PCS 902s x datasheet EN overseas general x r1 00

Pilot distance protection  Independent pilot zone forward direction and reverse direction, mho or quadrilateral characteristics  PUTT, POTT, Blocking, Unblocking, Zone Extension  Cu

About This Document

About This Document

The manual describes the control, protection, measurement and supervision functions with the information of relevant hardware for PCS-902S Line Distance Relay

Copyright © 2019 NR All rights reserved

NR, the NR logo are either registered trademarks or trademarks of NR Electric Co., Ltd No NR trademarks may be used without written permission NR products appearing in this document may be covered by P.R China and foreign patents NR Electric Co., Ltd reserves all rights and benefits afforded under P.R China and international copyright and patent laws in its products, including but not limited to software, firmware and documentation NR Engineering Co., Ltd is licensed to use this document as well as all intellectual property rights owned or held by NR Electric Co., Ltd, including but not limited to copyright, rights in inventions, patents, know-how, trade secrets, trademarks and trade names, service marks, design rights, database rights and rights in data, utility models, domain names and all similar rights

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To the extent required the products described herein meet applicable IEC and IEEE standards, but no such assurance is given with respect to local codes and ordinances because they vary greatly

Although every reasonable effort is made to present current and accurate information, this document does not purport to cover all details or variations in equipment nor provide for every possible contingency

to be met in connection with installation, operation, or maintenance Should further information be desired or should particular problems arise which are not covered sufficiently for your purposes, please

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Document Revision History

Document Revision History

Overview

Overview

PCS-902S is a high-speed transmission line distance relay featuring single-pole and three-pole tripping and reclosing with synchronism check, which can protect overhead and underground lines, feeders and cables on all voltage levels with highest selectivity possible The large number of protective and automatic functions available permits their utilization in all areas of line protection The devices contain control, measurement and monitoring functions The large number of communication interfaces and communication protocols satisfies the requirements of communication-based selective protection and of automated operation Their modular structure permits line protection devices always to be adapted flexibly to the individual requirements

 Various function modules can satisfy various situations according to the different requirements of users Flexible and universal logic programming, user-defined configuration of BI/BOs, buttons and LEDs and powerful analog programming are supported

 Modularized hardware design makes the device be easily upgraded or repaired by a qualified service person It can be mixed with different I/O modules, with online self-check and monitoring function, and the device can be restored from abnormal operation only need to replace a single abnormal module

 Support memory check and error correction function, ensure high reliability and safety

 Support the internet communication protocol of native PRP/HSR and RSTP

 Fully compatible with IEC 61850 edition 1 & edition 2, support MMS service, IEC 62351 communication service, GOOSE communication in station level & process level, SV communication with multi-sampling rate

 Full comply with cyber security standards, including IEC62443, IEC62351, IEEE1686, NERC-CIP, support role based access control (RBAC), security audit, security encryption communication and security tool, improve the cyber security capability of devices

 Powerful COMTRADE fault and disturbance recording function is supported The whole recording time is automatically configurable by the fault duration, which is convenient to fault analysis and replay The recording sample rate is up to 9.6kHz

 Settable secondary rated current (1A/5A) and settable voltage threshold of binary input

 Support small size and large size LCD, control and multifunction button

 Support flush mounting, semi-flush mounting, surface mounting, wall mounting and other mounting methods

 Cross screw IO, CT/VT terminals can support AWG12 specification connector and 4mm2 lead

 Multiple variants with case size 1/1 or 1/2 × 19"

 Protection class of front side is up to IP54

Highlights

 PCS-Studio is the application software on the user's PC for the interface with PCS S series devices providing all the related functionality It ranges from device configuration to full substation design of bay integration

 Support IEEE1588, IRIG-B clock synchronization

 Support actual system phase sequence, either ABC or ACB, incorrect connection of actual phase sequence can automatically be verified and relevant protection functions can be blocked

