A protection relay serves a few core functions: Trip the circuit breaker when a fault in the system is detected, preventing further damage. Can differentiate unfaulty operations from actual faults. This device functions to identify inconsistencies, like overloads or faults, in the electrical circuit operation. It sends signals to circuit breakers, directing them to disconnect or modify. Protective relays can be classified based on their operating principle, construction, or function: 1. Static Relays: Use electronic components without moving parts. Engineering use: Relays are used on feeders, transformers, buses, motors, generators, and transmission lines to protect equipment and improve system. 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. Design of the contact movement from the point of view of utmost reliability. The relay operating characteristic must match with the abnormal. The handbook for protection engineers includes guidelines on protective circuitry, protective relay principles, and testing procedures for switchgear and relays.
