气体泄漏对全封闭组合电器局部放电影响的仿真分析

气体泄漏对气体绝缘全封闭组合电器(gas insulated substation,GIS)局部放电的影响有待研究,但缺少相关研究手段。为此,首先提出等效相对介电常数的概念,推导等效相对介电常数与气室压强、温度、分子数等的关系,从极化原理上分析其表征气体泄露程度的可行性;然后利用XFdtd三维电磁场仿真软件建立同轴波导结构自由金属微粒缺陷下的局部放电(partial discharge,PD)模型,仿真分析发生气体泄露后的局部放电情况;通过对特高频(ultra high frequency,UHF)电磁波时域信号与放电频谱的分析,探究气体泄漏的影响。仿真结果表明,基于等效相对介电常数气体泄漏对GIS局部放电影响的分析得以实现,同时揭示了脉冲宽度、主频、信号幅值等特征量的变化规律。

Simulation Analysis of Partial Discharge of Gas Insulated Substation Considering Gas Leakage

The effect of gas leakage on partial discharge of GIS needs to be studied, but no available tool can be found. Therefore, the paper first puts forward a new concept of equivalent relative permittivity, deduces the relationship between the equivalent relative permittivity and the gas chamber pressure, temperature, molecular number etc, and analyzes the feasibility of the concept to characterize the degree of gas leakage based on the polarization principle; Then the partial discharge (PD) simulation model of the coaxial waveguide structure with the free metal particle defect is established in XFdtd, the 3D electromagnetic field simulation software. Partial discharge with different level of gas leakage is simulated and analyzed, the effects of gas leakage are explored by analyzing the ultra high frequency (UHF) electromagnetic wave time-domain signal and spectrum. The simulation results show that the equivalent relative permittivity can effectively support the partial discharge simulation analysis with gas leakage, while the change law of pulse width, main frequency, signal amplitude and other characteristics is revealed.