Effects of Space Charge on Breakdown and Creeping Discharge of Oil-Paper Insulation
Zhou Yuanxiang1, Sun Qinghua1, Li Guangfan2, Wang Yunshan1, Jiang Xinxin1, Qiu Yuzhou2, Li Jinzhong2, Wang Ninghua2
1. State Key Laboratory of Electrical Power System Tsinghua University Beijing 100084 China 2. China Electric Power Research Institute Beijing 100192 China
Abstract:As one of the most important apparatus used in high voltage direct current (HVDC) transmission system, converter transformer has complex structures and operates in a cruel environment. Therefore, more knowledge of the behavior of insulating systems is required. In this paper, experiments are designed according to the operating state of converter transformers, based on which the progress of breakdown and creeping discharge of oil-paper insulation are experimentally studied. Space charge accumulated in oil-paper insulation system is successfully measured. Polarity reversal effects in oil-paper insulation systems are demonstrated by the space charge testing results. In other words, space charge accumulated under the dc electrical stress showed influences on the breakdown of oil-paper insulation are experimentally confirmed. Moreover, the experiments show that space charge could also affect the creeping discharge of oil-paper insulation significantly. Based on these results, it is put forward that traditional transformer design rules may not be suitable for converter transformers. More attentions should be paid on space charge effects in the design and manufacture of converter transformers. Among these effects, the dispersing processes of space charge in oil-paper insulation are stressed to solve the insulation problem induced by polarity reversal in HVDC equipment.
周远翔, 孙清华, 李光范, 王云杉, 姜鑫鑫, 仇宇舟, 李金忠, 王宁华. 空间电荷对油纸绝缘击穿和沿面闪络的影响[J]. 电工技术学报, 2011, 26(2): 27-33.
Zhou Yuanxiang, Sun Qinghua, Li Guangfan, Wang Yunshan, Jiang Xinxin, Qiu Yuzhou, Li Jinzhong, Wang Ninghua. Effects of Space Charge on Breakdown and Creeping Discharge of Oil-Paper Insulation. Transactions of China Electrotechnical Society, 2011, 26(2): 27-33.
[1] 尹克宁. 变压器设计原理[M]. 北京: 中国电力出版社, 2003. [2] Hammer F, Kuchler A. Insulating systems for HVDC power apparatus[J]. IEEE Transactions on Electrical Insulation, 1992, 27(3): 601-609. [3] 韩晓东, 翟亚东. 高压直流输电用换流变压器[J]. 高压电器, 2002, 38(3): 5-6. Han Xiaodong, Zhai Yadong. Converter transformer used for HVDC transmission[J]. High Voltage Apparatus, 2002, 38(3): 5-6. [4] 王烜, 曹晓珑. 特高压换流站输电设备概述[J]. 电气技术, 2006(5): 9-14. Wang Xuan, Cao Xiaolong. Summarize of UHVDC station transmit electricity equipments[J]. Electrical Engineering, 2006(5): 9-14. [5] Martin J Heathcote. 变压器实用技术大全[M]. 北京: 机械工业出版社, 2008. [6] 谢毓城. 电力变压器手册[M]. 北京: 机械工业出版社, 2003. [7] 吕晓德, 陈世坤, 孙定华, 等. 各向异性非线性直流电场数值算法研究[J]. 电工技术学报, 1998, 13(4): 60-64. Lu Xiaode, Chen Shikun, Sun Dinghua, et al. The study on numerical method for anisotropic nonlinear DC electric field[J]. Transactions of China Electrotechnical Society, 1998, 13(4):60-64. [8] Li Ying, Takada T. Progress in space charge measurement of solid insulating materials in Japan[J]. IEEE Electrical Insulation Magazine, 1994, 10(5): 16-28. [9] 屠德民. 直流耐压试验对交联聚乙烯电缆绝缘的危害性[J]. 电线电缆, 1997(5): 33-37. Tu Demin. Perniciousness to XLPE cables of DC voltage endurance test[J]. Electric Wire & Cable, 1997(5): 33-37. [10] 赵畹君. 高压直流输电工程技术[M]. 北京: 中国电力出版社, 2004. [11] 王春玲, 李建华. 换流变压器阀侧绕组极性反转试验端部电场的计算与分析[J]. 变压器, 2005, 42(2): 11-14. Wang Chunling, Li Jianhua. Calculation and analysis of end electrical field in valve winding polarity reverser test for converter transformer[J]. Transformer, 2005, 42(2): 11-14. [12] 文闿成, 王瑞珍. 换流变压器阀侧试验对绝缘考核的有效性(上) [J]. 变压器, 1997, 34(11): 10-15. Wen Kaicheng, Wang Ruizhen. Effectiveness of dielectric tests on valve side of converter transformer for insulation examination (Part I) [J]. Transformer, 1997, 34(11): 10-15. [13] 文闿成, 王瑞珍. 换流变压器阀侧试验对绝缘考核的有效性(下) [J]. 变压器, 1997, 34(12) :28-30. Wen Kaicheng, Wang Ruizhen. Effectiveness of dielectric tests on valve side of converter transformer for insulation examination (Part II) [J]. Transformer, 1997, 34(12): 28-30. [14] 吕晓德, 陈世坤. 非线性油纸复合绝缘结构中交直流混合电场的数值计算[J]. 变压器, 1997, 34(1): 20-23. Lü Xiaode, Chen Shikun. Numerical calculation on combined AC-DC electric field in nonlinear oil-paper composite insulation[J]. Transformer, 1997, 34(1): 20-23. [15] 吕晓德, 陈世坤, 孙定华, 等. 换流变压器阀侧绕组端部电场的特性分析[J]. 变压器, 1998, 35(6): 15-20. Lü Xiaode, Chen Shikun, Sun Dinghua, et al. Analysis on characteristics of electric field at ends of valve-side winding in converter transformer[J]. Transformer, 1998, 35(6): 15-20. [16] 张杰. 换流变压器内部电场分析及油纸绝缘试验系统设计[D]. 哈尔滨: 哈尔滨理工大学, 2008. [17] 中华人民共和国国家技术监督局. GB 1408.2. 绝缘材料电气强度试验方法第2部分:对应用直流电压试验的附加要求[S]. 北京:中国标准出版社, 2006. [18] Zhou Yuanxiang, Wang Yunshan, Li Guangfan, et al. Space charge phenomena in oil-paper insulation materials under high voltage direct current[J]. Journal of Electrostatics, 2009, 67(2-3): 417-421. [19] 涂愈明, 王赞基, 江缉光, 等. 超高压变压器油流静电带电问题的研究现状[J]. 变压器, 1997, 34(6): 1-8. Tu Yuming, Wang Zanji, Jiang Jiguang, et al. The recent studies on the static electrification problem owing to oil flow in EHV transformers[J]. Transformer, 1997, 34(6): 1-8. [20] IEC 61378-2. Convertor Transformers-Part 2: Transformers for HVDC Applications[S]. Geneva: IEC, 2001.