Abstract：The iron core of converter transformer vibrates severely with the effect of DC bias, which affects the mechanical properties degradation of its insulation paper. Based on the purposely designed mechanical-thermal ageing oven, a series of accelerated ageing experiments were carried out at temperature 130℃, frequency 10 Hz and the amplitude 0 mm, 1.99 mm and 2.64 mm respectively. The tensile strength (TS) and degree of polymerization (DP) of the specimen were measured, and the microscopic structures of the specimen before and after ageing were compared with the X-ray diffraction (XRD) analysis method and scanning electron microscopy (SEM) photos. Connected with test data, the relations between the vibration amplitude and the percentage TS loss and percent DP loss are researched. It indicates that there exists both chemical reaction of free radical chain and physical reactions including fibre drawing and internal force attenuation in the cellulose degradation process, which makes the reaction rate is much quickly than that of pure thermal ageing experiments. With XRD and SEM analysis, it can be found that the mechanical-thermal synergy does not change the microcrystal type of the cellulose, while the relative crystallinity and grain size of the cellulose fiber become smaller. Meanwhile, mechanical vibration accelerates degradation in two ways, the refinement, bifurcation and breakage of fiber and appearance, increase and development of holes, which promotes the deterioration of the insulation paper mechanical properties. The study provides a reference for the research of deterioration mechanism of converter transformer insulation paper under the complex effect of mechanical-thermal-electrical and for the exploration of the accordingly suppression methods.
李长云, 王铮. 机-热协同作用下绝缘纸机械性能的劣化机理[J]. 电工技术学报, 2018, 33(21): 5090-5097.
Li Changyun, Wang Zheng. The Degradation Mechanism of Insulation Paper Mechanical Properties with Mechanical-Thermal Synergy. Transactions of China Electrotechnical Society, 2018, 33(21): 5090-5097.
[1] 赵畹君. 高压直流输电工程技术[M]. 北京: 中国电力出版社, 2005. [2] 李长云, 刘亚奎. 直流偏磁条件下变压器铁心磁化特性的Jiles-Atherton修正模型[J]. 电工技术学报, 2017, 32(19): 193-201. Li Changyun, Liu Yakui.Modified Jiles-Atherton model of transformer iron core magnetization characteristics with DC bias[J]. Transactions of China Electrotechnical Society, 2017, 32(19): 193-201. [3] 廖瑞金, 王季宇, 袁媛, 等. 换流变压器下新型纤维素绝缘纸特性综述[J]. 电工技术学报, 2016, 31(10): 1-15. Liao Ruijin, Wang Jiyu, Yuan Yuan, et al.Review on the characteristics of new cellulose insulation paper used in the converter transformer[J]. Transactions of China Electrotechnical Society, 2016, 31(10): 1-15. [4] 高洁, 汤烈贵. 纤维素科学[M]. 北京: 科学出版社, 1996. [5] 廖瑞金, 杨丽君, 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. Liao Ruijin, Yang Lijun, Zheng Hanbo, et al.Reviews on oil-paper insulation thermal aging in power transformers[J]. Transactions of China Electrotechnical Society, 2012, 27(5): 1-12. [6] 杨丽君, 廖瑞金, 孙会刚, 等. 变压器油纸绝缘热老化特性及特征量研究[J]. 电工技术学报, 2009, 24(8): 27-33. Yang Lijun, Liao Ruijin, Sun Huigang, et al.Investigation on properties and characteristics of oil-paper insulation in transformer during thermal degradation process[J]. Transactions of China Electrotechnical Society, 2009, 24(8): 27-33. [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] 廖瑞金, 解兵, 杨丽君, 等. 油纸绝缘电-热联合老化寿命模型的比较与分析[J]. 电工技术学报, 2006, 21(2): 17-21. Liao Ruijin, Xie Bing, Yang Lijun, et al.Analysis and selection of electrothermal life models used in oil-paper insulation[J]. Transactions of China Electrotechnical Society, 2006, 21(2): 17-21. [9] Zou Xuejun, Gurnagul N, Uesaka T, et al.Accelerated aging of cellulose-mechanism of degradation and embrittlement[J]. Polymer Degradation and Stability, 1994, 43(3): 393-402. [10] 廖瑞金, 唐超, 杨丽君, 等. 电力变压器用绝缘纸热老化的微观结构及形貌研究[J]. 中国电机工程学报, 2007, 27(33): 59-63. Liao Ruijin, Tang Chao, Yang Lijun, et al.Research on the microstructure and morphology of power transformer insulation paper after thermal aging[J]. Proceedings of the CSEE, 2007, 27(33): 59-63. [11] 向彬, 廖瑞金, 张勇, 等. 电力变压器用绝缘纸热老化微观机理的X射线衍射分析[J]. 高压电器, 2012, 48(3): 40-45, 51. Xiang Bin, Liao Ruijin, Zhang Yong, et al.Aging micro-mechanism of oil-paper insulation in power transformers by XRD analysis[J]. High Voltage Apparatus, 2012, 48(3): 40-45, 51. [12] Liu Zehong, Gao Liying, Wang Zuli, et al.R&D progress of ±1100 kV UHVDC technology[J]. CIGRE 2012, B4_201_2012. [13] Lescale V F, Åström U, Ma W, et al. The Xiangjiaba -Shanghai 800kV UHVDC project Status and special aspects[J]. CIGRE, 2010, B4_102_ 2010. [14] 中华人民共和国国家质量监督检验检疫总局, 中国国家标准化管理委员会. GB/T 1548—2004 纸浆粘度的测定[S]. 北京: 中国标准出版社, 2004. [15] 吕福荫. 电气绝缘纸的性能及制造技术[J]. 中国造纸, 2010, 29(增刊1): 77-82. Lü Fuyin.Performance and manufacturing technology of electrical insulating paper[J]. China Pulp & Paper, 2010, 29(S1): 77-82. [16] Hill D J T, Le T T, Darveniza M, et al. A study of degradation of cellulosic insulation materials in a power transformer. Part 2: tensile strength of cellulose insulation paper[J]. Polymer Degradation and Stability, 1995, 49(3): 429-435. [17] 杨丽君, 黄加佳, 许佐明, 等. 高压交流套管的油纸绝缘热老化特性及寿命模型研究[J]. 电工技术学报, 2016, 31(5): 144-151. Yang Lijun, Huang Jiajia, Xu Zuoming, et al.Investigation on thermal aging characteristics and lifetime model of oil-paper insulation for HV AC bushing[J]. Transactions of China Electrotechnical Society, 2016, 31(5): 144-151. [18] 詹怀宇. 纤维化学与物理[M]. 北京: 科学出版社, 2005. [19] Shroff D H, Stannett A W.A review of paper aging in power transformers[J]. IEE Proceedings C (Generation Transmission & Distribution), 1985, 132(6): 312-319. [20] 马礼敦. 近代X射线多晶衍射—实验技术与数据分析[M]. 北京: 化学工业出版社, 2004. [21] 鄢水强, 廖瑞金, 吕彦冬, 等. 纳米Al2O3掺杂对绝缘纸热老化电气特性的影响[J]. 电工技术学报, 2017, 32(1): 225-232. Yan Shuiqiang, Liao Ruijin, Lü Yandong, et al.Influence of nano-Al2O3 on electrical properties of insulation paper under thermal aging[J]. Transactions of China Electrotechnical Society, 2017, 32(1): 225-232.
2018, Vol. 33 
