基于等级划分隶属度函数的脆弱节点综合评估

复杂配电网中脆弱节点的评估日益困难,为有效建立评估指标等级的联系量化关系,提出一种等级划分的隶属度函数来刻画评估指标各等级之间的脆弱特性。首先,根据配电网的拓扑结构与实际运行工况,提出节点级数、有功度数以及基于负荷冲击、故障断线的电压增量严重度4个指标来分析整个配电网,根据指标变化的离散程度,采用熵权法来确定各指标的权重。然后,采用一种基于等级划分的隶属度函数,对脆弱节点的各项指标建立隶属等级模型。最后,通过隶属矩阵运算方法,计算配电网各节点的脆弱度值,来辨识配电网的薄弱环节。算例结果表明,所提出的综合脆弱度评估体系符合实际情况,能够有效辨识配电网中的脆弱节点,同时验证此脆弱度评估体系地合理性和实用性。

Comprehensive evaluation of vulnerable nodes based on hierarchical partition membership function

The evaluation of vulnerable nodes in complex distribution networks is becoming more and more difficult. In order to effectively establish the quantitative relationship among the levels of the evaluation indicators, a membership function of grade division is proposed to describe the vulnerability characteristics among the levels of the evaluation indicators. Firstly, according to the topological structure of the distribution network and the actual operating conditions, four indexes, namely node series, active power degree and voltage increment severity based on load impact and fault breaking, were proposed to analyze the entire distribution network. Based on the discrete degree of index changes, entropy weight method was adopted to determine the weight of each index. Then, a membership function is used to establish a membership model for each index of vulnerable nodes. Finally, the weak links in the distribution network are identified by calculating the vulnerability value of each node of the distribution network through membership matrix algorithm. The calculation results show that the proposed comprehensive vulnerability evaluation system is in line with the actual situation, effectively identify the vulnerable nodes in the distribution network, and verifies the rationality and practicability of the system.