中文摘要：

用MOV（氧化锌压敏电阻）的静态参数（压敏电压U1mA和漏电流IL）判定其劣化程度,只能直观反映压敏电阻的整体性能,而不能及时有效地的表征出压敏电阻的老化劣化趋势。根据MOV的U-I特性,结合肖特基势垒模型及离子迁移理论,提出MOV劣化过程中必然伴随着动态电阻Rd的变化。通过针对同一型号的MOV在不同脉冲电流下的大量实验分析得出：劣化前,8/20下Rd都呈＂U＂型分布,10/350下Rd呈缓慢递增后急速上升的趋势;劣化后,8/20下Rd没有明显变化,只有局部降低趋势而10/350下的Rd则出现不规则震荡。经实验论证,将Rd纳入MOV劣化评价体系,有效避免了静态参数值属于合格范围时其实已经老化严重的情况。

英文摘要：

In order to judge the deterioration degree of the Metal Oxide Varistor （MOV）, it is often to use the static parameters of MOV such as the varistor voltage U1mA and the leakage current IL. But these static parameters can only reflect the overall performance of the piezoresistor, and can＇t effectively characterize the aging deterioration trends of varistor. According to the volt-ampere features of MOV, combing with the double schottky barrier model as well as the ion migration theory, it is found that the dynamic resistance of MOV （Ra）increases with increasing degradation degree by the experiment of degradation MOV-model under different impulse current. Results are as follows： the dynamic resistance presents the distribution of ＂U＂ shape under 8/20 impulse current and a slow upward trend increasing rapidly under 10/350 impulse current before deterioration. After degradation, the dynamic resistance did not change significantly, only partially decreasing trend for 8/20 impulse current, but the while the dynamic resistance under 10/350 impulse current appears irregular osillation. The experiments demonstrated, when the dynamic resistance is brought into the evaluation system to MOV, it can be efficiently avoided that the static parameter values are still in normal qualified range, but the MOV has degradation seriously in fact.