Maximizing Protection by Minimizing Arcing Times in Medium-Voltage Systems

Arcing faults in the forest product industries are real risks that often lead to severe injuries and fires. From an economic point of view, the consequences due to direct and indirect costs can be extremely high as well. There are various opportunities to prevent arcing faults, but faults cannot be totally eliminated. This is why several approaches to mitigate the consequences of arcing faults have been introduced, particularly in the last decade. Several manufacturers have started to produce arc-flash protection relays based on optical detection of light energy from an arc event. In most applications, the light information is confirmed by overcurrent information before a trip command is initiated to an upstream current-breaking device. The tripping of a circuit breaker, for instance, occurs in only a few milliseconds. In most cases, this seems to be the state-of-the-art technology leading to very reasonable incident energy levels. However, it is essential to be able to minimize not only the thermal impact but also the pressure wave. This paper investigates technology aimed at maximizing the protection for the pressure wave.