Table 151:VRPVOC (51V) Non group settings (basic)Name Values (Range) Unit Step Default DescriptionGlobalBaseSel 1 - 6 - 1 1 Selection of one of the Global Base Valuegroups8.10.6 Monitored dataTable 152:VRPVOC (51V) Monitored dataName Type Values (Range) Unit DescriptionIMAX REAL - A Maximum phase currentmagnitudeUUMIN REAL - kV Minimum ph-to-ph voltagemagnitude8.10.7 Operation principle8.10.7.1 Measured quantitiesThe voltage-restrained time overcurrent protection VRPVOC (51V) function is alwaysconnected to three-phase current and three-phase voltage input in the configuration tool(ACT), but it will always measure the maximum of the three-phase currents and theminimum 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 in primarykV.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 the measuredcurrent quantity is bigger than the set level.Voltage restraint/control featureThe overcurrent protection operation is made dependent of a measured voltage quantity.This means that the pickup level of the overcurrent step is not constant but decreases withSection 8 1MRK 502 048-UUS ACurrent protection276Technical manual
