配电网电缆接头SiR-XLPE绝缘界面热应力与击穿电压关系的实验与分析

Experiment and Analysis of Relationship Between Thermal Stress and Breakdown Voltage of SiR-XLPE Insulated Interface of Distribution Network Cable Connector

通过构建电磁-热-应力多场耦合的电缆接头模型,建立配电网电缆不同稳态负荷电流条件下界面温度与绝缘界面压力的联系,随后通过电缆接头绝缘界面电压击穿实验探究界面压力对绝缘界面起始击穿电压的影响。结果表明:电缆接头绝缘界面压力与线路负荷状态存在强耦合关系,当电缆线芯达到90℃稳态运行时,绝缘界面处的界面压力为初始值的两倍以上;绝缘界面起始击穿电压随着界面压力的增大而增大。在实际线路运维过程中,可以适当提高电缆负荷,促使绝缘界面热应力增大,以提高绝缘界面起始击穿电压。

In this paper,the connection between interface temperature and insulated interface pressure of distribution network cables under dfferent steady-state load currents is established by constructing a multi-field coupling model of electromagnetic,thermal and stress cable joints.Subsequently,the influence of interface pressure on the initial breakdown voltage of insulation interface is explored through the voltage breakdown experiment of cable joint insulation interface.The results show that on the one hand,there is a strong coupling relationship between the insulated interface pressure and the line load state,when the cable core reaches a steady operation state of 90℃,theinterfacepressureat theinsulation interface is more than twice the initial value.On the other hand,the initial breakdown voltage of insulated interface increases with the increase of interface pressure.In the actual process of line operation and maintenance,the cable load can be appropriately increased to increase the thermal stress at the insulated interface,so as to increase the initial breakdown voltage at the insulated interface.