9.3 Two step residual overvoltage protectionROV2PTOV9.3.1 IdentificationFunction description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberTwo step residual overvoltageprotectionROV2PTOV3U0TRV V1 EN59N9.3.2 FunctionalityResidual voltages may occur in the power system during earth faults.Two step residual overvoltage protection ROV2PTOV function calculates theresidual voltage from the three-phase voltage input transformers or measures it froma single voltage input transformer fed from an open delta or neutral point voltagetransformer.ROV2PTOV has two voltage steps, each with inverse or definite time delay.Reset delay ensures operation for intermittent earth faults.9.3.3 Function blockIEC06000278-2-en.vsdROV2PTOVU3P*BLOCKBLKTR1BLKST1BLKTR2BLKST2TRIPTR1TR2STARTST1ST2IEC06000278 V2 ENFigure 242: ROV2PTOV function block9.3.4 SignalsTable 277:ROV2PTOV Input signalsName Type Default DescriptionU3P GROUPSIGNAL- Three phase voltagesBLOCK BOOLEAN 0 Block of functionBLKTR1 BOOLEAN 0 Block of operate signal, step 1Table continues on next page1MRK502052-UEN B Section 9Voltage protection505Technical manual
