aba>b OR|IOP|STINxANDHarmRestrainx=DisabledINx>BLKSTxBLOCKOR2ndH_BLOCK_IntCharacteristn=DefTimeDirModex=OffDirModex=Non-directionalDirModex=ForwardDirModex=ReverseANDANDFORWARD_IntREVERSE_IntOROR STEPx_DIR_IntIEC09000638_3_en.vsdCharacteristn=InversetxminANDInversetx TRINxANDCharacteristn= Inverse will be validfor n = 1 and 4IEC09000638 V3 ENFigure 70: Simplified logic diagram for residual overcurrentThe protection can be completely blocked from the binary input BLOCK. Outputsignals for respective step, STx and TRx and , can be blocked from the binary inputBLKSTx.8.4.7.7 Directional supervision element with integrated directional comparisonfunctionIt shall be noted that at least one of the four residual overcurrent stepsshall be set as directional in order to enable execution of thedirectional supervision element and the integrated directionalcomparison function.The protection has integrated directional feature. The operating quantity currentI3PDIR is always used. The polarizinwcg method is determined by the parametersetting polMethod. The polarizing quantity will be selected by the function in one ofthe following three ways:1. When polMethod = Voltage, UPol will be used as polarizing quantity.2. When polMethod = Current, IPol will be used as polarizing quantity.3. WhenpolMethod = Dual, UPol + IPol · ZNPol will be used as polarizing quantity.The operating and polarizing quantity are then used inside the directional element, asshown in figure 71, in order to determine the direction of the earth fault.Section 8 1MRK 504 135-UEN ACurrent protection166Technical manual
