The Influence of TA-Na+ Coating Interface Modification on the Electrical and Interface Properties of Optical Fiber Composite Insulating Cores
Li Le1, Wang Yang1, Zhang Haofeng2, Xu Kezhi1, Liu Yunpeng1
1. Yanzhao Electric Power Laboratory North China Electric Power University Baoding 071003 China; 2. CSG Electric Power Research Institute Co. Ltd Guangzhou 510663 China
Abstract：The rapid advancement of ultra-high voltage direct current（UHVDC）transmission technology has placed higher demands on the sampling accuracy and response speed of measurement equipment. Optical current transformers（OCTs）are widely used due to their high insulation, fast response, and electromagnetic interference resistance. As a key structural component, fiber-optic composite insulators serve the dual functions of information transmission and electrical insulation. However, the multi-dielectric interface between the optical fiber and the core material—typically low smoke zero halogen polyethylene（LSZHPE）and syntactic foams（SF)—is prone to defects that can lead to internal discharge or fiber breakage. This study addresses these reliability issues by proposing an interfacial modification strategy using a tannic acid-sodium（TA-Na+）coating method. By introducing active functional groups such as phenolic hydroxyl groups, this green and efficient method aims to achieve synergistic optimization of mechanical and electrical performance at the fiber-to-core interface. The investigation combined molecular dynamics simulations with experimental verification to evaluate the effectiveness of the TA-Na+ coating. Molecular dynamics simulations were performed using Materials Studio software to calculate surface energy and interfacial binding energy under varying coating coverage levels. For the experimental phase, LSZHPE fibers were ultrasonically cleaned and immersed in TA-Na+ solutions with concentrations of 1, 2, and 3 mg/L for durations of 1, 2, or 3 hours. These modified fibers were then embedded in an epoxy-based SF matrix composed of E-51 epoxy resin, methylhexahydrophthalic anhydride hardener, and polymethyl methacrylate hollow microspheres. The modified fibers were characterized using scanning electron microscopy and atomic force microscopy for surface morphology, while Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were employed to analyze chemical structures and elemental compositions. System performance was further assessed through breakdown strength tests, micro-bond tests for interfacial shear strength（IFSS), and water diffusion leakage current measurements. Molecular dynamics simulations indicated that TA-Na+ coatings significantly enhance surface energy, showing a 172.98% increase at 100% coverage due to the introduction of strong polar functional groups. Experimental characterization confirmed that tannic acid successfully attached to the fiber surface, with X-ray photoelectron spectroscopy identifying the chelation of tannic acid with sodium ions to form a stable three-dimensional network. Results demonstrate that low concentrations of TA-Na+ combined with longer treatment times produce the most uniform and stable coatings. The breakdown strength of modified samples reached a maximum of 14.266 kV/mm, representing an 8.57% improvement over unmodified cores. Interfacial performance showed substantial gains, with the maximum IFSS rising by 112.84%. Additionally, the water diffusion leakage current fell to a minimum of 54.09 μA. Conversely, excessive concentrations or treatment times led to coating cracks and deposits that degraded performance by causing electric field distortion. Ultimately, the TA-Na+ coating method proves to be a simple and efficient strategy for mitigating interface defects in fiber-optic composite insulators.
李乐, 王洋, 张豪峰, 徐克志, 刘云鹏. 单宁酸-钠涂层法界面改性对光纤复合绝缘芯体电气及界面性能的影响[J]. 电工技术学报, 2026, 41(16): 5424-5438.
Li Le, Wang Yang, Zhang Haofeng, Xu Kezhi, Liu Yunpeng. The Influence of TA-Na+ Coating Interface Modification on the Electrical and Interface Properties of Optical Fiber Composite Insulating Cores. Transactions of China Electrotechnical Society, 2026, 41(16): 5424-5438.
