identification with load encroachment for mho function FMPSPDIS, where also therelevant settings can be found. Information about the load encroachment fromFMPSPDIS to the zone measurement is given in binary format to the input signalLDCND.7.1.6.3 Basic operation characteristicsEach impedance zone can be switched On and Off by the setting parameterOperation.Each zone can be set to Non-directional, Forward or Reverse by setting the parameterDirMode .The mho characteristics can be classified into - Offset or Directional. The directionalmho characteristics can be set to Offset, Forward or Reverse by the setting parameterDirMode. The offset mho characteristic can be set to Forward or Reverse or Non-Directional by the setting parameter OffsetMhoDir.The operation for phase-to-earth and phase-to-phase fault can be individuallyswitched On and Off by the setting parameter OpModePE and OpModePP.For critical applications such as for lines with high SIRs as well as CVTs, it is possibleto improve the security by setting the parameter ReachMode to Underreach. In thismode the reach for faults close to the zone reach is reduced by 20% and the filteringis also introduced to increase the accuracy in the measuring. If the ReachMode is set toOverreach no reduction of the reach is introduced and no extra filtering introduced.The latter setting is recommended for overreaching pilot zone, zone 2 or zone 3elements and reverse zone where overreaching on transients is not a major issue eitherbecause of less likelihood of overreach with higher settings or the fact that theseelements do not initiate tripping unconditionally.The offset Mho characteristic can be set in Non-directional, Forward or Reverse bythe setting parameter OffsetMhoDir. When Forward or Reverse is selected adirectional line is introduced. Information about the directional line is given from thedirectional element and given to the measuring element as binary coded signal to theinput DIRCND.When DirMode is set to offset and offsetMhoDir is set as Non-Directional, ZDMRDIRdoes not have any effect on the measurement loop and operation of the function. WhenDirMode is selected as Forward or Reverse, a directional line is introduced.Information about the directional line is given from the directional element(ZDMRDIR) and given to the measuring element as binary coded signal to the inputDIRCND.The zone reach for phase-to-earth fault and phase-to-phase fault is set individually inpolar coordinates.The impedance is set by the parameters ZPE and ZPP and the correspondingarguments by the parameters ZAngPE and ZAngPP.Section 7 1MRK502052-UEN BImpedance protection182Technical manual
