临近悬浮体影响下的均压环放电特性研究

Research on discharge characteristics of the equalizing ring under the influence of the adjacent suspension

目前,现场交流耐压试验中被试设备顶部均压环安全距离范围内的悬浮体对试验的影响尚不清楚,开展临近悬浮体影响下的均压环放电特性研究对提高现场试验效率具有重要意义。首先搭建基于工频试验变压器的模拟试验平台,通过反复试验获得750kV、330kV和110kV三个电压等级共12种工况下的最大放电距离;其次建立三维模型,通过仿真计算掌握试验时的空间最大电场、悬浮体表面电势及其分布规律,通过引入修正系数及其拟合计算,使仿真模型具有普适性;最后考虑现场交流耐压试验电压频率为非工频的现状,开展空气击穿放电特性与试验电压频率的相关性研究,获得最大放电距离与试验频率的关系曲线。研究成果进一步完善了现场交流耐压试验体系,可为今后开展此类试验提供技术支撑。

During the on-site AC withstand voltage test, the influence of the suspension within the safe distance of the pressure equalizing ring on the top of the tested equipment is still unclear, it is important to carry out research on the discharge characteristics of the pressure equalizing ring under the influence of the adjacent suspension so as to improve the efficiency of the test significance. In this paper,a simulation test platform based on the power frequency test transformer is built first, and the maximum discharge distances under 12 working conditions of three voltage levels of 750kV, 330kV and 110kV are obtained through repeated tests. Secondly, a three-dimensional model is established, and the simulation calculation the maximum electric field in space, the surface potential of the suspended body and its distribution rules during the test are mastered, and the simulation model is universal by introducing the correction coefficient and its fitting calculation. Finally, it is considered that the voltage frequency of the on-site AC withstand voltage test is not 50Hz. At present, the correlation study between the air breakdown discharge characteristics and the test voltage frequency is carried out, and the relationship curve between the maximum discharge distance and the test frequency is obtained. The research results further improve the on-site withstand voltage test system, and provide technical support for such tests in the future.