[1] 高礼玉, 栾洪洲, 李天琦, 等. 基于阵列波导光栅的IGBT功率模块结温监测[J]. 电工技术学报, 2025, 40(6): 1796-1804. Gao Liyu, Luan Hongzhou, Li Tianqi, et al.Junction temperature monitoring of IGBT power module based on array waveguide grating[J]. Transactions of China Electrotechnical Society, 2025, 40(6): 1796-1804. [2] 刘彬, 邓小聘, 李建光, 等. 柔性直流光纤电流互感器阶跃响应特性研究[J]. 高压电器, 2024, 60(5): 140-146. Liu Bin, Deng Xiaopin, Li Jianguang, et al.Research on step response characteristics of flexible DC fiber-optic current transformer[J]. High Voltage Apparatus, 2024, 60(5): 140-146. [3] 董乃臻, 肖海, 刘云鹏, 等. 基于分布式动态应变传感的光纤复合相线脱冰跳跃监测技术[J]. 电工技术学报, 2026, 41(7): 2484-2497. Dong Naizhen, Xiao Hai, Liu Yunpeng, et al.De-icing jump monitoring technology of optical fiber composite phase conductor based on distributed dynamic strain sensing[J]. Transactions of China Electrotechnical Society, 2026, 41(7): 2484-2497. [4] 李乐, 赵天放, 刘云鹏, 等. 不同缠绕工艺GFRP空心支柱绝缘子力电性能试验及多尺度力学仿真[J]. 电工技术学报, 2025, 40(23): 7776-7792, 7805. Li Le, Zhao Tianfang, Liu Yunpeng, et al.Multi scale mechanical simulation and electromechanical experimental testing of GFRP hollow insulators based on different process parameters[J]. Transactions of China Electrotechnical Society, 2025, 40(23): 7776-7792, 7805. [5] Hao Yanpeng, Huang Lei, Wei Jie, et al.Interface quasi-distributed fibre Bragg grating positioning detection of glaze icing load on composite insulators[J]. IET Science, Measurement & Technology, 2022, 16(5): 316-325. [6] 马宪伟, 尚英强, 赵洋, 等. 环氧树脂层间绝缘界面电树枝生长与局部放电特性[J]. 电工技术学报, 2025, 40(21): 6894-6904. Ma Xianwei, Shang Yingqiang, Zhao Yang, et al.The growth of electrical trees and partial discharge characteristics at the interlayer insulation interface of epoxy resin[J]. Transactions of China Electrotechnical Society, 2025, 40(21): 6894-6904. [7] 李舒维, 焦石, 张健成, 等. 关于直流光学电流互感器光纤绝缘子内部放电机理的研究[J]. 电工技术, 2023(3): 216-220. Li Shuwei, Jiao Shi, Zhang Jiancheng, et al.Study on internal discharge mechanism of optical fiber insulator in DC optical current transformer[J]. Electric Engineering, 2023(3): 216-220. [8] 王志, 刘江明, 张翾喆, 等. 全光纤电流传感器用复合绝缘子击穿故障分析[J]. 电瓷避雷器, 2020(5): 242-247. Wang Zhi, Liu Jiangming, Zhang Xuanzhe, et al.Breakdown analysis of composite insulators for all-optic fiber current sensors[J]. Insulators and Surge Arresters, 2020(5): 242-247. [9] 史文强. 光纤复合绝缘子光纤内嵌技术研究[J]. 机械制造, 2022, 60(4): 30-32. Shi Wenqiang.Research on fiber embedding technology of optical fiber compound insulator[J]. Machinery, 2022, 60(4): 30-32. [10] 王敏吉, 李川, 张旭, 等. 高电压接触型光纤绝缘子的耐高压研究[J]. 电工电能新技术, 2014, 33(10): 44-46, 57. Wang Minji, Li Chuan, Zhang Xu, et al.High voltage withstanding study of high voltage contact fiber-optic insulator[J]. Advanced Technology of Electrical Engineering and Energy, 2014, 33(10): 44-46, 57. [11] 蔡定国, 杨祥江. 悬挂式光纤复合绝缘子: CN2582013Y[P].2003-10-22. [12] 李乐, 徐克志, 刘云鹏, 等. 基于环氧基复合泡沫材料的光纤复合绝缘子芯体性能研究[J]. 中国电机工程学报, 2025, 45(18): 7383-7394. Li Le, Xu Kezhi, Liu Yunpeng, et al.Research on the performance of fiber optic composite insulator core based on epoxy-based syntactic foam materials[J]. Proceedings of the CSEE, 2025, 45(18): 7383-7394. [13] Kalamkarov A L, Fitzgerald S B, MacDonald D O, et al. On the processing and evaluation of pultruded smart composites[J]. Composites Part B: Engineering, 1999, 30(7): 753-763. [14] 陈继东, 王家礼, 吴伯华, 等. 