【作者】 张依强；

【导师】 范建斌；

【作者基本信息】 西南交通大学 ， 高电压与绝缘技术， 2013， 硕士

【摘要】 变频牵引电机绝缘系统在方波脉冲条件F不仅要承受更强的电应力,同时还是受到机械力、温度和湿度等因素的影响,造成牵引电机绝缘系统出现过早失效,从而影响机车的安全运行。因此,对变频调速牵引电机绝缘系统失效机理的研究已经迫在眉睫,国内外专家已经在这方面做了大量工作,取得的研究成果也已在工程中得到应用。本论文将在国内外在该领域已取得成果的基础上,研究温度这一因素对变频调速牵引电机用电磁线绝缘特性的影响,通过此研究进一步完善有关变频调速牵引电机绝缘失效机理的理论,为绝缘系统的优化提供了理论根据。局部放电是造成电机绝缘失效的主要因素之一,因此局部放电测试是评估绝缘状态的重要手段,本文基于自行研制的方波脉冲电源开发了一套局部放电信号测试系统,并利用该系统对不同温度条件下的电磁线试样进行了局部放电测量并比较了纳米与非纳米材料试样的局部放电特性。试验结果表明,随着温度的升高,在相同的周期内放电次数增多,最大放电量减小；而且在相同的温度条件下,纳米材料试样的局部放电次数较非纳米的要多,但是最大放电量要比非纳米的要小。利用delta2000测试仪探讨了变频电机用电磁线介质损耗角正切值(tanδ)在不同老化时间和不同老化频率下的温度谱,从试验结果的分布图可以看出,在低温区,tanδ值随着温度的升高也会逐渐增大,在130。C左右tanδ值达到极值,温度再升高tanδ有小幅度的减小。基于IEC60851-5标准搭建了一套变频电机绝缘老化装置,研究了不同温度条件下电磁线试样击穿电压和老化寿命的变化规律。试验结果表明随着温度的升高,试样的击穿电压呈现下降趋势,而且相同温度条件下纳米材料试样比非纳米材料试样的击穿电压值要低,这是由于纳米颗粒改变了材料的内部结构；试样的老化寿命随着温度的升高而逐渐缩短,比较了不同的试验电压和不同的试验频率对老化寿命的影响,根据反幂函数的变化规律,建立了老化寿命随温度变化的数学模型。使用电子扫描电镜(SEM)分析了电磁线击穿点处的微观形貌,剖析了击穿点处绝缘材料的化学成分,试验结果表明击穿处呈现黑色粉末状,这是由于绝缘层被炭化,C元素含量过高造成的。更多还原

【Abstract】 The insulation system of inverter traction motor does not only have to bear stronger electrical stress, but also have to subject to the influence of mechanical forces, temperature factor and humidity factor in the square-wave pulse condition. It would lead to the premature failure of insulation system, which threaten the safe operation of the locomotive. Therefore, the research on the mechanism of insulation failure is desperately needed. Domestic and foreign experts have done some work about the insulation failure of inverter-fed motor now, and their research results have been used in some projects. Based on the existing results, this paper will study the temperature factor that influences the insulation characteristics of inverter-fed motor magnet wire, which will further improve the failure mechanisms thesis of insulation system.Partial discharge (PD) measurement is known as a necessary method to evaluate state insulating, because PD is an important factor leading to insulation failure. The paper built a PD test system on the basis of square-wave pulse power and the PD characteristics of magnet wire under different temperatures were measured. Then it compared with the PD properties of nano material and common material. The test results showed that numbers of discharge increase but the maximum discharge reduces as the temperature increasing at the same cycles.The paper explores the temperature spectrum of dielectric loss tangent (tan8) value at different aging time and different aging frequency by using delta2000device. The test results show that tanδ increases gradually as the temperature increasing In the low temperature region, and comes to max value at about130℃and then decreases with a small amplitude.In addition, a set of aging device for magnet wire of inverter-fed motor based on the IEC60851-5was designed, which is used to study the breakdown voltage and aging life of magnet wire under different temperature condition. The results show that the breakdown voltage of the sample has a declining trend with the increasing of the temperature and the breakdown voltage of nona material is lower than the common material under the same temperature, which is due to the internal structure of material is changed by the nano particles. The aging life of sample reduced gradually along with the rising of temperature, then compared the influence on aging life of different test voltage and test frequency. According to the inverse power function, the mathematical model of aging life was established. At last, the morphology of magnet wire at the breakdown point was analyzed by the technology of scanning electron microscopy (SEM) and researched the chemical composition of insulation material at the breakdown point. The test result showed that the breakdown point was black powder because insulation layer was carbonized and the C element content is too high.更多还原