Switch on to fault protection (SOTF) Switch on to fault protection (SOTF) is used to provide high-speed tripping when energizing a power line under fault condition. Exactly, switching on the circuit breaker without fault clearance (fault exist in the line). Switch on to fault protection trips the circuit breaker immediately without time delay. [wp_ad_camp_2] Switch … Continue reading SOTF Relay Working Principle – Switch On To Fault protection