6. Auxiliary devices and surge arrester accessories

6.1 Pressure relief valves

The failure of an arrester containing a volume of air always results in an arc bypassing the active part inside the sealed enclosure. Without special precautions, this internal arc would inevitably lead to the surge arrester exploding. For several years now, manufacturers have been developing devices to prevent explosion: these include diaphragms that tear or valves that deform as soon as the pressure reaches a few bar.

These systems expel the gases created by the internal arc and transfer the arc from inside to outside the enclosure. They act very quickly (within a few milliseconds), preventing the surge...