径向电流集中诱发的高压交联聚乙烯电缆缓冲层烧蚀研究  

Study on Ablation of Buffer Layer in High Voltage XLPE Cable Induced by Concentrated Radial Current

作　　者：刘宏亮 刘若溪[1] 赵西元 任志刚[1] 陈平[1] 李华春 高景晖 LIU Hongliang;LIU Ruoxi;ZHAO Xiyuan;REN Zhigang;CHEN Ping;LI Huachun;GAO Jinghui(State Grid Beijing Electric Power Company,Beijing 100075,China;State Key Laboratory of Electrical Insulation and Power Equipment,Xi'an Jiaotong University,Xi'an 710049,China)

机构地区：[1]国网北京市电力公司,北京100075 [2]西安交通大学电力设备电气绝缘国家重点实验室,陕西西安710049

出　　处：《绝缘材料》2021年第8期94-101,共8页Insulating Materials

基　　金：国家电网公司总部科技项目(520201190008)。

摘　　要：为研究皱纹铝护套高压交联聚乙烯绝缘电缆缓冲层烧蚀机理,首先,通过对发生烧蚀的110 kV XLPE绝缘电缆进行故障分析,提出电缆径向电流集中是导致烧蚀故障的原因。其次,建立故障电缆的仿真模型,计算缓冲层与皱纹铝护套接触部分的电流密度最大值及其分布情况,并通过模型试验与公式计算验证仿真结果,发现皱纹铝护套波谷嵌入缓冲层的深度和缓冲层体积电阻率影响着径向电流的大小与分布。最后,通过设计模拟试验,证明径向电流集中是导致缓冲层烧蚀的原因之一,并在恒温箱中对模拟烧蚀试验的环境条件进行控制,通过偏光显微镜对比试验样品和烧蚀铝护套的表面形貌。结果表明:模拟烧蚀试验中发生的烧蚀过程与实际故障电缆中的烧蚀过程相同,且随着缓冲层中电流密度最大值的增大,烧蚀的起始时间缩短。本文揭示了皱纹铝护套烧蚀故障径向电流集中的物理机理,为相关故障诊断及防护提供了理论和试验依据。In order to study the ablation mechanism of buffer layer of corrugation aluminum(Al) sheath high voltage cross-linked polyethylene(XLPE), firstly, we analyzed a ablation failure of 110 kV XLPE insulated cable,and proposed that the concentrated radial current was the cause of ablation failure. Secondly, a simulation model of the faulty cable was established. The current density and its distribution of the contact part of buffer layer and corrugated Al sheath were simulated, and the simulation results were proved by model experiment and calculation.It was found that the size and distribution of radial current were affected by the embedded depth of Al sheath in the buffer layer and the volume resistivity of the buffer layer. Finally, simulation experiments were designed to prove that the radial current concentrated was one of the causes of buffer layer ablation, and the experimental conditions of the simulated ablation experiment were controlled in the thermostat. The surface morphology of the experimental sample and the ablated Al sheath were compared by optical microscope. The results show that the ablation process in the ablation experiment is the same as that in the actual faulty cable, and with the increase of the current density in buffer layer, the ablation start time decreases. This paper reveals the physical mechanism of radial current concentration in the ablation fault of corrugated Al sheath, which provides guideline for relevant fault diagnosis and protection.

关 键 词：高压XLPE绝缘电缆 缓冲层烧蚀 径向电流集中 模拟烧蚀实验 

分 类 号：TM854[电气工程—高电压与绝缘技术]