一种油浸式电力变压器纸绝缘老化评估新特征量

Novel characteristic products of paper insulation aging assessment for oil-immersed power transformer

针对油中糠醛含量随变压器运行时间变化的分散性较大,难以准确评估油浸式变压器纸绝缘老化状态的不足,对甲醇、乙醇等低分子醇作为变压器纸绝缘老化评估新特征量进行了理论分析与实验研究。对绝缘纸的老化机理以及化学键断裂进行分析,从理论上探究甲醇、乙醇等低分子醇的产生原理及主要生成途径。采用气相色谱-质谱联用法对现场2台老旧变压器绝缘油样品中的甲醇、乙醇及糠醛含量进行了测定。实验结果表明,2组样品中均未检测到糠醛,但却检测到数量可观的乙醇。进一步地,对现场2台刚投运变压器的检测结果对比分析,分析结果揭示了乙醇可以作为一种有效表征变压器绝缘纸老化的新特征量,且比糠醛特征量相比更为有效。

The furfural content in oil may dispersedly change along with the operating time of transformer, which makes it difficuh to evaluate the paper insulation aging status of oil-immersed transformers. To overcome this shortage, the methanol, ethanol and other low molecular alcohols are theoretically analyzed and experimentally verified as new characteristic products of paper insulation aging evaluation. The generation principles and ways of low molecular alcohols such as methanol and ethanol are theoretically explored by analyzing the aging mechanism of insulating paper and the order of ehemical bond breaking. The content of fuffural, methanol and ethanol in two groups of insula- ting oil samples obtained fi-om two old transformers are measured by gas chromatography-mass spectrometry. The experimental results show that no furfural but a considerable amount of ethanol is detected in the two groups of sampies. Moreover, the detecting results of the two transformers newly put into operation are compared, the results show that compared with furfural,ethanol can be used as a more effeetive characteristic product to present the aging of transformer insulation paper.