球板电极下N_2的绝缘特性以及水分的影响

Insulation Characteristics of N_2 in Sphere-plate Electrodes and the Effect of Humidity

采用氮气(N_2)或干燥空气替代SF_6作为中压开关设备的绝缘介质是目前环保型开关设备的发展热点。要保证气箱结构紧凑小巧,需要完全掌握环保气体的绝缘特性,并对固体—气体复合绝缘的配合进行深入研究。文中从研究N_2的基础绝缘特性入手,研究了球板电极间隙下的N_2工频和雷冲耐压特性数据,以及水分对击穿电压的影响。结果表明,N_2击穿电压随着极间距的增大而上升,但会呈现出饱和的趋势。而且,在湿度为1 000μL/L以下时,N_2击穿电压基本不受水分的影响。

Using nitrogen （N2） or dry air to replace SF6 as high-voltage switchgear insulation media is a hot topic in the development of environmental friendly switching equipment. To ensure compact structure and small size, engineers need to fully understand the insulation characteristics of a new gas and study the solid-gas compound insulation. Based on the basic insulation characteristics of N2, the breakdown characteristics at power frequency and with lightning pulse in the sphere-plate electrodes has been studied and the effect of humidity on breakdown voltage analysed. Results shows that the breakdown voltage of N2 first increases with the gap distance and approaches saturation eventually. It also reveals that the breakdown voltage of N2 is not affected by water concentration under a humid condition of 1 000μL/L water content.