Reducing arc-flash hazards

In this article, we include some important industry definitions of arc flash and ways of measuring arc-flash hazards. We then examine the use of existing technologies, including digital relays and communications capabilities, to implement reduced trip times using instantaneous overcurrent relays, a fast bus-trip scheme, and differential schemes. We use a typical industrial switchgear lineup as an example of how to implement these schemes. Finally, we quantify the levels to which we can reduce arc-flash energy and its impact on safety.