基于激光诱导等离子体的 Mach⁃Zehnder 干涉法测量气体介质恢复特性的研究

Arc extinguishing gas is used widely in high voltage apparatus，and arc extinguishing performance of the gas is closely related to its recovery performance. As for the measurement of arc extinguishing performance of gas medium，there are obvious shortcomings in modeling and simulation methods and some direct or indirect methods for measuring electron density. For solving this problem，the use of Mach⁃Zehnder interferometry can accurately measure the electron density at each time point behind the arc，which is a key parameter for studying the recovery characteristics of gas medium. At the same time，considering the high cost of the new gas medium measurement under the circuit breaker structure，a laser induced plasma based gas medium recovery characteristics measurement experiment is designed in this paper. Through this experiment，the electron density attenuation characteristics of SF₆,CO₂ and N₂ are measured，the characteristic value of decay rate of electron density is SF₆(1)>CO₂(0.77)>N₂(0.72),and the feasibility of the proposed method is verified by comparing with the existing conclusion.