CSC-150 Busbar Protection IED Technical Application Manual

Transcription

1 CSC-150 Busbar Protection IED Technical Application Manual

2 CSC-150 Busbar Protection IED Technical Application Manual Compiled: Jin Rui Checked: Hou Changsong Standardized: Li Lianchang Inspected: Cui Chenfan Version: V1.01 Doc.Code:0SF (E) Issued Date:

3 Version:V1.01 Doc. Code: 0SF (E) Issued Date: Copyright owner: Beijing Sifang Automation Co., Ltd Note: the company keeps the right to perfect the instruction. If equipment does 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 Automation Co., Ltd. We reserve all rights to this document, even in the event that a patent is issued and a different commercial proprietary right is registered. Improper use, 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 us as soon as possible. The data contained in this manual is intended solely for the IED description and is not to be deemed to be a statement of guaranteed properties. In the interests of our customers, we constantly seek to ensure that our products are developed to the latest technological standards as a result it is possible that there may be some differences between the hardware/software product and this information product. Manufacturer: Beijing Sifang Automation Co., Ltd. Tel: , ext Fax: sf_sales@sf-auto.com Website: Add: No.9, Shangdi 4th Street, Haidian District, Beijing, P.R.C

4 Preface Purpose of this manual This manual describes the functions, operation, installation, and placing into service of IED CSC-150. In particular, one will find: Information on how to configure the IED scope and a description of the IED functions and setting options; Instructions for mounting and commissioning; Compilation of the technical specifications; A compilation of the most significant data for experienced users in the Appendix. Target audience This manual mainly face to installation engineer, commissioning engineer and operation engineer with perfessional electric and electrical knowledge, rich experience in protection function, using protection IED, test IED, responsible for the installation, commissioning, maintenance and taking the protection IED in and out of normal service. Applicability of this manual This manual is valid for CSC-150 multifunction protection IED. Technical support In case of further questions concerning the CSC family, please contact SiFang compay or your local SiFang representative. Safety information Strictly follow the company and international safety regulations. Working in a high voltage environment requires serious approch to aviod human injuries and damage to equipment Do not touch any circuitry during operation. Potentially lethal

5 voltages and currents are present Avoid to touching the circuitry when covers are removed. The IED contains electirc circuits which can be damaged if exposed to static electricity. Lethal high voltage circuits are also exposed when covers are removed Using the isolated test pins when measuring signals in open circuitry. Potentially lethal voltages and currents are present Never connect or disconnect wire and/or linker to or from IED during normal operation. Dangerous voltages and currents are present. Operation may be interrupted and IED and measuring circuitry may be damaged Always connect the IED to protective earth regardless of the operating conditions. Operating the IED without proper earthing may damage both IED and measuring circuitry and may cause injuries in case of an accident. Do not disconnect the secondary connection of current transformer without short-circuiting the transformer s secondary winding. Operating a current transformer with the secondary winding open will cause a high voltage that may damage the transformer and may cause injuries to humans. Do not remove the screw from a powered IED or from an IED connected to power circuitry. Potentially lethal voltages and currents are present Using the certified conductive bags to transport PCBs (modules). Handling modules with a conductive wrist strap connected to protective earth and on an antistatic surface. Electrostatic discharge may cause damage to the module due to electronic circuits are sensitive to this phenomenon

6 Do not connect live wires to the IED, internal circuitry may be damaged When replacing modules using a conductive wrist strap connected to protective earth. Electrostatic discharge may damage the modules and IED circuitry When installing and commissioning, take care to avoid electrical shock if accessing wiring and connection IEDs Changing the setting value group will inevitably change the IEDs operation. Be careful and check regulations before making the change

7 Contents Chapter 1 Introduction Overview Features Functions Protection functions Monitoring functions Station communication IED software tools... 6 Chapter 2 General IED application Display on LCD screen LCD screen display function Analog display function Report display function Menu dispaly function Report record Disturbance recorder Introduction Setting Self-supervision function Self supervision principle Self supervision report Time synchroniation function Introduction Synchronization principle Synchronization from IRIG Synchronization via PPS or PPM Synchronization via SNTP Setting Introduction Operation principle Authorization Introduction Chapter 3 Busbar differential protection Busbar differential protection Introduction Protection principle Operation principle Automatic ratio compensation Disconnector replica Circuit breaker status... 21

8 1.2.5 Current transformer open circuit supervision Differential current saturation supervision Sequence trip Logic diagram Input and output signals Setting parameters Setting list Reports Technical data Chapter 4 Circuit breaker failure protection Circuit breaker failure protection Introduction Protection principle General description of CBF protection The current criterion evaluation Logic diagram Input and output signals Setting parameters Setting list IED reports Technical data Chapter 5 Dead zone protection Dead zone protection Introduction Protection principle Function description Logic diagram Input and output signals Setting parameter Setting list IED reports Technical data Chapter 6 Secondary system supervision Current circuit supervision Introduction Function principle Current circuit supervision for feeder Current circuit supervision for busbar coupler Logic diagram Input and output signals Setting parameter Setting list IED reports Fuse failure supervision VT... 54

