Method and system for evaluating the aging state of oil-impregnated paper insulation in high-voltage current transformers

Abstract

The invention relates to a method and system for evaluating the aging state of oil paper insulation in a high-voltage current transformer. The method comprises: dielectric loss factor data of a pieceof oil paper at different test temperatures are obtained; polynomial equation fitting is carried out on the dielectric loss factor data to obtain a spectrum fitting curve; a slope function conformingto the spectrum fitting curve is established; the spectrum fitting curve is substituted into the slope function to obtain an extreme point; on the basis of a relationship between a frequency at whichthe extreme point is located and dielectric relaxation time, relaxation time activation energy of the oil paper is calculated; a moisture content of the oil paper is calculated and relaxation time activation energy of the oil paper under different water contents is calculated; according to the water content of the oil paper and the relaxation time activation energy, a quantitative representation relationship between the water content and the relaxation time activation energy is established; according to the quantitative representation relationship, oil paper insulation dielectric loss curve reduction equations at different water contents and different test temperatures are established and an oil paper insulation dielectric loss translation reduction curve under a low temperature is obtained; the obtained curve is compared with a practically measured curve and thus an aging state of oil paper insulation in a high-voltage current transformer is evaluated.

Description

technical field [0001] The invention belongs to the field of evaluating the aging state of oil-impregnated paper insulation, and in particular relates to a method and system for evaluating the aging state of oil-impregnated paper insulation in a high-voltage current transformer. Background technique [0002] The high-voltage current transformer is an important part of the complete and stable operation of the power grid. In northern China, due to the long winter and the low outdoor temperature, the assessment requirements for the high-voltage current transformer are relatively high. Due to the year-round operation, the oil-soaked paper inside the current transformer The insulation aging is obvious, so it is necessary to effectively evaluate the aging state of the oil-impregnated paper insulation inside the high-voltage current transformer. [0003] At present, there are few ways to evaluate the aging of high-voltage current transformers. In recent years, the non-destructive t...

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Problems solved by technology

[0005] In view of the above problems, the purpose of the present invention is to provide a method and system for evaluating the aging state of oil-impregnated paper insulation in high-voltage current transformers, so as to solve the problems caused by the frequency spectrum curve when the dielectric response test of high-voltage current transformers is carried out outdoors due to weather reasons. Analyze the problems that the accuracy of the evaluation of its internal oil-impregnated paper insulation aging state, water content, etc. is affected

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