parameters in the status menu before setting the protections, c residual current: check the core balance CT connection. Check that the core balance CT is a CSH. Symptoms Possible causes Remedies c a protection does not trip. c inhibition of the protection by a 999 type setting, c incorrect addressing of the protection output, c residual current protection: microswitches not set correctly. c check the set points, c check the output addressing. Make sure in particular that the ES1 board is included if relays AUX1, AUX3 and AUX4 are supposed to be used, c residual current protection: if the sum of the phase currents i used, check that the setting of the SW1 microswitches on the EM or EA board is as follows: SW1. A protection does not trip Guide de diagnostic 17 Sepam 1000 diagnosis guide (cont’d) Acknowledgement is impossible Symptoms Possible causes Remedies c the reset key is disabled, acknowledgement is impossible. c the fault at the origin of tripping is still present. c check for the presence of the fault (current, voltage, frequency): v think of undervoltage protections which trip when there is zero voltage, v also remember the thermal overload and starts per hour protections which remain in tripped status even when there is no current. In such cases, wait for the conditions which caused tripping to disappear. Frequency measurement and functions do not work Symptoms Possible causes Remedies c the frequency measurement is displaying hyphens, c the frequency protections do not trip. c incorrect wiring, c U21 or forward voltage too low. c check the wiring (direction of phase rotation), c check voltage amplitude: U21 voltage should be greater than 30% of Unp and forward voltage should be greater than 20% of Vnp. The logic input does not work Symptoms Possible causes Remedies c the logic input remains at zero, whether it is supplied with power or not, c the green on indicator is on, c the red indicator is off, c the display unit is working. c wiring error on the ES1 board connector, c ES1 board microswitch setting error, in the case of use with 24/30 VDC. c check the wiring and voltage on the input terminals, c if the input is used with 24/30 VDC, the microswitches on the ES1 board must be SW1, set as follows: c if the fault persists, replace the ES1 board. 18 Guide de diagnostic Sepam 1000 appendix Table of rear compartment board positions c the table below indicates the position of the boards in the rear compartment according to the different Sepam 1000 models. c failure to use the correct board positions is liable to damage Sepam 1000. slot 3 2 1 0 LX 1 A / 5 A CT sensor EM AS’ ES1 (option) LX CSP sensor EA AS’ ES1 (option) TX ET AS’ ES1 (option) Functions of rear compartment boards c EM: current inputs for 1 A or 5 A sensor and CSH core balance CT input for residual current measurement, c EA: current inputs for CSP sensor and CSH core balance CT input for residual current measurement, c ET: voltage inputs and residual voltage input, c AS’: power supply and 2 outputs 4 versions available: v 24/30 VDC, v 48/125 VDC, v 220/250 VDC and 100/127 VAC, v 220/240 VAC, c ES1: 1 logic input and 3 output relays and watchdog relays single multi-voltage version available. S05 model Guide de diagnostic 19 TRANSFORMER PROTECTION „ Protection functions : • Main characteristics • Protection by circuit breaker • Logic discrimination Division - Name - Date - Language „ Protection functions : • • • • • • • • • • • • 49 : thermal overload 50/51 : phase overcurrent 50N/51N : earth fault protection 59N : neutral voltage displacement 67 : directional overcurrent 67N : directional earth fault 27 : undervoltage 27R : remanent undervoltage 59 : overvoltage 50/51 : tank earth leakage 64REF : restricted earth fault 87T : differential protection 2 TRANSFORMER PROTECTION „ Main characteristics : • Transformer energizing inrush current : Ie t i e (t) = I e e e t îe(t): current peak value as a function of time Îe: value of maximum peak, i.e. the first peak τe: damping time constant • Inrush current at high voltage end of TRIHALtransformers: Power in kVA I e ne = In te (s) Division - Name - Date - Language 160 250 400 630 800 1000 1250 1600 2000 10.5 10.5 10 10 10 10 10 10 9.5 0.13 0.18 0.25 0.26 0.30 0.30 0.35 0.40 0.40 3 TRANSFORMER PROTECTION „ Main characteristics (cont'd) : • Vector group : Va A VA-VB B a C c b VC 11 VB Va VA VA-VB Dy11 Division - Name - Date - Language 4 TRANSFORMER PROTECTION „ Main characteristics (cont'd) : • For earth fault : IA JA During the fault : Ia A IB B a C c b Ia = Icc three - phase IA = -IB = 0.58 . Icc three - phase / k N Division - Name - Date - Language n.Ia = N.JA and IA = JA k : transformer ratio = 0.58 . N / n n 5 TRANSFORMER PROTECTION „ Main characteristics (cont'd) : • For phase to phase fault : During the fault : n.Ia = N.JA = -n.Ib = -N.JB Ia IA JA A IB B IC C JB Ib Ia = 0.866 Icc three - phase a IA = JA - JC b IA = Ia.n/N = 0.5.Icc three - phase / k IB = JB - JA c N n IB = -Ia.n/N -Ia.n/N IB = -2.Ia.n/N = - Icc three - phase / k IC = JC - JB IC = Ia.n/N = 0.5.Icc three - phase / k k : transformer ratio = 0.58 . N / n Division - Name - Date - Language 6 TRANSFORMER PROTECTION „ With DT curves „ With IDMT curves t (s) 100 t (s) 100 transformer transformer 10 10 cable switching device, busbar CT, relay cable switching device, busbar CT, relay 1 HV 1 HV MV MV I inrush 0.1 I inrush 0.1 0.01 0.01 1 10 Isc min MV Division - Name - Date - Language Isc max MV 100 Isc min HV Isc max HV I (A) 1 10 Isc min MV Isc max MV 100 Isc min HV Isc max HV I (A) 7 TRANSFORMER PROTECTION „ I < switch breaking capacity t (s) 100 t (s) 100 „ I > switch breaking capacity: BEWARE! transformer transformer MV low threshold MV low threshold 10 10 cable switching device, busbar CT, relay cable switching device, busbar CT, relay 1 1 LV LV BC switch BC switch I inrush 0.1 I inrush 0.1 MV fuses MV fuses 0.01 0.01 1 10 Isc min MV Division - Name - Date - Language Isc max LV 100 Isc max MV I (A) 1 10 Isc min MV Isc max LV 100 Isc max MV I (A) 8 TRANSFORMER PROTECTION „ Logic discrimination : Transformer 0.1 s 0.7 s Division - Name - Date - Language 1s Fault on busbar eliminated after 0.1 s without adding any other protection 0.7 s 9 TRANSFORMER PROTECTION „ Logic discrimination : Overcurrent (inst) ≥1 0 t Earth fault (inst) Output O14 : BI transmision Inhibition of BI transmision if fault not cleared & T3 = 0.2s Overcurrent (time) ≥1 ≥1 Earth fault (time) tripping Overcurrent (logic) ≥1 & Earth fault (logic) Input I12 : BI receipt Division - Name - Date - Language 10 TRANSFORMER PROTECTION „ Overcurrent (50/51) : • 1st setting : 1.25 Iscmaxdown <=Is1<=0.8 Iscminup Time setting ≈ 0.1 s • 2nd setting : 1.25 Isdown <=Is1<=0.8 Iscmindown Time setting ≈ Tdown + 0.3 s • Transient overreach = (Iso - Is1) / Is1 Iso = setting current, that is, r.m.s. value of steady state current required to operate the relay Is1 = steady state r.m.s. value of the fault current which when fully offset will just operate the relay Division - Name - Date - Language 11 TRANSFORMER PROTECTION „ Overcurrent (50/51) : • Current shape in case of saturation of CT: I ct Peak value Right value Fundamental value t Low value of fundamental current ⇒ risk of no detection of the fault ⇒ measurement of peak value Division - Name - Date - Language 12 TRANSFORMER PROTECTION „ Overcurrent (50/51) : • Current shape in case of no saturation of CT : I ct Peak value Filtered peak value t Transient overreach can be very high if only the peak value is considered ⇒ peak value is filtered (no DC component) Division - Name - Date - Language 13 TRANSFORMER PROTECTION „ Overcurrent (50/51) : • Conclusion : • Filtered peak detection is used to ensure tripping in case of CT saturation • Efficace value avoids the risk of unexpected tripping SEPAM MIX THE TWO MEASUREMENTS TO GUARANTEE A GOOD TRANSIENT OVERREACH (LESS THAN 10% FOR ANY TIME CONSTANT) Division - Name - Date - Language 14 TRANSFORMER PROTECTION „ Earth fault (50N/51N) : Harmonic 2 restrain An earth fault current (including harmonic 2) could appear in case of CT saturation if earth fault is measured by means of the sum of 3 TC. Division - Name - Date - Language 15 TRANSFORMER PROTECTION „ Thermal overload (49) : • Heat rise calculation : 2 dE  Ieq  +E = T×  dT Ib   Ieq 2 = I 2 + K × Ii 2 • I is the greatest value of I1, I2, I3 (at 50 Hz) and I1rms • Ii is the negative sequence current 2 2 t   Ieq   − T  Ieq  E =  Eo −   ×e +  Ib Ib       • Eo : initial heat rise Division - Name - Date - Language 16 TRANSFORMER PROTECTION „ Thermal overload (49) (cont'd) : • Operation E 2 2 t   Ieq   − T  Ieq  E =  Eo −   ×e +  Ib Ib       (Ieq/Ib)² Eo (Ieq/Ib)² Eo (Ieq/Ib)² Eo T T T t Division - Name - Date - Language 17 TRANSFORMER PROTECTION „ Thermal overload (49) : t 100 10 2 Cold curve 1 0.1  I    Ib t = T × Log  2   I    − Es 2  Ib  2 Hot curve  I    −1 Ib t = T × Log  2  I    − Es 2  Ib  Es2 = thermal setting point in % T = heat rise time constant Ieq/Ib Division - Name - Date - Language 18 TRANSFORMER PROTECTION „ Thermal overload (49) (cont'd) : • A transformer often has two operating modes (ONAN - ONAF) • Two groups of parameters are available • Switching from one mode to the other is controlled by a Sepam input • Accounting for ambient temperature when the temperature measured exceeds 40° Division - Name - Date - Language 19 TRANSFORMER PROTECTION „ Residual overvoltage (59N) : • For isolated neutral 59N protection is required to detect earth fault before closing the circuit breaker • This function can be located elsewhere in the network (on busbar for example) Division - Name - Date - Language 20 TRANSFORMER PROTECTION Phase directional overcurrent (67) : IccA IccB A B U Division - Name - Date - Language I 21 TRANSFORMER PROTECTION Phase directional overcurrent (cont'd) (67) : „ Fault in A : IccA IsA Relais U13 I3 U21 I1 IccA I2 U32 Division - Name - Date - Language 22 TRANSFORMER PROTECTION Phase directional overcurrent (cont'd) (67) : „ Fault in B : IsB IccB Relais I2 U13 U21 I1 IccB I3 U32 Division - Name - Date - Language 23 TRANSFORMER PROTECTION Phase directional overcurrent (cont'd) (67) : „ Measurement of the phase shift angle between a reference voltage, called the polarization voltage, and a current makes it possible to determine the current direction „ In practice: • polarization by phase-to-phase voltage • measurement of ϕ1= phase shift (U32,I1), ϕ2= phase shift (U13,I2) and ϕ3 = phase shift (U21,I3) I1 ( for ϕ = 0 ) U 21 V1 V1 90° polarising voltage V3 V3 polarising voltage Division - Name - Date - Language V2 90° U 32 V2 I3 ( for ϕ = 0 ) 24 TRANSFORMER PROTECTION Phase directional overcurrent (cont'd) (67) : „ Conventions : I1 ϕ1 ϕ1 = phase shift (U32,I1) varies according to the impedance of the circuit under consideration „ Conventional current direction: • Normal direction = from busbar to cable • Inverse direction = from cable to busbar Conventional CT wiring: normal direction inverse direction I1 in normal direction ϕ1 U32 „ I1 I1 in inverse direction Division - Name - Date - Language „ I I 25 TRANSFORMER PROTECTION Phase directional overcurrent (cont'd) (67) : „ Characteristic angle θ : „ Division of a current vectorial plane into 2 half-planes: • normal zone • inverse zone „ Characteristic angle θ = angle between the perpendicular at the zone limit - characteristic line and the polarization voltage „ Setting values of θ : • 30° if high reactance circuit ( ϕ1minimum) • 45° average case • 60° if high resistance circuit ( ϕ1 maximum) Normal zone θ Inverse zone Division - Name - Date - Language U32 26 TRANSFORMER PROTECTION Phase directional overcurrent (cont'd) (67) : „ Principle : I1 „ Association of 2 functions: • phase overcurrent protection function adjustable setting Is Definite or IDMT time • detection of the current direction characteristic angle θ „ Two-phase protection • I1 and ϕ1 (phase shift U32,I1) • I2 and ϕ2 (phase shift U13,I2) • I3 and ϕ3 (phase shift U21,I3) „ Protection operational if: polarization voltage > 1.5%Un ϕ1 θ=45° U32 Is Phase overcurrent Direction detection in normal direction Directional protection function tripping zone Division - Name - Date - Language 27 TRANSFORMER PROTECTION Directional earth fault (67N) : IscA IscB A B Vrsd Division - Name - Date - Language Irsd 28 TRANSFORMER PROTECTION Directional earth fault (67N) (cont'd): V2 ϕ0A Fault at A N Vrsd V1 IrsdA V3 Normal direction & & V rsd = − 3 × V 1 & & & where V 1 = Z N × I rsd & & & V rsd = − 3 Z N × I rsd ⇒ Division - Name - Date - Language 29 TRANSFORMER PROTECTION Directional earth fault (67N) (cont'd): IrsdB V2 Fault at B ϕ0B N V1 Vrsd Reverse direction V3 & & V rsd = − 3 × V 1 & & & where V 1 = Z N × I rsd & & & V rsd = − 3 Z N × I rsd ⇒ Division - Name - Date - Language 30 TRANSFORMER PROTECTION Directional earth fault (67N) (cont'd): „ Measurement of the phase shift angle between the residual voltage called the polarization voltage - and the earth fault current makes it possible to determine the direction V2 IrsdB ϕ0B N ϕ0A Vrsd V1 IrsdA Division - Name - Date - Language V3 31 TRANSFORMER PROTECTION Directional earth fault (67N) (cont'd): „ Division of a current vectorial plane into 2 half-planes: • normal zone • inverse zone „ Characteristic angle θ0 = angle between the perpendicular at the zone limit - characteristic line - and the polarization voltage „ Typical values of θ0: • 0° if N earthed by resistance • 15°, 30°, 45°, 60°: intermediate values • 90° if isolated neutral (Irsd=Icapa) • -45° if N earthed by reactance Inverse zone θ0 Vrsd Normal zone Division - Name - Date - Language 32 TRANSFORMER PROTECTION Directional earth fault (67N) (cont'd): inverse zone ϕ0 Is0 „ Association of 2 functions: • earth fault protection function adjustable setting Is0 Definite time • detection of the current direction characteristic angle θ0 „ Plane single-pole protection • Ip : projection of Irsd on the characteristic line • ϕ0: phase shift (Vrsd,Irsd) „ Protection operational if: polarization voltage >= 2.6% Un θ0=45° Vrsd Ip normal zone Irsd Earth fault Direction detection in normal direction Directional protection function tripping zone Division - Name - Date - Language 33 TRANSFORMER PROTECTION Directional earth fault (67N) (cont'd): COMPENSATED NEUTRAL SYSTEM : „ Petersen coil + resistor: • designed to compensate capacitive currents => Irsd is highly resistive => characteristic angle not adjustable: θ0 = 0° • self-extinguishing earth fault => short, recurring faults => protection memory time adjustable Tmem ~ 250 ms • in practice, the system is slightly dissymmetrical and the residual voltage is not zero when there is no fault => Vs0 setting adjustable Division - Name - Date - Language 34 TRANSFORMER PROTECTION „ Tank earth leakage : • If the transformer is not protected by a restricted earth fault differential protection (64REF), and if the transformer tank is isolated from the earth, a tank earth leakage protection is required 51 ? Transformer incomer Busbar Division - Name - Date - Language 35 TRANSFORMER PROTECTION „ Restricted earth fault (64REF) : • If the protection 64 REF is required • or if the transformer has a power rating of more or equal than 5 MVA the protection 64 REF is required on transformer incomer. • It offers the advantage of having greater sensitivity than differential protection (5% of In) 64 REF ? Transformer incomer Busbar Division - Name - Date - Language 36 TRANSFORMER PROTECTION „ Undervoltage (27) : Sepam Sepam Sepam Sepam Division - Name - Date - Language 37 TRANSFORMER PROTECTION Undervoltage (27) : coordination with overcurrent protection „ Undervoltage protection t „ Overcurrent protection t 27 51 T T Us Division - Name - Date - Language Un U In Is Isc I 38 TRANSFORMER PROTECTION „ Overvoltage (59) : Sepam Sepam Sepam Sepam Division - Name - Date - Language 39 TRANSFORMER PROTECTION „ Remanent undervoltage (27R) : • If the transformer supplies power to machines that should not be energized until the voltage, maintained by the machines after the opening of the circuit by an automatic changeover device, drops below a given value. Division - Name - Date - Language 40 TRANSFORMER PROTECTION „ Differential protection (87T) : • Protection of HV/MV, MV/MV and MV/LV transformers • Protection of 2-winding transformers • Protection of 3-winding transformers • Protection of auto-transformers • Protection of generator-transformer units