基于平均点线距的电压暂降系统级评估方法

为系统比较不同区域电压暂降的严重程度，从电网电压暂降整体水平出发，提出了系统级的电压暂降严重程度评估方法。该方法通过聚类分析确定持续时间区段，求取不同持续区段内残余电压的中位数并绘制中位数线。随后提出平均点线距指标以量化评估各个区域电压暂降严重程度，并根据不同区域的指标分布特征进行电压暂降水平等级划分。某市实际监测数据的评估验证了所提方法的正确性与合理性。该方法能在大量监测数据中有效提取不同区域电压暂降的严重程度信息，从残余电压和持续时间2个维度实现电压暂降的系统级评估，有利于区域间电压暂降水平的对比。

A System Assessment Method for Voltage Sag Severity Based on Average Point-To-Line Distance Index

In order to systematically compare the voltage sag severity of different regions, a system method is proposed to assess grid voltage sag severity. The method obtains the time duration intervals through cluster analysis, and gets the medians of residual voltages for different duration intervals, with which the median line is plotted. And then, the average point-to-line distance index is proposed to quantify the voltage sag severity for different regions. The voltage sag levels are graded according to index distribution features of different regions. The correctness and feasibility of the proposed assessment method are verified with the real monitoring data of a city power system. This method can effectively obtain from numerous monitoring data the voltage sag severity information of different regions, and realize the system assessment of the voltage sags from two dimensions: residual voltage and time duration, which is conducive to compare the voltage sag severity among different regions.