Power distribution system equipment overvoltage protection

Application of surge overvoltage protection devices in general is based upon rule of thumb without the benefit of understanding basic parameters, system components and configuration, and energy content of the surge. This may result in the selection of an inadequate device. Selection of surge protective devices should be based on the magnitude of surge overvoltage, and also upon the expected energy associated with the surge. Characteristics of surge arresters are reviewed from the application point of view. Fundamentals of surge energy are presented. The MOV surge arrester selection parameters are discussed. The need for industry standards for the application of DC surge arresters is contemplated