Research into rotating machine turn insulation life under repetitive impulse voltages from power converters

功率变换器重复脉冲电压下旋转电机匝数绝缘寿命研究

• 批准号: RGPIN-2018-04085
• 负责人: Cherney, Edward
• 金额: $ 4.08万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751575
• 关键词: Research; into; rotating; machine; turn

The design of rotating machine coil or bar insulation under power frequency sinusoidal voltage is well understood and testing procedures have been standardized which have served the industry well. However, today, medium voltage (13.8 kV) rotating machines, controlled by power electronics, are becoming common place in industrial plants and in renewable generation. The power electronics of an adjustable speed drive (ASD) synthesizes a sinusoidal waveform of variable frequency by means of a pulse width modulator (PWM) from a direct voltage supply. The overvoltage, electric field distribution, and partial discharge (PD) experienced by the insulation when fed by power electronics presents new challenges in the insulation of rotating machines. The ASD technology requires new test procedures and the purpose of this study is to provide rotating machine insulation, controlled by power electronics, the same level of reliability as conventional, power frequency supplied machines, which, at the present time, is not the case. From both laboratory studies and field monitoring of PD, if PD is incepted involving significant energy, they will increase, sometimes alternating between increasing and extinction periods, until they cause insulation failure, or breakdown. The IEC 600341842 standard considers that the aging factor is the peak-to-peak voltage, and therefore, the aging stress is the electric field resulting from the applied voltage and independent of the voltage waveform. This implies that PD, which is the aging driver, would not change from sinusoidal to repetitive impulse waveforms and consequently the life time is the same for any voltage waveform provided that the frequency of the supply voltage and the peak-to-peak voltage are the same. Recent publications investigating the life characteristics of rotating machine turn insulation has shown that both PD and life time under sinusoidal and repetitive impulse voltages differ significantly. In fact, the PD magnitude, repetition rate, and also time behavior, depend on the shape of the supply waveform and more importantly, on the rise time of the voltage waveform.The influence on accelerated aging from repetitive impulses, compared to AC sinusoidal voltage, has been clearly singled out and depending on the rise-time of the impulses, the energy involved in the PD process can be significantly higher than under AC. This reflects into shorter life times, and such behavior can be suitably modelled. This research proposes to investigate accelerated life tests on turn insulation specimens using sinusoidal and power electronic waveforms while monitoring PD during aging, up to breakdown, in order to explore the PD time behavior under different waveforms. By investigating the failure time behavior under sinusoidal and impulse waveforms, the type of life model that can be applied to power electronics fed insulation aging can be inferred.

在工频正弦电压下的旋转电机线圈或棒绝缘的设计是很好理解的，并且测试程序已经标准化，这很好地服务于该行业。然而，今天，由电力电子控制的中压（13.8 kV）旋转电机在工业工厂和可再生能源发电中变得越来越普遍。可调速驱动器（ASD）的电力电子装置通过脉宽调制器（PWM）从直流电压源合成可变频率的正弦波形。当由电力电子设备供电时，绝缘所经历的过电压、电场分布和局部放电（PD）对旋转电机的绝缘提出了新的挑战。 ASD技术需要新的测试程序，本研究的目的是提供由电力电子控制的旋转电机绝缘，与传统的工频供电电机具有相同的可靠性水平，而目前情况并非如此。从实验室研究和现场监测的局放，如果局放是incepted涉及大量的能量，他们会增加，有时之间交替增加和熄灭的时期，直到他们造成绝缘故障，或击穿。 IEC 600341842标准认为老化因子是峰-峰电压，因此，老化应力是由施加电压产生的电场，与电压波形无关。这意味着作为老化驱动器的PD将不会从正弦波形改变为重复脉冲波形，并且因此对于任何电压波形，只要电源电压的频率和峰-峰电压相同，则寿命相同。最近的出版物调查的旋转电机匝绝缘的寿命特性表明，在正弦和重复脉冲电压下的PD和寿命时间显着不同。事实上，局部放电的幅度、重复率和时间特性取决于电源波形的形状，更重要的是取决于电压波形的上升时间。与交流正弦电压相比，重复脉冲对加速老化的影响已经被清楚地挑出来，并且取决于脉冲的上升时间，局部放电过程中涉及的能量可以显著高于交流。这反映了更短的寿命，并且这种行为可以适当地建模。 本研究建议调查加速寿命试验的匝绝缘试样使用正弦和电力电子波形，同时监测PD老化过程中，击穿，以探讨不同波形下的PD时间行为。通过研究正弦和脉冲波形下的失效时间行为，可以推断出可以应用于电力电子馈电绝缘老化的寿命模型的类型。