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吴广宁, Yang Luo, Guangning Wu, Jiwu Liu, Guangya Zhu, Peng Wang, Jia Peng, Kaijang Cao
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-1年11月30日
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【期刊论文】Study on Charge Transport Mechanism and Space Charge Characteristics of Polyimide Films
吴广宁, L. R. Zhou, G. N. Wu, B. Gao, K. Zhou, J. Liu, K. J. Cao andL. J. Zhou
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-1年11月30日
Inverter-fed motor,, polyimide,, charge transport,, space charge,, PEA,, pulse voltage,, aging
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【期刊论文】Modeling of Transient Moisture Equilibrium in Oil-paper Insulation
吴广宁, L.J. Zhou, G.N. Wu and J. Liu
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-1年11月30日
Moisture equilibrium,, oil insulation,, paper insulation,, transient model.,
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43浏览
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吴广宁, WU GuangNing , BIAN ShanShan , ZHOU LiRen , ZHANG XueQin , RAN HanZheng, YU ChengLong
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-1年11月30日
high voltage,, storage capacitor,, partial discharge,, composite insulation,, DC,, pattern recognition
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吴广宁, Luo Yang, Wu Guang-Ning, Liu Ji-Wu, Peng Jia, Gao Guo-Qiang, Zhu Guang-Ya, Wang Peng, Cao Kai-Jiang
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-1年11月30日
Polyimide (PI) film is an important type of insulating material used in inverter-fed motors. Partial discharge (PD) under a sequence of high-frequency square impulses is one of the key factors that lead to premature failures in insulation systems of inverter-fed motors. In order to explore the damage mechanism of PI film caused by discharge, an aging system of surface discharge under bipolar continuous square impulse voltage (BCSIV) is designed based on the ASTM 2275 01 standard and the electrical aging tests of PI film samples are performed above the partial discharge inception voltage(PDIV). The chemical bonds of PI polymer chains are analyzed through Fourier transform infrared spectroscopy (FTIR)and the dielectric properties of unaged and aged PI samples are investigated by LCR testers HIOKI 3532-50. Finally, the micro-morphology and micro-structure changes of PI film samples are observed through scanning electron microscopy (SEM). The results show that the physical and chemical effects of discharge cut off the chemical bonds of PI polymerchains. The fractures of ether bond (C–O–C) and imide ring (C–N–C) on the backbone of a PI polymer chain leads to the decrease of molecular weight, which results in the degradation of PI polymers and the generation of new chemical groups and materials, like carboxylic acid, ketone, aldehydes, etc. The variation of microscopic structure of PI polymers can change the orientation ability of polarizable units when the samples are under an AC electric field, which would cause the dielectric constant e to increase and dielectric loss tan d to decrease. The SEM images show that the degradation path of PI film is initiated from the surface and then gradually extends to the interior with continuous aging. The injection charge could result in the PI macromolecular chain degradation and increase the trap density in the PI polymer bulk.
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