The resistive boundary RLdRev for load encroachment characteristic in reverse directioncan be calculated in the same way as RLdFwd, but use maximum importing power thatmight occur instead of maximum exporting power and the relevant Vmin voltage for thiscondition.6.2.3.3 Minimum operate currentsFDPSPDIS (21) has two current setting parameters which blocks the respective phase-to-ground loop and phase-to-phase loop if the RMS value of the phase current (ILn) andphase difference current (ILmILn) is below the settable threshold.The threshold to activate the phase selector for phase-to-ground (IMinPUPG) is set tosecurely detect a single phase-to-ground fault at the furthest reach of the phase selection.It is recommended to set IMinPUPP to double value of IMinPUPG.The threshold for opening the measuring loop for phase-to-ground fault (3I0Enable_PG)is set securely detect single line-to-ground fault at remote end on the protected line. It isrecommended to set 3I0BLK_PP to double value of 3I0Enable_PG.6.3 Faulty phase identification with load enchroachment formho FMPSPDIS (21)6.3.1 IdentificationFunction description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberFaulty phase identification with loadencroachment for mhoFMPSPDISS00346 V1 EN-6.3.2 ApplicationFaulty phase identification with load encroachment for mho (FMPSPDIS) function isdesigned to accurately select the proper fault loop in the Distance protection function(ZQMPDIS, 21) dependent on the fault type.The heavy load transfer that is common in many transmission networks may in some casesbe in opposite to the wanted fault resistance coverage. Therefore, FMPSPDIS has an built-in algorithm for load encroachment, which gives the possibility to enlarge the resistivesetting of both the Phase selection with load encroachment and the measuring zones FiveSection 6 1MRK 506 334-UUS AImpedance protection146Application manual
