高压直流电缆接头稳态温度场分布及其影响因素

Steady-State Temperature Field of HVDC Cable Joint and Its Influencing Factors

温度是反映电缆中间接头运行状态的重要参数。与交流不同,高压直流电缆中间接头绝缘层温度的变化影响着电场分布和空间电荷的积累,因此不仅要关注接头线芯的温度,更要研究绝缘层温度和绝缘层内外表面温差的变化。建立了高压直流XLPE绝缘电缆中间接头的简化模型,利用有限元软件进行仿真,得到了接头绝缘层稳态温度分布,并研究了不同线芯电流和电缆接头外表面温度分别对接头导线芯温度、XLPE主绝缘和硅橡胶(SIR)增强绝缘层温度分布以及绝缘层内外表面温差的影响。结果表明:直流高压下,线芯电流对三者影响较为显著;接头外表面温度对接头导线芯最高温度、绝缘层最高温度和绝缘层温度分布有影响,而对绝缘层内外表面温差的影响可忽略不计。

Temperature is an important parameter to reflect the operating state of a cable joint, Different from AC, the change of temperature in the insulation layer of HVDC cable joint impacts the distribution of electric field and the accumulation of space charge. As such research attention is required not only on the temperature of cable joint conductor but also the temperature of the insulation layer and the change in temperature difference between interior and exterior surfaces of the insulation layer. A simplified model of the HVDC XLPE cable joint is created and the finite element software is used to analyze the distribution of steady state temperature in the insulation layer and the respective impacts of the conductor current and the surface temperature of the joint on the temperature of the joint conductor, the temperature distribution of XLPE insulation and SIR reinforced insulation, and the temperature difference between interior and exterior surfaces of the insulation layer. The results showes that in the case of HVDC, the conduct current has considerable impacts on all three parameters. Moreover, the exterior surface temperature of the cable joint affects the maximum temperature of the conductor, the maximum temperature of the insulation layer, and the temperature distribution in the insulation layer, but has minimal effect on the temperature difference between interior and exterior surfaces of the insulation layer.