A line fault identification method based on pole-line voltage machine learning discrimination mechanism

Abstract

The invention relates to a line fault identification method based on an epipolar voltage machine learning discrimination mechanism. If a single pole ground fault occurs at a line, in-region fault points are set along a line MN; electromagnetic transient simulation is carried out at a sampling rate of 10kHz; epipolar voltage curve clusters in a full-line long-range fault mode and an external line fault mode are obtained respectively; data within 1ms are selected and a PCA clustering analysis is carried out on the data; and a two-dimensional PCA space formed by two principle components PC1 and PC2 is obtained. Two kinds of clustering point clusters of the line fault and the external fault are reflected in the PCA space; and a projection ot (q1,q2) of testing sample data one PC1 and PC2 coordinate axes in the PCA clustering space is calculated, wherein the projection ot is used as the input attribute of SVM; a prediction model is determined by using a radial basis function as a core function. A PCA clustering analysis is carried out on the testing data to obtain a projection o't and the projection information is inputted to the prediction model PCA-SVM to carry out classification discrimination, and whether the fault is a direct-current line fault is determined.

Description

technical field [0001] The invention relates to a line fault identification method based on a polar line voltage machine learning discrimination mechanism, and belongs to the technical field of direct current transmission line protection. Background technique [0002] At present, the DC transmission line protection that has been put into operation in my country is mainly based on the so-called traveling wave protection, differential undervoltage protection, longitudinal differential protection and low voltage protection based on the change rate and change amount. The research on DC line protection often focuses on improving the existing protection criteria in practical applications, and often adopts a single constant value for protection setting. Since the transmission distance of UHVDC lines is usually long, the causes of line faults are very complicated, such as lightning strikes on the line causing insulator flashover, common short circuit, bird damage, icing, de-icing bo...

AI Technical Summary

Problems solved by technology

Since the transmission distance of UHVDC lines is usually long, the causes of line faults are very complicated, such as lightning strikes on the line causing insulator flashover, common short circuit, bird damage, icing, de-icing bounce, mountain fire faults, and nonlinear time-varying caused by line-to-tree discharge For high-resistance faults, it is often difficult to characterize and analyze these faults with explicit mathematical relationships, so it is difficult to reliably achieve full-line quick action only by adjusting the protection setting.

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