Abstract The online diagnosis of local defects in cables is of significant importance for ensuring the power systems stable operation. Given its rich insulation information and compatibility with on-site detection requirements, the harmonic component of the loss current has been recognized as a highly promising detection method for achieving online monitoring and diagnosis. This article aims to explore the online diagnosis for cable local tip defects by analyzing the harmonic characteristics of the loss current In order to investigate the XLPE nonlinear conductivity phenomenon under high electric fields, a simulation model based on the carrier transport process has been developed to analyze the spike defect loss current density. The concepts of the total harmonic distortion (THD), the harmonic contribution rate (Hn) and the conductivity distortion rate (CDR) are introduced to describe the frequency domain characteristics of the loss current and to quantitatively measure the fluctuation degree of conductivity, respectively. To assess the defect severity influence on the harmonic characteristics of loss current density and the conductivity fluctuation, simulation analyses are performed under varying circumstances. The findings reveal that spike defects in XLPE lead to the presence of higher-order harmonic components in the loss current density, mainly the 3rd and 5th harmonics. The conductivity fluctuates synchronously with changes in power frequency voltage. Decreasing the curvature radius of the needle tip from 40 μm to 25 μm can result in 50.75%, 68.63% increase in THD and CDR, 18.63% decrease in H3 (the contribution rate of the 3rd harmonic), and 15.62%, 6.42% increase in H5 and H7 (the contribution rate of the 5th and 7th harmonic). Reducing the electrode spacing from 4mm to 3mm leads to 57.39%, 83.46% increase in THD and CDR, 20.69% decrease in H3, 14.41%, 6.42% increase in H5 and H7. Further analysis of the relationship between THD, CDR, and Hn indicates that the conductivity fluctuation causes the superposition of higher-order harmonic components. Specifically, The greater the fluctuation of conductivity over time, the higher the harmonics content, as well the proportion of 5th and 7th harmonic components. To examine the harmonic characteristics of the actual XLPE insulation spike defect loss current, a detection platform has been established for spike defect samples. The loss current of three different sample specifications has been measured and analyzed, and the results have been compared with the simulation results. The analysis demonstrates the good consistency between the simulated and measured results regarding the harmonic components of the loss current under varying defect severity levels. Furthermore, the measured results indicate that as the defect severity increases, the contribution rate of the 3rd harmonic gradually decreases, while the contribution rates of the 5th and 7th harmonics gradually increase, which is consistent with the simulation results. The harmonic characteristics analysis of the loss current proves effective for diagnosing local spike defects in cables, with the harmonic composition closely linked to the morphology of sharp defects. Based on comprehensive simulation and measurement studies on typical local sharp defects, the following main conclusions can be drawn: (1) The presence of a local spike defect in the cable leads to the existence of higher-order harmonics in the loss current, mainly the 3rd and 5th harmonics. (2) THD, as a diagnostic feature, exhibits the clear correlation with defect severity and can serve as a quantifiable parameter for assessing the severity of cable defects. (3) Comparative analysis results indicate that the severity and morphology of spike defects affect the harmonic components in the loss current. Specifically, higher defect severity and sharper spike shapes result in lower proportion of the 3rd harmonic and higher proportion of 5th and 7th harmonic.
Zhao Yan,Zheng Shusheng. Diagnosis of XLPE Cable Local Tip Defects Based on Analysis of Harmonic Characteristics of Loss Current[J]. Transactions of China Electrotechnical Society, 2023, 38(21): 5725-5737.
