CSC-326 Transformer Protection IED Product Guide

Transcription

1 CSC-326 Transformer Protection IED Product Guide

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3 Version:V1.11 Doc. Code: 0SF (E) Issued Date: Copyright owner: Beijing Sifang Automation Co., Ltd Note: The company keeps the t right to perfect the instruction. i If I equipments do not agree with the instruction at anywhere, please contact our company in time. We will provide you with corresponding service. is registered trademark of Beijing Sifang S Automation Co., Ltd. We reserve all rights to this document, even in the event that t a patent is issued and a different commercial proprietary right is registered. Improper use, u in particular reproduction and dissemination to third parties, is not permitted. This document has been carefully checked. If the user nevertheless detects any errors, he is asked to notify uss as soon as possible. The data contained in this manual is intended solely for the IED description and iss not to be deemed to be a statement off guaranteed properties. Inn the interestss of our customers, we constantly seek to ensure that our products are developedd to the latest technological standards as a result; it is possible that there may be some differences betweenn the hardware/software product and this information product. Manufacturer: Beijing Sifang Automation Co.,, Ltd. Tel: , ext Fax: Website: Add: No.9, Shangdi 4th Street,, Haidian District, Beijing, P.R.C

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5 Ov erview CSC-326 is selective, reliable and high speed IED (Intelligent Electronic Device) for transformer or reactor protection with powerful capabilities to cover following applications: For large and mediumm two-winding or three-winding transformer, and auto- -transformerr Shunt reactors with/ without neutral point grounding reactorr complicated application Communication withh station automation system The IED iss able to provide all main protection functions andd backup protection functions in one o case, ncluding differential protection for f transformer or reactor, restricted earth fault (REF), overexcitation, thermal overload, overcurrent, earth fault protection, etc. Used in a wide range of voltage levels, up to 1000kV For single or multi-breaker arrange- -ment Up to 7 three-phase sets of CTs input (special ordering) Work as main protection unit onlyy or full functions unit for thee The integrated flexible logic make the IED suitable to bee applied too (auto)transformers with all the possiblee vector groups, with/without earthing connection inside the protected zone. The wide application flexibility makes the IED an excellent choice for both new installations and retrofitting of the existing stations.. 1

6 Feature Protection and monitoring IED with extensive functional library, user configuration possibility and expand- -able hardware design to meet with user s special requirements Inter-lock between two CPU modules, avoiding mal-operation due to internal severe fault of one module Transformer differential protection (87T) Treble slope percent differential protection Two slope percent REF protection Automatic CT ratio matching CT saturation recognition REF differential current super- -vision Restricted earth fault protection for reactor(87nr) Two slope percent REF protection Automatic CT ratio matching CT saturation recognition Automatic CT ratio matching Automatic vector group and zero sequence current compensation REF differential current supervision Interturn fault protection (16) Settable 2 nd harmonic restraint function for transformer inrush Fuzzy waveform recognition restraint function for transformer inrush 3 rd or 5 th harmonic restraint for overexcitation CT saturation detection CT secondary circuit supervison Based on zero sequence direction Self-adpative interturn fault detection A complete protection functions library, include: Transformer differential protection (87T) Reactor differential protection (87R) Differential current alarm Reactor differential protection (87R) Treble slope percent differential protection Automatic CT ratio matching CT saturation detection CT secondarycircuit supervison Differential current supervision Restricted earth fault protection for transformer (87NT) Restricted earth fault protection for transformer(87nt) Restricted earth fault protection for reactor(87nr) Inter-turn protection (16) Overcurrent protection (50, 51, 67) Earth fault protection (50N, 51N, 67N) Neutral earth fault protection (50G, 51G, 67G) 2

7 Feature Thermal overload protection (49) Overload protection (50OL) Delta winding overload protection (50OL) Overexcitation protection (24) Overvoltage protection (59) Circuit breaker failure protection (50BF) Poles discordance protection (50PD) Dead zone protection (50DZ) Voltage transformer secondary circuit supervision (97FF) Current transformer secondary circuit supervision 2 sets external trip commands (BIs BOs Self-supervision to all modules in the IED reports and general operation reports. Any kinds of reports can be stored up to 2000 and be memorized in case of power disconnection Up to three electric /optical Ethernet ports can be selected to communicate with substation automation system by IEC61850 or IEC protocols Up to two electric RS-485 ports can be selected to communicate with substation automation system by IEC protocol Time synchronization via network (SNTP), pulse and IRIG-B mode Configurable LEDs and output relays satisfied users requirement Versatile human-machine interface Multifunctional software tool for setting, monitoring, fault recording analysis, configuration, etc. Complete information recording: tripping reports, alarm reports, startup 3

