LoadCurr must be set below the current that will flow on the healthy phase whenone or two of the other phases are faulty and the breaker has opened at remote end.Calculate the setting according to equation 131.min0.5 LoadBaseILoadCurr I×=EQUATION1320 V1 EN-US (Equation 131)where:ILoadmin is the minimum load current on the line during normal operation conditions.The timer tLoadOn is used to increase the security of the loss-of-load function forexample to avoid unwanted release due to transient inrush current when energizingthe line power transformer. The loss-of-load function will be released after thetimer tLoadOn has elapsed at the same time as the load current in all three phasesare above the setting LoadCurr. In normal acceleration applications there is noneed for delaying the release, so set the tLoadOn to zero.The drop-out timer tLoadOff is used to determine the window for the currentrelease conditions for Loss-of-load. The timer is by default set to 300ms, which isjudged to be enough to secure the current release.The setting of the minimum current detector, MinCurr, should be set higher thanthe unsymmetrical current that might flow on the non faulty line, when the breakerat remote end has opened. At the same time it should be set below the minimumload current transfer during normal operations that the line can be subjected to. Bydefault, MinCurr is set to 5% of IBase.The pick-up timer tLowCurr determine the window needed for pick-up of theminimum current value used to release the function. The timer is by default set to200 ms, which is judged to be enough to avoid unwanted release of the function(avoid unwanted trip).13.4 Scheme communication logic for residualovercurrent protection ECPSCH IP14711-1 v213.4.1 IdentificationM14882-1 v2Function description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberScheme communication logic forresidual overcurrent protectionECPSCH - 851MRK 505 393-UEN B Section 13Scheme communicationLine differential protection RED650 2.2 IEC 289Application manual