 Equipped with high-speed large capacity output relay, its operation speed is less than 1ms and its break capacity is up to 10A The real-time supervision for output drive circuit can detect the abnormality in advance

 Support setup up to 40 users and allow each user to own different password and access authority

 6 zones distance protection, independent zero-sequence compensation factor for each zone,

the phase-to-ground and phase-to-phase characteristic of distance protection can be set

independently

 The unique power swing blocking releasing logic and can properly supervise distance protection

during power swing, which ensures distance protection to operate correctly for internal faults

during power swing, and prevents distance protection from mal-operation during power swing

 Unique phase selector has the same protection zone as operation element The phase selection is

automatically resulted according to the reliability of phase selector, so that to avoid probable

mistaken multi-phase selection by adopting overreaching phase selector

 Special overcurrent element of breaker failure protection, its dropoff time is no more than 15ms

 The overcurrent protection is combined with harmonic blocking and cold load starting logic, which

can prevent from mal-operation affected by impulse current while the transformer is initiated on

no-load

 Selectable IEC, ANSI inverse-time characteristic curves, also the curve can be defined by users and

the inverse-time dropoff curve selection is supported

 Support single-ended impedance-based fault location, mutual compensation for parallel lines

arrangement is also available

 Both dedicated fiber channel and multiplexing fiber channel are supported, and single mode and

multi-mode channel combination operation mode is enable Communication rate supports 64kbit/s

and 2Mbit/s, and communication protocol supports C37.94 and G.703

Pilot distance protection

 Independent pilot zone (forward direction and reverse direction, mho or quadrilateral characteristics)

 PUTT, POTT, Blocking, Unblocking, Zone Extension

 Current reversal logic

 Weak infeed echo or echo&trip

 Open breaker echo

Pilot directional earth-fault protection

 Directional zero-sequence comparison element for pilot scheme

 PTT, Blocking and Unblocking

 Current reversal logic

 Weak infeed echo or echo&trip

 Open breaker echo

 Load encroachment for each zone

 Power swing blocking and releasing for each zone

 Faulty phase selection for each zone

Phase overcurrent protection

 Up to 6 stages with independent logic

 Voltage control element for each stage

 Optional direction element for each stage, including forward direction, reverse direction or non direction

 Optional definite-time characteristics and inverse-time characteristics for each stage

 Trip purpose or alarm purpose for each stage

 Harmonic control element for each stage

67G

50/51G

Earth fault protection

 Up to 6 stages with independent logic

 Optional direction element for each stage, including forward direction, reverse direction or non direction

 Optional definite-time characteristics and inverse-time characteristics for each stage

 Selectable trip purpose or alarm purpose for each stage

 Harmonic control element for each stage

67Q

50/51Q

Negative-sequence overcurrent

protection

 Up to 2 stages with independent logic

 Optional direction element for each stage, including forward direction, reverse direction or non direction

 Optional definite-time characteristics and inverse-time characteristics for each stage

SOTF Switch onto fault

 Via distance measurement elements

 Via dedicated earth fault element

 Via phase overcurrent element

59P Phase overvoltage protection

 Up to 2 stages with independent logic

 Optional definite-time characteristics and inverse-time characteristics for each stage

 Optional phase voltage or phase-to-phase voltage

 Optional “1-out-of-3” logic or “3-out-of-3” logic

 Selectable trip purpose or alarm purpose for each stage 27P Phase undervoltage protection  Up to 2 stages with independent logic

 Optional definite-time characteristics and inverse-time

Functions Overview

characteristics for each stage

 Optional phase voltage or phase-to-phase voltage

 Optional “1-out-of-3” logic or “3-out-of-3” logic

 Blocked by instantaneous VT circuit failure

 Selectable trip purpose or alarm purpose for each stage

 Optional auxiliary criterion, including CB position check and current check

59Q

Negative-sequence overvoltage

protection

 Up to 2 stages with independent logic

 Selectable trip purpose or alarm purpose for each stage

59G Residual overvoltage protection  Up to 2 stages with independent logic

 Selectable trip purpose or alarm purpose for each stage 81O Overfrequency protection  Up to 6 stages with independent logic

