110 kV海缆终端外绝缘故障分析及预防措施研究
周路遥，王少华，刘浩军，曹俊平，杨勇
（国网浙江省电力公司电力科学研究院，浙江 杭州 310014）
摘 要：针对110 kV海缆A1线、A2线中发生的瓷套式户外终端外绝缘故障，进行故障终端检测及事故原因分析，现场检测发现海缆故障相终端均存在外部放电痕迹，并伴有烧灼痕迹及金属熔化物。故障原因与区域特殊气候条件有较大关系，分析认为终端套管覆冰引起表面电场不均匀度加剧，在融冰过程中套管表面的盐污会增加泄漏电流，最终沿冰层表面发生闪络。通过电场仿真验证了覆冰、污秽以及加装硅橡胶增爬伞裙对终端外部电场的影响，结果表明加装增爬伞裙可以增加爬电距离，对防止冰闪有效果。为预防此类故障发生，可对终端套管进行防盐蚀处理、喷涂防污闪材料、加装增爬伞裙，并提升海缆在线监测和状态检测水平。
关键词：海缆终端；外绝缘；覆冰闪络；增爬伞裙
中图分类号：TM726.3 文献标识码：B 文章编号：1007-3175(2018)05-0042-04
Study on Diagnosis and Preventive Measures of 110 kV Submarine Cable Terminal External Insulation Fault
ZHOU Lu-yao, WANG Shao-hua, LIU Hao-jun, CAO Jun-ping, YANG Yong
（State Grid Zhejiang Electric Power Research Institute, Hangzhou 310014, China）
Abstract: Fault terminal diagnosis and the cause of the accident were analyzed for the external insulation fault of porcelain sleeve outdoor terminal in line A1 and line A2 of 11 0 kV submarine cable. Site detection showed that the fault phase terminal has external discharge traces, accompanied by burning traces and metal melting. The cause of the fault was related to the regional special climatic conditions. It is concluded that the bushing surface icing increased the unevenness of the surface electric field, and the salt current on the bushing surface would increase the leakage current during the melting process. Finally the flashover happened along the icing surface. The electric field simulation verified the effect of ice coating, contamination and the addition of silicone rubber creepage extender on the external electric field of the terminal. The results show that the installation of the creepage extender can increase the creepage distance and prevent the icing flashover. In order to prevent such failures, the terminal bushing can be treated with anti-corrosion treatment, spray anti-pollution flashover material, install the creepage extender, so as to improve the level of online monitoring and condition detection in submarine cable.
Key words: submarine cable terminal; external insulation; icing flashover; creepage extender
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