弓网电弧电气参数是高速铁路中弓网系统电接触特性的重要表征参量。为此,基于弓网电弧试验系统,研究了高速铁路中弓网电弧的伏安特性,分析了升弓过程中燃弧尖峰电压、燃弧时间和稳定燃弧电压的变化规律。测试了升弓过程中电弧电压,分析了其发展规律,利用气体电介质击穿理论和流注理论分析了弓网间隙击穿电压。对升弓过程中燃弧尖峰电压随弓网间隙距离的变化规律进行了曲线拟合。最后,研究了电流对电弧电压特性的影响。试验结果表明:弓网电弧伏安特性关于原点非对称;在受电弓连续升弓过程中,燃弧时间先增大后减小,燃弧尖峰电压与弓网间隙距离满足指数关系,拟合优度系数R〉0.97;电弧稳定燃弧电压随电流的增大而略有减小;燃弧尖峰电压变化斜率随电流的增大而增大。研究结果可为分析实际运行条件下的弓网电弧提供参考。
The electrical characteristics on pantograph-catenary arc are important indicator parameters of electrical contact performance for pantograph-catenary system in high speed railway. Therefore, firstly, the voltage-current (U-I) characteristics of pantograph-catenary arc in high speed railway were measured by a novel apparatus. Arcing peak voltage, arcing time and stable arcing voltage during pantograph rising were analyzed. Moreover, the voltage of pantograph-catenary arc during pantograph rising was measured and analyzed. Secondly, the experimental results of the breakdown voltage of air gap were interpreted by gas dielectric breakdown theory and streamer theory. The relationship between arcing peak voltage and the gap distance of pantograph and catenary wire in the process of pantograph rising was analyzed by curve fitting. Finally, the effect of supply current on the voltage characteristic of pantograph-catenary arc was studied. Conclu- sions are drawn from experimental results as follows: The voltage-current characteristics of pantograph-catenary arc are asymmetrical. During pantograph continuous rising process, arcing time increases firstly and then decreases, arcing peak voltage is an exponential function with the gap distance of pantograph and catenary wire, and the goodness of fit is more than 0.97; With the increasing of current, stable arcing voltage decreases slightly and the slope of arcing peak voltage change increases. The research results can provide references for analyzing pantograph-catenary arc in operating conditions.