Effects of impulse current stresses on the durability and protection performance of metal oxide surge arresters

The paper reveals a potential failure tendency of metal oxide surge arresters (MOAs): the exposure of arresters to a series of impulse current surges, simulating an environment of high lightning activity, caused surprisingly many arrester failures (9 out of 48 test specimens). The main failure mechanism in the damaged arresters proved to be a surface flashover of varistors inside the arrester. On the other hand, the paper shows that the protection performance (residual voltages) for MOAs which stand up without failure, a large number (up to 1000 surges) of impulse current pulses (with fairly low energy content) is very stable