直流叠加冲击电压下HVDC电缆暂态电场分布特性研究  

Research on the Transient Electric Field Distribution in HVDC Cable Under DC Voltage Superimposed Impulse Voltages

作　　者：郑欢[1] 刘乐乐[2] 李忠华[1] ZHENG Huan LIU Lele LI Zhonghua(Key Laboratory of Engineering Dielectric and Its Application, Ministry of Education （Harbin University of Science and Technology）, Harbin 150080, Heilongiiang Province, China Beijing Electric Power Company, Xicheng District, Beijing 100031, China)

机构地区：[1]工程电介质及其应用技术教育部重点实验室(哈尔滨理工大学),黑龙江省哈尔滨市150080 [2]北京市电力公司,北京市西城区100031

出　　处：《中国电机工程学报》2016年第24期6682-6692,共11页Proceedings of the CSEE

基　　金：基金项目:国家重点基础研究发展计划项目(973项目)(2014CB239504);国家自然科学基金项目(51177029)~~

摘　　要：运行中的HVDC电缆除了承受正常工作电压作用外,同时可能承受雷电和操作冲击电压的作用,因此在进行电缆绝缘结构设计时既要考虑稳态直流电场分布又要考虑冲击电压下暂态电场分布。由于HVDC电缆绝缘的电导率是电场及温度的函数,使得HVDC电缆在遭受雷电、操作冲击电压冲击时暂态电场分布更为复杂。为此,该文采用多物理场耦合软件COMSOL Multiphysics仿真研究了温度梯度、施压方式以及绝缘材料非线性电导属性对直流叠加冲击电压下电缆绝缘中暂态电场的影响规律。研究结果表明:直流叠加冲击电压时,暂态最大场强始终出现在电缆绝缘内屏蔽表面;当电缆结构、绝缘材料非线性属性和外加冲击电压幅值确定时,随绝缘内温度梯度的提高,直流叠加同极性冲击电压时暂态最大场强减小,而叠加反极性冲击电压时暂态最大场强却逐渐增大;降低材料电导活化能和提高电场依赖系数可有效改善暂态电场分布,降低暂态最大电场波的幅值并缩短波头和波尾时间。HVDC cables in operation will endure the lightning or switching impulse voltages superimposed on the DC working voltage, the steady DC electric field distribution and the transient electric field distribution under the impulse voltages superimposed on the DC voltage should be considered at the same time during the cable insulation structure design. Due to the conductivity of HVDC cable insulation as a function of the electric field and temperature, the transient electric field distribution in HVDC cable under the lightning and switching impulse voltage is more complex. Therefore, the effects of the temperature gradient, the applied voltage pattern and the nonlinear conductivity properties of the insulating materials on the transient field were studied with the COMSOL Multiphysics simulation software, for the cable insulation under the DC voltage superimposed impulse voltages. The research results show that： the transient maximum field is always appeared in the insulation near to the inner shield surface during applied the DC superposed impulse voltages on the cable insulation; for the certain cable structure, the certain nonlinear properties of insulating materials and the certain superposed impulse voltage amplitude, increasing the temperature gradient in the insulation reduce the transient maximum field under the DC superposed with same polarity impulse voltages, and increase the transient maximum field under the DC superposed with reverse Polarity impulse voltage; to reduce material conductance activation energy and to increase field dependence coefficient can effectivelyimprove the transient electric field distribution, reduce the amplitude and shorten the head and tail time of the transient maximum electric field wave.

关 键 词：HVDC电缆 温度梯度 冲击电压 暂态电场 非线性电导率 

分 类 号：TM854[电气工程—高电压与绝缘技术]