压敏电阻对冲击电流回路输出特性影响的仿真  

Simulation of Effect of Varistors on Output Characteristics of Impulse Current Circuit

作　　者：姚学玲[1] 陈景亮[1] 王任[1] 胡上茂[1] 

机构地区：[1]西安交通大学电气学院,西安710049

出　　处：《高电压技术》2009年第9期2250-2255,共6页High Voltage Engineering

基　　金：陕西省重大科技创新项目(2008ZKC02-10)~~

摘　　要：为研究压敏电阻的非线性特性及其性能评估,建立了非线性压敏电阻冲击电流特性的仿真模型,并研究了压敏电阻对不同特征阻抗8/20μs冲击电流回路输出电流波形参数的影响规律。研究结果表明:①压敏电阻的动态电阻r对冲击电流波参数有较大影响,随着r的降低,冲击电流波前时间tf增加,逐渐趋于8μs,冲击电流波半峰值时间tt减小,逐渐趋于20μs,tt与tf之比tt/tf减小,逐渐趋于2.5;②冲击电流回路的特征阻抗Z越小,r对回路输出电流波形参数的影响越大,对压敏电压为471V的压敏电阻负载,当Z为0.35Ω且电流幅值从4A到10kA变化时,tf的变化幅度为4.75μs,tt的变化幅度为19.537μs,tt/tf的变化幅度为9.75;而当Z为1Ω时,tf的变化幅度为2.8μs,tt的变化幅度为3.54μs,tt/tf变化幅度为2.093;③得出了压敏电阻动态电阻和输出满足IEC和国家试验标准要求的8/20μs冲击电流要求的最小电流幅值的关系规律,由此得出在实际应用中,对于电流幅值范围较宽的压敏电阻冲击电流回路,为了提高冲击电流回路输出的效率,应采用分段设计冲击电流回路。The simulation model was set up to study the impulse current characteristics of varistors, the influencing laws of dynamic resistance of varistors on 8/20 μs impulse current waveform parameters for different source resistance were presented. The following results were obtained. Firstly, the dynamic resistance of varistors r has notable impact on the 8/20 μs impulse current waveform parameters, with the decreasing of the dynamic impedance r, the front time tt of impulse current waveform increases and reaches to 8 μs, the half peak time tt of impulse current waveform decreases and reaches to 20 μs, the ratio of tt and tf decrease and reach to 2.5. Secondly, the smaller is the source impedance of the impulse current circuit, the greater influence on the 8/20 μs impulse current waveform parameters. According to the impulse current amplitude changing between 40 A and 10 kA, variation range of front time tt is 4.75 μs and 19. 537 μs for half peak time tt and 9.75 for the ratio of t, and tf respectively when the source impedance is 0.3 Ω. Whereas variation range of front time tf is 2.85 μs only and 3.54μs for half peak time tt and 2. 093 for the ratio of tf and tf respectively with the impulse current circuit of 0.9 Ω source impedance. Thirdly, the correlative law between the minimum impulse current amplitude and dynamic resistance of varistors is elicited, and according to requirements of test impulse current, simultaneously improving the output efficiency of the impulse current circuit, the different source impedance impulse current circuits should be adopted.

关 键 词：压敏电阻 非线性特性 仿真模型 动态电阻 冲击电流 波形参数 

分 类 号：TM83[电气工程—高电压与绝缘技术]