Research On Power Transformer Aging Analysis And Character

Power transformer is hardcore in energy conversion and transmission and the most important and critical equipment in power grid. Serious transformer accidents not only cause damage to transformer itself, but also cause the disruption of electricity supply and huge economic loss to society. Presently, in our country many large-scale transformers have run for more than 20 years or even longer, the question of insulation aging is becoming more and more serious day by day, which is a fatal hidden danger threatening power grid safety. Therefore, through accelerating insulation ageing process in laboratory, the paper does a research on various performance parameters'changing rule as time varying, thus establishes oil-paper insulation aging model based on the characteristic resultant, and carries out the evaluation and the breakdown diagnosis of transformer insulation aging degree.The article perfects the measurements on performance parameters in oil-paper insulation process under lab condition. And it meant to achieve the periodic measurements of physical and chemical characteristics in oilpaper insulation aging process. We have designed heat aging tests of the single factor of purely oil and oilpaper ban goods in 90℃, 110℃, 130℃, and tested periodically characteristics parameter in the ageing process, including the furfural of oil, the insulating paper polymerization degree, the characteristic gas, the acidity. Through studying relations between these characteristic performance parameters and time and insulating paper type, we conclude:1)The furfural density in oil elevates along with the hoist of temperature; and under the same condition the furfural content generated by different insulating paper is also very different.2)The insulating paper polymerization degree drops along with the temperature speeding up, under the same condition, the drop speed of different insulating paper polymerization degree is not same.3)The characteristic gas produced in the oil-paper ageing process is bigger than that in pure oil ageing process; and with temperature elevating, the characteristic gas which dissolves also increases; and the volume of characteristic gas produced by different oil paper varies.4)Under the same condition, the pure oil acidity must be higher than the acidity of oil-paper; and with temperature elevating along, the acidity increases, too.The furfural in oil is characteristic matter in the insulation aging which are studied only in recent years. The research of furfural stability is especially important. In the article, the experiment of influence on furfural by temperature and oxygen has been designed. The result reflects that along with temperature elevating, the furfural density descending rate increases and oxygen also takes effect on furfural density.Observing the insulating paper microscopic structure variation with AFM and SEM , we see that sweeping change has happened with the aged insulating paper structure; the atomic arrangement has become sparsely in uniformity; breakage has occurred between atomics; connections between the textile fiber becomes fewer; the hydrogen bond breakage was very obvious.The regression analysis is an analysis method that is commonly used statistically. Through the regression analysis, we have established the value relational model between insulation polymerization degree and the furfural content. We can judge the insulating paper polymerization degree size with furfural density, thus estimating insulating paper aged degree.