8 Function Protection functions Description ANSI Code IEC Logical Node Name IEC graphical symbol Differential protection Transformer differential protection 87T PDIF Reactor differential protection 87R PDIF Restricted earth fault protection for transformer 87NT PDIF Restricted earth fault protection for reactor 87NR PDIF Inter-turn fault protection 16 Current protection Overcurrent protection 50,51,67 Earth fault protection 50N, 51N, 67N PIOC PTOC PIEF PTEF 3I INV > 3I >> 3I >>> I 0INV > I 0 >> I 0 >>> Neutral earth fault protection 50G, 51G, 67G Thermal overload protection 49 PTTR Ith Overload protection 50OL PTOC 3I >OL Delta Winding Overload Protection 50OL Voltage protection Overexcitation protection 24 PVPH U/f> Overvoltage protection 59 PTOV Undervoltage protection 27 PTUV 3U> 3U>> 3U< 3U<< Breaker protection and control function Breaker failure protection 50BF RBRF Dead zone protection 50DZ 3I> BF I 0 >BF I 2 >BF 3I> DZ I 0 >DZ I 2 >DZ 4

9 Function STUB protection 50STUB PTOC 3I>STUB Poles discordance protection 50PD RPLD 3I< PD I 0 >PD I 2 >PD Secondary system supervision CT secondary circuit supervision VT secondary circuit supervision Other functions 2 sets external trip commands (BIs BOs) Monitoring functions Description Auxiliary contacts of circuit breaker supervision Self-supervision Fault recorder Station communication Description Front communication port Isolated RS232 port for maintaining Rear communication port 0-2 isolated electrical RS485 communication ports, support IEC protocol 0-3 Ethernet electrical/optical communication ports, support IEC protocol or IEC protocol Time synchronization port, support GPS pulse or IRIG-B code 5

10 Function IED software tools Functions Reading measuring value, IED report Setting IED testing Disturbance recording analysis IED configuration Printing 6

11 Function Application for two-winding transformer 7

12 Function Application for three-winding transformer 8

13 Function Application for autotransformer 9

14 Function Application for reactor 10

15 Protection Transformer differential protection (87T) The transformer differential protection function is provided to protect two-winding transformer, three-winding transformer and auto-transformer in various configurations up to 1000 kv voltage level, with internal CT ratio matching, vector group and zero sequence current compensation. The following features would be applied: Operating characteristic Figure 1 illustrates operating characteristic of treble slope percent differential protection and instantaneous differential protection. where: Figure 1 Characteristic of transformer differential protection I diff : Differential current I res : Restrain current I_TDiffInst: The pickup current of instantaneous differential protection I_TDiff: The pickup current of percentage differential protection I_TRes1, I_TRes2: Restrain current setting of breaker point 1 and breaker point 2 respectively Slope 1 represents the sensitivity threshold of the differential protection and considers constant error current e.g. magnetizing currents. Slope 2 takes into consideration current- -proportional errors which may result from transformation errors of the main CTs, the input CTs of the IED, or from erroneous current caused by the position of the tap changer in power transformer. In the range of high current which may give rise to high differential current as a result of CT saturation, slope 3 is applicable to provide more stabilization. The differential and restraining currents are calculated separately in each phase of the protected object. Automatic identification of fault location is fulfilled with recognition of differential and restraint current trace around the characteristic. The instantaneous differential protection is able to operate promptly regardless of the restraining quantity and harmonic content, if high current fault occurs in the protected zone. The instantaneous differential protection operating area is shaded yellow area shown in Figure 1, where differential current must be larger than I_TDiffInst setting. The treble slope percent differential protection uses a treble-slope dual break-point operating characteristic which make it possible to improve the restraint capability in case of CT saturation caused by serious external fault current. It further operates in conjunction with magnetizing inrush, overexcitation and CT failure restraint features. Furthermore, the integrated CT saturation detection feature ensures reliable blocking of percent 11

16 Protection differential protection in the case of CT saturation caused by external fault. At the same time, severe internal fault can cause fast protection tripping. Automatic ratio compensation The input currents of the IED are converted automatically in relation to the power transformer rated currents to be matched with each other. As a result, matching to various power transformer and CT ratios is performed purely mathematically inside the IED and no external matching CT is required. Automatic vector group and zero sequence current compensation Transformers have different vector groups, which cause a shift of the phase angles between the currents flowing through their high medium and low voltage sides. Without adequate correction, this phase shift would cause a false differential current. Furthermore, the existence of the neutral point(s) of the power transformer has a great impact on the differential current during through fault currents. The IED is capable to automatically compensate for the adverse effect of various vector groups of power trans- -formers as well as the zero sequence current which may flow into the protected zone, depending on the condition of the neutral point(s). This is achieved just by informing the IED about the vector group of the power transformer, and then, all necessary compensations would be per- -formed automatically by using coefficient matrices programmed inside the IED. This simplifies application of the IED in various configurations. Inrush restraint This feature is provided in the IED to prevent percent differential protection from false tripping caused by high short-time magnetizing currents which may be present during transformer energizing (inrush currents). Two algorithms are available in the IED to detect inrush conditions. The first one operates based on 2nd harmonic stabiliza- -tion, whereas the second algorithm utilizes fuzzy wave recognition of inrush conditions based on the current waveform. Furthermore, a cross blocking feature is provided which can be used to set the protection in a way that when the 2nd harmonic recognition is fulfilled only in one phase, not only the phase with the inrush current, but also the remaining phases of percent differential protection are blocked for a certain duration as well. Overexcitation restraint Stabilization of percent differential protection function is provided against unwanted differential currents caused by transformer overexcitation. Since steady state overexcitation is characterized by odd harmonics, the 3 rd or the 5 th harmonic can be selected in the IED to recognize for overexcitation condition. Current transformer saturation supervision This integrated function is capable to recognize CT saturation. CT saturation can be detected when both the 2 nd and 3 rd harmonic contents of phase currents amongst all phase currents are more than a threshold. If the CT saturation occurs simultaneously with external fault 12

