Analysis of Transition Process During Secondary Diffusion of Moisture in Oil-Paper Insulation
Lin Yuandi1, Liao Ruijin1, Xia Huanhuan2, Yang Lijun1
1. State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing 400044 China; 2. Yunnan Electric Power Research Institute (Group) Co. Ltd Kunming 650051 China
Abstract On basis of Fick’s second law, a mathematical model is established to analyze the secondary diffusion process of moisture in oil-paper insulation. The secondary diffusion occurs when the external conditions change during the first diffusion. Analysis focuses on the transient process during secondary diffusion, which is initiated by the insufficiency of the first diffusion and is verified by experiments. Two features of the transient process are proposed, namely transition time and relative error. Transient time is the time from the beginning of secondary diffusion to the time when the moisture diffusion direction is consistent everywhere. Transient time is independent of the temperature, paper thickness and the balance ratio of the first diffusion. Relative error emerges when the average moisture content of first diffusion is used as the initial distribution of secondary diffusion. The peak of relative error represents the strength of the transient process, which is influenced by the balance ratio of the first diffusion and steady moisture content. The peak time of relative error represents the speed of transient process, which is influenced by the temperature and paper thickness.
Lin Yuandi,Liao Ruijin,Xia Huanhuan等. Analysis of Transition Process During Secondary Diffusion of Moisture in Oil-Paper Insulation[J]. Transactions of China Electrotechnical Society, 2016, 31(10): 16-25.
[1] 陈伟根, 滕黎, 刘军, 等. 基于遗传优化支持向量机的变压器绕组热点温度预测模型[J]. 电工技术学报, 2014, 29(1): 44-51. Chen Weigen, Teng Li, Liu Jun, et al. Transformer winding hot-spot temperature prediction model of support vector machine optimized by genetic algorithm[J]. Transactions of China Electrotechnical Society, 2014, 29(1): 44-51. [2] 马志钦, 廖瑞金, 郝建, 等. 温度对油纸绝缘极化去极化电流的影响[J]. 电工技术学报, 2014, 29(4): 290-297. Ma Zhiqin, Liao Ruijin, Hao Jian, et al. Influence of temperature on polarization and depolarization current of oil-paper insulation[J]. Transactions of China Electrotechnical Society, 2014, 29(4): 290- 297. [3] 梁帅伟, 廖瑞金, 郝建, 等. 一种抗老化绝缘油对绝缘纸热老化影响及原因分析[J]. 电工技术学报, 2012, 27(5): 21-25. Liang Shuaiwei, Liao Ruijin, Hao Jian, et al. Effects on oil-immersed paper for an antioxidation insulation oil and cause analysis[J]. Transactions of China Electrotechnical Society, 2012, 27(5): 21-25. [4] Fofana I, Wasserberg V, Borsi H, et al. Challenge of mixed insulating liquids for use in high-voltage transformers, part 2: investigations of mixed liquid impregnated paper insulation[J]. IEEE Electrical Insulation Magazine, 2002, 18(4): 5-16. [5] Emsley A M, Stevens G C. Review of chemical indicators of degradation of cellulosic electrical paper insulation in oil-filled transformers[J]. IEEE Science Measurement and Technology, 1994, 141(5): 324-334. [6] 廖瑞金, 郝建, 梁帅伟, 等. 水分和酸对矿物油与天然酯混合油—纸绝缘热老化的影响[J]. 电工技术学报, 2010, 25(7): 31-37. Liao Ruijin, Hao Jian, Liang Shuaiwei, et al. Influence of water and acid on the thermal aging of mineral oil mixed with natural ester oil-paper insul- ation[J]. Transactions of China Electrotechnical Society, 2010, 25(7): 31-37. [7] 廖瑞金, 孙会刚, 尹建国, 等. 水分对油纸绝缘热老化速率及热老化特征参量的影响[J]. 电工技术学报, 2012, 27(5): 34-42. Liao Ruijin, Sun Huigang, Yin Jianguo, et al. Influence on the thermal aging rate and thermal aging characteristics caused by water content of oil-paper insulation[J]. Transactions of China Electrotechnical Society, 2012, 27(5): 34-42. [8] 杨丽君, 廖瑞金, 郑含博, 等. 电力变压器油纸绝缘热老化研究综述[J]. 电工技术学报, 2012, 27(5): 1-12. Yang Lijun, Liao Ruijin, Zheng Hanbo, et al. Reviews on oil-paper insulation thermal aging in power transformers[J]. Transactions of China Electro- technical Society, 2012, 27(5): 1-12. [9] Garcia B, Burgos J C, Alonso A, et al. A moisture- in-oil model for power transformer monitoring—part I: theoretical foundation[J]. IEEE Transactions on Power Delivery, 2005, 20(2): 1417-1422. [10] Garcia B, Burgos J C, Alonso A, et al. A moisture- in-oil model for power transformer monitorring—part II: experimental verification[J]. IEEE Transactions on Power Delivery, 2005, 20(2): 1423-1429. [11] IEC 60814 Insulating liquids-oil-impregnated paper and pressboard-determination of water by automatic coulometric Karl Fischer titration[S]. 1997. [12] Fabre J, Pichon A. Deteriorating processes and products of paper in oil application to trans- formers[C]//International Conference on Large High Voltage Electric System (CIGRE), Paris, 1960, 137: 18. [13] Oommen T V. Moisture equilibrium in paper-oil systems[C]//Proceedings of the Electrical I Elec- tronics Insulation Conference, Chicago, 1983: 162- 166. [14] Griffin P J, Bruce C M, Christie J D. Comparison of water equilibrium in silicone and mineral oil trans- formers[C]//Minutes of the Fifty-Fifth Annual Inter- national Conference of Doble Clients, 1988: 9-10. [15] 周利军, 汤浩, 张血琴, 等. 油纸绝缘微水扩散的暂态分布模型[J]. 中国电机工程学报, 2008, 28(7): 134-140. Zhou Lijun, Tang Hao, Zhang Xueqin, et al. Disequi- librium moisture partition in oil-paper insulation[J]. Proceedings of the CSEE, 2008, 28(7): 134-140. [16] Zhou L J, Wu G N, Liu J. Modeling of transient moisture equilibrium in oil-paper insulation[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2008, 15(3): 872-878. [17] Li J, Zhang Z T, Grzybowski S, et al. Characteristics of moisture diffusion in vegetable oil-paper insu- lation[J]. IEEE Transactions on Dielectrics and Elec- trical Insulation, 2012, 19(5): 1650-1656. [18] Bird R B, Steuart W E, Lightfoot E N. Transport phenomena[M]. New York: John Wiley & Sons Inc., 2002. [19] Du Y, Zahn M, Lesieutre B C. Dielectrometry measurements of effects of moisture and anti-static additive on transformer board[C]//IEEE Conference on Electrical Insulation and Dielectric Phenomena, Minneapolis, MN, 1997: 226-229. [20] Oommen T V. Moisture equilibrium charts for transformer lnsulation drying practice[J]. IEEE Transa- ctions Power Apparatus Systems, 1984, 103(10): 3063-3067. [21] IEC60641—3—1 Specification for pressboard and presspaper for electrical purpose. Part 3: specifi- cations for individual materials; sheet 1: requirements for pressboard, types B.0.1, B.2.1, B.3.1, B.3.3, B.4.1, B.4.3, B.5.1, B.6.1 and B.7.1[S]. 1992.
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