Power Transformer Fault Diagnosis Technology Based On The Dga Study

Transformer is one of the important hinge equipments in the electric power system. It is quite important for ensuring the safety running of electric power system. Examine the insulation situation of the transformer during it's running is very important for improving the reliability and economy of the equipments.Dissolved Gas Analysis (DGA) is one of the 32 preventing tests for the transformer. To judge the failure of transformer, DGA would be the first choice for testing.This paper first introduces the origin and the mechanism of the dissolved gas in the transformer oil. In the situation of failure, the transformer oil will be oxygen-decomposed and split-decomposed, and then create the hydrogen and low molecule gases. Non-saturation of the hydrocarbon gas will be increased according to the increase of the density (or temperature) of the splitting energy. For different failures, because of the different energy, different temperature and different insulation material of the different failure points, the situation of the gas is different. With method of DGA to judge the failure inside the equipment is just according to the principle of the gas produce characteristic of the insulation material.On the basis of analysis for the mechanism of the dissolved gas in the transformer oil and the gas produce characteristic, this paper centralizely discuss the adoption of DGA technology in and abroad for the diagnoses of transformer failures. According to the compare of the actual data and the alarm value of the dissolved gas in the oil, we can make whether there is failure and its primary characteristic for the transformer. Judge according to the ratio (three ratio, four ratio, non coding ratio, etc.) of some group of key characteristic gas, we may determine the character and situation of the failures. Summarizing large amount of information and engineering experience, the writer put forward the different notices for diagnosing the transformer failures by DGA.In Chapter 4 of this paper, with one example, the writer introduces the successful application of diagnosis method of three-ratio for the failure of insulation of reactance.