Division - Name - Date - Language 41 TRANSFORMER PROTECTION „ Biased characteristic • Id/It adjustable between 15 and 50% It Id „ 2nd harmonic restraint for : • a high stability on transformer inrush • a high stability on external fault • a secure tripping action on internal faults Id It & „ 5th harmonic restraint for : • a high stability during over-excitation of the transformer Restraint Ih2 Ih5 Division - Name - Date - Language 42 TRANSFORMER PROTECTION Restraint function is performed by neural network : „ 4 inputs „ A multitude of thresholds, factory set IdH 2 IdH 1 IdH 5 IdH 1 IdH 1 It H 1 For the best compromise between sensitivity and stability Division - Name - Date - Language 43 TRANSFORMER PROTECTION Artificial neural network: What’s the benefit ? idh2 idh2 Disable trip Disable trip Enable trip Enable trip idh5 Classical harmonic restraint regardless id and it idh5 Neural network harmonic restraint for one couple of id and it „ Neural network adapt the harmonic restraint to the level of differential and through current Division - Name - Date - Language 44 TRANSFORMER PROTECTION S2000D is sensitive and stable in rated conditions ... Id : differential current 24 „ Comparison of the tripping characteristics of : Sepam 2000 D, with neural network differential protection Conventional differential protection 12 „ For the same Id/It setting 0 Division - Name - Date - Language 12 24 It : through current „ In rated conditions : low 2nd and 5th harmonic ratios 45 TRANSFORMER PROTECTION S2000D is sensitive and stable … during transformer inrush Id : differential current 24 „ Comparison of the tripping characteristics of : Sepam 2000 D, with neural network differential protection Conventional differential protection 12 „ For the same Id/It setting 0 Division - Name - Date - Language 12 It : through current 24 „ On transformer inrush, with a 2nd harmonic ratio of 100% 46 TRANSFORMER PROTECTION Innovation to make easier customer’s life: Only one setting ??? „ For a conventional differential protection : Settings : I-DIFF> (0.15 - 2.00) SLOPE 1 (0.10 - 0.50) BASE PT 2 (0.0 - 10.0) SLOPE 2 (0.25 - 0.95) I-DIFF>> (0.15 - 2.00) 2nd HARMON (on - off) 2nd HARMON (10 -80%) CROSSB 2HM (0 - 1000 periods) n. HARMON (5th 4th 3rd) n. HARMON (10 - 80%) CROSSB nHM (0 - 1000 periods) IDIFFmax n (0.5 - 20.0) T-SAT-BLO (2 - 250 periods) SAT-RESTR (5.00 - 15.00) T-DELAY> (0.00 - 60.00s) T-DELAY>> (0.00 - 60.00s) T-RESET (0.00 - 60.00s) „ For Sepam 2000 D21/D22/D31 : - Slope of the percentage characteristic Division - Name - Date - Language 47 TRANSFORMER PROTECTION Simplified choice of sensors „ For a conventional differential protection current sensors specified according to BS142, with : Vk = (Rtc + Rf). Isat,  3  −1,τ7.T  Isat ≥ ( Id>> ) . −0,5.T  +ω τ 1−e  2   τ   1+e 1 et „ For Sepam 2000 D21/D22/D31 : 5P20 No interposing CT’s Division - Name - Date - Language 48 BUSBAR PROTECTION BUSBAR PROTECTION „ „ „ „ „ Division - Name - Date - Language Logic discrimination 87 : High impedance differential relay 87 : Percentage differential relay 81R : Rate Of Change Of Frequency 25 : Synchro-check 2 BUSBAR PROTECTION „ Logic discrimination : Source 0.1 s 0.7 s Division - Name - Date - Language 1s Fault on busbar eliminated after 0.1 s without adding any other protection 0.7 s 3 BUSBAR PROTECTION „ Logic discrimination : Overcurrent (inst) ≥1 0 t Earth fault (inst) Output O14 : BI transmision Inhibition of BI transmision if fault not cleared & T3 = 0.2s Overcurrent (time) ≥1 ≥1 Earth fault (time) tripping Overcurrent (logic) ≥1 & Earth fault (logic) Input I12 : BI receipt Division - Name - Date - Language 4 BUSBAR PROTECTION „ High impedance differential protection (87) : Source 1s 0.7 s 0.7 s Differential relay Division - Name - Date - Language 5 BUSBAR PROTECTION „ High impedance differential protection (87) (cont'd) : 3 incomers ∆I 7 feeders No busbar coupling Division - Name - Date - Language DATA „ Max. 3-phase Isc = 30 kA „ Sensors: • 10 CTs in parallel per phase • In/in: 2000 A / 5 A • RCT = 1.76 Ω • iµ = 20 mA for V=160 V • Iscs = 30000x5/2000 = 75A „ Wiring: • L = 2x15 m max. • S = 2.5 mm² Cu „ Setting: Is = 0.5In „ Surge limiter: iRN = 4 mA 6 BUSBAR PROTECTION „ High impedance differential protection (87) (cont'd) : „ Wiring resistance: RW = 0.0225× „ „ iscs VK < Rs ≤ is 2is 75 320 (1.76 + 0.27) × < Rs ≤ 0.5 × 5 2 × 0.5 × 5 61 < Rs ≤ 64 ⇒ Rs = 64Ω 30 = 0.27Ω 2.5 (RCT + RW) CT knee-point voltage: VK ≥ 2(RCT + RW)iscs 5 VK ≥ 2 × (1.76 + 0.27) × 30000 × = 304V 2000 ⇒ VK = 320 V Stabilizing resistance: „ Surge limiter: Vpk = 2 2VKRsiscs Vpk = 2 2 × 320 × 64 × 75 = 3500V Vpk > 3kV ⇒ surge limiter required Division - Name - Date - Language 7 BUSBAR PROTECTION „ High impedance differential protection (87) (cont'd) : „ Number of limiter units: N≥ „ iscs 75 = = 1.9 ⇒ N = 2 40 40 Total limiter unit leakage current: i RN = 4 N = 8 mA „ „ Minimum primary current detected: 2000 (iset +10iµ + iRN) 5 2000 (2.5 +10× 0.02+ 0.008) Id = 5 ⇒ Id = 1083A Id = Magnetizing current of a CT at Rs.Is: Rs.iset = 64× 2.5 = 160V ⇒ iµ = 20 mA Division - Name - Date - Language 8 BUSBAR PROTECTION „ Percentage differential protection (87) : • Avantages : – Low impedance differential protection – CT ratios can be different – Low cost solution Sepam D31 can be use to protect a busbar Division - Name - Date - Language 9 BUSBAR PROTECTION „ Percentage differential protection (87) (cont'd) : • 1 incomer, 1 bus tie, several feeders 2,5 Incomer Bus tie sepam D31 S S ≥ InCTs ≥ 0,1 3.Un 3.Un S = 3 × Un × Ids / 0.3 Un : Busbar rated voltage Sizing of CTs : IsatCTs ≥ 2.Isc and IsatCTs ≥ 20 InCTs Feeders without generator Same ratio for the three feeder CTs Isc : Maximum external short circuit current InCTs : Rated current of CTs Ids = 1.3 x maximum incomer (or feeder) rated current Division - Name - Date - Language 10 BUSBAR PROTECTION „ Percentage differential protection (87) (cont'd) : • 1 incomer, 2 feeders Incomer sepam D31 Feeders with or without generator Division - Name - Date - Language 11 BUSBAR PROTECTION „ Percentage differential protection (87) (cont'd) : • 2 incomers, several feeders Incomer Incomer sepam D31 Feeders without generator Division - Name - Date - Language 12 BUSBAR PROTECTION „ Percentage differential protection (87) (cont'd) : • example : Setting of the relay : S = 31.5 MVA In = In' = In" = 2500 A In = 1730 A Un = Un' = Un" = 10.5 kV phase shift = 0 Icc = 14 kA Sensitivity : Ids = 1.3 x 1730 = 2249 A 2500/5 Bus tie 2500/5 2500/5 2500/5 M 2500/5 M Icc = 4.8 kA (motor supply) P = 12.5 MW cos Phi = 0.9 S = 14.2 MVA Division - Name - Date - Language sepam D31 S= 3 × Un × Ids = 136 MVA 0.3 Slope : Id/It = 15% 0.4 ≤ S ≤ 10 3 × Un × In S = 2.99 3 × Un × In 13 BUSBAR PROTECTION „ Rate Of Change Of Frequency protection (81R) : • Loss of main application • Load shedding application • Complement to underfrequency (81L) and overfrequency (81H) protections • ROCOF measurement based on positive sequence voltage f Underfrequency protection (81L) t2 = fmin f − f min + timesetting df / dt Time setting t t1 Division - Name - Date - Language t2 14 BUSBAR PROTECTION „ Rate Of Change Of Frequency protection (81R) (cont'd) : Low set point : 1 Tripping time (s) Underrfrequency protection : df / dt = Fs ≤ 49.5 Hz T = 0.1 s 0.8 ∆P × Fn 2 × Sn × H ROCOF protection J ×ω 2 H= 2 × Sn High set point 0.4 Fn : Rated frequency H : Inertia constant Low set point 0.6 Sn : Rated power J : Inertia moment ω : machine speed (rd/s) 0 0 1 2 3 4 5 df/dt (Hz/s) Division - Name - Date - Language 15 BUSBAR PROTECTION „ Rate Of Change Of Frequency protection (81R) (cont'd) : • Typical inertia constant value : 0.5 ≤ H ≤ 1.5 for diesel and low rated generators (≤ 2 MVA) 2 ≤ H ≤ 5 for gas turbine and medium rated generators (≤ 40 MVA) • Low set point : – df/dt ≈ 0.2 Hz T ≈ 0.3 - 0.5 s – Disturbances such as fault, load variation... causes frequency swing • High set point : – df/dt ≈ 1 Hz T ≈ 0.15 s – To provide faster tripping than the frequency protection Division - Name - Date - Language 16 BUSBAR PROTECTION „ Synchro-check (25) : • dUs set point : can depend on power transit • dFs set point :depends only on accuracy • dPhi set point :can depend on