MOV Surge Arresters: Improved Substation Equipment Protection

The introduction of metal-oxide-varistor (MOV) surge arresters has added a new dimension to substation equipment protection. Through the optimal use of these arresters, it is possible to lower surge arrester ratings and thereby improve protective margins, resulting in a possible reduction of the insulation levels (BIL) of substation equipment. This reduction in BIL can lead to a significant reduction in the cost of substation equipment. General methods are delineated for selecting MOV surge arresters for substation protection and the resulting effect on substation equipment insulation levels.