9 2.1 Introduction Function principle Three phases (symmetrical) VT Fail Single/two phases (asymmetrical) VT Fail Logic diagram Input and output signals Setting parameter Setting list IED reports Technical data Auxiliary contacts of circuit breaker and disconnector supervision Chapter 7 Monitoring function Self-supervision Chapter 8 Station communication Overview Protocol IEC communication protocol IEC communication protocol Communication port Front communication port RS485 communication ports Ethernet communication ports Technical data Typical substation communication scheme Typical time synchronizing scheme Chapter 9 Hardware Introduction IED structure IED module arrangement Local human-machine interface Introduction Liquid crystal display (LCD) LED Keyboard IED menu Menu construction Operation status Settings Query report Setup Test BO Set Time Testing Contrast... 77

10 3 Analog input module Introduction Terminals of analog input module Technical data Communication module Introduction Terminals of communication module Substaion communication port RS232 communication ports RS485 communication ports Ethernet communication ports Time synchronization port Technical data Binary input module Introduction Terminals of binary input module Technical data Binary output module Introduction Terminals of binary output module Technical data Power supply module Introduction Terminals of power supply module Technical data Technical data Type tests IED design CE certificate Chapter 10 Appendix General setting list IED parameter Function setting list Binary setting list General report list Typical connection CT Requirement Overview Current transformer classification Abbreviations (according to IEC , -6, as defined) General current transformer requirements Protective checking current CT class Accuracy class

11 4.4.4 Ratio of CT Rated secondary current Secondary burden Rated equivalent secondary e.m.f requirements Busbar differential protection

12

13 Chapter 1 Introduction Chapter 1 Introduction About this chapter This chapter gives an overview of SIFANG Busbar Protection IED. 1

14 Chapter 1 Introduction 1 Overview The CSC-150 is selective, reliable and high speed busbar protection IED (Intelligent Electronic Device), with powerful capabilities to cover following applications: For various busbar arrangements, including those listed below: Single Busbar Two Single Busbars connected with bus coupler Two Separate Busbars in 1 CB arrangement Double Busbar Main and Transfer Busbar Double Main and one Transfer Busbar Main and Main/Transfer Busbar For solidly earthed, low impedance earthed or isolated power system Used in a wide range of voltage levels, up to 750kV Communication with station automation system The IED provides reliable busbar differential protection with integrated check zone, short saturation-free time and fast tripping time as well as circuit breaker failure protection and dead zone protection. 2

15 Chapter 1 Introduction 2 Features Protection and monitoring IED with extensive functional library, user configuration possibility and expandable hardware design to meet with user s special requirements Inter-lock between two CPU modules, avoiding maloperation due to internal severe fault of one module Busbar differential protection (87BB) Low-impedance centralized differential protection Selective zone tripping Extreme stability against exteral fault, short CT saturation-free time Phase-segraegated measuring system Integrated check zone Bus couplers/disconnetor is definable in busbar scheme A complete protection functions library, include: Busbar differential protection (87BB) Circuit breaker failure protection (50BF) Dead zone protection (50SH-Z) Voltage transformer secondary circuit supervision (97FF) Current transformer secondary circuit supervision Self-supervision to all modules in the IED Complete IED information recording: tripping reports, alarm reports, startup 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 (Light Emitting Diodes) and output relays satisfied users requirement Versatile human-machine interface 3

16 Chapter 1 Introduction Multifunctional software tool CSmart for setting, monitoring, fault recording analysis, configuration, etc. 4

17 Chapter 1 Introduction 3 Functions 3.1 Protection functions Description ANSI Code IEC Logical Node Name IEC graphical symbol Differential protection Busbar differential protection 87BB PDIF Breaker control function Breaker failure protection 50BF RBRF 3I> BF I 0 >BF I 2 >BF Dead zone protection 50SH-Z CT secondary circuit supervision Secondary system supervision VT secondary circuit supervision 97FF Position of circuit breaker, disconnector and other switching devices monitoring 3.2 Monitoring functions Self-supervision Fault recorder Description 3.3 Station communication Description Front communication port Isolated RS232 port Rear communication port 0-2 isolated electrical RS485 communication ports 5

18 Chapter 1 Introduction 0-3 Ethernet electrical/optical communication ports Time synchronization port Communication protocols IEC protocol IEC protocol 3.4 IED software tools Functions Reading measuring value Reading IED report Setting IED testing Disturbance recording analysis IED configuration Printing 6

19 Chapter 2 General IED application Chapter 2 General IED application About this chapter This chapter describes the use of the included software functions in the IED. The chapter discusses general application possibilities. 7

20 Chapter 2 General IED application 1 Display on LCD screen 1.1 LCD screen display function The LCD screen displays measured analog quantities, report ouputs and menu. 1.2 Analog display function The analog display includes measured Ia, Ib, Ic, 3I0, Ua, Ub, Uc. 1.3 Report display function The report display includes tripping, alarm and operation reports. 1.4 Menu dispaly function The menu dispaly includes main menu and debugging menu, see chapter Chapter 9 for detail. 8

21 2 Report record Chapter 2 General IED application The report record includes tripping, alarm and operation reports. See Chapter 10 general report list for detail. 9