 Voltage control element 81U Underfrequency protection  Up to 6 stages with independent logic

 Voltage control element 81R Rate of change of frequency protection  Up to 6 stages with independent logic

 Voltage control element 32R Reverse power protection  Up to 2 stages with independent logic

 Selectable trip purpose or alarm purpose for each stage

37 Undercurrent protection

 Optional auxiliary criterion, including CB position check and current check

 Selectable trip purpose or alarm purpose for each stage

50BF Breaker failure protection

 Phase-segregated re-trip and three-phases re-trip

 Optional current criterion (phase overcurrent element, zero-sequence overcurrent element, negative-sequence overcurrent element)

 Optional circuit breaker position check

 Two time delays 50DZ Dead zone protection  Clear the dead zone faults between CT and the circuit

breaker

62PD Pole discrepancy protection

 Initiated by three auxiliary contacts of phase-segregate circuit breaker

 Optional auxiliary criterion (zero-sequence current element

or negative-sequence current element)

46BC Broken conductor protection

 Adopt the ratio of negative-sequence current to positive-sequence current (Ι2/Ι1) to detect the broken conductor

25 Synchrocheck  Independent logic for auto-reclosing and manually closing

79 Auto-reclosing

 One shot or multi-shot

 1-pole AR, 3-pole AR or 1/3-pole AR

 Optional trigger mode, including protection operating and external binary input

Functions Overview

 Support synchro-check and voltage check

FL Fault location

 Single-end fault location

 Double-end fault location

 Zero-sequence mutual coupling compensation for parallel lines

DPFC is the abbreviation of deviation of power frequency component

Control Functions

 Circuit breaker & disconnector control (Remote/local)

 Synchronism check for remote and manual closing

 Event Recorder including 1024 disturbance records, 1024 binary events, 1024 supervision events,

256 control logs and 1024 device logs

 Disturbance recorder including 64 disturbance records with waveforms (The file format of disturbance recorder is compatible with international COMTRADE file.)

 Pilot communication channel supervision

 DC power supply supervision

 Channel status statistic

 System frequency supervision

Functions Overview Pilot channel scheme

 Optional single- or dual- pilot channels (fiber optic)

 Two RS-485 serial ports using IEC 60870-5-103

 One RS-485 serial port for clock synchronization

 Support GOOSE communication module using IEC 61850-8-1 GOOSE

 Full compatibility between IEC 61850 Editions 1 and 2

 Redundancy protocols PRP, HSR and RSTP

 One front RJ-45 port and one rear RJ-45 port for debugging

 4 Programmable operator pushbuttons with user-configurable labels

 Up to 18 programmable target LEDs with user-configurable labels

 1 RS-485 rear ports for printer

 Language switchover—English+ selected language

Functions Overview

 Parallel line compensation for fault location

 Switching system phase sequences function (ABC or ACB)

 Clock synchronization

 IRIG-B: IRIG-B via RS-485 differential level, TTL level or optical fibre interface

 PPS: Pulse per second (PPS) via RS-485 differential level or binary input

 PPM: Pulse per minute (PPM) via RS-485 differential level or binary input

 IEEE1588: Clock message based on IEEE1588 via optical fibre interface

 SNTP (PTP): Unicast (point-to-point) SNTP mode via Ethernet network

 SNTP (BC): Broadcast SNTP mode via Ethernet network

 Message (IEC103/Modbus/DNP3.0): Clock messages through IEC103 protocol, Modbus protocol and DNP3.0 protocol

Typical Application

Typical Application

PCS-902S protect overhead and underground lines, feeders and cables on all voltage levels with highest selectivity possible

