tResetn: Reset time for stepn if definite time delay is used, given in s. The default value is 25ms.tnMin: Minimum operation time for inverse time characteristic for stepn, given in s. For veryhigh voltages the overvoltage function, using inverse time characteristic, can give very shortoperation time. This might lead to unselective trip. By settingt1Min longer than the operationtime for other protections such unselective tripping can be avoided.ResetTypeCrvn: This parameter for inverse time characteristic can be set:Instantaneous,Frozen time,Linearly decreased. The default setting isInstantaneous.tIResetn: Reset time for stepn if inverse time delay is used, given in s. The default value is 25ms.kn: Time multiplier for inverse time characteristic. This parameter is used for co-ordinationbetween different inverse time delayed undervoltage protections.ACrvn,BCrvn,CCrvn,DCrvn,PCrvn: Parameters to set to create programmable under voltageinverse time characteristic. Description of this can be found in the technical reference manual.CrvSatn: When the denominator in the expression of the programmable curve is equal to zerothe time delay will be infinity. There will be an undesired discontinuity. Therefore a tuningparameterCrvSatn is set to compensate for this phenomenon. In the voltage intervalUn> uptoUn> · (1.0 +CrvSatn/100) the used voltage will be:Un> · (1.0 +CrvSatn/100). If theprogrammable curve is used, this parameter must be calculated so that:0100CrvSatnB C× - >EQUATION1448 V1 EN-US (Equation 96)HystAbsn: Absolute hysteresis set in % ofUBase. The setting of this parameter is highlydependent of the application. If the function is used as control for automatic switching ofreactive compensation devices the hysteresis must be set smaller than the voltage changeafter switching of the compensation device.8.3 Two step residual overvoltage protection ROV2PTOVIP14546-1 v48.3.1 IdentificationSEMOD54295-2 v5Function description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberTwo step residual overvoltageprotectionROV2PTOV3U0TRV V1 EN-US59N8.3.2 Application M13809-3 v7Two step residual overvoltage protection ROV2PTOV is primarily used in high impedanceearthed distribution networks, mainly as a backup for the primary earth-fault protection of thefeeders and the transformer. To increase the security for different earth-fault relatedfunctions, the residual overvoltage signal can be used as a release signal. The residual voltagecan be measured either at the transformer neutral or from a voltage transformer open delta1MRK 511 358-UEN A Section 8Voltage protection181Application manual
