Line fault identification method using polar fault current principle component cluster analysis

Abstract

The invention relates to a line fault identification method using polar fault current principle component cluster analysis, and belongs to the technical field of DC power transmission line protection. A batch of line metallicity grounding faults and line external faults are preset from near to far within a full-line-length scope, the sampling rate is 10kHz, a line fault curve of a fault current curve cluster of a measurement end is obtained through electromagnetic transient simulation, after the fault current curve cluster is subjected to normalization processing with a mean value of 0 and a variance of 1, principle component analysis (PCA) is carried out, a PCA space is formed, two clustering point clusters reflecting the line faults and the external faults are formed in the PCA space, a projection ot (q1, q2) of test sample data on a PC1-PC2 coordinate axis of the PCA cluster space is calculated, and distances between the test sample data and the cluster centers of the current curve clusters are measured by use of Euclidean distance so that the line faults are identified.

Description

technical field [0001] The invention relates to a line fault identification method using cluster analysis of principal components of polar line fault current, and belongs to the technical field of direct current transmission line protection. Background technique [0002] With the extensive development of DC system applications, the current research on DC line protection often focuses on improving the protection criteria of existing practical applications, and often uses a single constant value for protection setting. About half of DC transmission system faults are line faults. It is difficult for the traveling wave protection with the voltage change rate du / dt as the core criterion to rely on a single setting value to reliably and effectively detect and identify possible faults across the entire line within the extended time, so as to achieve rapid action across the entire line. At present, the research on DC line protection often focuses on improving the protection criteri...

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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