How to separate the ANSI 50 (instantaneous phase overcurrent) from ANSI 51 (delayed phase overcurrent) protection on a SEPAM relay

The ANSI 50/51 protection option in SEPAM relays combine both ANSI 50 instantaneous phase overcurrent protection and ANSI 51 delayed phase overcurrent protection.

In order to activate ANSI 50 protection, an instantaneous delay of 50ms must be set for the time delay. This is the lowest response time of the relay to a short-circuit fault. This includes Operating time + Overshoot time.

In order to activate ANSI 51 protection, a delay greater than 50ms must be set for the same parameter setting time delay. This will allow the to use ANSI 51 delayed phase overcurrent protection.

See online video that helps to program the basic needs for over current protection using circuit breaker control featuring the SEPAM 20 Series as an example.

Released for: Schneider Electric Ireland