Power distribution system equipment overvoltage protection

Characteristics of surge arresters are reviewed from the application point of view. Fundamentals of surge energy are presented, and the MOV (metal oxide varistor) surge arrester selection parameters are discussed. The need for industry standards for the application of DC surge arresters is contemplated. It is noted that, to avoid confusion and misapplication of MOV surge arresters, the present differences of IEC and ANSI standards should be reviewed. Special systems such as arc furnaces and capacitor bank switching should require transient overvoltage study before selection of appropriate surge protective devices