方波脉冲电压下聚酰亚胺材料的老化特性

Aging Properties of Polyimide Materials Under Square Impulse Voltage

为研究变频电机的匝间绝缘特性,在方波脉冲电压下,采用电热联合法对100HN绞线对和100CR绞线对进行老化试验,测试了各老化阶段其介质损耗特性和局部放电(PD)参量。试验结果表明:随着老化时间的增加,2种绞线对的介质损耗都增大,且局部放电的平均放电量和放电次数也都随之增大。但由于100CR中的纳米粒子周围形成了大量含有浅陷阱的界面区域,这些区域对电荷的输运能力较强,因此同一老化条件下,与100CR绞线对相比,100HN绞线对的介质损耗较大,局部放电的放电次数较多,平均放电量较小。此外,纳米粒子的协同效应有助于保护聚酰亚胺基体,延长100CR绞线对的绝缘寿命。

In order to investigate the inter-turn insulation of frequency-variable motor, using the electro-thermal method, we aged 100HN twisted cable pairs and 100CR twisted cable pairs with square impulse voltage, and measured their dielectric loss characteristics and partial discharge（PD） parameters during different aging stages. The results show that, for both of the cable pairs, 100HN and 100CR, their dielectric loss, mean PD quantity, and PD numbers increase with the aging time. However, there are inter-facial regions with a lot of shallow traps around the nanoparticles in 100CR, which raises the capacity of charge transport. Therefore, compared with 100HN under the same aging conditions, 100CR has larger dielectric loss and PD number but smaller mean PD quantity. Moreover, the synergistic effect of nanoparticles helps to protect the polyimide matrix in 100CR, and hence can extend the insulation lifetime of 100CR.