17 Protection recognition, differential protection will be blocked. Differential current supervision In normal operation condition, zero differential current is expected in each phase. The differential current supervision monitors the differential current of each phase. An alarm report will be given, if the differential current exceeds the threshold value for a delay time. Reactor differential protection (87R) The reactor differential protection function is provided to protect shunt reactor in various configurations up to 1000 kv voltage level, with internal CT ratio matching. The following features would be applied: Operating characteristic Figure 2 illustrates the operating characteristic of the treble slope percent differential protection and instantaneous differential protection. Figure 2 Characteristic of reactor differential protection where: I diff : Differential current I res : Restrain current I_RDiffInst: The pickup current of instantaneous differential protection I_RDiff: The pickup current of percentage differential protection I_RRes1, I_RRes2: Restrain current setting of breaker point 1 and breaker point 2 respectively Slope 1 represents the sensitivity threshold of the differential protection and considers constant error current e.g. magnetizing currents. Slope 2 takes into consideration current- -proportional errors which may result from transformation errors of the main CTs and the input CTs of the IED. In the range of high current which may give rise to high differential current as a result of CT saturation, slope 3 is applicable to provide more stabilization. The differential and restraining currents are calculated separately in each phase of the protected object. Automatic identification of fault location is fulfilled with recognition of differential and restraining current trace around the characteristic. The instantaneous differential protection is able to operate promptly regardless of the restraining quantity and harmonic content, if high current fault occurs in the protected zone. The instantaneous differential protection operating area shaded yellow area shown in Figure 2, where differential current must be larger than I_RDiffInst setting. The treble slope percent differential protection uses a treble-slope dual break-point operating characteristic with integrated CT saturation detection feature ensures reliable blocking of percent differential protection in the case of CT 13

18 Protection saturation caused by external fault. At the same time, severe internal fault can cause fast protection tripping. Automatic ratio compensation The input currents of the IED are converted automatically in relation to the shunt reactor rated currents to be matched with each other. As a result, matching to various shunt reactor and CT ratios is performed purely mathematically inside the device and no external matching CT is required. Current transformer saturation supervision This integrated function is capable to recognize CT saturation. CT saturation can be detected when both the 2 nd and 3 rd harmonic contents of phase currents amongst all phase currents are more than a threshold. If the CT saturation occurs simultaneously with external fault recognition, differential protection will be blocked. Differential current supervision In normal operation condition, zero differential current is expected in each phase. The differential current supervision monitors the differential current of each phase. An alarm report will be given, if the differential current exceeds the threshold value for a delay time. Restricted earth fault protection for transformer (87NT) The REF protection provides higher sensitivity and higher speed when they measure individually on each winding. They are capable to detect earth faults in (auto) transformer earthed. A precondition for using these functions is that a neutral CT should be provided. Operating characteristic Figure 3 illustrates the dual slope operating characteristics of the REF. Figure 3 Characteristic of REF protection where: I 0Diff : Zero sequence differential current I 0Res : Zero sequence restraint current I_NDiff: The sensitive threshold of pickup current of REF protection Slope_NDiff: Slope of the characteristic Restricted earth fault current supervision In normal operation condition, zero sequence differential current is expected for restricted earth fault protection. The restricted earth fault current supervision monitors differential current. An alarm is generated after a dropout time, if the restricted differential current exceeds the setting threshold. The alarm is given to draw the user attention to check the faulty connection and remove it in time. Current transformer saturation supervision This integrated function is capable to 14

19 Protection recognize CT saturation. In this situation, CT saturation is detected when both the 2nd and 3rd harmonic components of phase currents amongst all phase currents are more than a threshold. Using these measurements, if the CT saturation occurs simultaneous with external fault recognition, the restricted earth fault protection will be blocked. Difference of transient characteristic of CTs detection Difference of transient characteristic of phase or neutral CTs may result in zero-sequence current in REF protection during an external three-phase fault. To remove this problem, the situation is detected by using the calculated positive and zero-sequence currents. The condition is checked for each side of transformer separately. Restricted earth fault protection for reactor (87NR) The REF protection provides higher sensitivity and higher speed when they measure individually on each winding. They are capable to detect earth faults in reactor earthed. Operating characteristic Figure 4 illustrates the dual slope operating characteristics of the REF as well as instantaneous characteristic. Figure 4 Characteristic of REF protection where: I 0Diff : Zero sequence differential current I 0Res : Zero sequence restraint current I_NDiffInst: The pickup current of instantaneous REF protection I_NDiff: The sensitive threshold of pickup current of REF protection I_NRes: Restrain current setting of breaker point Slope_NDiff: Slope of the characteristic The function can be connected with calculated zero-sequence current from neutral-point CT of main reactor or external measuring neutral CT. Restricted earth fault current supervision In normal operation condition, less to zero differential current is expected for restricted earth fault protection. The restricted earth fault current supervision monitors differential current. An alarm is generated after a preset time, if the restricted differential current exceeds the setting threshold. The alarm is given to draw the user attention to check the faulty connection and remove it in time. 15

