Impact of Velocity on Breakdown Characteristics of Transformer Oil Containing Bubbles
Zhang Yongze1,2, Tang Ju1,3, Pan Cheng3, Luo Xinyu1, Yao Yuhang3
1. State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing University Chongqing 400030 China; 2. Xi'an XD Transformer Co. Ltd Xi'an 710077 China; 3. School of Electrical Engineering and Automation Wuhan University Wuhan 430072 China
Abstract：Bubbles are inevitable in transformer oil, which greatly degrade the insulation performance. Under the action of submersible pump and temperature difference, bubbles move with oil flow in oil duct. However, the breakdown mechanism of flowing transformer oil contacting bubbles is unclear. To explore the influence of oil flow rate on the breakdown process of transformer oil, a circulation device of transformer oil and a bubble motion observation system were set up. Breakdown experiments of transformer oil containing bubbles were also performed, and discharge signals, applied voltages and breakdown images were simultaneously collected. The results show that breakdown can be divided into three types according to the difference of bubble behavior in the pre-breakdown stage. The breakdown voltage of flowing transformer oil containing bubbles is always higher than that of the static transformer oil. With the increase of the oil flow rate, the breakdown voltage increases first and then basically keeps stable. The velocity affects the breakdown voltage by changing the arrangement of microbubble groups formed by the bubble burst and the development direction of the bubble tip.
张永泽, 唐炬, 潘成, 骆欣瑜, 姚雨杭. 油流速度对含气泡变压器油击穿特性的影响[J]. 电工技术学报, 2022, 37(2): 479-487.
Zhang Yongze, Tang Ju, Pan Cheng, Luo Xinyu, Yao Yuhang. Impact of Velocity on Breakdown Characteristics of Transformer Oil Containing Bubbles. Transactions of China Electrotechnical Society, 2022, 37(2): 479-487.
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