power transit • Us high : to detect presence of voltage • Us low : to detect absence of voltage • Time Ta : to take into account of the circuit breaker closing time Division - Name - Date - Language 17 BUSBAR PROTECTION „ Synchro-check (25) (cont'd) : ∆ϕ + 360 × ∆F × Ta < dPhis Usynch 1 Usynch 2 U>Us high Synchro check ∆F < dFs & U>Us high U>Us high ∆U < dUs U>Us high Division - Name - Date - Language 18 BUSBAR PROTECTION „ Synchro-check (25) (cont'd) : • 4 operating modes : Mode 2 Mode 1 Usynch 1 Usynch 2 Usynch 1 Usynch 2 Mode 3 Mode 4 OR Usynch 1 Division - Name - Date - Language Usynch 2 Usynch 1 AND Usynch 2 19 SUBSTATION PROTECTION SUBSTATION PROTECTION „ „ „ „ „ „ „ „ „ „ „ „ Division - Name - Date - Language Logic discrimination 50:51 : Phase overcurrent 50N/51N : earth fault 46 : Negative sequence / unbalance 27 : Undervoltage 27R : Remanent undervoltage 59 : Overvoltage 59N : Residual overvoltage 67 : Phase directional overcurrent 67N : Directional earth fault 32P : Reverse real power 81R : Rate Of Change Of Frequency 2 SUBSTATION PROTECTION „ Logic discrimination : Source 0.1 s 0.7 s Division - Name - Date - Language 1s Fault on busbar eliminated after 0.1 s without adding any other protection 0.7 s 3 SUBSTATION PROTECTION „ Logic discrimination : Overcurrent (inst) ≥1 0 t Earth fault (inst) Output O14 : BI transmision Inhibition of BI transmision if fault not cleared & T3 = 0.2s Overcurrent (time) ≥1 ≥1 Earth fault (time) tripping Overcurrent (logic) ≥1 & Earth fault (logic) Input I12 : BI receipt Division - Name - Date - Language 4 SUBSTATION PROTECTION „ Overcurrent (50/51) : • DT and IDMT curves Transient overreach = (Iso - Is1) / Is1 Iso = setting current, that is, r.m.s. value of steady state current required to operate the relay Is1 = steady state r.m.s. value of the fault current which when fully offset will just operate the relay Division - Name - Date - Language 5 SUBSTATION PROTECTION „ Overcurrent (50/51) : • Current shape in case of saturation of CT: I ct Peak value Right value Fundamental value t Low value of fundamental current ⇒ risk of no detection of the fault ⇒ measurement of peak value Division - Name - Date - Language 6 SUBSTATION PROTECTION „ Overcurrent (50/51) : • Current shape in case of no saturation of CT : I ct Peak value Filtered peak value t Transient overreach can be very high if only the peak value is considered ⇒ peak value is filtered (no DC component) Division - Name - Date - Language 7 SUBSTATION PROTECTION „ Overcurrent (50/51) : • Conclusion : • Filtered peak detection is used to ensure tripping in case of CT saturation • Efficace value avoids the risk of unexpected tripping SEPAM MIX THE TWO MEASUREMENTS TO GUARANTEE A GOOD TRANSIENT OVERREACH (LESS THAN 10% FOR ANY TIME CONSTANT) Division - Name - Date - Language 8 SUBSTATION PROTECTION „ Earth fault (50N/51N) : Harmonic 2 restrain An earth fault current (including harmonic 2) could appear in case of CT saturation if earth fault is measured by means of the sum of 3 TC. Division - Name - Date - Language 9 SUBSTATION PROTECTION „ Undervoltage (27) : Sepam Sepam Sepam Sepam Division - Name - Date - Language 10 SUBSTATION PROTECTION Undervoltage (27) : coordination with overcurrent protection „ Undervoltage protection t „ Overcurrent protection t 27 51 T T Us Division - Name - Date - Language Un U In Is Isc I 11 SUBSTATION PROTECTION „ Remanent undervoltage (27R) : • If the feeder supplies power to machines that should not be energized until the voltage, maintained by the machines after the opening of the circuit by an automatic changeover device, drops below a given value. Division - Name - Date - Language 12 SUBSTATION PROTECTION „ Overvoltage (59) : Sepam Sepam Sepam Sepam Division - Name - Date - Language 13 SUBSTATION PROTECTION „ Residual overvoltage (59N) : • For isolated neutral 59N protection is required to detect earth fault before closing the circuit breaker • This function can be located elsewhere in the network (on busbar for example) Division - Name - Date - Language 14 SUBSTATION PROTECTION „ Phase directional overcurrent (67) : • Necessary to have horizontal discrimination in case of several power supplies operating in parallel 1st power supply 2nd power supply 67 51 67 trip No trip 51 Busbar ddd d Division - Name - Date - Language 15 SUBSTATION PROTECTION Phase directional overcurrent (67) : IccA IccB A B U Division - Name - Date - Language I 16 SUBSTATION PROTECTION Phase directional overcurrent (cont'd) (67) : „ Fault in A : IccA IsA Relais U13 I3 U21 I1 IccA I2 U32 Division - Name - Date - Language 17 SUBSTATION PROTECTION Phase directional overcurrent (cont'd) (67) : „ Fault in B : IsB IccB Relais I2 U13 U21 I1 IccB I3 U32 Division - Name - Date - Language 18 SUBSTATION PROTECTION Phase directional overcurrent (cont'd) (67) : „ Measurement of the phase shift angle between a reference voltage, called the polarization voltage, and a current makes it possible to determine the current direction „ In practice: • polarization by phase-to-phase voltage • measurement of ϕ1= phase shift (U32,I1), ϕ2= phase shift (U13,I2) and ϕ3 = phase shift (U21,I3) I1 ( for ϕ = 0 ) U 21 V1 V1 90° polarising voltage V3 V3 polarising voltage Division - Name - Date - Language V2 90° U 32 V2 I3 ( for ϕ = 0 ) 19 SUBSTATION PROTECTION Phase directional overcurrent (cont'd) (67) : „ Conventions : I1 ϕ1 ϕ1 = phase shift (U32,I1) varies according to the impedance of the circuit under consideration „ Conventional current direction: • Normal direction = from busbar to cable • Inverse direction = from cable to busbar Conventional CT wiring: normal direction inverse direction I1 in normal direction ϕ1 U32 „ I1 I1 in inverse direction Division - Name - Date - Language „ I I 20 SUBSTATION PROTECTION Phase directional overcurrent (cont'd) (67) : „ Characteristic angle θ : „ Division of a current vectorial plane into 2 half-planes: • normal zone • inverse zone „ Characteristic angle θ = angle between the perpendicular at the zone limit - characteristic line and the polarization voltage „ Setting values of θ : • 30° if high reactance circuit ( ϕ1minimum) • 45° average case • 60° if high resistance circuit ( ϕ1 maximum) Normal zone θ Inverse zone Division - Name - Date - Language U32 21 SUBSTATION PROTECTION Phase directional overcurrent (cont'd) (67) : „ Principle : I1 „ Association of 2 functions: • phase overcurrent protection function adjustable setting Is Definite or IDMT time • detection of the current direction characteristic angle θ „ Three-phase protection • I1 and ϕ1 (phase shift U32,I1) • I2 and ϕ2 (phase shift U13,I2) • I3 and ϕ3 (phase shift U21,I3) „ Protection operational if: polarization voltage > 1.5%Un ϕ1 θ=45° U32 Is Phase overcurrent Direction detection in normal direction Directional protection function tripping zone Division - Name - Date - Language 22 SUBSTATION PROTECTION „ Directional earth fault (67N) : • Necessary to have horizontal discrimination in case of several earthing systems operating in parallel 1st earthing system 67N 51 2nd earthing system 67N trip No trip 51 Busbar Division - Name - Date - Language 23 SUBSTATION PROTECTION „ Directional earth fault (67N) : • Necessary to have horizontal discrimination in case of several feeders with high capacitive current comparing with maximum earthing fault current Busbar 67N trip Division - Name - Date - Language 67N No trip 24 SUBSTATION PROTECTION Directional earth fault (67N) : IscA IscB A B Vrsd Division - Name - Date - Language Irsd 25 SUBSTATION PROTECTION Directional earth fault (67N) (cont'd): V2 ϕ0A Fault at A N Vrsd V1 IrsdA V3 Normal direction & & V rsd = − 3 × V 1 & & & where V 1 = Z N × I rsd & & & V rsd = − 3 Z N × I rsd ⇒ Division - Name - Date - Language 26 SUBSTATION PROTECTION Directional earth fault (67N) (cont'd): IrsdB V2 Fault at B ϕ0B N V1 Vrsd Reverse direction V3 & & V rsd = − 3 × V 1 & & & where V 1 = Z N × I rsd & & & V rsd = − 3 Z N × I rsd ⇒ Division - Name - Date - Language 27 SUBSTATION PROTECTION Directional earth fault (67N) (cont'd): „ Measurement of the phase shift angle between the residual voltage called the polarization voltage - and the earth fault current makes it possible to determine