Thispaperpresentstheeectofmultipleimpulsevoltagesontheelectricalandphysicalpropertiesofazincoxide(ZnO)varistor.Toinvestigate the dynamic characteristics of a ZnO varistor subjected to multiple impulse voltages, we designed and fabricated the multi-ple...
Thispaperpresentstheeectofmultipleimpulsevoltagesontheelectricalandphysicalpropertiesofazincoxide(ZnO)varistor.Toinvestigate the dynamic characteristics of a ZnO varistor subjected to multiple impulse voltages, we designed and fabricated the multi-plecombinationwavegenerator.Themultiplecombinationwavegeneratorcanproducequintuple1.2/50l simpulsevoltagesof100 kVandquintuple8/20l simpulsecurrentsof12 kA.Applyingthesevoltagesandcurrents,theelectricalandphysicalpropertiesoftheZnOvaristor were evaluated. The multiple impulse failures of a ZnO varistor are mainly caused by the surface ashover. When multipleimpulse voltages are injected, the charge enhancement near the joined edges of a ZnO varistor and metal electrodes plays a decisiverole on the surface ashover or breakdown initiation and developments. Also, after the injection of the quintuple 8/20l s impulse cur-rents of 10 kA, the residual voltage and quiescent current of the ZnO varistor were changed markedly.