A novel solid-state integrated protection system for three phase induction motors

The conventional electro-mechanical and static protective devices used for the protection of three phase Induction motors in Industrial applications normally employ separate and Independent overload, short circuit, earth fault and single phasing protective devices In the circuit breaker to take care of motor protection. The proposed all-In-one protection scheme Integrates these Into a single static protective device and operates by sensing the positive, negative and zero sequence components of motor currents derived through three current transformers and a solid-state sequence components filter which provides fast and real-time separation of these components of motor currents.