氧化锌非线性电阻片微观结构及特性对电流分布的影响  

INFLUENCES OF THE MICROSTRUCTURE ON CURRENT DISTRIBUTION IN ZnO VARISTORS

作　　者：陈青恒[1] 何金良[1] 谈克雄[1] 陈水明[1] 

机构地区：[1]清华大学电机系,北京100084

出　　处：《中国电机工程学报》2002年第8期62-66,共5页Proceedings of the CSEE

基　　金：国家自然科学基金项目59907001~~

摘　　要：氧化锌(ZnO)非线性电阻片是电力避雷器的核心工作元件,其微观电流分布的非均匀性导致其冲击能量吸收能力的下降。文中建立了基于二维沃罗诺网络(Voronoi Diagram)的ZnO非线型电阻片的微观结构模型,以及晶界层伏安特性(I-V特性)数学物理模型,系统地仿真研究了氧化锌非线性电阻片中微观结构的不均匀性和晶界层I-V特性的差异对电流分布的影响。 结果表明电阻片内微观电流 分布与电压梯度紧密相关,低电场区和高电场区比较均匀,而在中电场区分布很不均匀。微观结构的不均匀性和晶界层I-V特性的差异都会引起电流集中现象,在中电场区(击穿区)微观结构的不均匀性的影响更突出。ZnO varistors are key functional element of surge arresters. The nonuniformity of current distribution in microstructure of ZnO varistor leads to the decreasing of its impulse energy absorption capability. In this paper, the microscopic model of ZnO varistors is described by the Voronoi network model and the equation of the I-V characteristics of grain boundaries is proposed ,which simulate the effects of the nonuniformity of the grain size and the variety of the I-V characteristics of grain junction on the distribution of current in ZnO varistor ceramics. The simulation result shows that the current distribution is closely related to the voltage gradient applied on the varistor, and concentrated on few paths especially on breakdown region. The result also shows that both the nonuniformity of grain size and the variety of the I-V characteristics of single grain junction contribute to the current concentration phenomenon in ZnO varistor. However, the nonuniformity of grain size plays a more important role in the current localization in ZnO varistor within breakdown region.

关 键 词：氧化锌非线性电阻片 微观结构 特性 电流分布 氧化锌避雷器 

分 类 号：TM862[电气工程—高电压与绝缘技术]