多脉冲雷电冲击下ZnO压敏电阻的劣化性能

Degradation Performance of ZnO Varistor Under Multi-pulse Lightning Impulse

针对ZnO压敏电阻的单脉冲雷电冲击实验无法真实有效模拟自然界雷击,且对其劣化性能研究不够精确完善的问题,利用新型多脉冲雷电发生器对ZnO压敏电阻进行冲击,通过改变脉冲数量、时间间隔和脉冲幅值等参数,分别从ZnO压敏电阻的耐受性能、电气参数、温度分布和能量吸收等方面定量研究其劣化特性。实验结果表明:ZnO压敏电阻在经过多次多重雷电冲击后,泄漏电流会产生跃变;不同于多次单脉冲冲击下的下降趋势,压敏电压数值表现为先上升后下降;不同于多次单脉冲冲击下的上升现象,电容值在小范围内波动起伏;ZnO压敏电阻的表面温度分布并不均匀,与冲击次数和位置有关;脉冲间隔的长短对样片能量吸收的影响很小。实验结论可为制定多脉冲雷电冲击下电涌保护器的性能指标和劣化监测预警提供参考。

The tests for single-pulse lightning impulse of ZnO varistors can not truly and effectively simulate the natural lightning,and the research on its degradation performance is not perfect.Consequently,we employed a new-type multi-pulse lightning generator to impact a ZnO varistor.By changing the parameters such as the number of multi-pulses,the time interval and the amplitude of the pulse,the degradation characteristics of the ZnO varistor were quantitatively studied from the aspects of tolerance,electrical parameters,temperature distribution,and energy absorption.The experimental results show that the leakage current of the ZnO varistor will change suddenly after multiple lightning strikes for several times;the varistor voltage value will rise first and then fall,which is different from the downward trend under singlepulse impact for several times;the capacitance value will fluctuate in a small range,which is different from the rising phenomenon under single pulse impact for several times;the surface temperature distribution is not uniform,which is related to the number of impacts and position;the length of the pulse interval has a negligible effect on the energy absorption of the sample.The experimental conclusions are of great significance for the development of performance indicators and degradation monitoring of surge protectors under multi-pulse lightning impulses.