Breaker failure protection function block description

Transcription

1 function block description Document ID: PRELIMINARY VERSION

2 User s manual version information Version Date Modification Compiled by Preliminary Preliminary version, without technical information Petri PRELIMINARY VERSION 2/10

3 CONTENTS 1 Breaker failure protection function Application Mode of operation The decision logic (Decision logic) Technical summary Technical data Summary of the parameters Summary of the generated output signals Summary of the input signals The symbol of the function block in the graphic editor PRELIMINARY VERSION 3/10

4 1 Breaker failure protection function 1.1 Application After a protection function generates a trip command, it is expected that the circuit breaker opens and/or the fault current drops below the pre-defined normal level. If not, then an additional trip command must be generated for all backup circuit breakers to clear the fault. At the same time, if required, a repeated trip command can be generated to the circuit breaker(s) which are expected to open. The breaker failure protection function can be applied to perform this task. 1.2 Mode of operation The starting signal of the breaker failure protection function is usually the trip command of any other protection function. The user has the task to define these starting signals using the graphic equation editor as the General Start (BRF50_GenSt_GrO_), or if the operation of the individual phases is needed, then the start signals for the phases individually. The phase start signals are: Start L1 (BRF50_StL1_GrO_), Start L2 (BRF50_StL2_GrO_) and Start L3 (BRF50_StL3_GrO_). Dedicated timers start at the rising edge of the start signals, one for the backup trip command and one for the repeated trip command, separately for operation in the individual phases. During the running time of the timers the function optionally monitors the currents, the closed state of the circuit breakers or both, according to the user s choice. The selection is made using the enumerated parameter BRF50_Oper_EPar_ (Operation). If this parameter setting is Current, the current limit values BRF50_StCurrPh_IPar_ (Start current Ph) and BRF50_StCurrN_IPar_ (Start current N) must be set correctly. The binary inputs indicating the status of the circuit breaker poles have no meaning. If this parameter setting is Contact, the current limit values BRF50_StCurrPh_IPar_ (Start current Ph) and BRF50_StCurrN_IPar_ (Start current N) have no meaning. The binary inputs indicating the status of the circuit breaker poles must be programmed correctly using the graphic equation editor. The input variables to be programmed are: BRF50_CBClL1_GrO_ (CB closed L1), BRF50_CBClL2_GrO_ (CB closed L2) and BRF50_CBClL3_GrO_ (CB closed L3). If this parameter setting is Current/Contact, the current parameters and the status signals must be set correctly. The breaker failure protection function resets only if all conditions for faultless state are fulfilled. If at the end of the running time of the backup timer the currents do not drop below the predefined level, and/or the monitored circuit breaker is still in closed position, then a backup trip command is generated in the phase(s) where the timer(s) run off. The time delay is defined using the parameter BRF50_BUDel_TPar_ (Backup Time Delay). If repeated trip command is to be generated for the circuit breakers that are expected to open, then the enumerated parameter BRF50_ReTr_EPar_ (Retrip) must be set to On. In this case, at the end of the timer(s) the delay of which is set by the timer parameter BRF50_TrDel_TPar_ (Retrip Time Delay), a repeated trip command is also generated. The pulse duration of the trip command is not shorter than the time defined by setting the parameter BRF50_Pulse_TPar_ (Pulse length). The breaker failure protection function can be enabled or disabled by setting the parameter BRF50_Oper_EPar_ (Operation) to Off. PRELIMINARY VERSION 4/10

5 Dynamic blocking is possible using the binary input BRF50_Blk_GrO_ (Block). The conditions are to be programmed by the user, using the graphic equation editor. 1.3 The decision logic (Decision logic) The decision logic module combines status signals, binary and enumerated parameters to generate the dead line or live line status signals. Binary status signals The breaker failure protection function has binary input signals. The conditions are defined by the user, applying the graphic equation editor. The binary input status signals of the breaker failure protection function are listed in Table 1-1. Binary status signal Title Explanation BRF50_Blk_GrO_ Block Blocking of the breaker failure protection function BRF50_CBClL1_GrO_ CB closed L1 Signal indicating the closed state of the circuit breaker in phase L1 BRF50_CBClL2_GrO_ CB closed L2 Signal indicating the closed state of the circuit breaker in phase L2 BRF50_CBClL3_GrO_ CB closed L3 Signal indicating the closed state of the circuit breaker in phase L3 BRF50_GenSt_GrO_ General Start General starting signal BRF50_StL1_GrO_ Start L1 Starting signal in phase L1 BRF50_StL2_GrO_ Start L2 Starting signal in phase L2 BRF50_IoSt_GrO_ Start Io Starting signal for the residual current Internal signal: IL1> Current in phase L1 is above the preset parameter value Internal signal: IL2> Current in phase L2 is above the preset parameter value Internal signal: IL3> Current in phase L3 is above the preset parameter value Internal signal: Io> Current 3Io is above the preset parameter value Enumerated parameter Current/Contact The monitored condition is current, contact or both Enumerated parameter Retrip On/Off The retrip command must be enabled (On) Table 1-1 The binary input status signals of the decision logic PRELIMINARY VERSION 5/10

