Characteristics of ZnO Varistor Blocks to Multiple Lightning Impulse Voltages

초록

Abstract: This paper presents the effect of multiple lightning impulse currents on zinc oxide(ZnO)varistors. To investigate the dynamic characteristics of a ZnO varistor with respect to multiple impulse voltages, we designed and fabricated the multiple combination wave generator. Applying the 1.2/50㎲ impulse voltages and 8/20㎲ impulse currents, the electrical and physical properties of the ZnO varistors were evaluated. The multiple impulse failures of ZnO varistors are mainly caused by the surface flashover. When multple impulse voltages are injected, the charge enhancement near the joined edges of ZnO arrester block and metal electrodes plays a decisive role on the surface flashover or breakdown initiation and developments.