Optical fibre channel or PLC channel

Communication channel via direct dedicated fibre, MUX or PLC

52

PCS-902S PCS-902S

Three-phase voltage

Single-phase voltage

Figure 0-2 Typical application of double circuit breakers

Protection Functions

Protection Functions

Circuit Breaker Position Supervision

In order to prevent that wrong status of CB position is input into the device via binary input, appropriate monitor method is used to check the rationality of the binary input When the binary input of CB open position is detected, the status of CB position will be thought as incorrect and an alarm [Alm_52b] will be issued if there is current detected in the line

Together with the status of circuit breaker and the information of external circuit, this function can be used to supervise control circuit of circuit breaker

Fault Detector (FD)

Fault detector is responsible to determine fault appearance on the protected power system The device will switch to protection calculation after the fault detector picks up, for example the calculation of distance protection, and to determine the operating logic If the fault is within the protected zone, the device will issue tripping command The fault detector continuously detects the change of phase-to-phase power frequency current and the calculated zero-sequence and negative-sequence currents The fault detector includes:

1 Fault detector based on DPFC current: DPFC current is greater than the setting value

2 Fault detector based on residual current: Zero-sequence current is greater than the setting value

3 Fault detector based on negative-sequence current: Negative-sequence current is greater than the setting value

Optical Pilot Channel (FO)

The devices can transmit Boolean quantities such as blocking signal, permissive signal and transfer trip signal to the remote end via optical fibre channel Up to 2 optical fibre channels are supported, which can

be dedicated optical fibre channel or multiplex channel, the channel mode could be selected as single-mode or multi-mode The communication rate can be 64kbits/s or 2048kbits/s, and G.703 or C37.94 are optional for communication protocol 8 digital bits are integrated in each frame of transmission message for various applications, and 8 binary signals are configurable Each received message frame via fibre optical channel will pass through security check to ensure the integrity of the message consistently

Pilot Distance Protection (85)

Pilot distance protection requires communication channel to exchange protection information at both ends The channel may be dedicated or multiplexed channel through optical fiber or any other communication media Pilot distance protection has schemes of permissive underreaching transfer trip (PUTT), permissive overreaching transfer trip (POTT) and blocking The device provides dual pilot

Protection Functions

distance protections The communication media and mode can be independent each other

Pilot distance protection determines whether it will send the signal to the remote end according to the discrimination result of the distance element or direction element Pilot distance protection can be divided into permissive scheme and blocking scheme according to whether the signal sent is used to permit tripping or block tripping For permissive scheme, it can be divided into overreaching mode or underreaching mode according to the setting of distance element and scheme selected, furthermore, it will provide the unblocking scheme as auxiliary function For overreaching mode, current reversal logic and weak infeed logic are available for parallel line operation and weak power source situation respectively

Pilot Directional Earth-fault Protection (85)

Pilot directional earth-fault protection can be used independently, for example, no distance protection is equipped with the device but fast operation is required for the whole line, or it is used as backup protection of pilot distance protection to enhance the sensitivity for an earth fault with high fault resistance

Pilot directional earth-fault protection comprises permissive scheme and blocking scheme It can share pilot channel 1 with pilot distance protection, or uses independent pilot channel 2 For underreach mode, pilot directional earth-fault always adopts independent pilot channel 2 Sending permissive signal (or terminating sending signal) to the opposite end is controlled by forward direction element Current reversal logic is available for parallel line operation and CB echo logic is provided once pilot directional earth fault protection is enabled Current reversal logic is only used for permissive scheme For blocking scheme, current reversal need not be considered because there is a settable time delay in pilot directional earth-fault protection

Distance Protection (21L)

Distance protection includes three independent phase-to-phase measuring loops as well as three independent phase-to-ground measuring loops Both mho and quadrilateral characteristics are available for different application In addition, load encroachment, power swing blocking and releasing, and faulty phase selection functions are also provided