the direction V2 IrsdB ϕ0B N ϕ0A Vrsd V1 IrsdA Division - Name - Date - Language V3 28 SUBSTATION PROTECTION Directional earth fault (67N) (cont'd): „ Division of a current vectorial plane into 2 half-planes: • normal zone • inverse zone „ Characteristic angle θ0 = angle between the perpendicular at the zone limit - characteristic line - and the polarization voltage „ Typical values of θ0: • 0° if N earthed by resistance • 15°, 30°, 45°, 60°: intermediate values • 90° if isolated neutral (Irsd=Icapa) • -45° if N earthed by reactance Inverse zone θ0 Vrsd Normal zone Division - Name - Date - Language 29 SUBSTATION PROTECTION Directional earth fault (67N) (cont'd): inverse zone ϕ0 Is0 „ Association of 2 functions: • earth fault protection function adjustable setting Is0 Definite time • detection of the current direction characteristic angle θ0 „ Plane single-pole protection • Ip : projection of Irsd on the characteristic line • ϕ0: phase shift (Vrsd,Irsd) „ Protection operational if: polarization voltage >= 2.6% Un θ0=45° Vrsd Ip normal zone Irsd Earth fault Direction detection in normal direction Directional protection function tripping zone Division - Name - Date - Language 30 SUBSTATION PROTECTION Directional earth fault (67N) (cont'd): COMPENSATED NEUTRAL SYSTEM : „ Petersen coil + resistor: • designed to compensate capacitive currents => Irsd is highly resistive => characteristic angle not adjustable: θ0 = 0° • self-extinguishing earth fault => short, recurring faults => protection memory time adjustable Tmem ~ 250 ms • in practice, the system is slightly dissymmetrical and the residual voltage is not zero when there is no fault => Vs0 setting adjustable Division - Name - Date - Language 31 SUBSTATION PROTECTION „ Rate Of Change Of Frequency protection (81R) : • Loss of main application • Load shedding application • Complement to underfrequency (81L) and overfrequency (81H) protections • ROCOF measurement based on positive sequence voltage f Underfrequency protection (81L) t2 = fmin f − f min + timesetting df / dt Time setting t t1 Division - Name - Date - Language t2 32 SUBSTATION PROTECTION „ Rate Of Change Of Frequency protection (81R) (cont'd) : Low set point : 1 Tripping time (s) Underrfrequency protection : df / dt = Fs ≤ 49.5 Hz T = 0.1 s 0.8 ∆P × Fn 2 × Sn × H ROCOF protection J ×ω 2 H= 2 × Sn High set point 0.4 Fn : Rated frequency H : Inertia constant Low set point 0.6 Sn : Rated power J : Inertia moment ω : machine speed (rd/s) 0 0 1 2 3 4 5 df/dt (Hz/s) Division - Name - Date - Language 33 SUBSTATION PROTECTION „ Rate Of Change Of Frequency protection (81R) (cont'd) : • Typical inertia constant value : 0.5 ≤ H ≤ 1.5 for diesel and low rated generators (≤ 2 MVA) 2 ≤ H ≤ 5 for gas turbine and medium rated generators (≤ 40 MVA) • Low set point : – df/dt ≈ 0.2 Hz T ≈ 0.3 - 0.5 s – Disturbances such as fault, load variation... causes frequency swing • High set point : – df/dt ≈ 1 Hz T ≈ 0.15 s – To provide faster tripping than the frequency protection Division - Name - Date - Language 34 RING NETWORK PROTECTION OPEN RING NETWORK PROTECTION source 51 51 substation substation Fault detector fault open substation Division - Name - Date - Language 2 CLOSED RING NETWORK PROTECTION source 51 Division - Name - Date - Language &67 substation ↑67 substation ↓67 ↑67 %67 ↑67 fault %67 ↓67 ↓67 &67 ↑67 substation ↓67 51 3 CAPACITOR PROTECTION CAPACITOR PROTECTION „ Logic discrimination „ 49 : Thermal overload „ 51 : Unbalance overcurrent protection Division - Name - Date - Language 2 CAPACITOR PROTECTION „ Logic discrimination : Source 0.1 s 0.7 s 1s Fault on busbar eliminated after 0.1 s without adding any other protection 0.7 s Capacitor bank Division - Name - Date - Language 3 CAPACITOR PROTECTION „ Logic discrimination : Output O14 : BI transmision Inhibition of BI transmision if fault not cleared Overcurrent (inst) ≥1 Earth fault (inst) t 0 & T3 = 0.2s Overcurrent (time) ≥1 tripping Earth fault (time) Division - Name - Date - Language 4 CAPACITOR PROTECTION „ Thermal overload (49) : • Heat rise calculation : 2 dE  Ieq  T× +E =  dT Ib   Ieq 2 = I 2 + K × Ii 2 • I is the greatest value of I1, I2, I3 (at 50 Hz) and I1rms • Ii is the negative sequence current 2 2 t   Ieq   − T  Ieq  E =  Eo −   ×e +  Ib Ib       • Eo : initial heat rise Division - Name - Date - Language 5 CAPACITOR PROTECTION „ Thermal overload (49) (cont'd) : E 2 2 t   Ieq   − T  Ieq  E =  Eo −   ×e +  Ib Ib       (Ieq/Ib)² Eo (Ieq/Ib)² Eo (Ieq/Ib)² Eo T T T t Division - Name - Date - Language 6 CAPACITOR PROTECTION „ Unbalance overcurrent protection (51N) : • To detect if some elements of the capacitor are damaged 51N Division - Name - Date - Language 7 MOTOR PROTECTION ASYNCHRONOUS MOTOR PROTECTION „ Generalities : • Main characteristics • Protection by circuit breaker • Protection by fuse • Logic discrimination Division - Name - Date - Language „ Protection functions : • • • • • • • • • • • • • • 49 : thermal overload 50/51 : phase overcurrent 50N/51N : earth fault protection 46 : negative phase unbalanced protection 48/51LR : excessive starting time and locked rotor 37 : phase undercurrent 66 : starts per hour 27D : positive sequence undervoltage 47 : phase rotation direction check 67N : directional earth fault 32P : real overpower 32Q/40 : reactive overpower/field loss 38/49T : temperature monitoring 87M : motor differential 2 ASYNCHRONOUS MOTOR PROTECTION „ MAIN CHARACTERISTICS : Starting current = k1/Un Motor torque = k2.U²n Resistive torque 0 Division - Name - Date - Language 1 Slip 3 ASYNCHRONOUS MOTOR PROTECTION „ Circuit breaker and definite time t (s) 100 cable switching device, busbar CT, relay Stator 49 10 Rotor 48 1 starting 51LR 51 0.1 reacceleration 0.01 1 10 Id Division - Name - Date - Language Isc min 100 Isc max I (A) 4 ASYNCHRONOUS MOTOR PROTECTION „ Contactor and fuses t (s) 100 cable switching device, busbar CT, relay Stator 49 10 Rotor 48 1 starting 51LR BC Switch 0.1 reacceleration 0.01 1 10 Id Division - Name - Date - Language Isc min 100 Isc max I (A) 5 ASYNCHRONOUS MOTOR PROTECTION „ Logic discrimination : Source 0.1 s 0.7 s 1s Fault on busbar eliminated after 0.1 s without adding any other protection 0.7 s Motor Division - Name - Date - Language 6 ASYNCHRONOUS MOTOR PROTECTION „ Logic discrimination : Output O14 : BI transmision Inhibition of BI transmision if fault not cleared Overcurrent (inst) ≥1 Earth fault (inst) t 0 & T3 = 0.2s Overcurrent (time) ≥1 tripping Earth fault (time) Division - Name - Date - Language 7 ASYNCHRONOUS MOTOR PROTECTION „ Overcurrent (50/51) : • I setting ≈ 1.2 x I starting • Time setting ≈ 0.1 s • DT and IDMT curves Transient overreach = (Iso - Is1) / Is1 Iso = setting current, that is, r.m.s. value of steady state current required to operate the relay Is1 = steady state r.m.s. value of the fault current which when fully offset will just operate the relay Division - Name - Date - Language 8 ASYNCHRONOUS MOTOR PROTECTION „ Overcurrent (50/51) : • Current shape in case of saturation of CT: I ct Peak value Right value Fundamental value t Low value of fundamental current ⇒ risk of no detection of the fault ⇒ measurement of peak value Division - Name - Date - Language 9 ASYNCHRONOUS MOTOR PROTECTION „ Overcurrent (50/51) : • Current shape in case of no saturation of CT : I ct Peak value Filtered peak value t Transient overreach can be very high if only the peak value is considered ⇒ peak value is filtered (no DC component) Division - Name - Date - Language 10 ASYNCHRONOUS MOTOR PROTECTION „ Overcurrent (50/51) : • Conclusion : • Filtered peak detection is used to ensure tripping in case of CT saturation • Efficace value avoids the risk of unexpected tripping SEPAM MIX THE TWO MEASUREMENTS TO GUARANTEE A GOOD TRANSIENT OVERREACH (LESS THAN 10% FOR ANY TIME CONSTANT) Division - Name - Date - Language 11 ASYNCHRONOUS MOTOR PROTECTION „ Earth fault (50N/51N) : Harmonic 2 restrain An earth fault current (including harmonic 2) could appear in case of CT saturation if earth fault is measured by means of the sum of 3 TC. Division - Name - Date - Language 12 ASYNCHRONOUS MOTOR PROTECTION „ Thermal overload (49) : • Heat rise calculation : 2 dE  Ieq  +E = T×  