Current reversal logicSetOperCurrRev toOn to activate the function.SettDelayRev timer at the maximum reset time for the communication equipment that givesthe carrier receive (CRLx) signal plus 30ms. A minimum setting of40ms is recommended,typical60ms.A longtDelayRev setting increases security against unwanted tripping, but delay the faultclearing in case of a fault developing from one line to involve the other one. The probability ofthis type of fault is small. Therefore settDelayRev with a good margin.Set the pickup delaytPickUpRev to <80% of the breaker operate time, but with a minimum of20ms.Weak-end infeed logicSetOperationWEI toEcho, to activate the weak-end infeed function with only echo function.SetOperationWEI toEcho&Trip to obtain echo with trip.SettPickUpWEI to10 ms, a short delay is recommended to avoid that spurious carrier receivedsignals will activate WEI and cause unwanted communications.Set the voltage criterionUPP< andUPE< for the weak-end trip to70% of the system basevoltageUBase. The setting should be below the minimum operate voltage of the system butabove the voltage that occurs for fault on the protected line. The phase-to-phase elementsmust be verified to not operate for phase to earth faults.When single phase tripping is required a detailed study of the voltages atphase-to-phase respectively phase-to-earth faults, at different fault locations,is normally required.13.4 Local acceleration logic ZCLCPSCH SEMOD52894-1 v413.4.1 IdentificationM14860-1 v4Function description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberLocal acceleration logic ZCLCPSCH - -13.4.2 Application M13821-3 v3The local acceleration logic (ZCLCPSCH) is used in those applications where conventionalteleprotection scheme is not available (no communication channel), but the user still requirefast clearance for faults on the whole line.This logic enables fast fault clearing during certain conditions, but naturally, it can not fullyreplace a teleprotection scheme.The logic can be controlled either by the autorecloser (zone extension) or by the loss-of-loadcurrent (loss-of-load acceleration).Section 13 1MRK 505 363-UEN AScheme communication262Application manual
