干燥空气绝缘环网柜中的复合绝缘工频特性研究

Investigations on Power Frequency Characteristics of Composite Insulation Configuration in Dry Air Insulated Ring Main Unit

采用干燥空气替代SF_6作为环网柜的绝缘介质满足了目前开关设备的环保型发展需求,但由于干燥空气绝缘强度远低于SF_6,需要对产品的固体—气体复合绝缘的配合进行深入研究,目前这方面的系统性研究较少。文中首先采用不同形式的基础电极,研究了电场均匀度、气压和间隙对干燥空气间隙工频特性的影响,得到了不同均匀度条件下的最大击穿电场强度数据。针对实际产品的套管位置开展了仿真和试验研究,系统性分析了复合绝缘结构对最大电场强度位置和数值的影响。结果表明,间隙下的电场均匀度与最大场强关系可作为复合绝缘耐压特性的判据,采用固体绝缘材料包覆、增大间隙以及优化电场均匀度等方法可有效提高复合绝缘的耐压特性。

Using dry air replace sulfur hexafluoride (SF6) as insulation medium for ring main unit meets the requirement of environmental protection development of switch equipment. However, the much lower dielectric strength of dry air than SF6 make the further study on the solid-gas composite insulation become necessary, on which area the systematical research work is limited. In this work, different types of fundamental electrode are used to research the influences of electrical field uniformity, gas pressure and gap distance on the power frequency characteristic. The data of maximum breakdown field strength on different field uniformity is obtained. Simulation and experimental researches are carried out on the insulation bush position of the actual product, on this basis, the influence of composite insulation structure on the position and value of maximum electric field strength is systematically analyzed. The results show that, the relationship between electric field uniformity and maximum field strength under gaps can be the criterion for the characteristics of composite insulation. Also, the voltage withstanding properties of composite insulation can be improved effectively by using solid insulation material covering, increasing distance and optimizing electric field uniformity.