22 Chapter 2 General IED application 3 Disturbance recorder 3.1 Introduction To get fast, complete and reliable information about fault current, voltage, binary signal and other disturbances in the power system is very important. This is accomplished by the disturbance recorder function and facilitates a better understanding of the behavior of the power system and related primary and secondary equipment during and after a disturbance. An analysis of the recorded data provides valuable information that can be used to explain a disturbance, basis for change of IED setting plan, improvement of existing equipment etc. The disturbance recorder, always included in the IED, acquires sampled data from measured analogue quantities, calculated analogue quantity, binary input and output signals. The function is characterized by great flexibility and is not dependent on the operation of protection functions. It can even record disturbances not tripped by protection functions. The disturbance recorder information is saved for each of the recorded disturbances in the IED and the user may use the local human machine interface or dedicated tool to get some general information about the recordings. The disturbance recording information is included in the disturbance recorder files. The information is also available on a station bus according to IEC and IEC Fault wave recorder with great capacity, can record full process of any fault, and can save the corresponding records. Optional data format or wave format is provided, and can be exported through serial port or Ethernet port by COMTRADE format. 3.2 Setting Abbr. Explanation Default Unit Min. Max. T_Pre Fault Time setting for recording time before fault occurred 0.05 s T_Post Fault Time setting for recording time after fault occurred 0.3 s DR_Sample Rate Sample rate for fault recording (0: 600Hz, 1: 1200Hz)

23 4 Self-supervision function Chapter 2 General IED application The IED may test all hardware components itself, including loop out of the relay coil. Watch can find whether or not the IED is in fault through warning LED and warning characters which show in liquid crystal display and display reports to tell fault type. The method of fault elimination is replacing fault board or eliminating external fault. 4.1 Self supervision principle Measuring the resistance between analog circuits and ground Measuring the output voltage in every class Checking the zero drift and scale Verifying alarm circuit Verifying binary input Checking actual live tripping including circuit breaker Checking the setting values and parameters 4.2 Self supervision report Table 1 Self supervision report Abbr.(LCD Display) CPU Abnormality EquipPara Discord SetGroup Discord Setting Discord Comm Recovery Call Config Fail PLC Verify Fail Description CPU is abnormal Equipment parameter discordance of two CPUs Setting group discordance of two CPUs Setting discordance of two CPUs Communication recovery Call configuration failure PLC verifying failure 11

24 Chapter 2 General IED application 5 Time synchroniation function 5.1 Introduction Use the time synchronization source selector to select a common source of absolute time for the IED when it is a part of a protection system. This makes comparison of events and disturbance data between all IEDs in a SA system possible. 5.2 Synchronization principle Time definitions The error of a clock is the difference between the actual time of the clock, and the time the clock is intended to have. The rate accuracy of a clock is normally called the clock accuracy and means how much the error increases, i.e. how much the clock gains or loses time. A disciplined clock is a clock that knows its own faults and tries to compensate for them, i.e. a trained clock. Synchronization principle From a general point of view synchronization can be seen as a hierarchical structure. A module is synchronized from a higher level and provides synchronization to lower levels. 12 A module is said to be synchronized when it periodically receives synchronization messages from a higher level. As the level decreases, the accuracy of the synchronization decreases as well. A module can have

25 Chapter 2 General IED application several potential sources of synchronization, with different maximum errors, which gives the module the possibility to choose the source with the best quality, and to adjust its internal clock from this source. The maximum error of a clock can be defined as a function of: The maximum error of the last used synchronization message The time since the last used synchronization message The rate accuracy of the internal clock in the module Synchronization from IRIG The built in GPS clock module receives and decodes time information from the global positioning system. The module is located on the CPU Module. The GPS interfaces to the IED supply two possible synchronization methods, IRIGB and PPS (or PPM) Synchronization via PPS or PPM The IED accepts PPS or PPM to the GPS interfaces on the CPU Module. These pulses can be generated from e.g. station master clock. If the station master clock is not synchronized from a world wide source, time will be a relative time valid for the substation. Both positive and negative edges on the signal can be accepted. This signal is also considered as a fine signal Synchronization via SNTP SNTP provides a Ping-Pong method of synchronization. A message is sent from an IED to an SNTP-server, and the SNTP-server returns the message after filling in a reception time and a transmission time. SNTP operates via the normal Ethernet network that connects IEDs together in an IEC61850 network. For SNTP to operate properly, there must be a SNTP-server present, preferably in the same station. The SNTP synchronization provides an accuracy that will give 1ms accuracy for binary inputs. The IED itself can be set as a SNTP-time server. 13

26 Chapter 2 General IED application 6 Setting 6.1 Introduction Settings are divided into separate lists according to different functions. The setting consists of two parts -setting list and communication parameters. 6.2 Operation principle The setting procedure can be ended at any time by the key SET or QUIT. If the key SET is pressed, the display shows the content of Select. The range of setting zone is from 1 to 4. After confirming with the setting zone-key SET, those new settings will be valid. If key QUIT is pressed instead, all modifications which have been changed will be ignored. 14

27 7 Authorization 7.1 Introduction Chapter 2 General IED application To safeguard the interests of our customers, both the IED and the tools that are accessing the IED are protected, subject of authorization handling. The concept of authorization, as it is implemented in the IED and the associated tools is based on the following facts: There are two types of points of access to the IED: local, through the local HMI remote, through the communication ports There are different levels (or types) of guest, super user and protection engineer that can access or operate different areas of the IED and tools functionality. 15

