DEGRADATION DUE TO ENERGY PULSE IN HIGH-ENERGY ZnO VARISTORS

来源期刊：中南大学学报(英文版)1997年第2期

论文作者：Zhang Shugao Huang Baiyun Fang Xunhua Ji Youzhang

文章页码：113 - 116

Key words：high-energy ZnO varistors; energy pulse; degradation; V-A characteristics; grain boundary barrier;ion migration

Abstract: The degradation phenomena due to the energy pulse in the high-energy ZnO varistors used for deexitation and overvoltage protection of hydroelectric generator are investigated. The energy pulse, obtained by releasing the energy stored in an inductor, can be equivalent to the combination of the DC field components and the energy component. The variations of the characterized voltages, nonlinear coefficients and pre-breakdown V-A characteristics, increase with the number of the applied energy pulse. The asymmetrical variations of the electric properties of the high-energy ZnO varistors after the energy pulse arise from the deformation of the double Schottky barriers due to the ion migration occuring in the depletion layer and in the grain boundary.