ABSTRACT
This chapter summarizes metal oxide surge arrester ratings and application principles for system voltage levels above 1 kV. Surge arresters are shunt, nonlinear, resistive devices that are installed to limit transient overvoltages, thereby protecting equipment insulation. Sometimes they have been called “lightning arresters,” and this may be due to the fact that many years ago, surge arresters were tailored to protect against the surge front times typical of lightning. Virtually all new applications will use metal oxide surge arresters. The surge arrester must be installed on something, such as a transformer tank or a pedestal. Surge arresters have both a voltage rating and a class, or type. For metal oxide, the important voltage rating is the maximum continuous operating voltage (MCOV), which is the steady-state voltage the arrester could support indefinitely. There are some cases like distribution feeders with poor voltage regulation, which might require a higher MCOV.
