绝缘护层对动车组电缆连接器雷电冲击闪络电压的影响分析

Influence of Insulation Layer on Lightning Impulse Flashover Voltage of Cable Connector in Electric Multiple Units

为提高动车组高压设备箱电缆连接器端部中心点到箱体内壁间空气间隙的雷电冲击电压耐受值,基于串联介质分压原理和静电场理论,分析护层结构及位置对改善电场分布、提高雷电冲击闪络电压耐受性能的可行性。通过理论及仿真验证不同厚度、不同安装方式的护层组合安装方式的设计效果,表明空气间隙中加装的护层厚度及位置影响电场强度分布。试验结果表明:2mm厚护层经50次左右的试验后被击穿;大于3mm厚的护层经300次试验后依旧完好。紧贴电缆连接器端部,包覆两层护层后的雷电冲击闪络电压值可达235kV,提高值为80kV,结论可为现场应用加装护层提高间隙雷电冲击闪络电压耐受值提供依据。

In order to improve the lightning impulse flashover voltage tolerance value of the air gap between the cable connector fitting surface center to the inner wall of the high voltage equipment box, the feasibility of the structure and location of the insulation sheath to improve the electric field distribution and improve the light ning impedance voltage tolerance capability was analyzed based on the principle of series dielectric division and electrostatic field theory. The theory and simulation results showed that, the insulation layer thickness and its installation method affected the distribution of electric field intensity. According to the theory and simulation results, various insulation layers with different thickness and installation methods were designed and their per formances were verified. The tests results show that, the 2 mm insulation layer is broken through after 50 tests. The thickness of the sheath greater than 3 mm is still intact after 300 tests. The lightning impulse flashtage can be up to which is 80 kV h for the field application of gap. 235 kV when two insulation layers were installed closed igher than that without insulation layer. The results of the protective layer to improve the lightning breakdown to the high vo this paper can provide a basis value of the gap.