基于多元线路特征因素融合的电压暂降严重程度评估

现有电压暂降严重程度评估方法未充分考虑多元线路特征因素对输电线路故障概率的影响，从而导致评估结果出现较大误差。由此，本文提出了基于多元线路特征因素融合的电压暂降严重程度评估方法。首先，基于线路历史故障数据，采用关联规则量化多元线路特征因素对线路故障的影响程度。然后，通过改进D-S证据理论融合多元线路特征因素建立准确的线路年故障概率模型；并采用基于最大熵模型的故障点法评估节点的电压暂降水平。最后，提出了一种同时考虑系统侧电压暂降严重程度和用户敏感设备耐受特性的综合电压暂降严重程度指标用于评估节点电压暂降严重程度。通过与某区域电网实际电能质量监测数据对比，本文所提方法的准确率可达到90%以上。同时通过与未充分考虑线路特征因素的评估案例对比，所提方法的准确率明显提高。因此，在进行电压暂降严重程度评估时，综合考虑线路特征因素可以有效的提高评估结果的准确率。

Voltage sag severity evaluation based on multiple line characteristic factors fusion

The existing methods for evaluating voltage sag severity do not sufficiently consider the effect of the multiple line characteristic factors on the line failure probability, which leads to a large error in the evaluation results. Therefore, this paper proposes an evaluation method for voltage sag severity based on multiple line characteristic factors fusion. First, based on line historical fault data, employ association rules to quantify the influence degree of multiple line characteristic factors on line fault. Second, by improving the D-S evidence theory to fuse multiple line characteristic factors, we establish an accurate line annual failure probability model; by introducing maximum entropy into the method of fault positions, we obtain the voltage sag severity of nodes. And finally, a comprehensive voltage sag severity index considering both voltage sag severity of power grid side and tolerance characteristics of sensitive equipment on the user side is proposed to evaluate node voltage sag severity. By comparing with the actual power quality monitoring data of a regional power grid, the accuracy of the proposed method can reach more than 90%. Meanwhile, the accuracy of the proposed method is significantly improved by comparing it with the evaluation cases that do not fully consider the multiple line characteristic factors. Therefore, when evaluating the voltage sag severity, comprehensive consideration of line characteristics can effectively improve the accuracy of evaluation results.