SN> is the operate power level for the directional function whenOpMode is set3I03U0Cosfi.The setting is given in % ofSBase. The setting should be based on calculation of the active orcapacitive earth fault residual power at required sensitivity of the protection.The input transformer for the Sensitive directional residual over current and power protectionfunction has the same short circuit capacity as the phase current transformers. Hence, there isno specific requirement for the external CT core, i.e. any CT core can be used.If the time delay for residual power is chosen the delay time is dependent on two settingparameters.SRef is the reference residual power, given in % ofSBase.kSN is the timemultiplier. The time delay will follow the following expression:inv0 0kSN Sreft 3I 3U cos (measured)j×= × ×EQUATION1957 V1 EN-US (Equation 40)INDir> is the operate current level for the directional function whenOpMode is set3I0 and fi.The setting is given in % ofIBase. The setting should be based on calculation of the earth faultcurrent at required sensitivity of the protection.OpINNonDir> is setOn to activate the non-directional residual current protection.INNonDir> is the operate current level for the non-directional function. The setting is given in% ofIBase. This function can be used for detection and clearance of cross-country faults in ashorter time than for the directional function. The current setting should be larger than themaximum single-phase residual current on the protected line.TimeChar is the selection of time delay characteristic for the non-directional residual currentprotection. Definite time delay and different types of inverse time characteristics are available:Table 13: Inverse time characteristicsCurve nameANSI Extremely InverseANSI Very InverseANSI Normal InverseANSI Moderately InverseANSI/IEEE Definite timeANSI Long Time Extremely InverseANSI Long Time Very InverseANSI Long Time InverseIEC Normal InverseIEC Very InverseIEC InverseIEC Extremely InverseIEC Short Time InverseIEC Long Time InverseIEC Definite TimeUser ProgrammableASEA RIRXIDG (logarithmic)1MRK 505 355-UEN A Section 6Current protection95Application manual
