Facilities need to perform installation tests, implement preventive maintenance programs, and perform comprehensive commissioning tests to verify the integrity of both existing protective relay systems and new protection systems. The testing and verification of protection devices and arrangements introduces a number of issues. When a fault is detected, the relay sends a signal to circuit breakers to isolate the faulty section, preventing damage to equipment and minimizing. THEY SHOULD BE GIVEN FIRST LINE MAINTENANCE ATTENTION. COMPREHENSIVE INSPECTION, MAINTENANCE AND TESTING PROGRAM. ” relay may only need to operate for 0.