Up to 8 zones distance protection are supplied, including 1 zone distance protection with fixed forward direction, 5 zones distance protection with settable direction, 1 zone pilot distance protection with fixed forward direction and 1 zone pilot distance protection with fixed reverse direction Each zone includes three independent phase-to-phase measuring loops as well as three independent phase-to-ground measuring loops Phase-to-ground distance element should be compensated by zero-sequence current

of local line Zone 2~6 can select forward direction, reverse direction and non direction

Load encroachment can distinguish effectively between heavily loaded line and faulty line, and the risk of encroachment of the load impedance into the tripping characteristics of the distance protection can be excluded

Power swing blocking and releasing can prevent distance protection from undesired operation during

Protection Functions

distance protection can operate reliably when a fault occurs during power swing

Based on distance protection characteristics, faulty phase can be identified correctly It is benefit for the faulty phase selection which is important to the line which uses phase-segregated circuit breaker and provides valid information for 1-pole AR and fault location

DPFC Distance Protection (21D)

As an independent fast protection, DPFC distance protection is mainly used to clear close up fault of long line quickly, its protected range can set as 60%~70% of the whole line Since DPFC distance protection only reflects fault component and is not influenced by current change due to load variation and power swing, power swing blocking (PSB) function is not required Moreover, there is no transient overreaching due to infeed current from the remote power supply because it is not influenced by load current

Distance Switch Onto Fault Protection (21SOTF)

Distance SOTF protection shares pickup signal as initiation condition with distance protection It is selectable among zone 2, 3 or 4 of distance protection which is accelerated to trip by manual closing or auto-reclosing, and they can enable or disable be controlled by power swing blocking Distance SOTF protection equips with independent time delay Zone 2 of distance protection is fixedly accelerated to trip

by 1-pole AR Zone 2 of distance protection is also accelerated to trip by pole discrepancy condition For single-phase fault, distance SOTF protection will accelerate to operate if another fault happens to the healthy phase before auto-reclosing

Phase Overcurrent Protection (50/51P)

The device can provide six stages of phase overcurrent protection with independent logic Each stage can be independently set as definite-time characteristics or inverse-time characteristics The dropout characteristics can be set as instantaneous dropout, definite-time dropout or inverse-time dropout It can

be chosen whether it is blocked by voltage control element or harmonic control element The direction control element can be set as no direction, forward direction and reverse direction Phase overcurrent protection picks up when the current exceeds the setting, and operates after a certain time delay Once the fault disappears, phase overcurrent protection will dropout Phase overcurrent protection can operate to trip or alarm

Phase Current SOTF Protection (50PSOTF)

Phase current SOTF protection will operate to trip three-phase circuit breaker with a time delay when manual closing or auto-reclosing For in-line transformer application, large inrush current generated during manual closing and auto-reclosing will lead to an undesired operation of phase current SOTF protection Second harmonic blocking can be selected to prevent maloperation due to inrush current

Protection Functions Earth Fault Protection (50/51G)

The device can provide six stages of earth fault protection with independent logic Each stage can be independently set as definite-time characteristics or inverse-time characteristics It can be chosen whether it is blocked by harmonic control element The direction control element can be set as no direction, forward direction and reverse direction The zero-sequence current used by earth fault protection always adopts calculated zero-sequence current Earth fault protection can operate to trip or alarm

Residual Current SOTF Protection (50GSOTF)

Residual current SOTF protection will operate to trip three-phase circuit breaker with a time delay via 1-pole auto-reclosing, manual closing or 3-pole auto-reclosing For in-line transformer application, large inrush current generated during manual closing and auto-reclosing will lead to an undesired operation of residual current SOTF protection Second harmonic blocking can be selected to prevent maloperation due to inrush current

Negative-sequence Overcurrent Protection (50/51Q)

The device can provide two stages of negative-sequence overcurrent protection with independent logic Each stage can be independently set as definite-time characteristics or inverse-time characteristics For parallel lines or a ring network line, the flow direction of negative-sequence current may be different Considering the selectivity of negative-sequence overcurrent protection, the direction control element can be set as no direction, forward direction and reverse direction Negative-sequence overcurrent protection can operate to trip or alarm