一种光纤光栅复合绝缘子及其制造方法: CN101937743B[P].2011-11-16. [15] Xu Bingkun, He Qinchuan, Wang Yiqun, et al.Construction of magnetic nanoparticle channels in SiC/SiO2 composite foam toward efficient electromagnetic wave absorption[J]. Applied Surface Science, 2023, 636: 157839. [16] Daoud A, Shenouda A Y, Abou El-Khair M T, et al. Electrochemical performance of novel Pb alloys reinforced with Ni-coated fly ash microballoon composite foams in lead acid battery[J]. Materials Chemistry and Physics, 2023, 294: 126987. [17] Dong Yanying, Wang Yonglin, Zhang Xiaofang, et al.Carbon-based elastic foams supported redox-active covalent organic frameworks for flexible super-capacitors[J]. Chemical Engineering Journal, 2022, 449: 137858. [18] 刘云鹏, 李乐, 张铭嘉, 等. 复合绝缘横担界面特性检测研究现状[J]. 电工技术学报, 2020, 35(2): 408-424. Liu Yunpeng, Li Le, Zhang Mingjia, et al.Research status of interface detection for composite cross-arm[J]. Transactions of China Electrotechnical Society, 2020, 35(2): 408-424. [19] 吴雄, 彭旭东, 田嘉宁, 等. 基于空心微珠/环氧材料的复合横担用轻质高绝缘复合芯棒老化特性研究[J]. 绝缘材料, 2026, 59(1): 94-101. Wu Xiong, Peng Xudong, Tian Jianing, et al.Study on ageing characteristics of lightweight high-insulation composite core rod for composite cross-arms based on hollow microspheres/epoxy[J]. Insulating Materials, 2026, 59(1): 94-101. [20] 张成, 谢继凯, 郭家杏, 等. 聚四氟乙烯改性研究进展[J]. 中国塑料, 2024, 38(11): 137-143. Zhang Cheng, Xie Jikai, Guo Jiaxing, et al.Research progress in modification of polytetrafluoroethylene[J]. China Plastics, 2024, 38(11): 137-143. [21] 马义蘅, 王建勇. PTFE纤维等离子体表面改性及机理研究[J]. 中国塑料, 2024, 38(6): 66-71. Ma Yiheng, Wang Jianyong.Study on plasma surface modification and mechanism of PTFE fiber[J]. China Plastics, 2024, 38(6): 66-71. [22] 叶卓然, 罗靓, 潘海燕, 等. 超高分子量聚乙烯纤维及其复合材料的研究现状与分析[J]. 复合材料学报, 2022, 39(9): 4286-4309. Ye Zhuoran, Luo Liang, Pan Haiyan, et al.Research status and analysis of ultra-high molecular weight polyethylene fiber and its composites[J]. Acta Materiae Compositae Sinica, 2022, 39(9): 4286-4309. [23] 尚晴, 赵晗, 赵宁, 等. 超高分子量聚乙烯纤维表面改性的研究进展[J]. 高分子通报, 2020, 33(4): 22-29. Shang Qing, Zhao Han, Zhao Ning, et al.Research progress on surface modification of ultra-high molecular weight polyethylene fiber[J]. Chinese Polymer Bulletin, 2020, 33(4): 22-29. [24] 杨旭, 程功, 张城城, 等. 接枝改性XLPE绝缘材料宽场域下的空间电荷与电导特性[J]. 电工技术学报, 2025, 40(21): 6882-6893. Yang Xu, Cheng Gong, Zhang Chengcheng, et al.Space charge and conductance characteristics of grafted XLPE insulation material in wide field range[J]. Transactions of China Electrotechnical Society, 2025, 40(21): 6882-6893. [25] 赵晗, 尚晴, 杨萌, 等. ZnO纳米棒改性超高分子量聚乙烯纤维及其性能研究[J]. 高分子学报, 2020, 51(6): 649-655. Zhao Han, Shang Qing, Yang Meng, et al.Surface modification and properties of UHMWPE fibers by ZnO nanorods[J]. Acta Polymerica Sinica, 2020, 51(6): 649-655. [26] Zhao Xiaolin, Du Jianhua, Yang Hongwei, et al.Surface modification of ultra-high molecular weight polyethylene fiber by different kinds of SiO2 nanoparticles[J]. Polymer Composites, 2017, 38(9): 1928-1936. [27] Shimel M, Gouzman I, Grossman E, et al.Enhancement of wetting and mechanical properties of UHMWPE-based composites through alumina atomic layer deposition[J]. Advanced Materials Interfaces, 2018, 5(14): 1800295. [28] Wu Jinhua, Han Chao, Wu Hao, et al.Nanocoating of Ce-tannic acid metal-organic coordination complex: surface modification of layered Li1.2Mn0.6Ni0.2O2 by CeO2 coating for lithium-ion batteries[J]. Ionics, 2019, 25(7): 3031-3040. [29] Wang Yueqing, Chen Si, Zhao Shuya, et al.Interfacial coordination assembly of tannic acid with metal ions on three-dimensional nickel hydroxide nanowalls for efficient water splitting[J]. Journal of Materials Chemistry A, 2020, 8(31): 15845-15852. [30] 陈天欢, 严成, 蒋干兵, 等. 单宁酸表面改性PE-UHMW纤维及其界面性能研究[J]. 