Effect of Mechanical Stress on Partial Discharge of Oil-Impregnated Pressboard
Cui Yanjie1, Ji Shengchang1, Zhu Lingyu1, Liu Zhihua1, Li Xining2
1. State Key Laboratory of Electrical Insulation for Power Equipment Xi'an Jiaotong University Xi'an 710049 China; 2. China Electric Power Research Institute Beijing 100192 China
Abstract：Oil-paper insulation materials in transformer bear thermal, electrical and mechanical stresses during operation and continues to age under these stresses. Nevertheless, the aging of the oil-paper insulation material under mechanical stress has not received enough attention. In order to study the evolution of oil-paper insulation materials under mechanical stress, the aging test of oil-impregnated insulation paper under different mechanical stresses was carried out. Then, the mechanical performance test, partial discharge test and surface morphology observation on the aged insulation cardboard were carried out. The results show that the influence of mechanical properties on the performance of insulating paperboard is divided into two parts with 20MPa as the boundary. When the mechanical stress is lower than 20MPa, the elastic modulus and residual deformation of the paperboard are small, and the insulation performance of the paperboard is improved with the increase of the mechanical stress. When the mechanical stress is higher than 20MPa, the elastic modulus and residual deformation of the paperboard increase remarkably. With the increase of the mechanical stress, the insulation performance of the paperboard decreases rapidly, and the partial discharge mode under the plate electrode also changes. The results of confocal-microscopy show that when the mechanical stress is higher than 20MPa, the fibers in the insulating paperboard change from elastic deformation to plastic deformation, and the fibers appear tiller, void and fracture, resulting in the decrease of the insulation performance of the paperboard.
崔彦捷, 汲胜昌, 祝令瑜, 刘志华, 李熙宁. 机械应力对油浸绝缘纸板局部放电影响[J]. 电工技术学报, 2021, 36(12): 2659-2666.
Cui Yanjie, Ji Shengchang, Zhu Lingyu, Liu Zhihua, Li Xining. Effect of Mechanical Stress on Partial Discharge of Oil-Impregnated Pressboard. Transactions of China Electrotechnical Society, 2021, 36(12): 2659-2666.
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2021, Vol. 36 