20 Protection Current transformer saturation supervision This integrated function is capable to recognize CT saturation, if calculated zero sequence current is used from neutral side CT of the main reactor, instead measured value from the dedicated neutral CT. In this situation, CT saturation is detected when both the 2 nd and 3 rd harmonic components of phase currents amongst all phase currents are more than a threshold. Using these measurements, if the CT saturation occurs simultaneous with external fault recognition, the restricted earth fault protection will be blocked. Interturn fault protection (16) the reactor, the zero-sequence voltage leads the zero-sequence current. However, for an external fault, the corresponding zero-sequence voltage will lag the zero-sequence current. So, the phase- -angle relation is used to distinguish the internal or external fault of the reactor. Overcurrent protection (50, 51, 67) The protection provides following features: Two definite time stages One inverse time stage 11 kinds of IEC and ANSI inverse time characteristic curves as well as optional user defined characteristic The inter-turn fault protection detects faults between reactor winding turns. A short circuit of a few turns of the winding will give rise to a heavy fault current in the short-circuited loop, but the terminal currents will be very small, because of the high ratio of transformation between the whole winding and the short-circuited turns. Therefore, the short circuited turns can be damaged by large short circuit current. In this case, partial winding flashover is more likely and the subsequent progress of the fault, if not detected in the earliest fault stage, may severely destroy the object. Selectable directional element charac- -teristic angle, to satisfy the different network conditions and applications Each stage can be set individually as directional/non-directional Directional element can be set to point protected object or system for all stages Each stage can be set individually for inrush restraint Cross blocking function for inrush detection The inter-turn fault protection in the IED uses zero-sequence component direction using zero-sequence current in neutral- -point of the main reactor and the calculated zero-sequence voltage at the HV terminal of the reactor. When there is inter-turn short-circuit inside Settable maximum inrush current VT secondary circuit supervision for directional protection. Once VT failure happens, the directional stage can be set to be blocked or to be non-directional Inrush restraint function 16

21 Protection The protection relay may detect large magnetizing inrush currents during transformer energizing. In addition to considerable unbalance fundamental current, Inrush current comprises large second harmonic current which doesn t appear in short circuit current. Therefore, the inrush current may affect the protection functions which operate based on the fundamental component of the measured current. Accordingly, inrush restraint logic is provided to prevent overcurrent protection from maloperation. Furthermore, by recognition of the inrush current in one phase, it is possible to set the protection in a way that not only the phase with the considerable inrush current, but also the other phases of the overcurrent protection are blocked for a certain time. This is achieved by cross-blocking feature integrated in the IED. The inrush restraint function has a maximum inrush current setting. Once the measuring current exceeds the setting, the overcurrent protection will not be blocked any longer. Characteristic of direction element The direction detection is performed by determining the position of current vector in directional characteristic. In other word, it is done by comparing phase angle between the fault current and the reference voltage, Figure 5 illustrates the direction detection characteristic for A phase element. Figure 5 Direction detection characteristic of overcurrent protection directional element where: Ф Ph_Char : The settable the characteristic angle The assignment of the applied measuring values used in direction determination has been shown in Table 1 for different types of faults. Table 1 Assignment of applied current and reference voltage for directional element Phase Current Voltage A B C I a I b I c U bc U ca Uab For three-phase short-circuit fault, without any healthy phase, memory voltage values are used to determine direction clearly if the measured voltage values are not sufficient. The detected direction is based on the voltage of previously saved cycles. 17

22 Protection Earth fault protection (50N, 51N, 67N) The earth fault protection can be used to clear phase to earth faults as system back-up protection. The protection provides following features: Two definite time stages One inverse time stage 11 kinds of the IEC and ANSI inverse time characteristic curves as well as optional user defined characteristic summation of 3 phase currents Directional element The earth fault protection adopts zero sequence directional element which compares the zero sequence system quantities: 3I 0, current is calculated from the sum of the three phase currents 3U 0, the voltage is used as reference voltage. It is calculated from the sum of the three phase voltages Zero sequence directional element Each stage can be set individually as directional/non-directional Directional element can be set to be forward toward the protected object or reverse toward system for all stage Settable directional element characteristic angle, to satisfy the different network conditions and applications Each stage can be set individually for inrush restraint Settable maximum inrush current Inrush restraint function adopting 2 nd harmonic measured phase or earth current settable VT secondary circuit supervision for directional protection function. Once VT failure happens, the directional stage can be set to be blocked or to be non-directional Zero-sequence current is calculated by Figure 6 Direction detection characteristic of zero sequence directional element where: Ф 0_Char : The settable characteristic angle There are two operation areas which are provided for direction determination, the forward area toward the protected object and the reverse area toward the system, which are shown in Figure 6. Furthermore, under the VT failure situation, it can be set to block directional earth fault protection or to apply non-directional earth fault protection. 18