Phase Overvoltage Protection (59P)

The device can provide two stages of phase overvoltage protection with independent logic When a high voltage occurs in the system, phase overvoltage protection will operate to isolate the fault from the system after a time delay if the voltage is greater than the setting In addition, phase overvoltage protection also provides the alarm function to notify that there is the overvoltage in the system and find the cause timely to prevent from further deterioration of the fault

Each stage of phase overvoltage protection can be independently set as definite-time characteristics or inverse-time characteristics The dropout characteristics can be set as instantaneous dropout and definite-time dropout

Phase voltage or phase-to-phase voltage can be selected to be used by the protection calculation

“1-out-of-3” or “3-out-of-3” logic can be selected for the protection criterion (1-out-of-3 means any of three phase voltages, 3-out-of-3 means all three phase voltages)

Residual Overvoltage Protection (59G)

Protection Functions

residual voltage is greater than the setting, residual overvoltage protection will operate to isolate the fault from the system after a time delay In addition, residual overvoltage protection also provides the alarm function to notify that there is an earth fault leading to residual voltage generation, and find the cause timely to prevent from further deterioration of the fault Residual overvoltage protection supports definite-time characteristics The dropout characteristics can be set as instantaneous dropout and definite-time dropout

Negative-sequence Overvoltage Protection (59Q)

The device provides two stages of negative-sequence overvoltage protection If negative-sequence voltage is greater than the setting, negative-sequence overvoltage protection will operate Negative-sequence overvoltage protection is with independent definite-time characteristics and definite-time or instantaneous dropout characteristics

Phase Undervoltage Protection (27P)

The device can provide two stages of phase undervoltage protection with independent logic When the voltage drops in the system and it is lower than the setting, phase undervoltage protection will operate to isolate the fault from the system after a time delay In addition, phase undervoltage protection also provides the alarm function to notify that there is the undervoltage in the system and find the cause timely to prevent from further deterioration of the fault

Each stage of phase undervoltage protection can be independently set as definite-time characteristics or inverse-time characteristics The dropout characteristics can be set as instantaneous dropout and definite-time dropout

Phase voltage or phase-to-phase voltage can be selected to be used “1-out-of-3” or “3-out-of-3” logic can be selected for the protection criterion (1-out-of-3 means any of three phase voltages, 3-out-of-3 means all three phase voltages) The circuit breaker position with/without the current condition can be as

an auxiliary criterion for phase undervoltage protection

Overfrequency Protection (81O)

The device can provide six stages of overfrequency protection If the system frequency is greater than the setting, overfrequency protection will operate to remove some part of active power supplies from the system Overfrequency protection is with independent definite-time characteristics and with instantaneous dropout characteristics

Underfrequency Protection (81U)

The device can provide a six stages of underfrequency protection If the system frequency is less than the setting, underfrequency protection will operate to shedding some part of loads from the system Underfrequency protection is with independent definite-time characteristics and with instantaneous dropout characteristics

Protection Functions Frequency Rate-of-change Protection (81R)

The device can provide six stages of frequency rate-of-change protection If the system frequency rate-of-change is greater than the setting, frequency rate-of-change protection will operate Frequency rate-of-change protection is with independent definite-time characteristics and with instantaneous dropout characteristics

Reverse Power Protection (32R)

The device can provide two stages of reverse power protection If the reverse power is detected and it is greater than the setting, reverse power protection will operate Reverse power protection is with independent operating definite-time characteristics and with instantaneous dropout characteristics Reverse power protection can be enabled or disabled by the settings and the signals For some specific applications, reverse power protection needs to be blocked by the external signal, so the device provides

an input signal to be used to block reverse power protection

Undercurrent Protection (37)

The device can provide one stage of undercurrent protection for tripping purpose or alarm purpose For different protected equipment, single-phase criterion or three-phase criterion can be selected The circuit breaker position and the load current also can be taken as the enabling conditions of undercurrent protection Undercurrent protection is with definite-time operating characteristics and instantaneous dropout characteristics

