The Response of Metal Oxide Surge Arresters to Steep Fronted Current Impulses

Measurements of the residual voltages of metal oxide surge arresters have been made using a variety of impulse current waveshapes. The behaviour of both metal oxide and conventional SiC non-linear resistors has been observed and compared. The appearance of "voltage spikes" at short times, ca 0.15 ¿s, on the fronts of residual voltage records has been found and examined in the case of metal oxide arresters. The overvoltage spikes are of short duration and cannot be considered dangerous to conventional equipment insulation. However their existence suggests the need for a test, equivalent to the front-of-wave sparkover test as applied to conventional arresters.