23 Protection Inrush restraint function The protection relay may detect large magnetizing inrush currents during transformer energizing. In addition to considerable unbalance fundamental current, Inrush current comprises large second harmonic current which doesn t appear in short circuit current. Therefore, the inrush current may affect the protection functions which operate based on the fundamental component of the measured current. Accordingly, inrush restraint logic is provided to prevent earth fault protection from mis-tripping. Since inrush current cannot be more than a specified value, the inrush restraint provides an upper current limit in which blocking does not occur. Neutral earth fault protection (50G, 51G 67G) The neutral earth fault protection focus on phase to earth faults. The measuring current is one phase current from dedicated neutral CT. The protection function provides following features: Two definite time stages One inverse time stage 11 kinds of the IEC and ANSI inverse time characteristic curves as well as optional user defined characteristic Each stage can be set to be directional/non-directional independently Zero sequence directional element. Its characteristic is same as earth fault protection illustrated in Figure 6 Directional element can be set to be forward toward the protected object or reverse toward system for all stages Setable directional element characteristic angle, to satisfy the different network conditions and applications Inrush restraint function can be set for each stage separately Settable maximum inrush current VT secondary circuit supervision for directional protection function Neutral current is measured from dedicated neutral CT Inrush restraint feature The neutral earth fault protection may detect large magnetizing inrush currents flowing when transformer is energized. Directional element Directional determination of neutral earth fault element adopts the zero sequence directional element as same as the one applied by earth fault protection. The only difference is the measured current, which is measured from the neutral point CT instead of being calculated from three phase currents. Thermal overload protection (49) The insulating material surrounding the 19

24 Protection windings ages rapidly if the temperature exceeds the design limit value. Thus, a thermal protection function is required to supplement the existing winding temperature device. The thermal overload protection estimates winding temperature and thus prevents it from thermal damaging. The thermal overload protection operates based on an approximate replica of the temperature rise in the protected object caused by overload. The thermal replica can be implemented based on thermal models (Cold or Hot Curve) of IEC standard. The thermal overload in the IED is provided with one trip stage as well as one alarm stage. It is possible to set the alarm stage at a certain percentage of the setting value applied at the trip stage. The calculation is performed separately for each phase, based on fundamental component and harmonic components. Overload protection (50OL) The IED supervises load flow in real time. If each phase current is greater than the dedicated setting for a set delay time, the protection will issue alarm. Transformer delta winding overload protection (50OL) When there is a dedicated CT for each phase of the transformer delta winding, the protection is provided to monitor the load flow in real time. If all three phase current are always greater than the setting of power swing for a setting time, the alarm will be reported. Overexcitation protection (24) The IED provides an overexcitation protection to detect impermissible over- -excitation conditions which can endanger power transformers as a result of saturation in iron core and resulting large eddy current losses which may lead to impermissible temperature rise inside the transformer core. The function measures the voltage /frequency (U/f) ratio which is proportional to the flux density in transformer core. One definite time stage for alarm One definite time stage for trip One thermal overexcitation time characteristic stage, which can be defined by user-defined settings (see Figure 7 Figure 7 Thermal overexcitation time characteristic 20

25 Protection Overvoltage protection (59) One voltage rise occur possibly in the power system during abnormal conditions such as no-load, lightly load, or open line end on long line. The protection can be used as open line end detector or as system voltage supervision normally. The protection provides following features: Two definite time stages First stage can be set to alarm or trip Measuring voltage between phase- -earth voltage and phase-phase selectable Settable dropout ratio Undervoltage protection (27) One voltage reduction can occur in the power system during faults or abnormal conditions. The protection provides following features: Two definite time stages First stage can be set to alarm or trip Measuring voltage between phase- -earth voltage and phase-phase selectable Current criteria supervision Circuit breaker aux. contact super- -vision VT secondary circuit supervision, the undervoltage function will be blocked when VT failure happens Settable dropout ratio Zero sequence over- -voltage protection (64) The zero sequence overvoltage protection is able to monitor the voltage displacement to detect the earth fault in power system. The displacement voltage 3U 0 can be either directly measured from VT or calculated based on connected three phases to earth voltages. In the latter case, the three voltages transformers input must be connected in an earth-wye configuration. The protection provide following features: Two definite time stages 3U 0 based on calculated summation of 3 phase voltage or measured injected residual voltage Breaker failure protection (50BF) The circuit breaker failure protection is able to detect a failure of the circuit breaker during a fault clearance. It ensures fast back-up tripping of surrounding breakers by tripping relevant bus sections. The protection can be three-phase started to allow use with three phase tripping applications. Once a circuit breaker operating failure occurs on a feeder/transformer, the bus 21

