重复脉冲上升时间对低压散绕变频电机匝间绝缘PDIV影响研究

Effect of Repetitive Impulsive Voltage Rise time on PDIV of Turn to Turn Insulation for Low-voltage Random-wound Inverter-fed Motor

重复脉冲电压下的局部放电起始电压(PDIV)是评估低压散绕变频电机绝缘性能的重要参数。不同于传统正弦电压,采用重复脉冲对变频电机散绕绕组感性负载匝间绝缘进行PDIV测试时,脉冲上升时间和极性是重点考虑的参数。本文在50、75、100、200 ns 4种脉冲上升时间的重复脉冲电压下,研究脉冲上升时间对3台不同规格的低压散绕变频电机匝间绝缘PDIV及放电能量分布的影响规律,并解释了PDIV随脉冲上升时间变化的机理。结果表明:随着脉冲上升时间的减少,3种电机的PDIV值均呈减小趋势,最大下降率达到28.1%。重复脉冲极性对低压散绕变频电机PDIV测试结果的影响有限,表明正、负极性均可客观反映电机的PDIV性能。随着脉冲上升时间的增加,正、负极性下放电频域能量均呈由高频向低频移动的趋势。研究结果有望为低压散绕变频电机的PDIV测试和相关标准的修订提供参考。

Partial discharge inception voltage(PDIV) under repetitive pulse voltage is an important parameter to evaluate the insulation performance of low-voltage random-wound inverter-fed motors. Different from the traditional sinusoidal voltage, the rise time and polarity of the impulse are critical parameters to be considered when PDIV test is carried out on the turn to turn insulation of the winding for inverter-fed motor at repetitive impulsive voltages. In this paper, the influence of repetitive impulsive voltage rise time on the PDIV and energy distribution features of turn to turn insulation for inverter-fed motors with three specification were investigated at repetitive impulse voltages with different impulse rise times(50 ns, 75 ns, 100 ns, and 200 ns), and the mechanism of variation of PDIV with different rise times was discussed. The results show that with the decrease of rise time,the PDIV of three motors decreases, and the maximum decline rate reaches 28.1%. The influence of repetitive pulse polarity on the PDIV test results of low-voltage random-wound inverter-fed motor is limited, indicating that both positive and negative can objectively reflect the PDIV performance of motor. With the increase of impulse rise time, the discharge energy in frequency domain moves from high frequency to low frequency. The research results are expected to provide reference for PDIV test of low voltage inverter-fed motor insulation and the revision of related standards.