Study On The Methodology About Condition Assessment Of Power Transformer

Power transformer is one of the most important and expensive equipment in power system, the state of the transformer is not only related to the safe operation of its own, but will also affect the power system stability and reliability. As China's economic development and power capacity increase, power transformer failure may lead to more serious consequences. Therefore, improving the reliability of power transformer operation and maintenance standards, the safe operation of the entire power grid has very important significance.Firstly, the transformer condition assessment at home and abroad was reviewed, a model for transformer assessment based on catastrophe theory is proposed because of the development of the physical process of transformer, and the model parameters is obtained through a large number of data, the attention value of C2H2/C2H4 is obtained from this model. The thermal fault of transforms is one of the primary fault, a model for forecasting the thermal fault based on cusp catastrophe is proposed, which uses the existing or on-line transformer DGA (dissolved gas analysis) data to assess the state of the transformer and prediction, and confirmed through a case feasibility of the model.Finally, the influence about lightning stroke to oil-paperboard insulation, especially to the power frequency breakdown voltage,flashover voltage and DGA of oil-paperboard insulation, is researched through test. By the data from the test, the conclusion that the power frequency breakdown voltage and flashover voltage decreased because of lightning stroke. In conclusion, lightning stroke can result in descend of oil-paperboard insulation.