基于陡波冲击试验的动车组车顶电缆终端绝缘热破坏过程研究

Research on Insulation Thermal Breakdown Process of Cable Terminal of EMU Roof Based on Steep Wave Impact Test

高速动车组车顶高压电缆终端运行在间歇性冲击性负荷环境,电缆终端内部缺陷加速发展,易引发绝缘破坏。文中针对上述问题开展研究,开展陡波冲击试验对比研究使用前后的电缆终端界面特性,结果表明:电缆终端使用后应力管与绝缘管交界处绝缘缺陷明显,在陡波冲击电压下缺陷暴露。建立电缆终端的电—热耦合模型,计算分析电缆电场及热场分布性。在运行电压下,电缆终端应力层及绝缘层交界处存在电场集中、接头处热场畸变明显,二者成为电缆终端的绝缘薄弱点,在频繁电热冲击作用下会加剧绝缘破坏,引发绝缘事故。研究结果为电缆终端的优化设计及制作工艺提供参考依据。

The high-voltage cable terminal on the roof of high-speed trains operates in intermittent and impact loads,and the development of defects inside the cable terminal accelerates and is easy to lead to insulation damage. The study on above issue is performed in this paper,the the steep wave impact test is developed characteristics of the cable terminal interface before and after the usage is compared and studied. The results show that after the usage of cable terminal,the insulation defects at the junction of the stress tube and the insulation tube are obvious and are exposed under the steep wave voltage. The electric-thermal coupling model of the cable terminal is set up to calculate and analyze the electric field and thermal field distribution of the cable terminal. Under operating voltage,the electric field concentration at the junction of the stress layer and the insulation layer of the cable terminal is existed the thermal field distortion is remarkable at the connection,which become into the weak point of the insulation of the cable terminal.The insulation damage will be aggravated under the frequent electrothermal shock and insulation accidents are caused. The research result can provide reference for the optimization design and manufacturing process of cable terminal.