高压真空灭弧室内部电场分布的影响因素

Analysis of Influencing Factors for Electric Field Distribution of High Voltage Vacuum Interrupter

为了解高电压真空灭弧室内部的电场分布情况,建立了真空灭弧室的电场数学模型。应用电场数值分析方法和有限元软件详细计算不同屏蔽罩与触头尺寸对真空灭弧室内部电场分布影响的结果表明,因高电压真空灭弧室开距较大,触头间隙不再是场强集中的区域,在高压真空灭弧室小型化设计过程中,除考虑电极间的绝缘外,更需考虑电极与屏蔽罩之间的绝缘。合理设计屏蔽罩的尺寸、位置和触头的形状可有效改善灭弧室内部的电场分布,提高真空灭弧室的耐压能力,从而为国内72.5kV以上电压等级真空灭弧室的研制提供了理论依据。

SF6 gas is now classified as a potential harmfulness greenhouse gas and has to be limited. In the world it is inclined to develop high voltage vacuum circuit breaker to replace SF6 circuit breaker which is widely used in high voltage level. For voltage level over 72. 5 kV, electric field optimization of vacuum interrupters is one of the key technologies of high voltage vacuum circuit breaker. In this paper, according to the structural feature of high voltage vacuum interrupters, a mathematical model is set up to analyze the electric field distribution of high voltage vacuum interrupters. With numerical analysis method and the finite element software, influence of various shields and contacts on the electric field distribution of high voltage vacuum interrupters is calculated and analyzed in detail and some advices for the high voltage vacuum interrupters design are proposed. As a result, in designing a high voltage vacuum interrupter, electric field intensity between the electrodes and the main shield must be considered because its peak value appears in the electrode comer of this gap. It is shown that suitable design dimension and position of shields and shape of contact can improve the insulation performance effectively and endure higher voltage, which will provide a theoretic basement for research on the vacuum interrupters from medium voltage to high voltage in China.