A protective relay is an automatic device that detects abnormalities in an electrical circuit and closes its contacts. This action completes the circuit breaker 's trip coil circuit, causing the breaker to trip and disconnect the faulty section from the healthy circuit. Types of Protective Relays: Protective relays are categorized by their mechanism (electromagnetic, static, mechanical) and function. Put simply, an Auto Recloser is a protection device that automatically trips and then attempts to reclose when a fault occurs on the line. The latest generations of trip units have evolved into powerful, intelligent devices with capabilities rivaling — and in some cases, matching — dedicated protective relays. They combine advanced protection, power quality monitoring, event logging, and digital communication, transforming the once.
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