低温环境下空气间隙流注放电特性研究

The energy development in the alpine region, such as the north pole, is a key point in the construction of Global Energy Interconnection. The construction of power transmission and transformation projects in the alpine region will face a range of unique problems induced by the low temperature environment. Propagation of streamer make significant impacts on the breakdown of air gaps and the flashover of insulators. In the process of air gaps’ breakdown and insulators’ flashover, streamer is the most important and complicated physical process. The research on the characteristics of streamer propagating in the air gap at low temperature, which is beneficial for researchers to cognize the mechanism of streamer discharge, has profound guiding significance for constructing power transmission and transformation projects in the alpine region. In this project, the test platform with controllable low temperature environment, which can be utilized in the study of the streamer discharge, will be built. The relationship between the temperature and the streamer discharge characteristics of short air gaps (such as the initial voltage, propagation velocity, discharge path, luminous intensity and so on) and breakdown characteristics (breakdown voltage) will be studied in the low-temperature environment. Then, the temperature correction of streamer discharge and breakdown at low temperature environment will be obtained. Based on the test results in low temperature environment, the influence mechanism of low temperature environment on the characteristics of streamer discharge and breakdown ought to be analysed. What’s more, a range of reasonable suggestions can be proposed for the external insulation design of power transmission and transformation equipment in the alpine region.

对北极等高寒地区能源资源的开发是构建全球能源互联网的一大重点。在高寒地区建设输变电工程，将面临低温环境所带来的一系列特有问题。流注的传播对空气间隙的击穿过程以及绝缘子的沿面闪络过程有着重要影响，是其中最为重要、物理过程最为复杂的一个阶段。对低温环境下空气间隙流注放电特性的研究，有利于认识低温环境下空气间隙的放电机理，对于高寒地区建设输变电工程具有重大的指导意义。本课题搭建低温环境流注放电试验平台，在低温环境下研究温度对于短空气间隙流注放电特性(传播概率、稳定传播场强、传播速度、放电路径、发光强度等)以及击穿特性（击穿电压）的影响规律，进而得到空气间隙流注放电和击穿特性在低温环境下的温度修正。基于低温环境下的试验结果，分析低温环境对空气间隙流注放电及击穿过程的影响机理，并为高寒地区输变电设备外绝缘的设计提出合理建议。

流注的传播对空气间隙的击穿过程以及绝缘子的沿面闪络过程有着重要影响，对低温环境下空气间隙流注放电特性的研究，有利于认识低温环境下空气间隙的放电机理，对于高寒地区建设输变电工程具有重大的指导意义。本项目完善了低温环境下的流注放电试验平台；完成了均匀电场“三电极”结构中绝缘介质覆冰表面流注传播参数与电场强度、环境温度变化规律的研究；完成了不均匀电场“三电极”结构中空气流注传播参数与电场强度、环境温度变化规律的研究。.实验结果表明，均匀电场下，环境温度降低使空气的相对密度提高，导致带电粒子在电场中的碰撞电离过程被减弱。因此，流注在低温环境下更难产生和传播。不均匀场的试验研究中，随着板电极上施加的直流高压的增大，流注传播速度、发光强度等均有所提高。不均匀场“三电极”结构中，流注发展路径较均匀场更为分散，分叉数目更多。研究认为电场不均匀程度改变对对流注起始特性和发光强度的影响较大。