雷电冲击电压下GIS盆式绝缘子暂态电场分析

Analysis for Transient Electric Field Computation of GIS Basin Insulator Under Lightning Impulse Voltage

GIS盆式绝缘子在雷电压下的暂态电场分布对其安全运行至关重要。工程上一般忽略雷电压下盆式绝缘子盆体材料转向极化的建立时间,采用工频电压下的静电场来近似替代雷电压下的暂态电场。为此利用建立的盆式绝缘子暂态电场数学模型,联合基于LM算法的介电谱分析方法,实现了盆式绝缘子的暂态电场计算,得出了盆式绝缘子屏蔽罩表面、盆体表面以及盆体与中心导杆界面等关键位置的暂态电场分布规律,对比了传统方法的计算结果,发现传统方法下凹面屏蔽罩以及盆体表面处场强最高值均高于暂态电场结果,差值分别为-2.2%、-1.21%和-4.37%;盆体与中心导杆界面处场强最高值在2种方法下相差相对较大,差值为4.46%。该方法能够在计算时间成本可接受的前提下,更精确地掌握GIS盆式绝缘子各关键位置的电场分布,为GIS盆式绝缘子的绝缘设计提供计算分析依据。

The transient electric field distribution of GIS basin insulator under lightning impulse voltage is of great importance for its safe operation. The establishment time of turning-direction polarization of basin insulator material under lightning impulse voltage is generally neglected, and then the electrostatic field under power frequency voltage has usually been used to replace the transient electric field in engineering. In this paper, the transient electric field calculation of the basin insulator is realized by using the established mathematical model of the transient electric field of the basin insulator and the dielectric spectrum analysis method based on LM algorithm. The distribution of transient electric field on the surface of shielding cover, basin insulator and the interface between basin and central conductor has been obtained and then investigated. The results from the traditional method have also been compared. The maximum electric field intensity on the surface of the concave shielding cover and basin is higher than that from the transient analysis. The differences are-2.2%,-1.21% and-4.37%, respectively. The difference of maximum electric field strength between two methods on the interface is about 4.46%. The method can be adopted to accurately compute the electric field distribution of each kf GIS basin insulator within an acceptable computation time. And the research in this paper can provide calculation of key position and analysis references for the insulation design of GIS basin insulator.