氮气与聚合物隔板复合绝缘工频击穿特性研究

Research on Power Frequency Breakdown Characteristics of Nitrogen-Polymer Barrier

采用适当压力的氮气(N2)作为SF6的替代气体是目前中压环保型开关设备的研究热点。在氮气中引入隔板与其组成气固复合绝缘间隙,能够更好地提升其耐压性能。通过改变隔板水平位置、竖直尺寸、材料及电极结构,得到不同情况下氮气中击穿电压的变化规律。同时将击穿路径分段分析,总结各分段击穿路径的类型及概率,最后结合仿真分析击穿路径上的电场分布变化。结果表明:一定开距范围内氮气中击穿电压随着电极距离的变化相比于空气更加规律;隔板距离高压电极越近及隔板竖直尺寸越大,击穿电压越高;三种材料的隔板中,聚四氟乙烯(PTFE)板对击穿电压的提升效果最弱,云母板对击穿电压的提升效果最好,但其击穿电压受水平位置影响显著。不同水平位置下击穿电压存在差异是因为电场分布情况不同,击穿电压与击穿路径没有太大关系,竖直尺寸是影响击穿路径类型的重要因素。研究结果可以为氮气与聚合物隔板复合绝缘的设计和优化提供参考。

The use of nitrogen(N 2)with appropriate pressure as the alternative gas for SF 6 is currently a research hotspot for medium-voltage environmentally friendly switchgear.The introduction of a barrier and its gas-solid composite insulation gap in nitrogen can better improve the withstand voltage.In this paper,by changing the horizontal position,vertical size,material and electrode structure of the barrier,the variation law of breakdown voltage in nitrogen under different conditions is obtained.At the same time,the breakdown path is analyzed in segments,the types and probabilities of each breakdown path are summarized,and finally the electric field distribution changes on the breakdown path are analyzed in combination with simulation.The results show that the breakdown voltage in nitrogen within a certain open distance changes more regularly with the distance of the electrode than that of air.The closer the barrier is to the high-voltage electrode and the larger the vertical size of the separator,the higher the breakdown voltage.Among the separators of the three materials,polytetrafluoroethylene(PTFE)plate has the weakest effect on the breakdown voltage,and mica plate has the best effect on breakdown voltage,but its breakdown voltage is significantly affected by the horizontal position.The difference in breakdown voltage at different horizontal positions is due to the different distribution of electric fields.The breakdown voltage has little to do with the breakdown path,and the vertical size is an important factor affecting the type of breakdown path.The research results can provide a reference for the design and optimization of composite insulation between nitrogen and polymer barriers.