dT Ib   Ieq 2 = I 2 + K × Ii 2 • I is the greatest value of I1, I2, I3 (at 50 Hz) and I1rms • Ii is the negative sequence current 2 2 t   Ieq   − T  Ieq  E =  Eo −   ×e +  Ib Ib       • Eo : initial heat rise Division - Name - Date - Language 13 ASYNCHRONOUS MOTOR PROTECTION „ Thermal overload (49) (cont'd) : • Operation E 2 2 t   Ieq   − T  Ieq  E =  Eo −   ×e +  Ib Ib       (Ieq/Ib)² Eo (Ieq/Ib)² Eo (Ieq/Ib)² Eo T T T t Division - Name - Date - Language 14 ASYNCHRONOUS MOTOR PROTECTION t „ Thermal overload (49) (cont'd) : Thermal overload function is used to protect the motor against too high requested active power that is to say if the power of the load increases. Cold curve : Eo = 0 Hot curve : Eo = 100% Ieq² = I ² + K × Ii ² 2 100 10 Cold curve 1 0.1  Ieq    Ib   t = T × Log 2  Ieq   − Es 2   Ib  Ii = current negative sequence Es2 = thermal setting point in % 2 Hot curve  Ieq   −1  Ib   t = T × Log 2  Ieq   − Es 2   Ib  T = heat rise (T1) or cooling (T2) time constant Ieq/Ib Division - Name - Date - Language 15 ASYNCHRONOUS MOTOR PROTECTION „ Thermal overload (49) (cont'd) : A K factor is used to take into account of the negative sequence current which induce high power losses in the rotor (because of the double frequency rotating current) Cd × K = 2× Cn 1  Id  g ×   Ib  2 −1 Cd, Cn = rated and starting torque Ib, Id = rated and starting current g = pole slipping The T1 and T2 time constants are global constants for the machine and are higher than the rotor time constant. Division - Name - Date - Language 16 ASYNCHRONOUS MOTOR PROTECTION „ Thermal overload (49) (cont'd) : • Two groups of parameters are available to take into account of thermal withstand with locked rotor • Switching from one mode to the other when the current is greater than an adjustable set point Is • Accounting for ambient temperature when the temperature measured exceeds 40° • Initial heat rise Eso can be use to reduce the cold tripping time 2  Ieq    − Eso Ib   t = T × Log 2  Ieq    − Es 2  Ib  Division - Name - Date - Language 17 ASYNCHRONOUS MOTOR PROTECTION „ Number of starts (66): This function is used to protect the rotor of the motor during starting operation. Note that the starting current remains constant and equal to the standstill current for the whole of the starting period. We can consider there is no/a little thermal exchange between rotor and stator during this period. So, there is no relation with the heating time constant of the machine and the limitation of the number of starts (cold, warm and per hour) Is Division - Name - Date - Language 18 ASYNCHRONOUS MOTOR PROTECTION „ Number of starts (66) (cont'd) : • How to set the hot point Es1? We can consider the hot state point Es1 corresponds at nominal operation of the motor during a sufficient time. That's to say we advise to set Es1 from 60% to 75%. This setting is only used to define cold state and hot state for the repeated starts function. Division - Name - Date - Language 19 ASYNCHRONOUS MOTOR PROTECTION „ Number of starts (66) (cont'd) : 1 starts 2 3 4 5 Detection of 5 starts per hour Detection of 3 consecutive starts Time (minutes) 12=60/5 (time interval for consecutive starts) 12=60/5 (time interval for consecutive starts) 60 (shifting window) Consecutive starts are counted over an interval of 60/Nstarts, i.e. 12 minutes Division - Name - Date - Language 20 ASYNCHRONOUS MOTOR PROTECTION „ Excessive starting time (48) and locked rotor (51LR) : Analog explanation as for number of starts i.e thermal overload is a global protection for steady state operation. Rotor losses increase a lot during locked rotor period and if there is a too long starting time. Current setting ≈ Starting current/2 Starting time setting ≈ starting time + several seconds Locked rotor tripping time ≈ 0;5 to 1 second Division - Name - Date - Language 21 ASYNCHRONOUS MOTOR PROTECTION „ Excessive starting time (48) and locked rotor (51LR) (cont'd) : t Stator thermal withstand 1 st 49 cold hot Rotor thermal withstand 48 Starting current 51LR cold hot 2 nd 49 51 I/Ib No discrimination between rotor thermal withstand and 48 function. Only 2nd 49 function can be used Division - Name - Date - Language 22 ASYNCHRONOUS MOTOR PROTECTION „ Excessive starting time (48) and locked rotor (51LR) (cont'd) : • Reacceleration : During reacceleration, the motor absorbs current that is similar to starting current without the current having previously dropped to a value less than 5% of Ib*. A logic data input may be used to • reset the excesive starting time protection • set the locked rotor protection time delay to a low value * starting is detected when the absorbed current is 5% of Ib Division - Name - Date - Language 23 ASYNCHRONOUS MOTOR PROTECTION „ Negative sequence / unbalance (46) : • You want to detect the loss of one phase in motor circuit ⇒DT curve with setting Is < 30% of Ib and time setting = starting time • You want to protect the rotor against negative sequence current High frequency currents in the rotor induce high power losses ⇒use IDMT curve or similar Setting indication : 30% of Ib and time setting = starting time Division - Name - Date - Language 24 ASYNCHRONOUS MOTOR PROTECTION „ Undercurrent (37) : To protect pump against running down 1.06 I setting I setting 0.015 In Time setting < 15 ms Output Case of current sag Division - Name - Date - Language Case of circuit breaker opening 25 ASYNCHRONOUS MOTOR PROTECTION „ Positive sequence undervoltage (27D) : Motor torque is proportional to the square of the rated positive sequence voltage Setting indication : Voltage setting = 0.8 rated voltage Time setting = 1 second Division - Name - Date - Language 26 ASYNCHRONOUS MOTOR PROTECTION Positive sequence undervoltage (27D) : coordination with overcurrent protection „ Undervoltage protection t „ Overcurrent protection t 27 51 T T Us Division - Name - Date - Language Un U In Is Isc I 27 ASYNCHRONOUS MOTOR PROTECTION Directional earth fault (67N) : IscA IscB A B Vrsd Division - Name - Date - Language Irsd 28 ASYNCHRONOUS MOTOR PROTECTION Directional earth fault (67N) (cont'd): V2 ϕ0A Fault at A N Vrsd V1 IrsdA V3 Normal direction & & V rsd = − 3 × V 1 & & & where V 1 = Z N × I rsd & & & V rsd = − 3 Z N × I rsd ⇒ Division - Name - Date - Language 29 ASYNCHRONOUS MOTOR PROTECTION Directional earth fault (67N) (cont'd): IrsdB V2 Fault at B ϕ0B N V1 Vrsd Reverse direction V3 & & V rsd = − 3 × V 1 & & & where V 1 = Z N × I rsd & & & V rsd = − 3 Z N × I rsd ⇒ Division - Name - Date - Language 30 ASYNCHRONOUS MOTOR PROTECTION Directional earth fault (67N) (cont'd): „ Measurement of the phase shift angle between the residual voltage called the polarization voltage - and the earth fault current makes it possible to determine the direction V2 IrsdB ϕ0B N ϕ0A Vrsd V1 IrsdA Division - Name - Date - Language V3 31 ASYNCHRONOUS MOTOR PROTECTION Directional earth fault (67N) (cont'd): „ Division of a current vectorial plane into 2 half-planes: • normal zone • inverse zone „ Characteristic angle θ0 = angle between the perpendicular at the zone limit - characteristic line - and the polarization voltage „ Typical values of θ0: • 0° if N earthed by resistance • 15°, 30°, 45°, 60°: intermediate values • 90° if isolated neutral (Irsd=Icapa) • -45° if N earthed by reactance Inverse zone θ0 Vrsd Normal zone Division - Name - Date - Language 32 ASYNCHRONOUS MOTOR PROTECTION Directional earth fault (67N) (cont'd): inverse zone ϕ0 Is0 „ Association of 2 functions: • earth fault protection function adjustable setting Is0 Definite time • detection of the current direction characteristic angle θ0 „ Plane single-pole protection • Ip : projection of Irsd on the characteristic line • ϕ0: phase shift (Vrsd,Irsd) „ Protection operational if: polarization voltage >= 2.6% Un θ0=45° Vrsd Ip normal zone Irsd Earth fault Direction detection in normal direction Directional protection function tripping zone Division - Name - Date - Language 33 ASYNCHRONOUS MOTOR PROTECTION Directional earth fault (67N) (cont'd): COMPENSATED NEUTRAL SYSTEM : „ Petersen coil + resistor: • designed to compensate capacitive currents => Irsd is highly resistive => characteristic angle not adjustable: θ0 = 0° • self-extinguishing