Protecting at the Speed of Light

In this article, we have outlined various methods to mitigate arc-flash hazard by using arc-resistant controls, optical or combined current, and optical sensing. When selecting an arc-flash protection method, speed and reduction of incident energy are the most important but not the only criteria. Analyzing different methods beyond existing work place safety standards is needed. Asset protection, along with protection reliability and selectivity, should be taken into account as in any protective system design. Early detec tion of an arc flash should be emphasized. The combination of the sensing of light and a specific overcurrent signature can prove to be a very efficient method for reducing arc-fault energy. This method can be applied by dedicated arc-flash protection systems or by using common numerical protec tion relays equipped with an arc-flash protection option. For the most demanding cases, ultrafast arc eliminating technol ogy is now available. When used in combination with arc resistant control products, a coordinated hybrid arc-protec tion solution can be achieved.