6 General Start IL1> Start L1 t RETRIP PULSE Retrip L1 IL2> Start L2 t RETRIP PULSE Retrip L2 IL3> Start L3 Start Io Current t RETRIP PULSE Retrip L3 Contact Io> CB closed L1 t BACKUP TRIP PULSE Backup Trip CB closed L2 CB closed L3 Retrip Figure 1-1 The logic scheme of the decision logic PRELIMINARY VERSION 6/10

7 The binary output status signals of the breaker failure protection function are listed in Table 1-2. Binary status signal Title Explanation BRF50_BuTr_GrI_ Backup Trip Trip command generated for the backup circuit breakers BRF50_TrL1_GrI_ Retrip L1 Repeated trip command in phase L1 BRF50_TrL2_GrI_ Retrip L2 Repeated trip command in phase L2 BRF50_TrL3_GrI_ Retrip L3 Repeated trip command in phase L3 Table 1-2 The binary output status signals of the decision logic PRELIMINARY VERSION 7/10

8 1.4 Technical summary Technical data Function Effective range* Accuracy* *To be defined by types tests Table 1-3 Technical data of the breaker failure protection function Summary of the parameters Enumerated parameters Parameter name Title Selection range Default Selection of the operating mode BRF50_Oper_EPar_ Operation Off,Current,Contact,Current/Contact Current Switching on or off of the repeated trip command BRF50_ReTr_EPar_ Retrip Off,On On Tables 1-4 Enumerated parameters of the breaker failure protection function Integer parameters Parameter name Title Unit Min Max Step Default Phase current setting BRF50_StCurrPh_IPar_ Start current Ph % Neutral current setting BRF50_StCurrN_IPar_ Start current N % Table 1-5 Integer parameters of the breaker failure protection function Timer parameters Parameter name Title Unit Min Max Step Default Time delay for repeated trip command generation BRF50_TrDel_TPar_ Retrip Time Delay msec Time delay for trip command generation for the backup circuit breaker(s) BRF50_BUDel_TPar_ Backup Time Delay msec Trip command impulse duration BRF50_Pulse_TPar_ Pulse lenght msec Table 1-6 Timer parameters of the breaker failure protection function PRELIMINARY VERSION 8/10

9 1.4.3 Summary of the generated output signals The binary output status signals of the breaker failure protection function are listed in Table 1-7. Binary status signal Title Explanation BRF50_BuTr_GrI_ Backup Trip Trip command generated for the backup circuit breakers BRF50_TrL1_GrI_ Retrip L1 Repeated trip command in phase L1 BRF50_TrL2_GrI_ Retrip L2 Repeated trip command in phase L2 BRF50_TrL3_GrI_ Retrip L3 Repeated trip command in phase L3 Table 1-7 Binary output status signals of the breaker failure protection function Summary of the input signals Binary status signals The breaker failure protection function has binary input status signals. The conditions are defined by the user, applying the graphic equation editor. The binary input status signals of the breaker failure protection function are listed intable 1-8. Binary status signal Title Explanation BRF50_Blk_GrO_ Block Blocking of the breaker failure protection function BRF50_CBClL1_GrO_ CB closed L1 Signal indicating the closed state of the circuit breaker in phase L1 BRF50_CBClL2_GrO_ CB closed L2 Signal indicating the closed state of the circuit breaker in phase L2 BRF50_CBClL3_GrO_ CB closed L3 Signal indicating the closed state of the circuit breaker in phase L3 BRF50_GenSt_GrO_ General Start General starting signal BRF50_StL1_GrO_ Start L1 Starting signal in phase L1 BRF50_StL2_GrO_ Start L2 Starting signal in phase L2 BRF50_StL3_GrO_ Start L3 Starting signal in phase L3 BRF50_IoSt_GrO_ Start Io Starting signal for the residual current Table 1-8 Binary input signals of the breaker failure protection function PRELIMINARY VERSION 9/10

10 1.4.5 The symbol of the function block in the graphic editor The names of the input and output signals are parts of the Binary status signal names listed in Table 1-7 andtable 1-8 PRELIMINARY VERSION 10/10