基于场景构建的电压暂降特征量随机评估方法

Random evaluation method of voltage sag characteristics based on scenario construction

电压暂降幅度与持续时间分布是电压暂降的主要特征量,也是敏感负荷损失预估及治理方案选择的重要依据。但现有随机评估方法往往存在计算量大、精度低等不足,使得分析得到的电压暂降特征值难以进行实际应用。针对配电网节点众多、负荷变化特征明显等特点,选择将场景法应用于电压暂降特征量随机评估中。首先通过K-medoids聚类方法进行节点类别划分及典型节点选取。其次通过节点加权网络等值实现了配电网初始运行状态的多维场景降维处理。进而结合短路故障概率分布曲线及网络阻抗折算,提出了典型电压暂降场景集生成方法。最后以某配电网网架结构为例,计算了其供区内敏感负荷点处电压暂降特征量,验证了方法的有效性与可行性。

The distribution of voltage sag amplitude and duration is the main characteristic quantity of voltage sag,and it isalso an important basis for sensitive load loss estimation and treatment scheme selection.However,the existing stochasticevaluation methods often have shortcomings of needing a lot of calculation and having low accuracy.This makes it difficultto apply the obtained characteristic value of voltage sag in practice.In view of the characteristics of distribution network withmany nodes and obvious load variation,the scenario method is applied to the voltage sag characteristic evaluation.First,theK-medoids clustering method is used to classify the node types and select the typical nodes.Secondly,a multidimensionalscene dimension reduction of the initial operation state of the distribution network is realized through the node weightednetwork equivalence,and then the short-circuit fault probability distribution curve and network impedance conversion arecombined to propose a generation method of a typical voltage sag scene set.Finally,taking a distribution network structure asan example,the characteristic value of voltage sag at sensitive load points in the power supply area is calculated to verify theeffectiveness and feasibility of the method.