应用磁场分布特征提取的35 kV XLPE电缆劣化评估

Degradation Evaluation on 35 kV XLPE Cable Based on Characteristics Extraction of Magnetic Field Distribution

35 kV交联聚乙烯电缆在配电网中得到了广泛应用,但在运行中热、机械、电等因素会引发电缆绝缘劣化。为提高电力电缆状态评估的可靠性,本文提出了一种基于磁场分布特征分析的电缆绝缘劣化评估方法。基于搭建的35 kV单芯交联聚乙烯电缆仿真计算模型,分析了主绝缘气隙和半导电层凸起缺陷时电缆磁场分布特征,建立了缺陷类型、大小、位置和劣化程度与磁场强度和磁场畸变特征的关系,利用磁场畸变特征检测电缆故障,提升了电缆故障检测的有效性和准确性。

In power distribution network,35 kV cross-linked polyethylene(XLPE)power cables have been widely applied.However,degradation may occur in the cable insulation due to thermal,mechanical,electrical or other factors.To improve the evaluation reliability of power cable states,a novel cable insulation degradation evaluation method on the basis of magnetic field distribution characteristics is proposed in this paper.Based on an established finite element simulation model of 35 kV single-core XLPE cable,the magnetic field distribution characteristics of cable are analyzed in the case of insulation voids or protrusion in the semiconducting layer.The correspondence between the defect type,size,position and degree of deterioration and the magnetic field strength and magnetic field distortion characteristics is formulated,and the magnetic field distortion characteristics are used to detect the cable defect,which is helpful in enhancing the effectiveness and accuracy of cable defect detection.