Method for assessing insulation state of oil paper based on characteristic quantity of frequency domain dielectric spectroscopy

Abstract

The invention relates to a method for assessing an insulation state of oil paper based on characteristic quantity of frequency domain dielectric spectroscopy. The method comprises following steps: utilizing a linear medium response equivalent circuit to simulate polarization characteristics of the insulation state of oil paper for a transformer and setting up the relationship between linear medium response equivalent circuit parameters, frequency-domain characterization complex capacitance and dielectric loss factors; then, utilizing complex capacitances with high frequency bands and a parametric equivalent circuit model for dielectric loss characteristic quantity and finally, integrating dielectric loss curves with low frequency bands at prediction sections, wherein the range of frequency bands in a dielectric loss frequency domain is equally divided into n frequency points (n larger than or equal to 1), n frequency points correspond to n dielectric loss integral value and n frequencies and corresponding dielectric loss integral value are fitted to a function curve. The method for assessing an insulation state of oil paper based on characteristic quantity of frequency domain dielectric spectroscopy has following beneficial effects: in order to obtain much more insulation information carried by dielectric loss factors within the limited measurement frequency domain, integrals of dielectric loss factors are utilized in the predicted low-frequency section as characteristic parameters for assessment of insulation state; and dielectric loss integral value within the low-frequency stage obtained by calculations is utilized for determining the insulation aging state of oil paper.

Description

technical field [0001] The invention relates to the technical field of electrical equipment insulation aging and life prediction, in particular to a method for quantitatively evaluating the aging state of oil-paper insulation of an oil-immersed power transformer based on frequency-domain dielectric spectrum characteristic quantities. Background technique [0002] Power transformer, as the core and hub of power transmission and distribution, is one of the most important and expensive equipment in the power system, and its operating status directly affects the safety and stability of the power grid. Oil-immersed transformers are mainly divided into external insulation and internal insulation. The external insulation is the surrounding air insulation, the internal insulation is the insulation inside the transformer, and the oil-paper insulation is the main component of the transformer internal insulation. The oil-paper insulation system is a composite oil- In the long-term oper...

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Problems solved by technology

[0005] In view of this, the technical problem to be solved by the present invention is: aiming at the problems such as the existing research only stays in qualitatively indicating the impact of influencing factors on the FDS characteristic parameters and the low frequency band measurement time is too long, the characteristic parameter data is insufficient, etc., provide a A method for evaluating the insulation state of oil-paper based on the frequency-domain dielectric spectrum characteristic quantity, that is, using the frequency-domain dielectric spectrum method to infer the low-frequency measurement data from the high-frequency measurement data, and introducing the integral of the dielectric loss factor as the characteristic parameter of the insulation state evaluation, In this way, more insulation information carried by the dielectric loss factor can be obtained in the limited measurement frequency band, avoiding the measurement of low frequency band data, and reducing the measurement time of frequency domain dielectric spectroscopy

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