28 Chapter 2 General IED application 16

29 Chapter 3 Busbar differential protection Chapter 3 Busbar differential protection About this chapter This chapter describes the protection principle, input and output signals, parameter, logic diagram, IED report and technical data used for busbar differential protection. 17

30 Chapter 3 Busbar differential protection 1 Busbar differential protection 1.1 Introduction Busbar differential protection represents the main protection function of the IED. It is characterized by a high measurement accuracy as well as flexible matching to most of busbar configurations. The operation is based on the percentage restraint principle with an extreme stability feature against heavy CT saturation caused by external fault. 1.2 Protection principle Operation principle Figure 1 illustrates the characteristic of busbar differential protection function. idiff K=1 Operating zone K=K_Diff I_Diff ires Figure 1 Characteristic of busbar differential protection where: i Diff : Busbar differential current i Res : Busbar restraint current I_Diff: The sensitive threshold of pickup current of busbar differential protection K_Diff: the settable slope of the characteristic If a short circuit occurs on the busbars whereby the same phase relation 18

31 Chapter 3 Busbar differential protection applies to all infeeding currents, then the fault characteristic is a straight line inclined at 45. Any difference in phase relation of the fault currents leads to a lowering of the fault characteristic. The settable slope, K_Diff is represented as a straight line with corresponding gradient and forms the operating characteristic. The differential current i Diff and the restraining current i Res are calculated in the IED according to following formula. The following definitions are applied for each phase. where: n 1, n 2, n n : CT transformation ratios of various feeders connected to the busbar. The IED is informed about these values by user-defined settings The IED evaluates the differential current and the restraining current at consecutive sampling intervals. For a continual N samples evaluating window, the busbar protection would issue a trip command if there are more than (N-2) samples fulfilling following condition in the program observation window: The above mentioned calculation is performed in relevant bus zones as well as in check zone, respectively. The trip command can be issued only when both the faulty bus zone and the check zone are in operating area. 19

32 Chapter 3 Busbar differential protection S1 S2 S1 S2 S1 S2 S1 S2 Bus coupler CB1 CB2 CBn CBn Bus zone I S1 CB1 CB2 CB1 CB2 Check zone CBn Feeder 1 Feeder 2 Feeder n Bus zone II S2 CB1 CB2 CBn Figure 2 Measurement method for the check zone, bus zone I and bus zone II on double busbar arrangement Automatic ratio compensation CT ratios of the system may be different in various feeders, because the load conditions may be different in the feeders. The IED adjusts CT ratio of all feeders automatically, making the secondary currents fulfilling Krichhoff s current law (KCL). In order to insure the accuracy, the difference of CT ratios among various feeders should not be more than 4 times Disconnector replica The IED confirms the disconnector status by monitoring the disconnector status contacts. For each disconnector, both the normally open status contact (NO) and normally close status contact (NC) are required. Based on the status of these two contacts, the IED can discriminate error of the contacts and then alarm or/and block the relevant bus zone of differential protection depending on the setting. If blocking of the protection is selected, the IED would issue an alarm signal and would block the protection. If no blocking is 20

33 Chapter 3 Busbar differential protection selected, only alarm signal would be issued and the protection would continue to its operation according to the previous healthy state of the disconnector before the contacts error Circuit breaker status The feeder or coupler circuit breaker status contacts together with disconnector status contacts are used to determine the actual bus connection state for differential current calculation and indication of busbar connection Both normally open status contact and normally close status contact of circuit breakers of all feeders including bus coupler are connected to the IED. Based on the status of these two contacts, the IED can discriminate error of the contacts and then alarm until the error is cleared, and the protection would continue its operation according the previous healthy state of the breaker before the contacts error Current transformer open circuit supervision When an open circuit occurs in secondary circuit of current transformers, differential current appears in bus-section selective zones. Furthermore, if the faulty current transformer corresponds to a feeder, differential current would further appear in check zone and bus zone to which the feeder is connected. The IED detects such a condition and issues respective alarm report. Moreover, it is possible to block busbar differential protection when a CT open circuit is detected Differential current saturation supervision When an external fault occurs near the busbar, it may lead to current transformer saturation on the faulty feeder. The resulting differential current may cause the protection to maloperate if no measure is taken to detect saturation condition. To cope with the problem, the IED provides a sensitive element to detect current transformer saturation according to the waveform characteristics of differential and restraining current. Before the fault occurrence, current flowing through current transformers are almost in rated value and therefore secondary current can be transformed accurately. When the short circuit happens, still current transformer can transform current value without saturation for short period after short circuit. In other words, current transformers will not go into saturation immediately 21

34 Chapter 3 Busbar differential protection after sever short circuit occurrence. At these instants, the differential current is zero. The IED adopts this characteristic to detect current transformer saturation. The free time for CT saturation detection is only 2 ms Sequence trip In case of bus coupler with only one CT, when a fault occurs between the CT and bus coupler circuit breaker while the circuit breaker is closed, the IED will trip the bus section near bus coupler circuit breaker instantaneously, and after a fixed time delay, if the bus coupler circuit breaker is opened, the IED will trip the other bus section. The tripping logic is illustrated in Figure 3. Delay trip Instantaneous trip Bus A Bus B IFAULT Line A1 Line An Line B1 Line Bm Legend: Closed CB Figure 3 Trip logic to clear fault between coupler breaker and its CT Logic diagram 22

