7.10.6 Monitored dataTable 124:VR2PVOC Monitored dataName Type Values (Range) Unit DescriptionIMAX REAL - A Maximum phase currentmagnitudeUUMIN REAL - kV Minimum ph-to-phvoltage magnitude7.10.7 Operation principle7.10.7.1 Measured quantitiesThe voltage-restrained time overcurrent protection (VR2PVOC) function is alwaysconnected to three-phase current and three-phase voltage input in the configurationtool (ACT), but it will always measure the maximum of the three-phase currentsand the minimum of the three phase-to-phase voltages.7.10.7.2 Base quantitiesThe parameter settings for the base quantities, which represent the base (100%) forstart levels of all measuring stages shall be entered as setting parameters forVR2PVOC function.Common base IED values for primary current (IBase), primary voltage (UBase),and primary power (SBase) are set in Global base values for the settings functionGBASVAL. Setting GlobalBaseSel is used to select a GBASVAL function for thereference of base values.IBase shall be entered as rated phase current of the protected object in primaryamperes.UBase shall be entered as rated phase-to-phase voltage of the protected object inprimary kV.7.10.7.3 Overcurrent protectionThe overcurrent step simply compares the magnitude of the measured currentquantity with the set start level. The overcurrent step starts 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 start level of the overcurrent step is not constant butdecreases with the decrease in the magnitude of the measured voltage quantity.Two different types of dependencies are available:1MRK 502 034-UEN - Section 7Current protection213Technical Manual
