What is protective relays?

Protective relays are devices designed to detect abnormal conditions in electrical power systems (e.g., faults, overloads, or undervoltages) and initiate corrective actions, such as tripping circuit breakers to isolate the faulty equipment or section. They are crucial for protecting equipment, preventing widespread outages, and ensuring the stability and reliability of the power grid. They work by continuously monitoring electrical parameters like current, voltage, and frequency, and comparing these values against pre-set thresholds. When a threshold is violated, the relay operates to remove the faulted component from service.