基于金属护层环流的高压电缆外护套绝缘电阻在线监测方法

Online monitoring method for insulation resistance of high-voltage cable outer sheath based on mental sheath circulation current

高压电缆外护套的绝缘电阻是衡量高压电缆绝缘状态的重要参数,本文提出了一种基于金属护层环流的在线监测方法,以评估高压电缆外护套的绝缘电阻,从而实现高压电缆绝缘状态的实时监测。该方法分析了金属护层环流形成及其与外护套绝缘电阻之间的关系,推导出计算模型,并对单端接地和交叉互联接地的高压电缆开展了在线监测方法的现场应用。结果表明:所提出的在线监测方法与离线测量方法的误差在20%以内,且该方法对交叉互联接地高压电缆中间段的测量效果明显好于两边电缆段,对于高压电缆的状态监测和金属护层故障定位具有重要意义。

The insulation resistance of the outer sheath of high-voltage cables is an important parameter for measuring the insulation state of high-voltage cables.In this paper,an online monitoring method based on metal sheath circulation current was proposed to evaluate the insulation resistance of the outer sheath of high-voltage cables,so as to realize the real-time monitoring of the insulation state of high-voltage cables.The formation of mental sheath circulation current and its relationship with the insulation resistance of outer sheath were analyzed,and a calculation model was derived.Then the online monitoring of high-voltage cable with single-end grounding and cross-linked grounding have been carried out.The results show that the error between the online monitoring method and the offline measurement method is less than 20%,and the measurement effect of the method is significantly better in the cross-linked grounding segments than in the two-sided cable segments,which is of great significance for the condition monitoring and fault location of the metal sheath of high-voltage cables.