I3PW2CT1: Phase currents for winding 2 first current transformer set. Used forautotransformers.I3PW2CT2: Phase currents for winding 2 second current transformer set for multi-breaker arrangements. Used when protecting an autotransformer. When not required,configure input to "GRP-OFF".Recommendation for Binary input signalsRefer to the pre-configured configurations for details.BLOCK: The input will block the operation of the function. It can be used, forexample, to block the operation during special service conditions for a limited time.Recommendation for output signalsRefer to pre-configured configurations for details.START: The start output indicates that Idiff is in the operate region of thecharacteristic.TRIP: The trip output is activated when all operating criteria are fulfilled.DIROK: The output is activated when the directional criteria has been fulfilled.BLK2H: The output is activated when the function is blocked due to high level ofsecond harmonic.7.4.3.2 SettingsThe parameters for the restricted earth fault protection, low impedance functionREFPDIF are set via the local HMI or PCM600.Common base IED values for primary current (IBase), primary voltage (UBase) andprimary power (SBase) are set in a Global base values for settings functionGBASVAL.GlobalBaseSel: It is used to select a GBASVAL function for reference of base values.Operation: The operation of REFPDIF can be switched On/Off.IdMin: The setting gives the minimum operation value. The setting is in percent of theIBase value of the chosen GlobalBaseSel. For function operation, the neutral currentmust be larger than half of this value. A recommended setting is 30% of powertransformer-winding rated current for a solidly earthed winding.ROA: Relay operate angle for zero sequence directional feature. It is used todifferentiate an internal fault and an external fault based on measured zero sequencecurrent and neutral current.CTFactorPri1: A factor to allow a sensitive function also at multi-breakerarrangement where the rating in the bay is much higher than the rated current of thetransformer winding. The stabilizing can then be high so an unnecessary high fault1MRK 502 071-UEN - Section 7Differential protectionGenerator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062 181Application manual
