综合考虑系统与设备侧的节点电压暂降评估

Comprehensive evaluation of node voltage sag based on power system and equipment sensitivity analysis

针对从供需两侧评估电网节点电压暂降水平的需求,提出考虑系统和设备侧的节点电压暂降严重程度评估方法。首先,根据系统与设备评估重点构建指标:基于累积/互补累积分布函数、严重性指标及暂降统计表定义节点平均电压暂降影响度指标,与电压暂降频度指标共同构建系统侧指标集;由节点综合电压耐受曲线及能量损失公式构造节点综合故障率作为设备侧指标,再形成兼顾系统和设备侧的综合评价指标集。其次,对指标集赋权,并采用基于马氏距离的逼近理想点(TOPSIS)法刻画节点电压暂降严重程度,在IEEE 30节点系统仿真,并使用所提方法评估节点电压暂降严重程度,实现了电压暂降薄弱节点的辨识。最后,通过模糊C均值聚类方法对不同组合指标进行评估合理性分析,结果证明文中所提方法能解决单一指标评价片面的问题。

Aiming at the demand of evaluating voltage sag severity considering both electric utilities and users,an evaluation method based on power system and equipment sensitivity analysis is proposed.Initially,based on the focus of voltage sag assessment on system and user-side,the comprehensive attribute set is formed.The system-side index set is constructed with the average influence degree index as well as the voltage sag frequency index,further forms a comprehensive evaluation index set with the failure rate index.The average influence degree index is formed based on cumulative distribution density functions,statistical table and severity indices.The failure rate index is formed based on the comprehensive voltage tolerance curve and energy loss calculation.Then,the indices are weighted and Mahalanobis distance-based technique for order preference by similarity to ideal solution(TOPSIS)is used to reflect the voltage sag severity levels.The simulation model of the IEEE 30-bus system is built so that the proposed method could be used to evaluate the voltage sag severity.The result could help find out the nodes which suffer from greater impacts of voltage sag events.Finally,the fuzzy C-clustering method is used to analyze the evaluation results.It is verified that the proposed evaluation method is helpful to overcome the one-sided problem of single index evaluation.