中国塑料, 2024, 38(8): 26-32. Chen Tianhuan, Yan Cheng, Jiang Ganbing, et al.Study on surface modification of PE-UHMW fiber by tannic acid and its interfacial property[J]. China Plastics, 2024, 38(8): 26-32. [31] Wang Shicheng, Ma Jinyang, Feng Xia, et al.An effective surface modification of UHMWPE fiber for improving the interfacial adhesion of epoxy resin composites[J]. Polymer Composites, 2020, 41(4): 1614-1623. [32] Xing Tianji, Ying Lixia, Wu Chunxi, et al.Study on the effect of surface tannic acid/silane conversion film on properties of epoxy resin coatings[J]. Anti-Corrosion Methods and Materials, 2019, 66(4): 446-453. [33] Li Feizhou, Lu Zhenglin, Yang Zhihuai, et al.Surface interaction energy simulation of ceramic materials with epoxy resin[J]. Polimery, 2015, 60(7/8): 468-471. [34] Zhu Hong, Han Wenfeng, Liu Huazhang.Influence of oxidation on heat-treated activated carbon support properties and metallic dispersion of Ru/C catalyst[J]. Catalysis Letters, 2007, 115(1): 13-18. [35] Wang Xiaobo, Tang Chao, Wang Qian, et al.Selection of optimal polymerization degree and force field in the molecular dynamics simulation of insulating paper cellulose[J]. Energies, 2017, 10(9): 1377. [36] 裴三女. 氢氧化镁阻燃剂的表面改性及其在EVA树脂中的优化应用[D]. 扬州: 扬州大学, 2023. Pei Sannü.Surface modification of magnesium hydroxide flame retardant and its optimization application in ethylene-vinyl acetate copolymer resin[D]. Yangzhou: Yangzhou University, 2023. [37] Nam S, Easson M W, Condon B D, et al.A reinforced thermal barrier coat of a Na-tannic acid complex from the view of thermal kinetics[J]. RSC Advances, 2019, 9(19): 10914-10926. [38] Li Dongying, Li Jiarun, Wang Siwei, et al.Dually crosslinked copper-poly(tannic acid) nanoparticles with microenvironment-responsiveness for infected wound treatment[J]. Advanced Healthcare Materials, 2023, 12(17): 2203063. [39] Chen Chen, Yang Hao, Yang Xiao, et al.Tannic acid: a crosslinker leading to versatile functional polymeric networks: a review[J]. RSC Advances, 2022, 12(13): 7689-7711. [40] 汪维海, 陈宏, 黄志超, 等. 多酚-氨基硅烷改性超高分子量聚乙烯纤维的制备及其界面性能[J]. 现代纺织技术, 2022, 30(6): 63-72. Wang Weihai, Chen Hong, Huang Zhichao, et al.Preparation and interfacial properties of UHMWPE fibers modified by polyphenol & amino silane[J]. Advanced Textile Technology, 2022, 30(6): 63-72. [41] He Runqin, Niu Fenglian, Chang Qiuxiang.The effect of plasma treatment on the mechanical behavior of UHMWPE fiber-reinforced thermoplastic HDPE composite[J]. Surface and Interface Analysis, 2018, 50(1): 73-77. [42] Han Lei, Cai Haifeng, Chen Xu, et al.Study of UHMWPE fiber surface modification and the properties of UHMWPE/epoxy composite[J]. Polymers, 2020, 12(3): 521. [43] Sun Yan, Mudasir M, Qian Ye.Catalytic deposition of polydopamine and nanoclay bi-layer formation on UHMWPE fibers for enhanced performance in fiber-reinforced cementitious composites (FRCC)[J]. Composite Interfaces, 2026, 33(3): 601-620. [44] Wang Jing, Dai Tianyi, Wu Hao, et al.Tannic acid-Fe3+ activated rapid polymerization of ionic conductive hydrogels with high mechanical properties, self-healing, and self-adhesion for flexible wearable sensors[J]. Composites Science and Technology, 2022, 221: 109345. [45] Mahdy A M, Anis H I, Ward S A.Electrode roughness effects on the breakdown of air-insulated apparatus[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 1998, 5(4): 612-617. [46] Saha S, Dawood S, Butreddy P, et al.Novel biodegradable low-κ dielectric nanomaterials from natural polyphenols[J]. RSC Advances, 2021, 11(27): 16698-16705. [47] Li Zhiyong, Li Zhuo, Fu Jialong, et al.Sodium-ion conducting polymer electrolytes[J]. Rare Metals, 2023, 42(1): 1-16.
2026, Vol. 41 
