高压XLPE电缆线路状态评估综合体系的建立及应用

Establishment and Application of a Comprehensive System for Condition Assessment of HV XLPE Cable Lines

近年来,高压交联聚乙烯电缆线路的投运数量及运行年限持续增加,为运检工作带来严峻挑战,当前的检测手段及测试数据无法提供电缆系统状态的全面信息,而调研评分的方法在理论性及定量表征方面存在不足。为此,将运维信息与检测数据有效结合,构建了高压交联电缆线路状态综合评估体系。一方面,设计了包括年限、负荷、故障及环境4大模块的运维信息评分表,对线路中电缆本体及附件的整体状态进行综合反映;另一方面,选取红外热像、金属护层接地电流和局部放电3个在线检测试验项目的结果,对系统性能进行实时表征。此外,通过典型失效率曲线、相关性分析及层次分析法等的应用提高了条目设计的合理性及权重分配的有效性,而可缺项输入运行的设计则拓展了工程实用性。最后,应用该文体系对5根退运110 kV交联电缆线路开展状态评估,并从电缆绝缘上取样测得了工频击穿场强、羰基指数以及交联度数据。结果表明,测试结果与评估结论具有良好的对应性,验证了评估体系设计。

In recent years,the circuit number and operation life of high voltage(HV)cross-linked polyethylene(XLPE)cable lines continue to increase,which brings a severe challenge to the operation-maintenance personnel in power grid.The existing detection methods and test data cannot provide comprehensive information about the system status,while the survey-based scoring methods have been criticized for theoretical insufficiency and poor quantitative characterization.In this paper,a condition assessment system of HV XLPE cable line is constructed based on the combination of operation-maintenance information and on-line detection data.On the one hand,an operation-maintenance scoring table is designed,which includes four modules of life,load,fault,and environment,to comprehensively reflect the overall status of the cable and accessories.On the other hand,the data of three on-line tests,including the infrared thermal imaging,metal sheath grounding current and partial discharge measurement,are chosen to characterize the real-time system performance.Besides,through the application of typical failure rate curve,correlation analysis,and analytic hierarchy process,the rationality of item design and the effectiveness of weight allocation are improved.The system can work when some inputs are missing,which expands its engineering practicability.Finally,the status of five retired 110 kV cable lines are evaluated by the comprehensive condition assessment system,including comparing the experimental results of the breakdown strength,carbonyl index and crosslinking degree measured on the XLPE insulation samples taken from the cables.The consistency between the test results and the evaluation conclusions can be a good verification for the design of the evaluation system.