变压器油的热分解动力学研究及其寿命预测

Thermal Degradation Kinetics and Thermo-Life of Transformer Oil

基于热分析动力学理论,采用热重法分析研究K125AX型超高压变压器油在不同升温速率(5、10、20、30、40℃/min)下的热解过程.利用微分法和积分法分别计算比较变压器油样的动力学参数(活化能、反应级数和指前因子).计算结果表明:绝缘油的热分解过程是单步反应,采用不同的热动力学参数计算方法得到的热分解动力学参数都不相同,其中以Coats-Redfern方法计算结果最为可信,计算获得线性相关系数最接近1,绝缘油样的活化能为57.48 kJ/mol,同时得出变压器油具有动力学补偿效应的结论.在以质量损失2%为寿终指标的情况下,进一步推得变压器油的热老化质量损失寿命方程,为评估变压器油寿命提供参考.

Based on the thermal kinetics, the thermal degradation behaviour of K125AX extrahigh voltage transformer oil was investigated by thermogravimetric analysis at five different heating rates： 5, 10, 20, 30 and 40 ℃/min respectively. With differential method and integral method, kinetic parameters of the transformer oil were obtained. The results indicate that the decomposition process undergoes a single step. The kinetic parameters available get different from each other under various treating methodologies, while the result with Coats-Redfern method is probably much more reliable with a correlation coefficient approaching to 1, and the activation energy of the transformer oil is 57.48 kJ/mol. The mass loss lifetime equation is determined at mass loss ration of 2% to facilitate the assessment of the lifetime of transformer oil.