V_AV_BV_CV_AFIL1FV_BV_C3V0ANSI07000189-1-en.vsdANSI07000189 V1 ENFigure 290: Ground fault in Direct grounded system10.3.3.6 Settings for two step residual overvoltage protectionOperation: Disabled or EnabledVBase (given in GlobalBaseSel) is used as voltage reference for the set pickup values. Thevoltage can be fed to the IED in different ways:1. The IED is fed from a normal voltage transformer group where the residual voltageis calculated internally from the phase-to-ground voltages within the protection. Thesetting of the analogue input is given as VBase=Vph-ph.2. The IED is fed from a broken delta connection normal voltage transformer group. Inan open delta connection the protection is fed by the voltage 3V0 (single input).Section Analog inputs in the Application manual explains how the analog input needsto be set.3. The IED is fed from a single voltage transformer connected to the neutral point of apower transformer in the power system. In this connection the protection is fed by thevoltage VN=V0 (single input). Section Analog inputs in the Application manualexplains how the analog input needs to be set.ROV2PTOV (59N) will measure the residual voltage corresponding to the nominalphase-to-ground voltage for a high-impedance grounded system. The measurement willbe based on the neutral voltage displacement.The setting parameters described below are identical for the two steps (n = step 1 and 2).Therefore the setting parameters are described only once.Section 10 1MRK 506 369-UUS -Voltage protection578 Line distance protection REL670 2.2 ANSIApplication manual
