单因子老化中定子线棒等温松弛电流的研究

为研究电机定子线棒老化后的绝缘特性，制备了按实际线棒尺寸比例缩小的线棒试样，并对其进行了单独的热、电老化实验，后测量了不同老化程度线棒试样的等温松弛电流，并基于等温松弛理论研究分析了线棒绝缘内的陷阱分布变化。结果表明:线棒绝缘在冷热循环老化过程中存在“后固化”的现象，绝缘内陷阱密度先增加后减小；而在电老化过程中，试样绝缘内浅能级陷阱密度增加。根据不同极化过程对等温松弛电流的贡献，建立了定子线棒等温松弛电流的三阶指数衰减模型。研究表明，电机线棒老化的主要表现是环氧树脂和云母之间界面中缺陷的增加，而三指数衰减模型对等温松弛电流数据的拟合结果也足够准确。

Isothermal Relaxation Current Research of Stator Bar Insulation in Single Factor Aging Experiments

In this paper, a non-destructive method based on isothermal relaxation current theory was used to determine the insulation condition of stator bar. The stator bar specimens scaled down from the actual size were manufactured. The isothermal relaxation current of the specimens at different aging conditions were measured after thermal aging and electrical aging. According to the current data, the trap distribution in insulation was obtained. In thermocycling aging experiment, the post cure phenomenon exited. So the trap density in insulation increased at first and then decreased. In electric aging experiment, the specimen aged in electric field and the number of shallow traps in the specimen increased. Depending on the contribution of polarization process to the isothermal relaxation current, third order exponential model was obtained. The results show that the performance of stator bar aging is the interface defects between epoxy resin and mica tape increasing. Meanwhile, the fitting result of third order exponential model is accuracy enough.