Breaker Failure Protection (50BF)

According to the tripping information from the device and the auxiliary information (the current and the position) of target circuit breaker, breaker failure protection constitutes the criterion to discriminate whether the target circuit fails to open If the criterion is confirmed, breaker failure protection will operate

to trip the target circuit breaker with the re-tripping time delay, trip it again with the first time delay and trip the adjacent circuit breakers with the second time delay As a special backup protection, breaker failure protection can quickly isolate the fault, reduce the affected range by the fault, keep system stability and prevent generators, transformers and other primary equipments from seriously damaged For breaker failure protection, phase-segregated re-trip, three-phases re-trip and two time delays are available

Dead Zone Protection (50DZ)

For some wiring arrangement (for example, circuit breaker is located between CT and the line), if fault occurs between CT and circuit breaker, line protection can operate to trip circuit breaker quickly, but the fault have not been cleared since local circuit breaker is tripped Here dead zone protection is needed in order to trip relevant circuit breaker

Protection Functions

Broken Conductor Protection (46BC)

Broken-conductor fault mainly is single-phase broken or two-phases broken, so broken conductor protection based on the ratio of negative-sequence current to positive sequence current can detect the broken-conductor fault According to the ratio of negative-sequence current to positive-sequence current (I2/I1), it is used to judge whether there is an broken-conductor fault Negative-sequence current under normal operating condition (i.e unbalance current) is due to CT error and unbalance load, so the ratio of negative-sequence current to positive-sequence current (amplitude) is relative steady The value with margin can then be used as the setting of broken conductor protection It is mainly used to detect broken-conductor fault and CT circuit failure as well

Pole Discrepancy Protection (62PD)

The pole discrepancy of circuit breaker may occur during operation of a breaker with segregated operating gears for the three phases Pole discrepancy protection determines three-phase breaker pole discrepancy condition by its phase segregated CB auxiliary contacts In order to improve the reliability of pole discrepancy protection, zero-sequence current element or negative-sequence current element can

be selected as auxiliary criterion

Transfer Trip (TT)

The device provides phase-segregated transfer trip and three-phases transfer trip, which can be controlled by local fault detector In addition, the input signals of phase-segregated transfer trip and three-phases transfer trip are always supervised, and the device will issue an alarm and block transfer trip once the binary input is energized for longer than the setting value Both phase-segregated transfer trip and three-phases transfer can be selected to operate to block AR

Trip Logic (TRP)

Trip logic gathers signals from phase selection and protection tripping elements and then converts the operation signal from protection tripping elements to appropriate tripping signals The device can implement phase-segregated tripping or three-phase tripping, and may output the contact of blocking AR and the contact of initiating breaker failure protection

Automatic Reclosure (79)

AR can be used with either integrated device or external device When AR is used with integrated device, the internal protection logic can initiate AR, moreover, a tripping contact from external device can be connected to the device via input signal to initiate integrated AR

When AR is used as an independent device, it can be initiated by operating signal of protections The device can output some configurable output signals (such as, contact signals or digital signal, for example, GOOSE signal) to initiate external AR or block external AR The contact signals includes phase-segregated tripping signal, single-phase tripping signal, three-phase tripping signal, blocking AR

Fault Location (FL)

The device provides single-end fault location Fault location picks up after the device operates to trip when there is a fault in the line If the pickup time is greater than 25ms, fault location is calculated with a time delay of 10ms after the device operates to trip If the pickup time is smaller than 25ms, fault location

is calculated with a time delay of 20ms after the device operates to trip

When there is a protection tripping with faulty phase selection, the calculation of the fault impedance is initiated According to the fault impedance to locate the fault point, two calculation results are provided, which is the length of the fault point distance from the end of the device and its percentage of lines length

