Protection Relay (Sepam or Easergy) can be replaced by “T300” which can operate all function mentioned above as well as protection relay.

The usage of SC150 is dedicated for Fault indication but not qualified for protection trip. Even if we refer to the same standardized definition and vocabulary (ANSI curves), we don’t use it for protection purposes.
The differences between a FPI and a protection relay consist mainly in 2 points.

1. the hardware technology of FPI is less costly than a protection relay due to the fact that it neither operates a CB with a fast tripping by a coil or an actuator nor monitors the trip circuit (ANSI P17 TCM function),
2. It also needs not to be connected to Class P protection CTs requiring a high precision of the short circuit current (but also providing a poorer precision for usual values (0,1In – 1,2In) .
3. The configuration of a FPI is a dedicated one, simpler and easier to set than a protection relay which needs to know perfectly the protection plan of the networks.

Released for:Schneider Electric India