The Correlation Mechanism That Micro-Structure Parameters of ZnO Varistor to the Macroscopic Electrical Characteristics
Meng Pengfei1, Guo Jingke1, Zhang Hengzhi2, Qin Feng3, Xie Shijun4, Lei Xiao4, Wu Hongmei5, Hu Jun6
1. College of Electrical Engineering Sichuan University Chengdu 610065 China;
2. Tibet Electric Power Research Institute of State Grid Lhasa 850000 China;
3. Northwest Institute of Nuclear Technology Xi’an 710024 China;
4. State Grid Sichuan Electric Power Research Institute Chengdu 610041 China;
5. Tibet Agriculture & Animal Husbandry University Linzhi 860000 China;
6. Department of Electrical Engineering Tsinghua University Beijing 100084 China
The development of UHV technology has put forward higher requirements for various electrical characteristics of ZnO varistors. As the voltage level of UHV transmission system is too high, the volume, cost and operation reliability of equipment are largely dependent on the insulation level of the system[3-4]. While the insulation coordination of the system is based on the overvoltage level of the system in various conditions, which is directly determined by the protection capability of the arrester used in the UHV transmission system. Therefore, there are many vital technical problems to be solved in order to develop excellent performance of the arrester for high voltage, such as excellent performance ZnO varistors, uniformity of potential distribution, structural design, and so on. ZnO varistors are the core components of arresters, parameters such as voltage gradient E1mA, nonlinear coefficient α1mA, residual voltage K, leakage current IL, etc., all play a critical role in the overall performance of arrester. Besides, the preparation process of ZnO varistors is complicated and involves many processes, together with performance testing, which lead to a long preparation cycle and high material cost. At present, the improvement of computing power provides a new means for the study of complex systems. The composition, structure and performance of ZnO varistors can be simulated by computer to control performance, which can significantly improve the research efficiency.
Firstly, we studied the correlation mechanism between micro-structure and properties of ZnO varistors through Voronoi network simulation model established by our research group, and optimized the parameters to describe the true conduction mechanism of grain boundary barrier clearly and accurately. Secondly, since choice of the quantity of ZnO grain is the key problem to study the electrical performance parameters of varistor by using simulation model. We analyzed the equivalence effect of different ZnO grain sizes and and found that the simulation results are closer to the real effect as the grain size increases. Finally, the number of 50×50 grain size is used as the equivalent model with good effect and not a long calculation time. The effects of different grain sizes, inhomogeneity of size, grain resistivity, porosity ratio and sample diameter on the macroscopic electrical performance parameters of ZnO varistors are simulated and calculated, then, the influences of these microscopic parameters on various macroscopic electrical performance parameters, such as voltage gradient, nonlinear coefficient, residual voltage ratio, leakage current, etc., are analyzed successively. Then, the microscopic structure parameters and macroscopic electrical performance parameters are classified according to different effects. The microstructure and electrical properties of ZnO varistors were used as optimization variables. The optimization objectives are classified into two categories according to whether any optimization variable has the same influence on all kinds of optimization objectives, the optimization variables can be divided into three categories according to whether the optimization variables of the same classification have the same effect on the electrical performance parameters.
From the simulation analysis, the previous batching - ball milling - spray granulation - water cut - pressing - firing - side insulation treatment and many other processes, plus the performance test and other steps, a long preparation cycle, high material cost of the experimental method has been transformed into a high efficiency and low cost calculation research, which greatly reduces the time and cost. In addition, this paper summarizes and classifies various micro-structure parameters and macro-electrical performance parameters, and simplifies the research process from a complex multi-objective and multi-variable problem to an optimization problem with only two types of objectives and three types of variables, which greatly reduces the difficulty of the problem. Based on the above, a simple optimization strategy is proposed, which has guiding significance for the production of high performance ZnO varistor.
[1] 张刘春. ±1100 kV特高压直流输电线路防雷保护[J]. 电工技术学报, 2018, 33(19): 4611-4617.
Zhang Liuchun.Lightning protection of ±1 100 kV UHVDC transmission line[J]. Transactions of China Electrotechnical Society, 2018, 33(19): 4611-4617.
[2] 刘鹏, 郭伊宇, 吴泽华, 等. 特高压换流站大尺寸典型电极起晕特性的仿真与试验[J]. 电工技术学报, 2022, 37(13): 3431-3440.
Liu Peng, Guo Yiyu, Wu Zehua, et al.Simulation and experimental study on corona characteristics of large size typical electrodes used in UHV converter station[J]. Transactions of China Electrotechnical Society, 2022, 37(13): 3431-3440.
