Also principles of various protective relays and schemes including special protection schemes like differential, restricted, directional and distance relays are explained with sketches. This handbook covers the code of practice in protection circuitry including standard lead and device numbers, mode of connections at terminal strips, colour codes in multicore cables, dos and donts in execution. Different Types of Protective Relays What is a Protective Relay? A protective relay is an. A protective relay is an intelligent electrical device designed to detect faults in power systems and initiate corrective actions such as tripping a circuit breaker. It functions as a watchdog by constantly surveying multiple system components including voltage, current, frequency, and phase angle.
