真空断路器真空度与电场电位关系研究

Influence of Shield Electric Potential on Pressure in Vacuum Interrupter

基于屏蔽罩电位测量真空度的方法,是真空断路器真空度在线检测方法中的一个主要研究方向。但是,目前还没有一个基于本方法的实用高真空度测量系统。为了进一步探究断路器屏蔽罩电位与真空度间的关系,本文借助于由克-莫方程建立的相对介电常数-压强间的关系,通过有限元分析工具对不同压强下的真空断路器进行二维电场分析。结果表明,屏蔽罩电位与真空度具有一定的对应关系,并可以通过真空断路器外电场电位的测量来反应;真空断路器外电场电位在压强小于10-2Pa时的变化十分微弱,而在大于10-2Pa时电位有较明显的变化。并通过实验室模拟测量实验,进一步验证了该结果的正确性。本文的分析结果给出了真空断路器外电场电位随真空度变化的规律,对基于屏蔽罩电位法在线测量真空断路器真空度具有一定的指导意义。

A novel technique was developed for rapid on-line evaluation of the pressure in a vacuum interrupter by measuring the electric potential of its shield. The influence of the electric field around the shield of the vacuum interrupter on the pressure was empirically modeled in 2-dimension,theoretically calculated with Clausius-Mossotti equation,numerically simulated in finite element method with software ANSYS,and experimentally investigated online with a lab-built setup. The calculated and simulated results show that the electric field in the vicinity of the shield has a major impact on the pressure in the vacuum interrupter. To be specific,a pressure below 10- 2Pa weakly affects the potential,whereas a pressure above 10- 2Pa results in an abrupt increase of the potential. The simulated and measured results were found to be in good agreement. We suggest that the dependence of the pressure on the shield electric potential be of some technological interest in online measurement of the pressure of vacuum interrupter.