[3] 卢毓欣, 韩永霞, 朱志芳, 等. ±1000kV特高压直流换流站绝缘配合[J]. 电工技术学报, 2014, 29(增刊1): 516-523.
Lu Yuxin, Han Yongxia, Zhu Zhifang, et al.The insulation and coordination of ±1 000k V UHVDC converter station[J]. Transactions of China Electrotechnical Society, 2014, 29(S1): 516-523.
[4] 舒印彪, 张文亮. 特高压输电若干关键技术研究[J]. 中国电机工程学报, 2007, 27(31): 1-6.
Shu Yinbiao, Zhang Wenliang.Research of key technologies for UHV transmission[J]. Proceedings of the CSEE, 2007, 27(31): 1-6.
[5] Li Shengtao, Li Jianying, Liu Wenfeng, et al.Advances in ZnO varistors in China during the past 30 years—fundamentals, processing, and applications[J]. IEEE Electrical Insulation Magazine, 2015, 31(4): 35-44.
[6] 何金良, 杨霄, 胡军. 非线性均压材料的设计理论与参数调控[J]. 电工技术学报, 2017, 32(16): 44-60.
He Jinliang, Yang Xiao, Hu Jun.Progress of theory and parameter adjustment for nonlinear resistive field grading materials[J]. Transactions of China Electrotechnical Society, 2017, 32(16): 44-60.
[7] 何金良, 邬锦波, 孟鹏飞, 等. 深度限制特高压系统操作过电压的可行性分析[J]. 高电压技术, 2018, 44(1): 210-217.
He Jinliang, Wu Jinbo, Meng Pengfei, et al.Analysis on feasibility for deeply suppressing switching overvoltage in AC UHV systems[J]. High Voltage Engineering, 2018, 44(1): 210-217.
[8] 邬锦波, 胡军, 孟鹏飞, 等. 深度限制特高压系统操作过电压对避雷器的要求[J]. 高电压技术, 2017, 43(12): 4132-4138.
Wu Jinbo, Hu Jun, Meng Pengfei, et al.Requirements of arresters for deeply suppressing switching overvoltage in AC UHV systems[J]. High Voltage Engineering, 2017, 43(12): 4132-4138.
[9] 孟鹏飞, 胡军, 邬锦波, 等. 采用镓离子掺杂的高通流容量氧化锌压敏电阻[J]. 中国电机工程学报, 2017, 37(24): 7377-7383, 7452.
Meng Pengfei, Hu Jun, Wu Jinbo, et al.High impulse current discharge capability of ZnO varistors by doping gallium ions[J]. Proceedings of the CSEE, 2017, 37(24): 7377-7383, 7452.
[10] 高婷婷. 氧化锌避雷器局部老化对热电特性影响研究[D]. 沈阳: 沈阳工业大学, 2022.
[11] 尚京城. 氧化锌避雷器的老化机理与状态评价研究[D]. 大连: 大连理工大学, 2018.
[12] Nahm C W.Effect of Yb2O3 addition on varistor properties and aging characteristics of ZnO-V2O5-Mn3O4 system[J]. Journal of Materials Science: Materials in Electronics, 2018, 29(4): 2958-2965.
[13] 刘志远, 于晓军, 李秀广, 等. 基于吸收能量均衡的多柱并联避雷器组电阻片配组方法研究[J]. 电瓷避雷器, 2022(1): 62-68.
Liu Zhiyuan, Yu Xiaojun, Li Xiuguang, et al.Matching method ofVaristors in multi-column arrester based on the balance of withstand energy[J]. Insulators and Surge Arresters, 2022(1): 62-68.
[14] 贺子鸣, 陈维江, 陈秀娟, 等. 多柱芯体并联结构避雷器暂态热特性计算方法[J]. 高电压技术, 2012, 38(8): 2129-2136.
He Ziming, Chen Weijiang, Chen Xiujuan, et al.Calculation method for transient thermal characteristics of multi-column parallel structure surge arrester[J]. High Voltage Engineering, 2012, 38(8): 2129-2136.
[15] 孟鹏飞, 胡军, 邬锦波, 等. 氧化锌压敏电阻综合性能的多元掺杂综合调控[J]. 高电压技术, 2018, 44(1): 241-247.
Meng Pengfei, Hu Jun, Wu Jinbo, et al.Comprehensive performances of ZnO varistors tailored by multi-elements doping[J]. High Voltage Engineering, 2018, 44(1): 241-247.
