Add trip security to arc-flash detection for safety and reliability

Arc-flash detection sensors provide a cost-effective way to reduce arc-flash energy by minimizing detection times. High-speed light detection and tripping can compromise protection security by misoperating during changing light conditions. Trip circuits using arc-flash light detection should be supervised using overcurrent protection with similar fast detection speeds. Combining arc-flash detection and high-speed overcurrent from a protective relay provides fast tripping and security, using both instantaneous overcurrent and light from the arc flash. The combination of relay and arc sensor provides independent fault detection with two separate technologies, thereby eliminating false trips from lighting and providing the fastest detection and tripping possible. Time coordination delays are eliminated when the arc is detected concurrently with an overcurrent. This paper presents the advantages of fast overcurrent detection combined with arc-flash measurement to produce a sensitive, fast, and secure tripping scheme.