Abstract:The ageing of XLPE insulation can cause the change of trap energy properties, and further affect the distribution of space charge in the bulk of insulation. It would threaten the security of HVDC. In this paper, the slices from a 160kV DC cable were stressed at 90℃ and 135℃, respectively. The space charge distributions of the samples were measured by the pulsed electro-acoustic (PEA) method. And then the space charge decay model was established. Combined with the isothermal relaxation theory, a method to analyze the trap energy properties of the insulation materials based on the PEA method was proposed. The results showed that due to the post-crosslinking in the 90℃ thermal process, parts of the deep electron traps were converted to shallow traps, which would benefit the dissipation of the space charge. However, as the aging time further increased, the density and level of the electron traps both had a certain degree of growth, resulting in the increase of the amount of space charge. Under the 135℃ thermal stress, not only the crystalline morphology of the XLPE is greatly destroyed, but also the density and depth of the electron traps increased greatly because of the intense thermal oxidative degradation in the XLPE insulation.
刘云鹏, 刘贺晨, 高丽娟, 李演达. 电声脉冲法研究热老化对160kV直流电缆绝缘材料陷阱特性的影响[J]. 电工技术学报, 2016, 31(24): 105-112.
Liu Yunpeng, Liu Hechen, Gao Lijuan, Li Yanda. Influence of Thermal Stress on the Traps Energy Properties of 160kV HVDC Cable Insulation Material Based on Pulsed Electro-Acoustic Method. Transactions of China Electrotechnical Society, 2016, 31(24): 105-112.
[1] 张彦涛, 张志强, 张玉红, 等. 应用特高压直流输电技术实现亚欧洲际输电方案的设想[J]. 电网技术, 2015, 39(8): 2069-2075. Zhang Yantao, Zhang Zhiqiang, Zhang Yuhong, et al. Application research on UHVDC technology in Asia-Europe power transmission planning[J]. Power System Technology, 2015, 39(8): 2069-2075. [2] 余欣, 张若林, 徐晓刚, 等. 柔性直流电缆及附件系统型式试验设计方法[J]. 广东电力, 2015, 28(5): 90-94, 108. Yu Xin, Zhang Ruolin, Xu Xiaogang, et al. Design method for type test on flexible direct current cable and accessory system[J]. Guangdong Electric Power, 2015, 28(5): 90-94, 108. [3] 王霞, 陈少卿, 成霞, 等. 电声脉冲法测量聚合物绝缘表面陷阱能级分布[J]. 中国电机工程学报, 2009, 29(1): 127-132. Wang Xia, Chen Shaoqing, Cheng Xia, et al. Measuring energy distribution of surface trap in polymer insulation by PEA method[J]. Proceedings of the CSEE, 2009, 29(1): 127-132. [4] 严有祥, 方晓临, 张伟刚, 等. 厦门±320kV柔性直流电缆输电工程电缆选型和敷设[J]. 高电压技术, 2015, 41(4): 1147-1153. Yan Youxiang, Fang Xiaolin, Zhang Weigang, et al. Cable section and laying of Xiamen ±320kV flexible DC cable transmission project[J]. High Voltage Engineering, 2015, 41(4): 1147-1153. [5] 杨黎明, 朱智恩, 杨荣凯, 等. 柔性直流电缆绝缘料及电缆结构设计[J]. 电力系统自动化, 2013, 37(15): 117-124. Yang Liming, Zhu Zhien, Yang Rongkai, et al. Insulation material and structure design of HVDC flexible cable[J]. Automation of Electric Power System, 2013, 37(15): 117-124. [6] 王继业, 马士聪, 仝杰, 等. 中日韩电网关键技术发展及趋势分析[J]. 电网技术, 2016, 40(2): 491- 499. Wang Jiye, Ma Shicong, Tong Jie, et al. Current development and trend analysis of power grid key technologies in China, Japan and Republic of Korea[J]. Power System Technology, 2016, 40(2): 491-499. [7] 郑煜, 吴建东, 王俏华, 等. 空间电荷与直流电导联合测试技术用于纳米MgO抑制XLPE中空间电荷的研究[J]. 电工技术学报, 2012, 27(5): 126-131. Zheng Yu, Wu Jiandong, Wang Qiaohua, et al. Research on the space charge suppressing mechanism of Nano-MgO in XLPE with a joint measuring technology of DC conduction and space charge[J]. Transactions of China Electrotechnical Society, 2012, 27(5): 126-131. [8] 田付强, 杨春, 何丽娟, 等. 聚合物/无机纳米复合电介质介电性能及其机理最新研究进展[J]. 电工技术学报, 2011, 26(3): 1-12. Tian Fuqiang, Yang Chun, He Lijuan, et al. Recent research advancement in dielectric properties and the corresponding mechanism of polymer/inorganic nanocomposite[J]. Transactions of China Electro- technical Society, 2011, 26(3): 1-12. [9] 曹雨, 吴建东, 刘松, 等. 单因子老化中定子线棒等温松弛电流的研究[J]. 电工技术学报, 2015, 30(1): 242-248. Cao Yu, Wu Jiandong, Liu Song, et al. Isothermal relaxation current research of stator bar insulation in single factor aging experiments[J]. Transactions of China Electrotechnical Society, 2015, 30(1): 242- 248. [10] 雷勇, 蒋世超, 周凯, 等. 