26 Protection section which the feeder/transformer is connected with can be selectively isolated by the protection. In addition a The CBs of the other windings of the transformer are tripped at the same time. In the event of a circuit breaker failure with a busbar fault, a trip signal is issued to trip the CBs of the other windings of the transformer. The current criteria are in combination with three phase current, zero and negative sequence current to achieve a higher security. The function can be set to give three phase re-tripping of the local breaker to avoid unnecessary tripping of surrounding breakers in the case of two available trip coils. Self-adaptive for bus side CT or line side CT Two trip stages (local and surrounding breaker tripping) Internal/ external initiation Selectable CB Aux contacts checking Current criteria checking (including phase current, zero and negative sequence current) Figure 8 Tripping logic when applying bus side CT When one bus side CT of feeder is applied, once a fault occurs in the dead zone, the IED trips the relevant busbar zone. Tripping logic is illustrated in Figure 8. Dead zone protection (50DZ) The IED provides this protection function to protect dead zone, namely the area between circuit breaker and CT in the case that CB is open. Therefore, by occurrence of a fault in dead zone, the short circuit current is measured by protection relay while CB auxiliary contacts indicate the CB is open. Internal/ external initiation 22

27 Protection The protection performs following features: 3 phase CB Aux contacts supervision Current criteria checking (including phase current, zero and negative sequence current) Secondary system supervision Current transformer secondary circuit supervision Open or short circuited CT cores can cause unwanted operation of some protection functions such as earth fault current and negative sequence current functions. Figure 9 Tripping logic when applying transformer side CT When one transformer side CT is applied, when a fault occurs in the dead zone, protection relay trip the circuit breakers of the others transformer winding. Tripping logic is illustrated in Figure 9. Poles discordance protection (50PD) The phase segregated operating circuit breakers can be in different positions (close-open) due to electrical or mechanical failures during the system normal operation. The protection operates based on information from auxiliary contacts of the circuit breaker with additional criteria. During the normal operation without any disturbance, the IED monitors the three phase currents of all sides of transformer. If only one or two phase currents drop down less than a threshold and the differential current is larger than a preset threshold, CT secondary circuit open is determined and alarm will be issued. The CT open alarm can be set to block differential protection or not. Voltage transformer secondary circuit supervision A measured voltage failure, due to a broken conductor or a short circuit fault in the secondary circuit of voltage transformer, may result in unwanted operation of the protection functions which work based on voltage criteria. VT failure supervision function is provided to block these protection functions and 23

28 Protection enable the backup protection functions. The features of the function are as follows: Symmetrical/asymmetrical VT failure detection Zero and negative sequence current monitoring Applicable in solid grounded, compensated or isolated networks 3-phase AC voltage MCB monitoring 1-phase AC voltage MCB monitoring 24

29 Monitoring Self-supervision All modules can perform self- -supervision to its key hardware components and program, as soon as energizing. Parts of the modules are self-supervised in real time. All internal faults or abnormal conditions will initiate an alarm. The fatal faults among them will result in the whole IED blocked CPU module and communication module perform real time inter- -supervision. Therefore communication interruption between them is detected and related alarm will be given CRC code checks for the setting, program and configuration, etc. 25

30 Communication Station communication Overview The IED is able to connect to one or more substation level systems or equipments simultaneously, through the communication ports with communica- -tion protocols supported. (Shown in Figure 9) Front communication port There is a serial RS232 port on the front plate of all the IEDs. Through this port, the IED can be connected to the personal computer for setting, testing, and configuration using the dedicated Sifang software tool. RS485 communication ports Up to 2 isolated electrical RS485 communication ports are provided to connect with substation automation system. These two ports can work in parallel for IEC Ethernet communication ports Up to 3 electrical or optical Ethernet communication ports are provided to connect with substation automation system. These two out of three ports can work in parallel for protocol, IEC61850 or IEC Figure 9 Connection example for multi networks of station automation system Note: All four ports can work in parallel Communication protocol The IED supports station communication with IEC and IED protocols. By means of IEC61850, GOOSE peer-to-peer communication make it possible that bay IEDs can exchange information to each other directly, and a simple master-less system can be set up for bay and system interlocking and other interactive function. Time synchronization port All IEDs feature a permanently integrated electrical time synchronization port. It can be used to feed timing telegrams in IRIG-B 26

31 Communication or pulse format into the IEDs via time synchronization receivers. The IED can adapt the second or minute pulse in the pulse mode automatically. Meanwhile, SNTP network time synchro- -nization can be applied. Figure 10 illustrates the optional time synchronization modes. Figure 10 Time synchronizing modes 27

32 Software tools A user-friendly software tool is offered forr engineering, setting, disturbance e analysiss and monitoring. It providess versatilee functionalities requiredd throughout the life cycle of protectionn IEDs. Its features are as follows: diagrams, vector v diagrams, bar charts and data sheet. Device administration in projects with freely configurable hierarchies for any substation and electrical power station topology Intelligent plausibility p checks rule out incorrect input Graphical visualization of charac- -teristics andd zone diagrams with direct manipulatio n of the curves Password-p protected access for Modification, import and export of parameter sets sorted by protection functions, with setting logicality checkk different jobs such as parameter setting, commission ing andd controlling (authorized staff only) Precise fault analysis with visualization of fault records in curves, circle Testing andd diagnostic functions decisive support in thee commissioning phase 28

