重复脉冲电压对大型旋转电机线棒低阻防晕层影响的试验研究及仿真分析

Experimental and simulation analysis on effect of repetitive pulse voltage on conductive armor tape of large rotating motor bar

在不同上升时间条件下,探讨重复脉冲对不同悬空长度和增加固定金属板的变频电机转子线棒绝缘表面电位的影响规律,然后结合电荷弛豫理论以及有限元仿真,探讨绝缘表面电位的变化机理。结果表明:线棒表面电位峰峰值随重复脉冲上升时间增加而减小,当脉冲上升时间达到800 ns时,低阻防晕层末端电位峰峰值接近2倍外施电压峰峰值;在工况条件下,绝缘表面温度超过150℃时会产生白烟并伴随局部放电现象。分析认为具有较短上升时间的跳变电压是影响线棒电热性能的重要参数。最后根据实验和仿真结果为变频电机线棒绝缘设计提出了合理的改进建议。

The effects of repetitive pulse voltage on the surface potential of the inverter-fed motor rotor bar insulation with different length of extension part and fixed metal plate were discussed under different rise times.Then the changing mechanism of the insulation surface potential was discussed combined with charge relaxation theory and finite element simulation.The results show that the surface potential peak-to-peak value of bar decreases with the increase of repetitive pulse rise time.When the pulse rise time reaches 800 ns,the potential peak-to-peak value at the end of the conductive armor tape is close to twice of the applied voltage peak-to-peak value.Under working conditions,when the insulation surface temperature exceeds 150℃,white smoke will be generated and accompanied by partial discharge phenomenon.It is analyzed that the jump voltage with short rise time is an important parameter affecting the electrical and thermal properties of bar.Finally,according to the experimental and simulation results,some reasonable improvement suggestions are proposed for the insulation design of inverter-fed motor bars.