Method for evaluating oil-paper insulation aging state of converter transformer

Abstract

The invention discloses a method for evaluating the oil paper insulation aging state of a converter transformer, which belongs to the technical field of converter transformer operation and maintenance. The method comprises the following steps of: obtaining polarization and depolarization current initial data of an oil paper insulation test sample through a micro-current sampling system; calculating an oil-paper composite insulation interface polarization attenuation current, performing differential transformation to obtain a time domain dielectric response function dielectric spectrum curve, extracting a double-peak branch polarization charge quantity Q (t), relaxation time tau n and a branch shape parameter alpha n, fitting main relaxation time and an oil-paper polymerization degree valueto obtain a fitting curve, obtaining the oil paper polymerization degree of the actual converter transformer according to the differential time domain spectrum main relaxation time of the actual converter transformer, and evaluating the aging state of the oil paper insulation structure of the converter transformer. The problem that a polarization depolarization current method cannot be directly and accurately used for evaluating the oil paper insulation aging degree of a complex transformer oil paper insulation system is solved.

Description

technical field [0001] The invention belongs to the technical field of operation and maintenance of converter transformers, and in particular relates to a method for evaluating the aging state of oil-paper insulation of converter transformers. Background technique [0002] The converter transformer is one of the important power equipment for power transmission in the power grid. Its safe and stable operation is the key to the stability of the power grid. The converter transformer is subjected to the combined effects of multiple factors and multiple physical fields, which makes its internal oil-paper insulation aging faster. Therefore, how to accurately judge the aging degree of the oil-paper insulation of the converter transformer has become a hot spot for on-site operation and maintenance personnel. [0003] The insulating material of the converter transformer is mainly composed of transformer oil and solid insulation (paper, cardboard, etc.). The traditional detection meth...

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Problems solved by technology

[0006] In order to overcome the shortcomings of the existing technology: the present invention provides a method for evaluating the aging state of the oil-paper insulation of converter transformers, which is used to solve the problem that the oil-paper insulation system of a complex transformer cannot be directly and accurately evaluated by the polarization and depolarization current method The problem of insulation aging degree

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