ABB REL650 Product Manual

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Contents

ABB REL650 Product Manual Manual pdf 22 page image

SAPFRC (81) measures frequency with high accuracy, and can beused for generation shedding, load shedding and remedial actionschemes. SAPFRC (81) can discriminate between a positive ornegative change of frequency. A definite time delay is provided foroperate.SAPFRC (81) is provided with an undervoltage blocking.8. Secondary system supervisionCurrent circuit supervision CCSRDIF (87)Open or short circuited current transformer cores can causeunwanted operation of many protection functions such asdifferential, ground-fault current and negative-sequence currentfunctions.It must be remembered that a blocking of protection functions atan occurrence of open CT circuit will mean that the situation willremain and extremely high voltages will stress the secondarycircuit.Current circuit supervision (CCSRDIF, 87) compares the residualcurrent from a three phase set of current transformer cores withthe neutral point current on a separate input taken from anotherset of cores on the current transformer.A detection of a difference indicates a fault in the circuit and isused as alarm or to block protection functions expected to giveinadvertent tripping.Fuse failure supervision SDDRFUFThe aim of the fuse failure supervision function SDDRFUF is toblock voltage measuring functions at failures in the secondarycircuits between the voltage transformer and the IED in order toavoid inadvertent operations that otherwise might occur.The fuse failure supervision function basically has three differentdetection methods, negative sequence and zero sequence baseddetection and an additional delta voltage and delta currentdetection.The negative sequence detection is recommended for IEDs usedin isolated or high-impedance grounded networks. It is based onthe negative-sequence measuring quantities, a high value ofnegative sequence voltage 3V2 without the presence of thenegative-sequence current 3I2.The zero sequence detection is recommended for IEDs used indirectly or low impedance grounded networks. It is based on thezero sequence measuring quantities, a high value of zerosequence voltage 3V0 without the presence of the zero sequencecurrent 3I0.For better adaptation to system requirements, an operation modesetting has been introduced which makes it possible to select theoperating conditions for negative sequence and zero sequencebased function. The selection of different operation modes makesit possible to choose different interaction possibilities betweenthe negative sequence and zero sequence based detection.A criterion based on delta current and delta voltagemeasurements can be added to the fuse failure supervisionfunction in order to detect a three phase fuse failure, which inpractice is more associated with voltage transformer switchingduring station operations.Breaker close/trip circuit monitoring TCSSCBRThe trip circuit supervision function TCSSCBR is designed tosupervise the control circuit of the circuit breaker. The trip circuitsupervision generates a current of approximately 1 mA throughthe supervised control circuit. The validity supervision of a controlcircuit is provided for power output contacts T1, T2 and T3.The function picks up and trips when TCSSCBR detects a tripcircuit failure. The trip time characteristic for the function is ofdefinite time (DT) type. The function trips after a predefinedoperating time and resets when the fault disappears.9. ControlSynchrocheck, energizing check, and synchronizing SESRSYN(25)The Synchronizing function allows closing of asynchronousnetworks at the correct moment including the breaker closingtime, which improves the network stability.Synchrocheck, energizing check, and synchronizing SESRSYN(25) function checks that the voltages on both sides of the circuitbreaker are in synchronism, or with at least one side dead toensure that closing can be done safely.SESRSYN (25) function includes a built-in voltage selectionscheme for double bus and breaker-and-a-half or ring busbararrangements.Manual closing as well as automatic reclosing can be checked bythe function and can have different settings.For systems, which are running asynchronous, a synchronizingfunction is provided. The main purpose of the synchronizingfunction is to provide controlled closing of circuit breakers whentwo asynchronous systems are going to be connected. Thesynchronizing function evaluates voltage difference, phase angledifference, slip frequency and frequency rate of change beforeissuing a controlled closing of the circuit breaker. Breaker closingtime is a parameter setting.Line distance protection REL650 ANSI 1MRK 506 337-BUS BProduct version: 1.322 ABB