earth fault => short, recurring faults => protection memory time adjustable Tmem ~ 250 ms • in practice, the system is slightly dissymmetrical and the residual voltage is not zero when there is no fault => Vs0 setting adjustable Division - Name - Date - Language 34 ASYNCHRONOUS MOTOR PROTECTION „ Motor differential (87M) : Id = I - I' X In Without harmonic 2 restrain 100% Id1²/8 - It1²/32 = (0.05In)² I Current transformers 5P20 I' M Id² - It²/32 = Is² Harmonic 2 restrain Only one setting : 0.05 In < Is < 0.5 In √2 Division - Name - Date - Language External fault induces saturation of the CTs and false differential current It = (I + I')/2 X In 35 ASYNCHRONOUS MOTOR PROTECTION „ Temperature monitoring (49T/38) : • The protection detects if an RTD is shorted or disconnected. – RTD shorting is detected when the measured temperature is less than -70 ± 10°C – RTD disconnection is detected when the measured temperature is greater than 302 ± 27°C • For Sepam 1000+, RTD can be Pt100, NI100, NI120 type • For Sepam 2000, RTD can be Pt100 only Division - Name - Date - Language 36 SYNCHRONOUS MOTOR PROTECTION „ Real overpower (32P) : Against generator operation : Reverse real power (ANSI 32P) • Ps = 0.05 Pn • Time delay ~ 1 sec „ Reactive overpower (32Q) : Against field loss : Reactive overpower (ANSI 32Q) Equivalent to 40 function by adding 27 function • Qs ~ 0.3 Sn • Time delay : several seconds Division - Name - Date - Language 37 GENERATOR PROTECTION GENERATOR PROTECTION „ Generalities : • Main applications • Logic discrimination „ Protection functions : • • • • 38/49T : temperature set points 64REF : restricted earth fault 87G : bias differential 25 : synchronism check Division - Name - Date - Language „ Protection functions : • • • • • • • • • • • • • • 50/51 : phase overcurrent 49 : thermal overload 50V/51V : voltage restrained overcurrent 46 : negative sequence / unbalance 50N/51N : earth fault 27 : undervoltage 59 : overvoltage 59N/64 : neutral voltage displacement 67 : directional overcurrent 67N : directional earth fault 32P: reverse real power 32Q/40 : reverse reactive power/field loss 81L : underfrequency 81H : overfrequency 2 GENERATOR PROTECTION : Single generator not coupled with the network 3U/Vo 59N 51V 27 59 81L 81H 87T (optional) G ECM 49 51 46 38 51G 49T 64REF Division - Name - Date - Language 3 GENERATOR PROTECTION : Single generator coupled with the network 3U/V o 25 51 V 32P 32 Q 3U/V o 59N 27 87T 59 (optional) 81L G 81H ECM 67 67N possible in a second relay 49 51 46 51G 38 49T Division - Name - Date - Language 4 GENERATOR PROTECTION : Generators in 2 solutions parallel 51 V 32P 59N 38 27 49T 59 32 Q 38 3U/V o 49T 3U/V o 81L 81H 87 G 51 G 27 59 81L ECM2 81H G G 51 V 32P 32 Q 67 67 N ECM1 49 59N 49 51 ECM1 51 46 46 51G 64REF Synchro check function 25 is outside the Sepam Division - Name - Date - Language 5 GENERATOR PROTECTION : Single block set ECM2 51 38 51N/G 49T 51 V 3U/V o 59N 32P 27 32 Q 59 81L 87T with 64 REF (optional) 81H G ECM1 49 51 46 51G Division - Name - Date - Language 6 GENERATOR PROTECTION : Block sets in parallel 59N 38 3U/V o 27 49T 59 81L 81H ECM 51 51G 64REF 67 67 N 32P 32 Q 87T with 64 REF (optional) G G 3U/V o 59N 51 V 32P 46 ECM 49 32 Q 51 51G Synchro check function 25 is outside the Sepam Division - Name - Date - Language 7 GENERATOR PROTECTION Phase faults „ Constant excitation current Ik = 0.5 Ib t (s) 100 „ t (s) 100 10 Overexcitation Ik = 2 to 3 Ib 10 49 49 1 1 51V at U=0 51V 51V at U=Un 51 0.1 0.1 Isc Isc 0.01 0.01 1 10 Ik Division - Name - Date - Language Ib 100 I (A) I"k 1 10 Ib 100 Ik I (A) I"k 8 GENERATOR PROTECTION „ Logic discrimination : Source 0.1 s 0.7 s Generator Division - Name - Date - Language 1s Fault on busbar eliminated after 0.1 s without adding any other protection 0.7 s Generator 9 GENERATOR PROTECTION „ Logic discrimination : 67 (inst) ≥1 0 t 67N (inst) Output O14 : BI transmision Inhibition of BI transmision if fault not cleared & T3 = 0.2s 67 (time) ≥1 67N (time) ≥1 51 (time) tripping ≥1 51N (time) 51 (logic) ≥1 & 51N (logic) Input I12 : BI receipt Division - Name - Date - Language 10 GENERATOR PROTECTION „ Overcurrent (50/51) : • I setting ≈ 1.2 x I inrush (transformer, motor reacceleration) • Time setting ≈ 0.1 s • DT and IDMT curves Transient overreach = (Iso - Is1) / Is1 Iso = setting current, that is, r.m.s. value of steady state current required to operate the relay Is1 = steady state r.m.s. value of the fault current which when fully offset will just operate the relay Is1 > Is0 Division - Name - Date - Language 11 GENERATOR PROTECTION „ Overcurrent (50/51) : • Current shape in case of saturation of CT: I ct Peak value Right value Fundamental value t Low value of fundamental current ⇒ risk of no detection of the fault ⇒ measurement of peak value Division - Name - Date - Language 12 GENERATOR PROTECTION „ Overcurrent (50/51) : • Current shape in case of no saturation of CT : I ct Peak value Filtered peak value t Transient overreach can be very high if only the peak value is considered ⇒ peak value is filtered (no DC component) Division - Name - Date - Language 13 GENERATOR PROTECTION „ Overcurrent (50/51) : • Conclusion : • Filtered peak detection is used to ensure tripping in case of CT saturation • Efficace value avoids the risk of unexpected tripping SEPAM MIX THE TWO MEASUREMENTS TO GUARANTEE A GOOD TRANSIENT OVERREACH (LESS THAN 10% FOR ANY TIME CONSTANT) Division - Name - Date - Language 14 GENERATOR PROTECTION „ Voltage restrained overcurrent (50V/51V) : Sensors Outputs Principle Measurement of phase currents: 3 CTs or 3 CSPs I1 I2 I3 I > k Is U21 k 1 0.2 Measurement of phaseto-phase voltages: 3 VTs Division - Name - Date - Language 0 time-delayed instantaneous k U32 U13 t U 0.2Un 0.8Un Settings: Fixed parameter: - Is: current setting - T: time-delayed tripping time, definite time only - Un: rated primary voltage (status) 15 GENERATOR PROTECTION „ Earth fault (50N/51N) : Harmonic 2 restrain An earth fault current (including harmonic 2) could appear in case of CT saturation if earth fault is measured by means of the sum of 3 TC. Division - Name - Date - Language 16 GENERATOR PROTECTION „ Real overpower (32P) : Against motor operation : Reverse real power (ANSI 32P) • Turbine : Ps = 1 to 5% of Pn • Diesel : Ps = 5 to 20% of Pn • Time delay ≥ 1 sec „ Reactive overpower (32Q) : Against field loss : Reactive overpower (ANSI 32Q) • Qs ~ 0.3 Sn • Time delay : several seconds Division - Name - Date - Language 17 GENERATOR PROTECTION : Reverse reactive power relay / impedance relay (32Q/40) Q X 3.V²/2.Qo Qo A P B R I C Motor Motor Generator G 3.V²/2.Qo V C X/R²+X²=Qo/3.V² R = Real part ( V/I) Q = 3.X.V²/X²+R² X = Imaginary part ( V/I) P = 3.R.V²/X²+R² Generator A B Point A : P # 0 , Q = Qo , ⇒ X = (Qo/P).R ⇒ R.Q = X.P Point B : P = P1 , Q = Qo , ⇒ X = (Qo/P1).R Point C : P = P2 , Q = Qo , ⇒ X = (Qo/P2).R Generator connected to a source able to supply reactive power ⇒ correct voltage Generator connected to a source unable to supply reactive power ⇒ drop in voltage with reverse reactive power relay : correct operation with reverse reactive power relay : correct operation by adding 27 function with impedance relay : correct operation with impedance relay : correct operation Division - Name - Date - Language 18 GENERATOR PROTECTION „ Thermal overload (49) : • Heat rise calculation : 2 dE  Ieq  +E = T×  Ib dT   Ieq 2 = I 2 + K × Ii 2 • I is the greatest value of I1, I2, I3 (at 50 Hz) and I1rms • Ii is the negative sequence current 2 2 t   Ieq   − T  Ieq  E =  Eo −   ×e +  Ib Ib       • Eo : initial heat rise Division - Name - Date - Language 19 GENERATOR PROTECTION „ Thermal overload (49) (cont'd) : • Operation E 2 2 t   Ieq   − T  Ieq  E =  Eo −   ×e +  Ib Ib       (Ieq/Ib)² Eo (Ieq/Ib)² Eo (Ieq/Ib)² Eo T T T t Division - Name - Date - Language 20 GENERATOR PROTECTION „ Thermal overload (49) : Thermal overload function is used to protect the generator against too high requested active power that is to say if the power of the load increases. t 100 10 2 Cold curve 1 0.1  I    Ib t = T × Log  2   I    − Es 2  Ib  Es2 = thermal setting point in % T = heat rise (T1) or cooling (T2) time constant 2 Hot curve  I    −1 Ib t = T × Log  2  I    − Es 2  Ib  NB : For generator, K factor = 0 Ieq/Ib Division - Name - Date - Language 21 GENERATOR PROTECTION „ Negative sequence / unbalance (46) : • You want to detect the loss of one phase ⇒DT curve with setting Is < 15% of Ib and time setting = several seconds • You want to protect the machine against negative sequence current High frequency currents in the dampers induce high power losses ⇒use IDMT curve or similar Setting indication : 15% of Ib and time setting = several seconds Division - Name - Date - Language 22 GENERATOR PROTECTION Phase directional overcurrent (67) : IccA IccB A B U Division - Name - Date - Language I 23 GENERATOR PROTECTION Phase directional overcurrent (cont'd) (67) : „ Fault in A : IccA IsA Relais U13 I3 U21 I1 IccA I2 U32 Division - Name - Date - Language 24 GENERATOR PROTECTION Phase directional overcurrent (cont'd) (67) : „ Fault in B : IsB IccB Relais I2 U13 U21 I1 IccB I3 U32 Division - Name - Date - Language 25 GENERATOR PROTECTION Phase directional overcurrent (cont'd) (67) : „ Measurement of the phase shift angle between a reference voltage, called the polarization voltage, and a current makes it possible to determine the current direction „ In practice: • polarization by phase-to-phase voltage • measurement of ϕ1= phase shift (U32,I1), ϕ2= phase shift (U13,I2) and ϕ3 = phase shift (U21,I3) I1 ( for ϕ = 0 ) U 21 V1 V1 90° polarising voltage V3 V3 polarising voltage Division - Name - Date - Language V2 90° U 32 V2 I3 ( for ϕ = 0 ) 26 GENERATOR PROTECTION Phase directional overcurrent (cont'd) (67) : „ Conventions : I1 ϕ1 ϕ1 = phase shift (U32,I1) varies according to the impedance of the circuit under consideration „ Conventional current direction: • Normal direction = from busbar to cable • Inverse direction = from cable to busbar Conventional CT wiring: normal direction inverse direction I1 in normal direction ϕ1 U32 „ I1 I1 in inverse direction Division - Name - Date - Language „ I I 27 GENERATOR PROTECTION Phase directional overcurrent (cont'd) (67) : „ Characteristic angle θ : „ Division of a current vectorial plane into 2 half-planes: • normal zone • inverse zone „ Characteristic angle θ = angle between the perpendicular at the zone limit - characteristic line and the polarization voltage „ Setting values of θ : • 30° if high reactance circuit ( ϕ1minimum) • 45° average case • 60° if high resistance circuit ( ϕ1 maximum) Normal zone θ Inverse zone Division - Name - Date - Language U32 28 GENERATOR PROTECTION Phase directional overcurrent (cont'd) (67) : „ Principle : I1 „ Association of 2 functions: • phase overcurrent protection function adjustable setting Is Definite or IDMT time • detection of the current direction characteristic angle θ „ Three-phase protection • I1 and ϕ1 (phase shift U32,I1) • I2 and ϕ2 (phase shift U11,I2) • I3 and ϕ3 (phase shift U21,I3) „ Protection operational if: polarization voltage > 1.5%Un ϕ1 θ=45° U32 Is Phase overcurrent Direction detection in normal direction Directional protection function tripping zone Division - Name - Date - Language 29 GENERATOR PROTECTION Directional earth fault (67N) : IscA IscB A B Vrsd Division - Name - Date - Language Irsd 30 GENERATOR PROTECTION Directional earth fault (67N) (cont'd): V2 ϕ0A Fault at A N Vrsd V1 IrsdA V3 Normal direction & & V rsd = − 3 × V 1 & & & where V 1 = Z N × I rsd & & & V rsd = − 3 Z N × I rsd ⇒ Division - Name - Date - Language 31 GENERATOR PROTECTION Directional earth fault (67N) (cont'd): IrsdB V2 Fault at B ϕ0B N V1 Vrsd Reverse direction V3 & & V rsd = − 3 × V 1 & & & where V 1 = Z N × I rsd & & & V rsd = − 3 Z N × I rsd ⇒ Division - Name - Date - Language 32 GENERATOR PROTECTION Directional earth fault (67N) (cont'd): „ Measurement of the phase shift angle between the residual voltage called the polarization voltage - and the earth fault current makes it possible to determine the direction V2 IrsdB ϕ0B N ϕ0A Vrsd V1 IrsdA Division - Name - Date - Language V3 33 GENERATOR PROTECTION Directional earth fault (67N) (cont'd): „ Division of a current vectorial plane into 2 half-planes: • normal zone • inverse zone „ Characteristic angle θ0 = angle between the perpendicular at the zone limit - characteristic line - and the polarization voltage „ Typical values of θ0: • 0° if N earthed by resistance • 15°, 30°, 45°, 60°: intermediate values • 90° if isolated neutral (Irsd=Icapa) • -45° if N earthed by reactance Inverse zone θ0 Vrsd Normal zone Division - Name - Date - Language 34 GENERATOR PROTECTION Directional earth fault (67N) (cont'd): inverse zone ϕ0 Is0 „ Association of 2 functions: • earth fault protection function adjustable setting Is0 Definite time • detection of the current direction characteristic angle θ0 „ Plane single-pole protection • Ip : projection of Irsd on the characteristic line • ϕ0: phase shift (Vrsd,Irsd) „ Protection operational if: polarization voltage >= 2.6% Un θ0=45° Vrsd Ip normal zone Irsd Earth fault Direction detection in normal direction Directional protection function tripping zone Division - Name - Date - Language 35 GENERATOR PROTECTION Directional earth fault (67N) (cont'd): COMPENSATED NEUTRAL SYSTEM : „ Petersen coil + resistor: • designed to compensate capacitive currents => Irsd is highly resistive => characteristic angle not adjustable: θ0 = 0° • self-extinguishing earth fault => short, recurring faults => protection memory time adjustable Tmem ~ 250 ms • in practice, the system is slightly dissymmetrical and the residual voltage is not zero when there is no fault => Vs0 setting adjustable Division - Name - Date - Language 36 GENERATOR PROTECTION „ Generator differential (87G) : Id = I - I' X In Without harmonic 2 restrain 100% Id1²/8 - It1²/32 = (0.05In)² I I' M Id² - It²/32 = Is² Harmonic 2 restrain Only one setting : 0.05 In < Is < 0.5 In √2 Division - Name - Date - Language External fault induces saturation of the CTs and false differential current It = (I + I')/2 X In 37 GENERATOR PROTECTION „ Undervoltage (27) : Sepam Sepam Sepam Sepam Division - Name - Date - Language 38 GENERATOR PROTECTION Undervoltage (27) : coordination with overcurrent protection „ Undervoltage protection t „ Overcurrent protection t 27 51 T T Us Division - Name - Date - Language Un U In Is Isc I 39 GENERATOR PROTECTION „ Overvoltage (59) : Sepam Sepam Sepam Sepam Division - Name - Date - Language 40 GENERATOR PROTECTION „ Residual overvoltage (59N) : • For isolated neutral 59N protection is required to detect earth fault before closing the circuit breaker • This function can be located elsewhere in the network (on busbar for example) Division - Name - Date - Language 41 GENERATOR PROTECTION „ Restricted earth fault (64REF) : • If the protection 64 REF is required • or if the generator has a power rating of more or equal than 5 MVA the protection 64 REF is required. • It offers the advantage of having greater sensitivity than differential protection (5% of In) G Division - Name - Date - Language 64REF 42 GENERATOR PROTECTION „ Temperature monitoring (49T/38) : • The protection detects if an RTD is shorted or disconnected. – RTD shorting is detected when the measured temperature is less than -70 ± 10°C – RTD disconnection is detected when the measured temperature is greater than 302 ± 27°C • For Sepam 1000+, RTD can be Pt100, NI100, NI120 type • For Sepam 2000, RTD can be Pt100 only Division - Name - Date - Language 43 GENERATOR PROTECTION „ Synchro-check (25) : • dUs set point : can depend on power transit • dFs set point :depends only on accuracy • dPhi set point :can depend on power transit • Us high : to detect presence of voltage • Us low : to detect absence of voltage • Time Ta : to take into account of the circuit breaker closing time Division - Name - Date - Language 44 GENERATOR PROTECTION „ Synchro-check (25) (cont'd) : ∆ϕ + 360 × ∆F × Ta < dPhis Usynch 1 Usynch 2 U>Us high Synchro check ∆F < dFs & U>Us high U>Us high ∆U < dUs U>Us high Division - Name - Date - Language 45 GENERATOR PROTECTION „ Synchro-check (25) (cont'd) : • 4 operating modes : Mode 2 Mode 1 Usynch 1 Usynch 2 Usynch 1 Usynch 2 Mode 3 Mode 4 OR Usynch 1 Division - Name - Date - Language Usynch 2 Usynch 1 AND Usynch 2 46