35 Chapter 3 Busbar differential protection id > (I_Diff) and id > K_Diff if : Busbar I & Trip BusBar 1 id > (I_Diff) and id > K_Diff if : Check zone id > (I_Diff) and id > K_Diff if : Busbar II & Trip BusBar 2 Figure 4 Busbar differential protection logic diagram for double busbar arrangement 1.3 Input and output signals IP1 IP2 IP3 CB Open CB Close Isolator ON Isolator Off Trip Table 2 Analog input list Signal Description IP1 Signal for current input 1 IP2 Signal for current input 2 IP3 Signal for current input 3 Table 3 Binary output list Signal Trip Description Busbar differential protection issue trip command 1.4 Setting parameters Setting list Table 4 Function setting list for busbar differential protection 23

36 Chapter 3 Busbar differential protection NO. Default Abbr. Explanation Unit Min. Max I_Diff K_Diff I_CTFailAlm:Feeder I_CTFailBlk:Feeder I_CTFailAlm:B/C I_CTFailBlk:B/C Current setting for busbar differential protection A Restraint factor for busbar differential protection Current setting for CT failure alarm: feeder A Current setting for CT failure blocking: feeder A Current setting for CT failure alarm: Bus Coupler A Current setting for CT failure blocking: Bus A Coupler Table 5 Binary setting list for busbar differential protection Name Description Default Unit Min. Max. Func_Diff ON Busbar differential protection enabled or disabled CT Fail Alarm ON CT fail alarm enabled or disabled CT Fail Block ON CT fail blocking enabled or disabled Reports Table 6 Event information list Information Diff Startup BZ1 Diff Tp: PhA BZ1 Diff Tp: PhB BZ1 Diff Tp: PhC BZ2 Diff Tp: PhA BZ2 Diff Tp: PhB BZ2 Diff Tp: PhC BZT Diff Tp: PhA BZT Diff Tp: PhB BZT Diff Tp: PhC Description differential protection startup Phase A differential protection of Bus zone 1 trip Phase B differential protection of Bus zone 1 trip Phase C differential protection of Bus zone 1 trip Phase A differential protection of Bus zone 2 trip Phase B differential protection of Bus zone 2 trip Phase C differential protection of Bus zone 2 trip Phase A differential protection of Transfer bus zone trip Phase B differential protection of Transfer bus zone trip Phase C differential protection of Transfer bus zone trip 1.6 Technical data 24

37 Chapter 3 Busbar differential protection Table 7 Technical data for busbar differential protection Item Rang or Value Tolerance Differential Current 0.4 Ir to Ir ±5% setting or ±0.02Ir Stabilization factor Differential current reset threshold Operating time Reset time 0.1 Ir < 15ms typically at 200% settg < 50ms 25

38 Chapter 3 Busbar differential protection 26

39 Chapter 4 Circuit breaker failure protection Chapter 4 Circuit breaker failure protection About this chapter This chapter presents the protection principle, input and output signals, parameter, logic diagram, IED report and technical data included in circuit breaker protection. 27

40 Chapter 4 Circuit breaker failure protection 1 Circuit breaker failure protection 1.1 Introduction 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 operates separately for each feeder and coupler with dedicated settings. Once a circuit breaker operating failure occurs on a feeder/transformer, the bus section which the feeder/transformer is connected with can be selectively isolated by the protection. In addition a transfer trip signal is issued to trip the remote end circuit breaker of the feeder or other transformer windings. In the event of a circuit breaker failure with a busbar fault, a transfer trip signal is issued to trip the remote end circuit breaker of the feeder or other transformer windings. The current criteria are in combination with three phase current, zero and negative sequence current to achieve a higher security. 2 trip stages (local and surrounding breaker tripping) Related bus zone tripping in second stage Transfer trip command to the remote line end in second stage Internal/ external initiation Single/three phase CBF initiation Current criteria checking (including phase current, zero and negative sequence current) 1.2 Protection principle General description of CBF protection 28 Circuit breaker failure protection can be enabled or disabled for each bay in

41 Chapter 4 Circuit breaker failure protection the IED via binary setting. If setting 1 is applied for the corresponding bay, CBF protection would be enabled. In this case, by operation of a protection function, and subsequent CBF initiation by respective protection function, a programmed timer runs toward a preset time delay limit. This time delay is set by user under the settings, for example, T_CBF1 Bay1. If the circuit breaker has not been opened after expiration of the preset time limit, the circuit breaker failure protection issues a command to trip circuit breaker (e.g. via a second trip coil). If the circuit breaker doesn t respond to the repeated trip command, until another preset delay time which is set at T_CBF2 Bay1, the protection issues a trip command to isolate the fault by tripping other surrounding backup circuit breakers (e.g. the other CBs connected to the same bus section as the faulty CB). This operation logic and setting described for CBF protection of bay1, is available for the other bays too and the operation logic and settings are same as bay1. Initiation of CBF protection can be performed by both the internal and external protection functions. If it is desired to initiate the CBF protection by means of external protection functions, specified binary inputs (BI) should be marshaled. Internal protection functions can initiate the CBF protection integrated in the IED. The principle for breaker failure detection based on the current criterion which is to check whether the actual current flow effectively disappeared after a tripping command had been issued The current criterion evaluation The current elements of the CBF protection include the phase current detector, the zero sequence current detector and the negative sequence current detector. If one of the three current elements is met, the current element is open. Since circuit breaker is supposed to be open when current disappears from the circuit, the first criterion (current monitoring) is the most reliable way for IED to be informed about proper operation of circuit breaker. Therefore, current monitoring is applied to detect circuit breaker failure condition. In this context, the monitored current of each phase is compared with the pre-defined setting. Furthermore, it is possible to implement current checking in case of zero-sequence ( ) and negative-sequence currents (3I 2 =I A +a 2 I B +ai C ) via binary setting. If the zero-sequence and negative-sequence currents checking are enabled, zero sequence and negative-sequence current are compared separately with the corresponding settings. 29

