8.10.6 Monitored dataTable 135:VR2PVOC(51V) Monitored dataName Type Values (Range) Unit DescriptionIMAX REAL - A Maximum phase currentmagnitudeVUmin REAL - kV Minimum ph-to-ph voltagemagnitude8.10.7 Operation principle8.10.7.1 Measured quantitiesThe voltage-restrained time overcurrent protection (VR2PVOC, 51V) function isalways connected to three-phase current and three-phase voltage input in theconfiguration tool (ACT), but it will always measure the maximum of the three-phasecurrents and the minimum of the three phase-to-phase voltages.8.10.7.2 Base quantitiesGlobalBaseSel: Selects the global base value group used by the function to define(IBase), (VBase) and (SBase).IBase shall be entered as rated phase current of the protected object in primary amperes.VBase shall be entered as rated phase-to-phase voltage of the protected object inprimary kV.8.10.7.3 Overcurrent protectionThe overcurrent step simply compares the magnitude of the measured current quantitywith the set pickup level. The overcurrent step picks up if the magnitude of themeasured current quantity is bigger than the set level.Voltage restraint/control featureThe overcurrent protection operation is made dependent of a measured voltagequantity. This means that the pickup level of the overcurrent step is not constant butdecreases with the decrease in the magnitude of the measured voltage quantity. Twodifferent types of dependencies are available:• Voltage restraint overcurrent (when setting parameter VDepMode = Slope)1MRK 502 043-UUS B Section 8Current protection247Technical Manual
