加速寿命試験によるZnO素子の劣化検証 [in Japanese] Degradation of ZnO Varistors Estimated by Ageing Tests [in Japanese]
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We have been operated ZnO surge arresters on our power systems since 1970's. But we have been anxious for 1<sup>st</sup> stage ZnO surge arresters, because these surge arresters have the thermal runaway behavior with the applied continuous operating voltage. I have been examined the resistive leakage currents of ZnO varistors which were enclosed in ZnO surge arresters installed in our substations 20 years ago. I estimated the resistive leakage currents with the long term ageing tests which were repeatedly consisted of supplied AC voltage periods and no voltage periods. As a result, changes of these leakage currents are caused by the migrations of interstitial zinc ions and oxygen ions. On this paper, I describe these ion migrations which are caused by supplied voltages or no supplied voltage and the cracks of depletion layers which could be caused by the migration of oxygen ions.
- IEEJ Transactions on Power and Energy
IEEJ Transactions on Power and Energy 128(4), 661-674, 2008-04-01
The Institute of Electrical Engineers of Japan