Node voltage sag severity comprehensive assessment method based on weighted ideal point method

Abstract

The invention belongs to the technical field of power quality analysis and especially relates to a node voltage sag severity comprehensive assessment method based on a weighted ideal point method. The method is characterized in that the method comprises the following steps: to begin with, establishing an attribute set and a scheme set; then, determining combination weight of each index in the attribute set based on an entropy weight method and a variation coefficient method; and finally, carrying out voltage sag severity comprehensive assessment based on the weighted ideal point method. Weighted distance between each scheme and positive and negative ideal solutions in the ideal point method and relative closeness between the scheme and the positive ideal solution are calculated respectively, and the schemes are ranked in a descending order in sequence to obtain an optimal scheme order. The method reflects voltage sag severity from the perspectives of frequency, duration and amplitude angle, and reflects influencing characteristics of sag frequency on the voltage sag severity from perspectives of the part and the whole, so that erroneous judgment due to single-index assessment is effectively prevented, voltage sag information of each node can be reflected more comprehensively and accurately, and the obtained result is objective, accurate and more realistic.

Description

technical field [0001] The invention belongs to the technical field of power quality analysis, in particular to a method for comprehensively evaluating the severity of node voltage sags based on a weighted ideal point method. Background technique [0002] Voltage sag refers to the sudden drop in the root mean square value of the power supply voltage in a short period of time, which is an inevitable short-term disturbance phenomenon in the operation of the power system. In many regions, voltage sag has become the most important power quality problem affecting industrial users. The harm caused by voltage sag and the huge economic losses it brings are important issues faced by many users. Therefore, accurate evaluation of the severity of voltage sag is of great significance for rational planning and transformation of power grids, reducing economic losses, and improving user satisfaction. [0003] The amplitude and duration of voltage sag are important characteristic quantities...

AI Technical Summary

Problems solved by technology

However, a large number of experiments have proved that due to the lack of scientific description and accurate measurement of the uncertainty of equipment failure events, probabilistic or fuzzy methods will still cause problems such as over-estimation or under-estimation, and this type of model is based on the voltage withstand curve of sensitive equipment This method is not applicable to nodes whose device connection status is unknown

[0005] In view of this, the present invention proposes a comprehensive evaluation method for the severity of voltage sags applicable to multiple nodes, which overcomes the shortcomings of using a single index and probability method or fuzzy method to evaluate the severity of voltage sags

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