42 Chapter 4 Circuit breaker failure protection Logic diagram Bay n Func_CBF On 3I0: Bay n > 3I0_CBF:Bay n 3I2: Bay n > 3I2_CBF:Bay n Bay n CBF Chk 3I0/3I2 Bay n CBF Chk 3I0/3I2 OR PhA Ini BF Bay n IA: Bay n > I_CBF:Bay n OR AND T_CBF1:Bay n Trip PhA: Bay n PhB Ini BF Bay n IB: Bay n > I_CBF:Bay n OR AND T_CBF1:Bay n Trip PhB: Bay n PhC Ini BF Bay n IC: Bay n > I_CBF:Bay n OR AND T_CBF1:Bay n Trip PhC: Bay n 3Ph Ini BF Bay n OR OR AND T_CBF1:Bay n Trip 3Ph: Bay n Diff Prot Trip: BZ1 Bay n Connected to BUS1 OR OR T_CBF2:Bay n Diff Prot Trip: BZ2 Bay n Connected to BUS2 OR Trip BUS to which Bay n connected Block AR: Bays on Bus Bay n Init from Ext CBF Trans Trip: Bay n 3I0: Bay n > 0.1In 3I2: Bay n > 0.1In OR IA: Bay n > 0.1In OR AND IB: Bay n > 0.1In OR AND IC: Bay n > 0.1In OR AND OR T_CBF2:Bay n OR AND Trip BUS to which Bay n connected Block AR: Bays on Bus Trans Trip: Bay n Figure 5 Logic diagram for CBF protection 1.3 Input and output signals 30

43 Chapter 4 Circuit breaker failure protection IP1 IP2 IP3 PhA init BF PhB init BF PhC init BF 3Ph init BF CBF1 Trip CBF2 Trip Table 8 Analog input list Signal Description IP1 Signal for current input 1 IP2 Signal for current input 2 IP3 Signal for current input 3 Table 9 Binary input list Signal PhA init BF PhB init BF PhC init BF 3Ph init BF Description Phase A initiate CBF protection Phase B initiate CBF protection Phase C initiate CBF protection Three hase initiate CBF protection Table 10 Binary output list Signal CBF1 Trip CBF2 Trip Description Circuit breaker failure protection stage 1 trip Circuit breaker failure protection stage 2 trip 1.4 Setting parameters Setting list Table 11 Function setting list for circuit breaker failure protection NO. Default Abbr. Explanation Unit Min. Max I_CBF:Bay1 Phase current setting for CBF protection of bay I0_CBF:Bay1 Zero sequence current setting for CBF 31

44 Chapter 4 Circuit breaker failure protection NO. Default Abbr. Explanation Unit Min. Max. protection of bay I2_CBF:Bay1 Negative sequence current setting for CBF protection of bay T_CBF1:Bay T_CBF2:Bay I_CBF:Bay I0_CBF:Bay I2_CBF:Bay T_CBF1:Bay T_CBF2:Bay I_CBF:Bay I0_CBF:Bay I2_CBF:Bay T_CBF1:Bay T_CBF2:Bay I_CBF:Bay I0_CBF:Bay I2_CBF:Bay T_CBF1:Bay4 Time delay for CBF stage 1 of bay 1 s Time delay for CBF stage 2 of bay 1 s Phase current setting for CBF protection of bay 2 Zero sequence current setting for CBF protection of bay 2 Negative sequence current setting for CBF protection of bay 2 Time delay for CBF stage 1 of bay 2 s Time delay for CBF stage 2 of bay 2 s Phase current setting for CBF protection of bay 3 Zero sequence current setting for CBF protection of bay 3 Negative sequence current setting for CBF protection of bay 3 Time delay for CBF stage 1 of bay 3 s Time delay for CBF stage 2 of bay 3 s Phase current setting for CBF protection of bay 4 Zero sequence current setting for CBF protection of bay 4 Negative sequence current setting for CBF protection of bay 4 Time delay for CBF stage 1 of bay 4 s

