抄録
Overvoltages as lightning surges and/or switching surges will affect power apparatuses and electric appliances, which make them of deterioration. However, recent AC testing apparatuses haven't been functions generating an impulse voltage. Moreover, the apparatuses with controlling an impulse voltage haven't been utilized except the low voltage function generator. Therefore, an AC phase controlled testing apparatus with an impulse voltage (0.8/6μs) has been developed in order to elucidate mechanism of the degradation in insulating materials with a AC power supply simulating the overvoltages.
