The protective relays operate under two principles electromagnetic induction and electromagnetic attraction. It functions as a watchdog by constantly surveying multiple system components including voltage, current, frequency, and phase angle. Meanwhile, protective devices have also gone through significant advancements from the electromechanical devices to the multifunctional, numerical. The article provides an overview of protective relaying principles and their applications for high-voltage power system components. The. Relay protection is the discipline of designing schemes that detect faults, coordinate relays, and isolate equipment without outages.
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