三工位开关断口的空气击穿电压试验研究

Research on Air Breakdown Voltage Tests of Three-Position Switch Fracture

气体绝缘开关柜三工位开关断口距离的气隙击穿情况可以通过雷电冲击耐压试验来判断其耐压能力,对于不同的外形尺寸和不同的断口距离,其雷电冲击耐压结果也就各不相同。提出用电场不均匀系数η和50%雷电冲击击穿场强Eb的关系来表示三工位开关断口绝缘能力的方法,先利用电磁场有限元软件对六氟化硫(SF6)用三工位开关模型进行计算分析求得不同断口距离下的电场不均匀系数η,再在空气中进行一定数量的雷电冲击试验,计算得到50%雷电冲击击穿场强Eb,并绘制成曲线关系图。通过N2用三工位开关的断口来验证该曲线的误差,结果证明该方法具有实用性和有效性,可以用于三工位开关断口的研究与开发。

The lightning impulse withstand voltage test can be used to judge the voltage capability of the air-gap breakdown of three-position switch fracture distance of gas-insulated switchgears,and the voltage capability results are various because of their different shape sizes and fracture distance.The paper proposes a method to represent the insulation capability of the three-position switch fracture through the relationship between the non-uniformity coefficient of electric fieldηand the 50%lightning impulse breakdown field strength Eb.Firstly,the electromagnetic field finite element software is used to calculate and analyze the three-position switch model of SF6 to obtain the non-uniformity coefficient of electric fieldηunder different fracture distances.Then,a certain number of lightning impulse tests are carried out in the air to get the 50%lightning impulse breakdown field strength Eb and to plot them as a curve diagram.The error of this curve is verified by the fracture of the three-position switch of N2.The result proves that the method is practical and effective and can be used for research and development of the three-position switch fracture.