[16] 程宽, 赵洪峰, 周远翔. B2O3掺杂对直流ZnO压敏电阻老化特性的影响[J]. 电工技术学报, 2022, 37(13): 3413-3421.
Cheng Kuan, Zhao Hongfeng, Zhou Yuanxiang.Effect of B2O3 doping on the aging characteristics of DC ZnO varistor ceramics[J]. Transactions of China Electrotechnical Society, 2022, 37(13): 3413-3421.
[17] 王兰义, 任鑫, 黄海, 等. 国内外避雷器用氧化锌电阻片的技术现状与发展趋势[J]. 电瓷避雷器, 2021(6): 30-44.
Wang Lanyi, Ren Xin, Huang Hai, et al.The development trends of zinc oxide varistor used in surge arrester both in China and abroad[J]. Insulators and Surge Arresters, 2021(6): 30-44.
[18] Hembram K, Rao T N, Ramakrishana M, et al.Influence of CaO doping on phase, microstructure, electrical and dielectric properties of ZnO varistors[J]. Journal of Alloys and Compounds, 2020, 817: 152700.
[19] Wu Kangning, Wang Yao, Hou Zongke, et al.Colossal permittivity due to electron trapping behaviors at the edge of double Schottky barrier[J]. Journal of Physics D: Applied Physics, 2021, 54(4): 045301.
[20] 孟鹏飞, 刘政, 曹伟, 等. 考虑微观特性的ZnO压敏电阻计算模拟模型[J]. 中国电机工程学报, 2021, 41(5): 1588-1597.
Meng Pengfei, Liu Zheng, Cao Wei, et al.The calculation model for ZnO varistor considering micro-characteristics[J]. Proceedings of the CSEE, 2021, 41(5): 1588-1597.
[21] Topcagic Z, Mlakar M, Tsovilis T E.Electrothermal and overload performance of metal-oxide varistors[J]. IEEE Transactions on Power Delivery, 2020, 35(3): 1180-1188.
[22] Zhou Qibin, Yang Hongxiang, Huang Xin, et al.Numerical modelling of MOV with Voronoi network and finite element method[J]. High Voltage, 2021, 6(4): 711-717.
[23] Clarke D R.Varistor ceramics[J]. Journal of the American Ceramic Society, 1999, 82(3): 485-502.
[24] Bartkowiak M, Mahan G D.Nonlinear currents in Voronoi networks[J]. Physical Review B, Condensed Matter, 1995, 51(16): 10825-10832.
[25] 胡军. 用于特高压避雷器的高电压梯度氧化锌压敏电阻研究[D]. 北京: 清华大学, 2008.
[26] 汤霖, 赵冬一, 迟旭, 等. ZnO非线性压敏电阻晶界微观结构的最新研究进展[J]. 电瓷避雷器, 2021(3): 162-178.
Tang Lin, Zhao Dongyi, Chi Xu, et al.Research progress of ZnO nonlinear varistor grain boundary microstructure[J]. Insulators and Surge Arresters, 2021(3): 162-178.
[27] Zhou Qibin, Yang Hongxiang, Huang Xin.Influence of micro-structure disorder in the numerical modeling of metal oxide varistor on current distribution[C]//The Proceedings of the 9th Frontier Academic Forum of Electrical Engineering, Xi’an, China, 2021, 1: 211-219.
[28] Meng Pengfei, Zhao Xiaolei, Yang Xiao, et al.Breakdown phenomenon of ZnO varistors caused by non-uniform distribution of internal pores[J]. Journal of the European Ceramic Society, 2019, 39(15): 4824-4830.
[29] 康晟淋, 赵学童, 张洁心, 等. 冷烧结技术的研究进展及其在电工领域的潜在应用[J]. 电工技术学报, 2022, 37(5): 1098-1114.
Kang Shenglin, Zhao Xuetong, Zhang Jiexin, et al.Recent research progress of cold sintering process and its potential application in electrotechnical fields[J]. Transactions of China Electrotechnical Society, 2022, 37(5): 1098-1114.
[30] 祝志祥, 张强, 曹伟, 等. 特高压直流避雷器用ZnO电阻片研究进展[J]. 中国陶瓷, 2022, 58(4): 9-15.
Zhu Zhixiang, Zhang Qiang, Cao Wei, et al.Research progress of ZnO resistor for ultra high voltage direct current(UHVDC) arrester[J]. China Ceramics, 2022, 58(4): 9-15.