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.8.11.3.3 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.8.12 High speed distance protection ZMFPDIS (21)8.12.1 IdentificationFunction description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberHigh speed distance protection zone ZMFPDISS00346 V1 EN218.12.2 ApplicationThe fast distance protection function ZMFPDIS in the IED is designed to provide sub-cycle, down to half-cycle operating time for basic faults. At the same time, it is specificallydesigned for extra care during difficult conditions in high-voltage transmission networks,like faults on long heavily loaded lines and faults generating heavily distorted signals.These faults are handled with utmost security and dependability, although sometimes witha reduced operating speed.1MRK 506 369-UUS - Section 8Impedance protectionLine distance protection REL670 2.2 ANSI 355Application manual
