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

Checking of the slopeThe slope can be checked by simulating a phase-toearthfault inside the zone to be protected on a networkwith the circuit breaker closed. In this case, the fault isdetected by the neutral point CT and partially by thephase CT.c To facilitate the test and calculations, set Ino to thesame value as In.c To perform the test, wire according to the diagramopposite.ECM33B635241AI13A654321CSH 30AI neutralc Inject a current through the CSH30 interposing ringCT and a phase current in the opposite direction.The restraint current is equal to I1, the differentialcurrent is equal to I1 + I neutral.When there is no I neutral, the slope is equal to100%.c Gradually inject Io until tripping occurs.c Record I neutral and I1 and calculate100 x (I1 + I neutral)/I1 and compare to 105%.c Stop the injection.c Press reset (1) on Sepam 2000 to erase themessages and reset the output to 0.Io - I neutralI1 + I neutralI1IsoI neutral105 %100 %I1Io(1)this function cannot be activated if the control logic hasbeen customizedSepam 2000 - Testing 1/53