Protective relays were discovered more than 150 years ago. The switchgear is capable of detecting any fault in the electrical system. The relay can guide the circuit breaker so that any defective element is isolated in the system. A protective relay can be installed in the electrical system to keep track of the abnormal conditions in the circuits.
It can measure the electrical configuration and can find out whether the system has faulty or normal conditions. Some of the variables of an electric system may include frequency, voltage, current, impedance, and phase angles. When a variable changes in its measurement, the signal of a fault is sent to the protective relays along with its location and type.
Once a protection relay detects a fault, it will operate automatically and will close down the breaker’s trip circuit. This way the faulty circuit will be disconnected from the system and the circuit breaker will be open.
