Triggered Current Limiters—Their Arc Flash Mitigation and Damage Limitation Capabilities

Triggered current limiters (TCL) have traditionally been applied to protect overdutied switchgear in medium voltage substations but increasing trends include the applications of damage limitation and Arc Flash mitigation. TCLs are effective at minimizing damage from short circuits due to their speed, which results in their peak current limitation capabilities. Their subcycle response time (extinction in 1/4-1/2 cycle) can often reduce the I²t available in the system to less than 1% of its potential value compared to a fice-cycle breaker. TCLs are capable of reducing the incident energy enough to reduce the Arc Flash hazard category and required personal protective equipment for onsite personnel. A TCL can commonly reduce the Arc Flash hazard category from category 4 to category 2 in medium voltage. For low voltage, most applications should be reduced to category 0 or 1. This paper aims to address the applications of Arc Flash reduction and damage limitation for substation design and generating stations, and highlights the benefits a TCL can provide.