车载牵引变压器油纸绝缘热老化特性及机理研究

Thermal Aging Characteristics and Mechanism Analysis of Oil-paper Insulation in On-board Traction Transformer

车载牵引变压器绝缘系统性能优劣是动车组能否安全运行的因素之一,以Nomex绝缘纸和常规绝缘油为媒介,对其进行180℃加速热老化试验,测试不同老化周期油纸试样的油中溶解气体含量和红外光谱,研究车载牵引变压器油纸绝缘热老化特性及机理.研究表明:随着老化时间的增加,烃类气体含量先上升后趋于平稳,CO含量持续上升.热老化使Nomex纤维分子链断裂,并生成新官能团,Nomex绝缘纸主要成分在老化后已不全为全芳香族聚酰胺纤维;在热老化过程中,Nomex绝缘纸发生水解和均裂2种形式的老化反应,老化初期水解可能为主要反应,老化中后期均裂可能加剧,可能有一定关联性存在于水解、均裂反应和老化阶段之间,这为评估车载牵引变压器绝缘老化状态提供基础.

The performance of vehicle traction transformer insulation system is one of the factors that determine the safe operation of high speed train.In this paper,Nomex paper and insulating oil were used as the media and an accelerated thermal aging test of 180℃on Nomex paper and insulating oil was carried out.to measure the dissolved gas content and IR spectrum of the oil-paper samples in different aging periods,and to study the thermal aging characteristics and mechanism of oil paper insulation of on-board traction transformer.The results show that as the aging goes on,the content of hydrocarbons gas increases first and finally tends to be stable,and the content of CO increases continuously.The molecular chain of Nomex paper is broken and new functional groups are formed due to thermal aging.The main components of Nomex paper are not all aromatic polyamide fibers after aging.In the thermal aging process,hydrolysis reaction and homolytic reaction occur in insulating paper.Hydrolysis reaction may be the main reaction in the early stage of aging and the homolytic reaction may intensify in the middle and late stage of aging.There may be a certain correlation between hydrolysis,homolytic reaction and aging stage,which provides the basis for evaluating the aging state of the insulation of onboard traction transformer.