雷电冲击电压下GIS瞬时绝缘数值分析方法

Numerical Analysis Method for Transient Insulation of GIS Under Lightning Impulse Voltage

为描述雷电冲击电压下气体绝缘金属封闭开关设备(gas insulated metal-enclosed switchgear,GIS)绝缘被破坏过程的内在机理,提出一种瞬时绝缘数值分析新方法,采用电磁暂态分析与优化模拟电荷法相结合的方法,以某550kV GIS为研究对象,对雷电冲击电压下550kV GIS的瞬时绝缘特性进行仿真计算与分析。结果表明:新方法计算所得GIS场强峰值比传统绝缘分析方法高约8%左右;在0-15μs时间段内,GIS内电压虽未达到峰值,但由于电压变化剧烈,导致电场畸变严重,此时GIS绝缘被击穿的概率增大;在进行绝缘结构优化设计时,应抑制场强幅值变化率,以降低绝缘被击穿概率。

In order to describe the process of insulation destruction of GIS under lightning impulse voltage, we proposed a novel method of transient insulation numerical analysis. A combination of the electromagnetic transient analysis method and optimized charge simulation method (CSM) was put forward to calculate and analyze the transient insulation characteristics of a 550 kV GIS under lightning impulse voltage. The instantaneous insulation of GIS was characterized to provide a theoretical basis for insulation optimization design of GIS. The results show that, compared to the calculation results by traditional insulation analysis method, the calculated electric field strength peak values of GIS by the proposed method is increased by about 8%. Within 0~15 μs, though the voltage of GIS does not approach to its peak value, there exists severe electric field distortion caused by the sharp voltage variation with higher probability of GIS insulation breakdown. Additionally, for the GIS insulation structure optimization design, it is advisable to restrain the change rate of electric field strength amplitude in order to reduce the probability of insulation breakdown.