Case Study: Real-Life ARC-Flash Mitigation Event on 380 VAC Switchgear

Abstract

This paper describes the implementation of always-on arc-flash detection using a combination of overcurrent and optical light sensors, along with the authors’ extensive experience in planning, implementation, testing, and real-life events in a 380 Vac switchgear system. The rapid detection and interruption of arc-flash events is crucial in controlling the risk associated with potentially life-threatening incidents and turning them into valuable lessons without the high cost to life and equipment. Mitigation occurs within milliseconds, significantly reducing the total arc-flash energy between phase conductors or from phase to ground. High-speed mitigation is achieved by automatically tripping the molded case circuit breaker (MCCB) of the motor control center (MCC) or feeder where the arc flash occurs, thereby quickly lowering the calories per centimeter squared. The oscillography event report and accompanying photographs presented in this paper clearly demonstrate how this always-on technology can save lives.