Method for evaluating insulation aging state of oil paper insulation electrical equipment on basis of frequency domain spectroscopy

Abstract

A method for evaluating insulation aging state of oil paper insulation electrical equipment on the basis of frequency domain spectroscopy comprises the following steps of: disconnecting the oil paper insulation electrical equipment to be tested from a power circuit, reliably grounding a frequency domain spectroscopy tester and connecting the frequency domain spectroscopy tester with the oil paper insulation electrical equipment to be tested; measuring and obtaining the frequency characteristic curve of an oil paper insulation layer complex capacitor; performing spectrum unfolding processing to the frequency characteristic curve of the complex capacitor, thereby obtaining the frequency characteristic curve of the spectrum-unfolded complex capacitor and obtaining a corresponding characteristic frequency (fp); calculating by the following formula to obtain the current average degree of polymerization (DP) of an oil immersed paper plate; and obtaining the aging situation of the oil paper insulation electrical equipment to be tested according to the range zone of the obtained DP value. According to the embodiment of the invention, the average degree of polymerization (DP) of the insulation paper can be exactly evaluated and the insulation aging state of the oil paper can be judged without lifting a core, damaging the insulation material or sampling.

Description

technical field [0001] The invention belongs to the field of insulation state diagnosis and life evaluation of oil-paper insulated power equipment, and relates to a method for evaluating the insulation aging state of oil-paper insulated power equipment based on frequency-domain dielectric spectrum. Background technique [0002] Oil-paper composite insulation is an important and excellent insulation combination method, which has been successfully used in large transformers, bushings, transformers, capacitors, cables and other power equipment. During the operation of oil-paper insulated power equipment, its oil-paper insulation is subjected to various external stresses such as heat, electricity, machinery, and chemistry for a long time, which leads to a gradual decline in its own insulation and mechanical properties and may cause failure. Therefore, accurate diagnosis of the aging state of the oil-paper insulation system is very important to predict the life of oil-paper insul...

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Problems solved by technology

Among them, methods such as DGA detection method and furfural criterion have different deficiencies; while tensile stress measurement and polymerization degree measurement both require power failure to collect paper samples (for example, the transformer needs to be core-hanging to extract insulating paper samples), and the operation The procedure is complicated and may damage the transformer insulation. In addition, when the area selected for the insulation paper pattern is different, it will cause errors in the aging assessment, and the aging trend of the solid insulation cannot be discovered in time.

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