ABB REL670 Product Manual

Also see for RELION REL670: Installation manual Installation manual Commissioning manual Product guide Communication protocol manual

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To accomplish this, three separate communication channels,that is, one per phase, each capable of transmitting a signal ineach direction is required.ZC1PPSCH can be completed with the current reversal andWEI logic for phase segregated communication, when foundnecessary in Blocking and Permissive overreaching schemes.Current reversal and weak-end infeed logic for distanceprotection ZCRWPSCHThe ZCRWPSCH function provides the current reversal andweak end infeed logic functions that supplement the standardscheme communication logic. It is not suitable for standaloneuse as it requires inputs from the distance protection functionsand the scheme communications function included within theterminal.On detection of a current reversal, the current reversal logicprovides an output to block the sending of the teleprotectionsignal to the remote end, and to block the permissive tripping atthe local end. This blocking condition is maintained longenough to ensure that no unwanted operation will occur as aresult of the current reversal.On verification of a weak end infeed condition, the weak endinfeed logic provides an output for sending the receivedteleprotection signal back to the remote sending end and otheroutput(s) for local tripping. For terminals equipped for single-and two-pole tripping, outputs for the faulted phase(s) areprovided. Undervoltage detectors are used to detect the faultedphase(s).Current reversal and weak-end infeed logic for phasesegregated communication ZC1WPSCHCurrent reversal and weak-end infeed logic for phasesegregated communication (ZC1WPSCH) function is used toprevent unwanted operations due to current reversal whenusing permissive overreach protection schemes in applicationwith parallel lines where the overreach from the two endsoverlaps on the parallel line.The weak-end infeed logic is used in cases where the apparentpower behind the protection can be too low to activate thedistance protection function. When activated, received carriersignal together with local undervoltage criteria and no reversezone operation gives an instantaneous trip. The received signalis also echoed back to accelerate the sending end.Local acceleration logic ZCLCPSCHTo achieve fast clearing of faults on the whole line, when nocommunication channel is available, local acceleration logic(ZCLCPSCH) can be used. This logic enables fast fault clearingand re-closing during certain conditions, but naturally, it can notfully replace a communication channel.The logic can be controlled either by the autorecloser (zoneextension) or by the loss-of-load current (loss-of-loadacceleration).Scheme communication logic for residual overcurrentprotection ECPSCHTo achieve fast fault clearance of earth faults on the part of theline not covered by the instantaneous step of the residualovercurrent protection, the directional residual overcurrentprotection can be supported with a logic that usescommunication channels.In the directional scheme, information of the fault currentdirection must be transmitted to the other line end. Withdirectional comparison, a short operate time of the protectionincluding a channel transmission time, can be achieved. Thisshort operate time enables rapid autoreclosing function afterthe fault clearance.The communication logic module for directional residual currentprotection enables blocking as well as permissive under/overreaching, and unblocking schemes. The logic can also besupported by additional logic for weak-end infeed and currentreversal, included in Current reversal and weak-end infeed logicfor residual overcurrent protection (ECRWPSCH) function.Current reversal and weak-end infeed logic for residualovercurrent protection ECRWPSCHThe Current reversal and weak-end infeed logic for residualovercurrent protection (ECRWPSCH) is a supplement toScheme communication logic for residual overcurrentprotection ECPSCH.To achieve fast fault clearing for all earth faults on the line, thedirectional earth fault protection function can be supported withlogic that uses tele-protection channels.This is why the IEDs have available additions to the schemecommunication logic.If parallel lines are connected to common busbars at bothterminals, overreaching permissive communication schemescan trip unselectively due to fault current reversal. Thisunwanted tripping affects the healthy line when a fault is clearedon the other line. This lack of security can result in a total loss ofinterconnection between the two buses. To avoid this type ofdisturbance, a fault current reversal logic (transient blockinglogic) can be used.Permissive communication schemes for residual overcurrentprotection can basically operate only when the protection in theremote IED can detect the fault. The detection requires asufficient minimum residual fault current, out from this IED. Thefault current can be too low due to an opened breaker or high-positive and/or zero-sequence source impedance behind thisIED. To overcome these conditions, weak-end infeed (WEI)echo logic is used. The weak-end infeed echo is limited to 200ms to avoid channel lockup.1MRK 506 372-BEN -Line distance protection REL670 2.2Product version: 2.238 ABB