reach with load encroachment characteristic". If the characteristic for the impedancemeasurement shall be shaped with the load encroachment algorithm, the parameterOperationLdCmp in the phase selection has to be switched On.8.5.3.9 Setting of minimum operating currentsThe operation of the distance function will be blocked if the magnitude of the currents isbelow the set value of the parameter IMinOpPE.The default setting of IMinOpPE is 20% of IBase where IBase is the chosen base currentfor the analogue input channels. The value have been proven in practice to be suitable inmost of the applications. However, there might be applications where it is necessary toincrease the sensitivity by reducing the minimum operating current down to 10% of theIED base current. This happens especially in cases, when the IED serves as a remote back-up protection on series of very long transmission lines.If the load current compensation is activated, there is an additional criteria IMinOpIN thatwill block the phase-ground loop if the 3I0<IMinOpIN. The default setting of IMinOpINis 5% of the IED base current IBase.The minimum operating fault current is automatically reduced to 75% of its set value, ifthe distance protection zone has been set for the operation in reverse direction.8.5.3.10 Setting of timers for distance protection zonesThe required time delays for different distance-protection zones are independent of eachother. Distance protection zone1 can also have a time delay, if so required for selectivityreasons. One can set the time delays for all zones (basic and optional) in a range of 0 to 60seconds. The tripping function of each particular zone can be inhibited by setting thecorresponding Operation parameter to Off. Different time delays are possible for the ph-E (tPE) measuring loops in each distance protection zone separately, to further increasethe total flexibility of a distance protection.8.6 Additional distance protection directional function forearth faults ZDARDIRSection 8 1MRK 506 369-UUS -Impedance protection300 Line distance protection REL670 2.2 ANSIApplication manual
