多重雷击下氧化锌避雷器的冲击老化特性

Impact Aging Characteristics of Zinc Oxide Arrester Under Multiple Lightning Strikes

多重雷击会导致氧化锌避雷器老化速率加快,使用寿命及电气性能降低,甚至直接造成避雷器破裂损坏。为研究遭受多重雷击后氧化锌避雷器的介电性能及内部微观参量的变化规律,对氧化锌避雷器开展了多重雷击实验与冲击老化特性研究。首先,对氧化锌避雷器进行了双重冲击实验,测量了不同冲击次数下避雷器的直流伏安特性曲线及频域介电谱数据;然后,利用避雷器的电流–温度特性研究了氧化锌晶界的势垒高度与耗尽层宽度随冲击次数变化的规律;最后,通过灰狼优化算法对基于扩展德拜模型(extended Debye model,EDM)的避雷器等效电路中的参数进行了辨识与分析。结果表明:无论是低温区还是高温区,氧化锌晶界的势垒高度均随冲击次数增加而降低,但高温区势垒高度下降速率更快;势垒宽度与冲击次数呈负相关关系,且低场强区的势垒宽度大于高场区的;EDM中的绝缘电阻R_(0)、几何支路时间常数τ和第1条极化支路时间常数τ随冲击次数增加而减小,第3条极化支路电容C随冲击次数增加而增加。研究成果可为氧化锌避雷器冲击老化的判断提供依据。

Multiple lightning strikes will accelerate the aging rate of a zinc oxide arrester,reduce its service life and electrical performance,and even directly cause breakage and damage to it.In order to study the dielectric properties and the variation of internal microscopic parameters of the zinc oxide arrester after subjected to multiple lightning strikes,the multiple lightning strike experiment was carried out and its impact aging characteristics were studied.Firstly,the doubleimpact experiment on the zinc oxide arrester was carried out,and the DC voltammetric characteristic curves and the frequency domain dielectric spectroscopy data of the arrester were measured under different impact times.Secondly,the change of barrier height and depletion layer width of the zinc oxide grain boundary with the number of impacts was studied by using the current-temperature characteristics of the arrester.Finally,the parameters in the equivalent circuit of the arrester based on the extended Debye model(EDM)were identified and analyzed by using the grey wolf optimization algorithm.The results show that the barrier height of the zinc oxide grain boundary decreases with the increase of the impact times in both the low temperature area and the high temperature area,but the barrier height decreases faster in the high temperature area.There is a negative correlation between the barrier width and the impact times,and the barrier width in the low field strength area is larger than that in the high field strength area.In the EDM,the insulation resistance R_(0),the geometric branch time constantτand the first polarized branch time constantτdecrease with the increase of the impact times,and the third polarized branch capacitance Cincreases with the increase of the impact times.The research results can provide a basis for the judgment of impact aging of zinc oxide arresters.