45 Chapter 4 Circuit breaker failure protection NO. Default Abbr. Explanation Unit Min. Max T_CBF2:Bay I_CBF:Bay I0_CBF:Bay I2_CBF:Bay T_CBF1:Bay T_CBF2:Bay I_CBF:Bay I0_CBF:Bay I2_CBF:Bay T_CBF1:Bay T_CBF2:Bay I_CBF:Bay I0_CBF:Bay I2_CBF:Bay T_CBF1:Bay T_CBF2:Bay I_CBF:Bay I0_CBF:Bay8 Time delay for CBF stage 2 of bay 4 s Phase current setting for CBF protection of bay 5 Zero sequence current setting for CBF protection of bay 5 Negative sequence current setting for CBF protection of bay 5 Time delay for CBF stage 1 of bay 5 s Time delay for CBF stage 2 of bay 5 s Phase current setting for CBF protection of bay 6 Zero sequence current setting for CBF protection of bay 6 Negative sequence current setting for CBF protection of bay 6 Time delay for CBF stage 1 of bay 6 s Time delay for CBF stage 2 of bay 6 s Phase current setting for CBF protection of bay 7 Zero sequence current setting for CBF protection of bay 7 Negative sequence current setting for CBF protection of bay 7 Time delay for CBF stage 1 of bay 7 s Time delay for CBF stage 2 of bay 7 s Phase current setting for CBF protection of bay 8 Zero sequence current setting for CBF protection of bay 8 33

46 Chapter 4 Circuit breaker failure protection NO. Default Abbr. Explanation Unit Min. Max. Negative sequence I2_CBF:Bay T_CBF1:Bay T_CBF2:Bay I_CBF:Bay I0_CBF:Bay I2_CBF:Bay T_CBF1:Bay T_CBF2:Bay I_CBF:Bay I0_CBF:Bay I2_CBF:Bay T_CBF1:Bay T_CBF2:Bay I_CBF:Bay I0_CBF:Bay I2_CBF:Bay T_CBF1:Bay11 34 current setting for CBF protection of bay 8 Time delay for CBF stage 1 of bay 8 s Time delay for CBF stage 2 of bay 8 s Phase current setting for CBF protection of bay 9 Zero sequence current setting for CBF protection of bay 9 Negative sequence current setting for CBF protection of bay 9 Time delay for CBF stage 1 of bay 9 s Time delay for CBF stage 2 of bay 9 s Phase current setting for CBF protection of bay 10 Zero sequence current setting for CBF protection of bay 10 Negative sequence current setting for CBF protection of bay 10 Time delay for CBF stage 1 of bay 10 s Time delay for CBF stage 2 of bay 10 s Phase current setting for CBF protection of bay 11 Zero sequence current setting for CBF protection of bay 11 Negative sequence current setting for CBF protection of bay 11 Time delay for CBF stage 1 of bay 11 s

47 Chapter 4 Circuit breaker failure protection NO. Default Abbr. Explanation Unit Min. Max T_CBF2:Bay11 Time delay for CBF stage 2 of bay 11 s I_CBF:Bay12 Phase current setting for CBF protection of bay I0_CBF:Bay12 Zero sequence current setting for CBF protection of bay I2_CBF:Bay12 Negative sequence current setting for CBF protection of bay T_CBF1:Bay12 Time delay for CBF stage 1 of bay 12 s T_CBF2:Bay12 Time delay for CBF stage 2 of bay 12 s I_CBF:Bay13 Phase current setting for CBF protection of bay I0_CBF:Bay13 Zero sequence current setting for CBF protection of bay I2_CBF:Bay13 Negative sequence current setting for CBF protection of bay T_CBF1:Bay13 Time delay for CBF stage 1 of bay 13 s T_CBF2:Bay13 Time delay for CBF stage 2 of bay 13 s I_CBF:Bay14 Phase current setting for CBF protection of bay I0_CBF:Bay14 Zero sequence current setting for CBF protection of bay I2_CBF:Bay14 Negative sequence current setting for CBF protection of bay T_CBF1:Bay14 Time delay for CBF stage 1 of bay 14 s T_CBF2:Bay14 Time delay for CBF stage 2 of bay 14 s I_CBF:Bay15 Phase current setting for CBF protection of bay 35

48 Chapter 4 Circuit breaker failure protection NO. Default Abbr. Explanation Unit Min. Max I0_CBF:Bay15 Zero sequence current setting for CBF protection of bay I2_CBF:Bay15 Negative sequence current setting for CBF protection of bay T_CBF1:Bay T_CBF2:Bay I_CBF:Bay I0_CBF:Bay I2_CBF:Bay T_CBF1:Bay T_CBF2:Bay I_CBF:Bay I0_CBF:Bay I2_CBF:Bay T_CBF1:Bay T_CBF2:Bay17 Time delay for CBF stage 1 of bay 15 s Time delay for CBF stage 2 of bay 15 s Phase current setting for CBF protection of bay 16 Zero sequence current setting for CBF protection of bay 16 Negative sequence current setting for CBF protection of bay 16 Time delay for CBF stage 1 of bay 16 s Time delay for CBF stage 2 of bay 16 s Phase current setting for CBF protection of bay 17 Zero sequence current setting for CBF protection of bay 17 Negative sequence current setting for CBF protection of bay 17 Time delay for CBF stage 1 of bay 17 s Time delay for CBF stage 2 of bay 17 s Table 12 Binary setting list for circuit breaker failure protection Name Description Default Unit Min. Max. Bay1 Func_CBF On CBF protection enabled or disable for bay