33 Hardware Front plate The whole front plate is divided into zones, each of them with a well-defined functionality: 1 Liquid crystal display (LCD) 2 LEDs 3 Shortcut function keys 4 Arrow keys 5 Reset key 6 Quit key 7 Set key 8 RS232 communication port Rear plate Note: For reactor protection, X2 and X3 are not used. 29

34 Hardware Modules Analogue Input Module (AIM) The analogue input module is used to galvanically separate and transform the secondary currents and voltages generated by the measuring transformers. CPU Module (CPU) The CPU module handles all protection functions and logic. There are two CPU modules in the IED, CPU1 and CPU2, with the same software and hardware. They work in parallel and interlock each other to prevent maloperation due to the internal faults of one CPU modules. Moreover, the redundant A/D sampling channels are equipped. By comparing the data from redundant sampling channels, any sampling data errors and the channel hardware faults can be detected immediately and the proper alarm and blocking is initiated in time. Communication Module (COM) The communication module performs communication between the internal protection system and external equipments such as HMI, engineering workstation, substation automation system, RTU, etc., to transmit remote metering, remote signaling, SOE, event reports and record data. Up to 3 channels isolated electrical or optical Ethernet ports and up to 2 channels RS485 serial communication ports can be provided in communication module to meet the communication demands of different substation automation system and RTU at the same time. The time synchronization port is equipped, which can work in pulse mode or IRIG-B mode. SNTP mode can be applied through communication port. In addition, a series printer port is also reserved. Binary Input Module (BIM) The binary input module is used to connect the input signals and alarm signals such as the auxiliary contacts of the circuit breaker (CB), etc. Binary Output Module (BOM) The binary output modules mainly provide tripping output contacts, initiating output contacts and signaling output contacts. All the tripping output relays have contacts with a high switching capacity and are blocked by protection startup elements. Each output relay can be configured to satisfy the demands of users. Power Supply Module (PSM) The power supply module is used to provide the correct internal voltages and full isolation between the terminal and the battery system. 30

35 Hardware Dimension Figure 11 4U, 19 case with rear cover Table 2 Dimension of the IED case Legend A B C D E Dimension (mm) Figure 12 Cut-out on the panel Table 3 Dimension of the cutout for IED mounting Legend A B C D E Dimension (mm)

36 Connection A. Typical rear terminal diagram 32

37 Connection 33

38 Connection 34

39 Connection B. Typical analogue inputs connection for 2 windings transformer with 2 breakers on high and low voltage windings respectively 35

40 Connection C. Typical analogue inputs connection for 2 windings transformer with 1 breaker on high and low voltage windings respectively 36

41 Connection D. Typical analogue inputs connection for 3 windings transformer with 1 breaker on high, medium and low voltage windings respectively 37

42 Connection E. Typical analogue inputs connection for 3 windings transformer with 2 breakers on high and medium voltage winding and 1 breaker on low voltage windings respectively 38

43 Connection F. Typical analogue inputs connection for 3 windings transformer with 3 breaker on high and low voltage windings respectively, and 1 breaker on medium voltage winding 39

44 Connection G. Typical analogue inputs connection for autotransformer with 2 breaker on high voltage winding, and 1 breaker on medium and low voltage windings respectively * * AIM 1 a01 b01 * * IH1A * * IH1 IH1B IH1C a02 a03 b02 b03 A B C IH1A IH1B IH1C IH1 IH1N IH2N IH2C IH2B IH2A IH2 C B A IH2 IH1N IH2A IH2B IH2C a04 a05 a06 b04 b05 b06 UH UHA UHB UHC UHN IH0 IH2N IREFH IREFH INBKH a07 a08 b07 b08 IG IM1 INBKH IG1C IG1BIG1A IG1N IM1N IM1AIM1B IM1C UHA a11 A B C UH UHB UHC a10 b10 IH0 IREFH IREFH INBKH * * * * * * * * IM1 UHN IM1A IM1B IM1C b11 a01 a02 a03 AIM 2 b01 b02 b03 INBKH IM1N IG1A a04 b04 IG IG1B IG1C a05 a06 b05 b06 IG1N UMA a11 UL ULAULBULCUHN * * * IL1N IL1C IL1B IL1A UMAUMBUMC UMN UM IL1 UM IL1 UMB UMC UMN IL1A IL1B IL1C IL1N a10 b10 b11 a01 a02 a03 AIM 3 b01 b02 b03 IL2A a04 b04 A IL2 IL2B IL2C a05 a06 b05 b06 B IL2N C UL ULA ULB ULC a11 a10 b10 ULN b11 40

45 Connection H. Typical analogue inputs connection for reactor application with all CTs 41

46 Connection I. Typical analogue inputs connection for reactor application with three-phase CTs on HV and LV side of reactor 42

47 Connection J. Typical analogue inputs connection for reactor application with three-phase CTs on HV side of main reactor and single phase CT of neutral point reactor (near grounding) 43