For parallel lines, there is a mutual coupling between each phase, and there is also a mutual coupling between parallel lines The coupling strength between parallel lines associated with the transposition way For parallel lines with fully transposition, positive-sequence and negative-sequence mutual coupling is very small, and usually can be ignored But zero-sequence mutual coupling has a greater influence on the line, so the measured impedance must consider the effect

Control Functions

Control Functions

Switchgear Control

A control command can realize various control signals such as the CB/DS/ES opening/closing In order

to ensure the reliability of the control output, a locking circuit is added to each control object The operation is strictly in accordance with the selection, check and execution steps, to ensure that the control operation can be safely and reliably implemented In addition, the device has a hardware self-checking and blocking function to prevent hardware damage from maloperation output

When the device is in the remote control mode, the control command may be sent via the IEC 60870-5-103 or IEC 61850 protocol; when it is in the local control mode, the local operation may be performed on the device LCD or panel handle

A complete control process is:

1 Protocol module sends a selection command;

2 Control module responds the success or failure result of selection;

3 If the selection is successful, the protocol module sends an execution command, otherwise it sends

a cancel command;

4 Control module responds the success or failure result of execution;

5 The control operation may be open/close or up/down/stop

When the device is in the maintenance status, it can still respond to local control commands

The switchgear control function can cooperate with functions such as synchronism check and interlocking criteria calculation to complete the output of the corresponding operation command It can realize the normal control output in one bay and the interlocking and programmable logic configuration between bays This device supports the following functional control module:

CSWI Control of circuit breaker (CB), disconnector switch (DS) or earthing switch (ES)

RMTLOC Remote or local control mode

XCBR Synthesis of CB position, three-phase or phase separated

XSWI Synthesis of DS/ES position

SXCBR/SCSWI Trip statistics of CB/DS/ES

RSYN Synchronism check for CB closing

CILO Interlocking logic for CB/DS/ES control

MCSWI Manual control of CB/DS/ES

Control Functions

The initiation of a control command may be sent to the device by the SCADA or the NCC through protocol IEC 60870-5-103 or IEC 61850 It may also be the operation of the device LCD or the manual triggering through configured signal The command is sent by the CPU to the control module for processing, and a control record is made on the CPU module according to the control result

Manual Closing Synchronism Check

The synchronism check includes synchro-check and dead charge check By comparing between the reference voltage and the synchronization voltage, the synchro-check is satisfied if the voltage difference, frequency difference, slip frequency difference and phase angle difference are all within their setting ranges The dead charge check mode checks only the synchro-check voltage Several dead charge check modes are supported, including dead synchronism voltage & dead reference voltage check, live synchronism voltage is & dead reference voltage, synchronism voltage is dead & live reference voltage, dead reference voltage, dead synchronism voltage, live synchronism voltage & dead reference voltage or dead synchronism voltage & live reference voltage, dead synchronism voltage or reference voltage

Voltage Switching

The voltage switching function can be used to switch the reference and synchronization voltages for double busbar and 3/2 CB arrangements The "Near priority" principle is adopted by default, and the user interface for programmable switching logic is also reserved

For double busbar arrangement, selection of appropriate voltage signals from Bus 1 and Bus 2 for synchronizing are required Line VT signal is taken as reference to check synchronizing with the voltage after voltage selection function

For one and a half breakers arrangement, selection of appropriate voltage signals among Line1 VT, Line2 VT and Bus 2 VT as reference voltage to check synchronizing with Bus 1 voltage signal for closing breaker at Bus 1 side

VT (secondary circuit) MCB auxiliary contact as a binary input can be connected to the binary input circuit of the device If MCB is open, the device will consider the VT circuit is not in a good condition and issues an alarm without a time delay If the auxiliary contact is not connected to the device, VT circuit supervision will be issued with time delay as mentioned in previous paragraph

CT Circuit Supervision (CTS)

Under normal conditions, CT secondary signal is continuously supervised by detecting the residual current and voltage If residual current is larger than the setting whereas residual voltage is less than the setting, and any phase current is less than 0.04In, CT circuit failure is considered