基于风险评估的高压电缆巡检周期优化模型

Optimization Model for Risk-based Maintenance Scheduling of HV Cable

高压电缆日常巡检与消缺工作能够及时发现并消除电缆故障隐患,是降低故障率的有效措施。但忽略风险差异的定期巡检方案会导致人力资源被浪费在不必要的检查与测试环节。为了保证电缆可靠运行且兼顾经济性要求,该文提出了基于风险评估的高压电缆巡检周期优化方法。首先针对历史故障数据,提出了一种高压电缆故障数据记录方法,计算电缆故障频率。其中将电缆线路按照巡检目标分为电缆通道、本体、中间接头、终端与接地系统五部分,并引用失效危险指数(IFC)模型计算各部分的故障频率;之后结合线路故障修复时间与线路重要性,计算电缆线路各部分的风险;并考虑电缆系统运行风险阈值,针对不同线路各部分的风险差异实现巡检周期优化计算。以某地区电缆线路为例应用上述方法,结果表明:基于IFC模型的故障频率计算方法无需人为干预,且在故障样本较少的条件下仍能产生有效结果;基于风险评估的巡检周期优化方法能够合理制定巡检方案,有效降低电缆运行风险,优化后电缆系统风险可降低70%。

Regular maintenance and inspections can timely detect and eliminate defects of high-voltage cables, which is essential in reducing failure probability. However, a time-based maintenance without considering the difference in operational risk of individual circuit will lead to waste of resources. In order to ensure reliable and economical operation of cables, an optimization model for periodicity of inspections of HV cable based on risk assessment is proposed in this paper. According to the target of inspection, the cable circuit is divided into five parts: cable conduit, main body, joint, termination, and earthing system. And the index of failure criticality(IFC) model is used to calculate the frequency of failure of each cable circuit component. Then the time required to repair and the importance of the circuit are also considered, and all of them are applied in risk assessment. Moreover, the risk threshold requirements of cable system are taken into consideration. According to the different risk for each part of different circuits, the periodicity of inspection is optimized. Finally, after taking the HV cables from a certain area as an example, the above method is applied to effectively reduce the risk value of the cable circuit operation. The results show that the proposed method of determining failure frequency based on IFC model has the advantages that it does not depend on human intervention and does not need a large sample size to generate valid results. The optimization method for periodicity of inspections based on risk assessment can effectively reduce the risk of cable operation, and the cable system risk can be reduced by 70% after optimization.