A method for assessing oilpaper insulating aging state on the basis of polarization and depolarization charge differences

Abstract

The invention belongs to the technical field of electrical equipment insulation diagnosis, and provides a method for assessing oilpaper insulating aging states on the basis of polarization and depolarization charge differences. A polarization and depolarization charge difference can be calculated through detecting polarization currents and depolarization currents of internal oilpaper insulation of electrical equipment; a degree of polymerization of insulation paper insulation states is represented through the polarization and depolarization charge difference of the paper insulation; assessment of insulation states of the oilpaper insulation is carried out; and thus a damaging assessment method for assessing oilpaper insulation through the degree of polymerization is changed into a lossless assessment method in combination with the polarization and depolarization current method and the polymerization degree method. No dismounting is needed for the electrical equipment with oilpaper insulation as an insulating layer, and for example, lossless, accurate and rapid assessment can be carried out on insulation states of the oilpaper insulation inside a voltage transformer or a high-voltage bushing without cover hanging of the voltage transformer or dismounting of the high-voltage bushing, and thus a basis and a reference are provided for detection of insulation aging states and replacing of the oilpaper insulation inside the electrical equipment.

Description

technical field [0001] The invention belongs to the technical field of electrical equipment insulation diagnosis, mainly evaluates the insulation state of the oil-paper insulation inside the electrical equipment with the oil-paper insulation as the insulation layer, and relates to a method for evaluating the aging state of the oil-paper insulation based on the polarization and depolarization charge difference. Background technique [0002] In recent years, my country's power transmission and transformation industry has developed rapidly. Oil-paper insulation is the main insulation structure inside electrical equipment such as power transformers and high-voltage bushings. During the normal use and operation of electrical equipment, due to the effects of various factors such as electric field, magnetic field and temperature, oil-paper insulation will age, deteriorate or even break down, reducing its insulation performance and causing great harm to the safe operation of electric...

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Problems solved by technology

[0004] (1) The content of dissolved gas and furfural in the oil in the chemical method will change due to transformer oil change and maintenance, and cannot accurately characterize the insulation state of oil-paper insulation

The degree of polymerization is recognized as the most basic characteristic quantity to characterize the insulation state of insulating paper, but the detection of the degree of polymerization requires the lifting of the transformer and the disassembly of the high-voltage bushing, which brings certain difficulties to the application of the degree of polymerization method.

[0005] (2) The electrical evaluation method can only qualitatively evaluate the insulation state of oil-paper insulation at present, and the recovery voltage method is easily affected by the shape, size and aging uniformity of oil-paper insulation

[0006] (3) At present, there is a lack of a practical method that can quantitatively evaluate the aging state of oil-paper insulation, and even predict its life

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