基于模糊专家系统的输电线路非解析可靠性模型

Non-analytic reliability model of transmission lines based on fuzzy expert system

输电线路故障被认为是致使电网连锁故障发展的主要因素,因此,考虑系统运行状况及线路运行环境评估输电线路的可靠性水平,是准确评估电力系统运行可靠性的基础。通过计算p-值对影响线路故障率的因素进行重要度排序,并筛选出了重要因素。在此基础上,建立基于模糊专家系统的线路非解析可靠性模型。该模型结合专家的知识和经验选择合适的模糊集、隶属度函数和模糊规则,考虑各影响因素对线路故障率的综合影响,弥补了历史数据不完善带来的缺陷。通过IEEERTS算例,分析不同天气和系统状态下,线路故障率的变化情况。计算结果表明,线路非解析可靠性模型能够正确反映天气状况和系统状态的变化,为评估线路运行风险和电力系统运行可靠性提供了基础。

The outage of the transmission line is considered to be one of the most important factors which accelerate the propagation of the cascading failures. Thus, considering the influence of the system operating state and the ambient on the reliability of the transmission lines is the basis of evaluation of the system operational reliability. The p-value is adopted to analyze the importance of the random factors which affect the failure rates of the transmission lines. Then the random factors with higher importance values are screened out and taken as the inputs of the non-analytical reliability model of the transmission line. The non-analytical reliability model is built up on the fuzzy expert system which contains fuzzy sets, membership functions and fuzzy ＂if-then＂ rules. This model combines the knowledge and experience of the experts, considers the integrated influence of different random factors and remedies the defect caused by lacking of the historical data. The non-analytic reliability model of the transmission line is applied to IEEE RTS system. The failure rates of the transmission lines are calculated under different weather conditions and system operating states. The results illustrate that the failure rates of the transmission lines increase with the deterioration of the weather condition and system operating state, which provides the foundation of operational risk assessment of the transmission lines and operational reliability of the power system.