49 Chapter 4 Circuit breaker failure protection Name Description Default Unit Min. Max. Bay1 CBF Chk 3I0/3I2 Enable or disable the function of checking zero and negative sequence current for bay Bay1 Init from Ext CBF Bay2 Func_CBF On Bay2 CBF Chk 3I0/3I2 Bay2 Init from Ext CBF Bay3 Func_CBF On Bay3 CBF Chk 3I0/3I2 Bay3 Init from Ext CBF Bay4 Func_CBF On Bay4 CBF Chk 3I0/3I2 Bay4 Init from Ext CBF Bay5 Func_CBF On Bay5 CBF Chk 3I0/3I2 Bay5 Init from Ext CBF Bay6 Func_CBF On Bay6 CBF Chk 3I0/3I2 Bay6 Init from Ext CBF Bay7 Func_CBF On Initiation from external CBF function for bay CBF protection enabled or disable for bay Enable or disable the function of checking zero and negative sequence current for bay 2 Initiation from external CBF function for bay CBF protection enabled or disable for bay Enable or disable the function of checking zero and negative sequence current for bay 3 Initiation from external CBF function for bay CBF protection enabled or disable for bay Enable or disable the function of checking zero and negative sequence current for bay 4 Initiation from external CBF function for bay CBF protection enabled or disable for bay Enable or disable the function of checking zero and negative sequence current for bay 5 Initiation from external CBF function for bay CBF protection enabled or disable for bay Enable or disable the function of checking zero and negative sequence current for bay 6 Initiation from external CBF function for bay CBF protection enabled or disable for bay

50 Chapter 4 Circuit breaker failure protection Name Description Default Unit Min. Max. Bay7 CBF Chk 3I0/3I2 Enable or disable the function of checking zero and negative sequence current for bay Bay7 Init from Ext CBF Bay8 Func_CBF On Bay8 CBF Chk 3I0/3I2 Bay8 Init from Ext CBF Bay9 Func_CBF On Bay9 CBF Chk 3I0/3I2 Bay9 Init from Ext CBF Bay10 Func_CBF On Bay10 CBF Chk 3I0/3I2 Bay10 Init from Ext CBF Bay11 Func_CBF On Bay11 CBF Chk 3I0/3I2 Bay11 Init from Ext CBF Bay12 Func_CBF On Bay12 CBF Chk 3I0/3I2 Bay12 Init from Ext CBF Bay13 Func_CBF On Initiation from external CBF function for bay CBF protection enabled or disable for bay Enable or disable the function of checking zero and negative sequence current for bay 8 Initiation from external CBF function for bay CBF protection enabled or disable for bay Enable or disable the function of checking zero and negative sequence current for bay 9 Initiation from external CBF function for bay CBF protection enabled or disable for bay Enable or disable the function of checking zero and negative sequence current for bay Initiation from external CBF function for bay CBF protection enabled or disable for bay Enable or disable the function of checking zero and negative sequence current for bay 11 Initiation from external CBF function for bay CBF protection enabled or disable for bay Enable or disable the function of checking zero and negative sequence current for bay 12 Initiation from external CBF function for bay CBF protection enabled or disable for bay 13 38

51 Chapter 4 Circuit breaker failure protection Name Description Default Unit Min. Max. Bay13 CBF Chk 3I0/3I2 Enable or disable the function of checking zero and negative sequence current for bay Bay13 Init from Ext CBF Bay14 Func_CBF On Bay14 CBF Chk 3I0/3I2 Bay14 Init from Ext CBF Bay15 Func_CBF On Bay15 CBF Chk 3I0/3I2 Bay15 Init from Ext CBF Bay16 Func_CBF On Bay16 CBF Chk 3I0/3I2 Bay16 Init from Ext CBF Bay17 Func_CBF On Bay17 CBF Chk 3I0/3I2 Bay17 Init from Ext CBF Initiation from external CBF function for bay CBF protection enabled or disable for bay Enable or disable the function of checking zero and negative sequence current for bay 14 Initiation from external CBF function for bay CBF protection enabled or disable for bay Enable or disable the function of checking zero and negative sequence current for bay 15 Initiation from external CBF function for bay CBF protection enabled or disable for bay Enable or disable the function of checking zero and negative sequence current for bay Initiation from external CBF function for bay CBF protection enabled or disable for bay Enable or disable the function of checking zero and negative sequence current for bay 17 Initiation from external CBF function for bay IED reports Table 13 Event information list Information CBF Startup CBF1 Trip BZ1 CBF2 Trip Description CBF protection startup CBF protection stage 1 trips CBF protection stage 2 of bus zone I trips 39

52 Chapter 4 Circuit breaker failure protection Information BZ2 CBF2 Trip BZT CBF2 Trip CBF Transf.Trip Description CBF protection stage 2 of bus zone II trips CBF protection stage 2 of transfer bus zone issues trip command The IED issues transfer trip command to the remote end of the feeder or the other windings of transformer. 1.6 Technical data Table 14 Technical data for circuit breaker failure protection Item Rang or Value Tolerance phase current Negative sequence current zero sequence current 0.08 Ir to Ir ±3% setting or ±0.02Ir Time delay of stage s to s, step 0.01s ±1% setting or +25 ms, at Time delay of stage s to s, step 0.01s 200% operating setting Reset time of stage 1 < 20ms 40