All this is applicable for all measuring zones when no Power swing detectionfunction ZMRPSB is activated in the IED. Use an additional safety margin ofapproximately 20% in cases when a ZMRPSB function is activated in the IED,refer to the description of Power swing detection function ZMRPSB.8.9.3.8 Load impedance limitation, with Phase selection with loadencroachment, quadrilateral characteristic function activatedGUID-68C89E77-77E1-47A2-A0D2-B6236CB63AB1 v1The parameters for shaping of the load encroachment characteristic are found in thedescription of Phase selection with load encroachment, quadrilateral characteristicfunction (FRPSPDIS).8.9.3.9 Setting of minimum operating currents GUID-DAFBA182-ABD1-42F7-B958-E292B8E0E161 v1The operation of Distance protection zone, quadrilateral characteristic (ZMQPDIS)can be blocked if the magnitude of the currents is below the set value of theparameter IMinOpPP and IMinOpPE.The default setting of IMinOpPP and IMinOpPE is 20% of IBase where IBase isthe chosen current for the analogue input channels. The value has been proven inpractice to be suitable in most of the applications. However, there might beapplications where it is necessary to increase the sensitivity by reducing theminimum operating current down to 10% of IBase. This happens especially incases, when the IED serves as a remote back-up protection on series of very longtransmission lines.Setting IMinOpIN blocks the phase-to-earth loop if 3I0<IMinOpIN. The defaultsetting of IMinOpIN is 5% of IBase.The minimum operating fault current is automatically reduced to 75% of its setvalue, if the distance protection zone has been set for the operation in reversedirection.8.9.3.10 Setting of timers for distance protection zones GUID-E6DD460D-2189-45E9-AD4D-E127DCA8EBAC v1The required time delays for different distance protection zones are independent ofeach other. Distance protection zone 1 can also have a time delay, if so required forselectivity reasons. Time delays for all zones can be set in a range of 0 to 60seconds. The tripping function of each particular zone can be inhibited by settingthe corresponding Operation parameter to Off. Different time delays are possiblefor the phase-to-earthtPE and for the phase-to-phase tPP measuring loops in eachdistance protection zone separately, to further increase the total flexibility of adistance protection.Section 8 1MRK 506 369-UEN BImpedance protection312 Line distance protection REL670 2.2 IECApplication manual
