Network voltage sag frequency estimation method and device with distributed power supply

Abstract

The invention relates to a network voltage sag frequency estimation method and device with a distributed power supply. The method comprises the following steps: calculating a node impedance matrix according to a node admittance matrix of the system; calculating the self-impedance and mutual impedance at the fault point after short circuit occurs in the system; calculating the voltage sag amplitudeof the estimated busbar under different fault types; determining the voltage sag duration of the estimated busbar; performing statistics of the sag frequency of the estimated busbar according to thevoltage sag amplitude and the voltage sag duration of the estimated busbar. According to the method and device provided by the invention, the estimation accuracy of the voltage sag with a distributedpower supply system is improved; by adopting kernel density estimation, the distribution law of the fault occurrence positions better conforms to the practical situation according to the history faultinformation, thus the estimation result of voltage sag is more accurate and conforms to the practice.

Description

technical field [0001] The present application relates to the field of automatic control, in particular to a method and device for evaluating the frequency of power grid voltage sags with distributed power sources. Background technique [0002] With the development of new industries and the improvement of industrial automation, more new power electronic devices have been put into use. Sensitive equipment is extremely sensitive to voltage sags, and a single voltage sag event will bring great losses to users. Therefore, it is of great significance to analyze the short-circuit fault of the power system and accurately evaluate the frequency of voltage sags. [0003] There are two main types of evaluation methods for the frequency of voltage sags: measured statistical methods and random evaluation methods. The measured statistics method uses measurements to statistically determine the characteristics and frequency of sags. The time and economic cost of the actual measurement m...

AI Technical Summary

Problems solved by technology

Due to factors such as bad weather, tree branches or animals, short-circuit faults on transmission lines can occur, and it is difficult to predict the location of short-circuit faults, and the location of line faults is uncertain.

However, most of the random evaluation methods proposed in the existing literature make simple assumptions on the distribution of fault locations, which will cause deviations in the estimation of the voltage sag frequency and affect the accuracy of the evaluation of the sag frequency.

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