A monitoring method for abnormal state of oil-immersed transformer

Abstract

The invention provides a monitoring method for an abnormal state of an oil-immersed transformer. The monitoring method comprises the following steps: (1) circularly detecting the concentration of each gas component by using a component concentration detecting module and sequentially comparing all concentration values Di with extreme values Di0 corresponding to the gas components; counting by a counter N once the detected concentrations of the gas components exceed the extreme values; and starting graded alarming once counting of the counter N is equal to or more than K, which shows that K sets of gas components exceed the extreme values; and (2) respectively detecting a total hydrocarbon content C and a total hydrocarbon absolute gas production speed V of the transformer by utilizing a hydrocarbon content detecting module and a gas production speed detecting module, respectively; and comparing a first threshold value C0 and a second threshold value C1 of the total hydrocarbon content of the transformer with the total hydrocarbon content C of the transformer, and comparing relations among the total hydrocarbon absolute gas production speed V and a first threshold value V0, a second threshold value V1 and a third threshold value V2 of the total hydrocarbon absolute gas production speed, thus judging different alarming grades.

Description

technical field [0001] The invention relates to a method for monitoring the abnormal state of an oil-immersed transformer, belonging to the technical field of power transmission. Background technique [0002] Oil-immersed power transformers are widely used in power systems. During normal operation, the transformer will slowly age under the influence of mechanical stress, heat, electricity and other factors, and generate some flammable gases. If there is an internal latent fault in the transformer, the energy released from the faulty part will accelerate the cracking of the insulating material, which will greatly increase the content of dissolved gas in the oil and the rate of gas production. By obtaining transformer oil samples, gas chromatography can be used to obtain the content of each component of dissolved gas in the oil, so as to evaluate the health of the transformer or analyze the failure of abnormal transformers. Therefore, the analysis of dissolved gases in trans...

AI Technical Summary

Problems solved by technology

[0003] As one of the DGA technologies, the three-ratio method has played a certain role in engineering practice, but due to the limited ratio coding, the fault types are only divided into some classic types, which cannot cover all fault types in actual operation. There is ambiguity in the mapping relationship between types. A simple one-to-one mapping cannot fully and objectively reflect the complex coupling relationship between symptoms and faults. At the same time, there are some inaccuracies in gas content that may be caused by various factors. , and then form a misjudgment of the fault type

Therefore, it is necessary to improve the current DGA technology to improve the accuracy and stability of diagnosing oil-immersed transformer faults, and to avoid misjudgment and adverse effects.

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