摘要
ZnO压敏电阻是金属氧化物避雷器(MOA)的核心器件,电力系统的过电压水平和设备的绝缘水平直接取决于ZnO压敏电阻性能的好坏。我国特高压输电工程正在逐步建设,要求MOA能够有效地限制电力系统过电压。相比于传统MOA中采用的ZnO压敏电阻阀片,应用于特高压MOA的阀片需要具有高电压梯度、低残压比、大通流容量和耐老化性能等特点。目前报导的应用于特高压MOA的压敏电阻阀片,压敏电压梯度可达400V/mm以上,残压比可低至1.38,冲击能量吸收密度可达300J/cm3,老化系数可低至0.6。在调研国内外文献报导的基础上,分析了高电压梯度ZnO压敏电阻数值仿真计算的研究现状和导电机理的最新进展。基于Voronoi网格和ZnO压敏电阻晶界真实的导电机理模型的仿真计算,可以较好地仿真出ZnO压敏电阻的直流、交流和冲击响应。
ZnO varistors are key elements in metal oxide arrestors（MOA）.The overvoltage level of power systems and the insulation level of power apparatus are directly determined by the electrical properties of ZnO varistors.With the construction of ultra high voltage（UHV） power transmission projects,the capability of MOA in suppressing power system overvoltage is required to be elevated.It is claimed that varistors utilized in UHV arrestors should be with high voltage gradient,low residual voltage ratio,large current withstanding capability and high stability,compared with traditional MOA varistors.According to reported literatures,ZnO varistors used in UHV metal oxide arrestors possess voltage gradient up to 400 V/mm,residual voltage ratio as low as 1.38,pulse energy withstand capability up to 300 J/cm3,and ageing coefficient as low as 0.6.The latest developments of high voltage gradient ZnO varistors are thus summarized based on the foreign and domestic literatures.The research progress of ZnO varistor in numerical simulation calculations and conduction mechanism is discussed,as well.Simulations,which are based on Voronoi network and the actual grain boundary conduction models,can simulate the DC,AC and pulse response of ZnO varistors.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2011年第3期634-643,共10页
High Voltage Engineering
基金
国家自然科学基金重点项目(50737001)~~
关键词
氧化锌压敏电阻
金属氧化物避雷器
特高压输电系统
高电压梯度
残压比
通流容量
ZnO varistors
metal oxide arrestors
ultra high voltage transmission system
high voltage gradient
residual voltage ratio
current withstand capability
