A test method for damp state of oil-immersed casing

Abstract

The invention relates to a testing method for moisture states of an oil-immersed type bushing. Due to the influence to the oil-immersed type bushing by over-standard of drying production technology, sealing failure of outer insulation, insulation aging of oil paper and the like, the water in the insulation paper always maintains the nonuniform distribution state; the moisture state of the bushingis evaluated by the ground insulation resistance of a bushing tap, tangent value of dielectric loss angle, and electric capacitance; however, the previous testing process cannot obviously reflect thewater content in the insulation paper of the bushing, and the sensitivity is lower, so that the moisture state of the oil-immersed type bushing cannot be effectively evaluated. The testing method hasthe advantages that the hidden Markov model parameters of the bushing under different moisture states and at different temperatures can be obtained; according to the tested dielectric spectrum curve,the probability of different moisture states of the bushing is calculated by a shuffled frog leaping algorithm, so as to effectively test the moisture states of the oil-immersed type bushing.

Description

technical field [0001] The invention belongs to the field of evaluating the insulation state of an oil-immersed bushing, in particular to a method for testing the damp state of an oil-immersed bushing. Background technique [0002] Oil-immersed bushing is an insulating device commonly used in power systems for insulation and support, and is one of the key components of transformers. Once the bushing fails, it will directly affect the safety of the transformer and even the normal operation of the entire power system. Existing studies have shown that moisture is one of the main factors that seriously affect the insulation performance of bushings after temperature. Moisture will not only accelerate the aging rate of insulating materials, but also increase the dielectric loss of insulating materials. When it is severely damp, it will affect heat dissipation, resulting in thermal breakdown of insulation. At present, the dielectric loss tangent value and capacitance test of the ...

AI Technical Summary

Problems solved by technology

Moisture will not only accelerate the aging rate of insulating materials, but also increase the dielectric loss of insulating materials. When it is severely damp, it will affect heat dissipation, resulting in thermal breakdown of insulation

At present, the dielectric loss tangent value and capacitance test of the bushing in the project do not reflect the moisture content in the bushing obviously, and the sensitivity is low. When the test finds a significant change, the internal insulation may have been severely damp and cannot be effectively tested. Therefore, there is an urgent need for a test method for the damp state of oil-immersed casings.

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