Sepam - HV/MV Protection and control units (ENG) - Trinet

Restricted earth fault protectionANSI codefunction n°64 REFF641, F651, F661Equipmentc single-phase current generatorc ammeterc documentationWiringc B7, B14, B15 diagramc protective relays:F641/1, F651/1, F661/1Testc read the section entitled measurement and testingmethodc check the SW microswitchesc status parameter setting:v choose the Io measurement method, by CSH corebalance CT or TC + CSH30v check the connection of the core balance CT to theconnectorv make the function settingsProcedureChecking of set pointThe Iso set point is checked by simulating a fault between the neutral point CT anda phase CT, when the circuit breaker is open. In this case, only the neutral pointCT detects the fault. There is zero restaint current.c wire according to the B7 diagramc inject a current in the the CSH neutral I current measurement sensor (CSHsensor installed at the neutral point or CSH 30 associated with the CT installed atthe neutral point) and progressively raise the current being injected until it exceedsthe setting value.c check the current value measured on the ammeter at the time the output contactassociated with the function picks up (or read the TRIP 0 value if trip currentmeasurement is associated with the function)c stop the injectionc press reset (1) on Sepam 2000 to erase the messages and reset the output relaytesting of stabilityThe stability can be checked by considering a phase-to-earth fault outside the zoneto be protected.This test is only possible if Ino is equal to In for the winding to which the restrictedearth fault protection is linked.c wire (according to B14 or B15 diagram) to inject the same current in series in theCSH neutral point current measurement sensor and in one of the phase currentinputs to simulate a fault outside the zone, for example:injectionB(o)(o)414A1c inject a current of 2 In in the circuitc check that the output contact associated with the function remains dropped outc stop the injection.(1)this function cannot be activated if the control logichas been customized.1/52Sepam 2000 - Testing