48 Connection K. Typical analogue inputs connection for reactor application with three-phase CTs on HV side of main reactor and single phase CT of neutral point reactor (near main reactor) Protection IED a10 a09 b09 b10 UHA UHB UHC UHN * * * a01 b01 a02 b02 a03 b03 IHA IHB IHC * b07 3IH0 a07 44

49 Technical data Frequency Item Standard Data Rated system frequency IEC Hz or 60Hz Internal current transformer Item Standard Data Rated current I r IEC or 5 A Nominal current range Nominal current range of sensitive CT 0.05 I r to 30 I r to 1 A Power consumption (per phase) 0.1 VA at I r = 1 A; 0.5 VA at I r = 5 A 0.5 VA for sensitive CT Thermal overload capability IEC IEC I r for 1 s 4 I r continuous Internal voltage transformer Item Standard Data Rated voltage V r (ph-ph) IEC V /110 V Nominal range (ph-e) Power consumption at V r = 110 V IEC DL/T V to 120 V 0.1 VA per phase Thermal overload capability (phase-neutral voltage) IEC DL/T V r, for 10s 1.5 V r, continuous Auxiliary voltage Item Standard Data Rated auxiliary voltage U aux IEC to 250V Permissible tolerance IEC ±%20 U aux Power consumption at quiescent state Power consumption at maximum load IEC IEC W per power supply module 60 W per power supply module Inrush Current IEC T 10 ms/i 25 A per power supply 45

50 Technical data module, Binary inputs Item Standard Data Input voltage range IEC /125 V 220/250 V Threshold1: guarantee operation IEC V, for 220/250V 77V, for 110V/125V Threshold2: uncertain operation IEC V, for 220/250V ; 66V, for 110V/125V Response time/reset time IEC Software provides de-bounce time Power consumption, energized IEC Max. 0.5 W/input, 110V Max. 1 W/input, 220V 46

51 Technical Data Binary outputs Item Standard Data Max. system voltage IEC V /~ Current carrying capacity IEC A continuous, 30A,200ms ON, 15s OFF Making capacity IEC W( ) at inductive load with L/R>40 ms 1000 VA(AC) Breaking capacity IEC V, 0.15A, at L/R 40 ms 110V, 0.30A, at L/R 40 ms Mechanical endurance, Unloaded IEC ,000,000 cycles (3 Hz switching frequency) Mechanical endurance, making IEC cycles Mechanical endurance, breaking IEC cycles Specification state verification Contact circuit resistance measurement Open Contact insulation test (AC Dielectric strength) IEC IEC IEC IEC IEC IEC IEC IEC UL/CSA TŰV 30mΩ AC1000V 1min Maximum temperature of parts and materials IEC Front communication port Item Number 1 Data Connection Communication speed Max. length of communication cable Isolated, RS232; front panel, 9-pin subminiature connector, for software tools 9600 baud 15 m 47

52 Technical Data RS485 communication port Item Data Number 0 to 2 Connection Max. length of communication cable Test voltage 2-wire connector Rear port in communication module 1.0 km 500 V AC against earth For IEC protocol Communication speed Factory setting 9600 baud, Min baud, Max baud Ethernet communication port Item Electrical communication port Data Number 0 to 3 Connection Max. length of communication cable RJ45 connector Rear port in communication module 100m For IEC protocol Communication speed 100 Mbit/s For IEC protocol Communication speed 100 Mbit/s Optical communication port ( optional ) Number 0 to 2 Connection Optical cable type Max. length of communication cable SC connector Rear port in communication module Multi-mode 2.0km IEC protocol Communication speed 100 Mbit/s IEC protocol Communication speed 100 Mbit/s 48

53 Technical Data Time synchronization Mode IRIG-B signal format Item Pulse mode IRIG-B000 Data Connection Voltage levels 2-wire connector Rear port in communication module differential input Environmental influence Item Recommended permanent operating temperature Storage and transport temperature limit Permissible humidity Data -10 C to +55 C (Legibility of display may be impaired above +55 C /+131 F) -25 C to +70 C 95 % of relative humidity IED design Case size Weight Item 4U 19inch 10kg Data 49

54 Technical Data Product safety-related Tests Item Standard Data Over voltage category IEC Category III Pollution degree IEC Degree 2 Insulation IEC Basic insulation Degree of protection (IP) Power frequency high voltage withstand test Impulse voltage test Insulation resistance IEC IEC IEC EN ANSI C37.90 GB/T DL/T IEC IEC EN ANSI C37.90 GB/T DL/T IEC IEC EN ANSI C37.90 GB/T DL/T Front plate: IP40 Rear, side, top and bottom: IP 30 2KV, 50Hz 2.8kV between the following circuits: auxiliary power supply CT / VT inputs binary inputs binary outputs case earth 500V, 50Hz between the following circuits: Communication ports to case earth time synchronization terminals to case earth 5kV (1.2/50μs, 0.5J) If U i 63V 1kV if U i <63V Tested between the following circuits: auxiliary power supply CT / VT inputs binary inputs binary outputs case earth Note: U i : Rated voltage 100 MΩ at 500 V 50