Application of MOVs in the distribution environment

The introduction of the MOV (metal oxide varistor) arrester for distribution systems followed the successful use of these arresters in the transmission area. Higher than expected failure rates for these arresters have brought up the question of whether most of these failures are caused by system conditions related to poor application methods or by poor product quality. This paper investigates distribution concerns such as line-to-ground fault voltages, ferroresonance, cogeneration, and switching surges and how the effects of these should be considered when applying these newer arresters. Arrester test results are shown along with computer simulations of the distribution effects