基于极化-去极化电流方法的交联聚乙烯电缆绝缘无损检测[J]. 高电压技术, 2015, 41(8): 2643-2649. Lei Yong, Jiang Shichao, Zhou Kai, et al. Non- destructive detection of XLPE cable insulation based on the method of polarization-depolarization current[J]. High Voltage Engineering, 2015, 41(8): 2643-2649. [11] 李陈, 雷勇, 周凯, 等. 极化去极化电流技术用于诊断XLPE电缆绝缘老化状态[J]. 电工电能新技术, 2014, 33(4): 32-35, 66. Li Chen, Lei Yong, Zhou Kai, et al. Diagnosis of XLPE cable insulation using polarization and depolarization current measurements[J]. Advanced Technology of Electrical Engineering and Energy, 2014, 33(4): 32-35, 66. [12] 刘刚, 金尚儿, 赵璐, 等. 基于IRC和逐级耐压法的110kV XLPE电缆剩余寿命评估[J]. 华南理工大学学报(自然科学版), 2015, 43(12): 41-47. Liu Gang, Jin Shanger, Zhao Lu, et al. Residual life assessment of 110kV XLPE cable based on isothermal relaxation current method and stepwise voltage-endurance method[J]. Journal of South China University of Technology (Natural Science), 2015, 43(12): 41-47. [13] 贺鹏. 基于等温松弛电流的高压电缆绝缘老化状态评定[D]. 哈尔滨: 哈尔滨理工大学, 2014. [14] 王雅群, 尹毅, 李旭光, 等. 等温松弛电流用于10kV XLPE电缆寿命评估的方法[J]. 电工技术学报, 2009, 24(9): 33-37, 52. Wang Yaqun, Yin Yi, Li Xuguang, et al. The method of lifetime evaluation on 10kV XLPE cables by isothermal relaxation current[J]. Transactions of China Electrotechnical Society, 2009, 24(9): 33-37, 52. [15] Li J Y, Zhou F S, Min D M, et al. The energy distribution of trapped charges in polymers based on isothermal surface potential decay model[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2015, 22(3): 1723-1732. [16] 郝建, 廖瑞金, Chen George, 等. 绝缘油老化对油纸绝缘介质空间电荷形成及迁移特性的影响[J]. 中国电机工程学报, 2012, 32(16): 173-181. Hao Jian, Liao Ruijin, Chen George, et al. Influence of oil aging on the formation and migration behavior of space charge in oil-paper insulation dielectrics[J]. Proceedings of the CSEE, 2012, 32(16): 173-181. [17] 唐超. 油纸绝缘介质的直流空间电荷特性研究[D]. 重庆: 重庆大学, 2010. [18] Simmons J G, Tam M C. Theory of isothermal currents and the direct determination of trap para- meters in semiconductors and insulators containing arbitrary trap distributions[J]. Physical Review B (Solid State), 1973, 7(8): 3706-3713. [19] 徐俊, 王晓东, 欧阳本红, 等. 热老化对交联聚乙烯电缆绝缘理化结构的影响[J]. 绝缘材料, 2013, 46(2): 33-37. Xu Jun, Wang Xiaodong, Ouyang Benhong, et al. Effect of thermal aging on the physicochemical structure of XLPE cable insulation[J]. Insulation Materials, 2013, 46(2): 33-37. [20] Li W W, Li J Y, Wang X, et al. Physicochemical origin of space charge dynamics for aged XLPE cable insulation[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2014, 21(2): 809-820. [21] Parpal J L, David E, Seguin J N, et al. Microphysical characterization of XLPE cable insulation after electrical aging[C]//IEE Third International Con- ference on Power Cables and Accessories 10kV- 500kV, London, UK, 1993: 160-164. [22] Eriksson P A, Boydell P, Eriksson K, et al. Effect of thermal-oxidative aging on mechanical, chemical, and thermal properties of recycled polyamide 66[J]. Journal of Applied Polymer Science, 1997, 65(8): 1619-1630. [23] 李淑琦, 朱永华, 罗兵, 等. 型式试验对挤塑绝缘高压直流电缆老化状态的影响研究[J]. 绝缘材料, 2015, 48(7): 73-78. Li Shuqi, Zhu Yonghua, Luo Bing, et al. Influence of type test on ageing status of extruded cross-linked polyethylene (XLPE) high voltage direct current (HVDC) cables[J]. Insulation Materials, 2015, 48(7): 73-78. [24] Suresh B, Maruthamuthu S, Khare A, et al. Influence of thermal oxidation on surface and thermo- mechanical properties of polyethylene[J]. Journal of Polymer Research, 2011, 18(6): 2175-2184. [25] Fu M, Chen G, Dissado L A, et al. Influence of thermal treatment and residues on space charge accumulation in XLPE for DC power cable app- lication[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2007, 14(1): 53-64. [26] 尹毅, 屠德民, 李明, 等. 用等温电流法研究自由基清除剂的作用机理—— 聚合物电老化陷阱理论的实验验证[J]. 中国电机工程学报, 2000, 20(3): 14-16, 26. Yin Yi, Tu Demin, Li Ming, et al. Study on the action mechanism of the free radical scavenger with isothermal-current-decay method-an experimental verification of trap theory for electrical aging in polymer[J]. Proceedings of the CSEE, 2000, 20(3): 14-16, 26.