Overheating fault diagnosis method of transformer

Abstract

The invention relates to an overheating fault diagnosis method of a transformer. The method comprises steps of calculating basic probability distribution functions of all kinds of faults on the evidence of codeless four ratios and characteristic gas by use of a posterior probability SVM; and then according to evidence theory definition, calculating fusion results of all kinds of the results under combined effects of multi-evidence bodies for belief functions of different evidence bodies. A probability estimation module is introduced in a 'one versus one' multiclass SVM by use of a pair-wise coupling algorithm, so defects of limitations on following data processing imposed by hard decision output when a traditional SVM is solving multiclass problems are overcome and an SVM probability output problem is effectively solved. According to the invention, by fully using redundant and complementation information of chromatographic data and electric test data and applying the D-S evidence theory, correction and reliability of comprehensive diagnosis results based on multi-default characteristics are greatly improved than the diagnosis based on single-default characteristics, which facilitates diagnosis of fault types of the transformer and has practical significance for formulation of maintenance strategies of the transformer.

Description

Technical field: [0001] The invention relates to a method for diagnosing a transformer overheating fault, in particular to a method for diagnosing a transformer overheating fault based on posterior probability SVM and evidence synthesis technology. Background technique: [0002] In the power system, the transformer is an important equipment of the power system, and its working status directly affects the stability of the power grid. Therefore, it is of great practical significance to study the transformer fault diagnosis technology and improve the operation and maintenance level of the transformer. In transformer overheating fault diagnosis, dissolved gas analysis in oil DGA is recognized as an effective means to detect transformer initial faults. Transformer overheating faults refer to high temperature overheating faults, medium temperature overheating faults and low temperature overheating faults, which are used for transformer fault diagnosis The characteristic gases diss...

AI Technical Summary

Problems solved by technology

This type of research pays more attention to the performance of a single algorithm itself, and the decision-making results depend on the filtered feature information and classification algorithms. In transformer fault diagnosis, only using the fault feature information on one side of the equipment is uncertain, and even some results Unreliable, it is necessary to comprehensively utilize various fault information of the equipment in order to realize a comprehensive and accurate diagnosis of the equipment

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