[1] 陈向荣, 洪泽林, 朱光宇, 等. 高温下电压稳定剂对交联聚乙烯电树枝化及局部放电特性的影响[J]. 电工技术学报, 2023, 38(3): 577-586. Chen Xiangrong, Hong Zelin, Zhu Guangyu, et al.Effect of voltage stabilizer on electrical treeing and partial discharge characteristics of crosslinked polyethylene at high temperature[J]. Transactions of China Electrotechnical Society, 2023, 38(3): 577-586. [2] 王昊月, 李成榕, 王伟, 等. 高压频域介电谱诊断XLPE电缆局部绝缘老化缺陷的研究[J]. 电工技术学报, 2022, 37(6): 1542-1553. Wang Haoyue, Li Chengrong, Wang Wei, et al.Local aging diagnosis of XLPE cables using high voltage frequency domain dielectric spectroscopy[J]. Transa-ctions of China Electrotechnical Society, 2022, 37(6): 1542-1553. [3] Al-Arainy A, Malik N H, Qureshi M I, et al.The performance of strippable and bonded screened medium-voltage XLPE-insulated cables under long-term accelerated aging[J]. IEEE Transactions on Power Delivery, 2007, 22(2): 744-751. [4] 李蓉, 周凯, 万航, 等. 基于输入阻抗谱的电力电缆本体局部缺陷类型识别及定位[J]. 电工技术学报, 2021, 36(8): 1743-1751. Li Rong, Zhou Kai, Wan Hang, et al.Identification and location of local defects in power cable body based on input impedance spectroscopy[J]. Transactions of China Electrotechnical Society, 2021, 36(8): 1743-1751. [5] 王昊月, 孙茂伦, 赵凯杰, 等. 电缆绝缘老化的高压频域介电谱诊断评估方法[J]. 中国电机工程学报, 2023, 43(9): 3630-3642. Wang Haoyue, Sun Maolun, Zhao Kaijie, et al.High voltage FDS diagnosis and evaluation method for cable insulation aging[J]. Proceedings of the CSEE, 2023, 43(9): 3630-3642. [6] 张牧烨. 电力电缆故障定位和故障诊断方法研究[D]. 济南: 山东大学, 2022. [7] 吴沛航, 吴旭升, 高嵬. 舰船电缆绝缘在线监测技术综述[J]. 电工技术学报, 2021, 36(增刊2): 713-722. Wu Peihang, Wu Xusheng, Gao Wei.A review of online conditon monitoring of marine cable insulation[J]. Transactions of China Electrotechnical Society, 2021, 36(S2): 713-722. [8] 王昊月, 王晓威, 孙茂伦, 等. XLPE电缆绝缘热老化的高压频域介电谱诊断方法[J]. 电工技术学报, 2022, 37(17): 4497-4507. Wang Haoyue, Wang Xiaowei, Sun Maolun, et al.High voltage frequency domain dielectric spectroscopy diagnosis method for thermal aging of XPLE cables[J]. Transactions of China Electrotechnical Society, 2022, 37(17): 4497-4507. [9] CIGRE WG JWG D1/B1.20. Non-destructive water-tree detection in XLPE cable insulation[R]. CIGRE, 2012. [10] Yagi Y, Tanaka H, Kimura H.Study on diagnostic method for water treed XLPE cable by loss current measurement[C]//1998 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.98CH36257), Atlanta, GA, USA, 2002: 653-656. [11] Hvidsten S, Ildstad E, Sletbak J, et al.Understanding water treeing mechanisms in the development of diagnostic test methods[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 1998, 5(5): 754-760. [12] 赵世纯, 凌标灿, 朱希安, 等. HDS电气设备带电状态诊断技术及应用[M]. 北京: 电子工业出版社, 2017. [13] 魏强. 基于谐波分量法XLPE电缆水树老化测试系统的研究[D]. 哈尔滨: 哈尔滨理工大学, 2004. [14] 高震. 变频谐振电源条件下电缆绝缘损耗电流谐波分量的测量[D]. 哈尔滨: 哈尔滨理工大学, 2012. [15] 李闯. 损耗电流谐波分量测试系统的研制[D]. 哈尔滨: 哈尔滨理工大学, 2010. [16] 靳雪君. 基于谐波特征的电缆绝缘带电诊断技术[D]. 北京: 北方工业大学, 2022. [17] 符劲松, 陈俊武, 舒舟, 等. 含水树枝的XLPE电力电缆损耗电流建模仿真计算[J]. 高压电器, 2013, 49(5): 86-89. Fu Jinsong, Chen Junwu, Shu Zhou, et al.Modeling water tree for XLPE cable loss current numerical calculation[J]. High Voltage Apparatus, 2013, 49(5): 86-89. [18] 兰莉. 温度对聚合物绝缘中空间电荷行为的影响[D]. 上海: 上海交通大学, 2015. [19] 刘德远. 交直流电场下电缆绝缘中空间电荷测量与数值模拟技术研究[D]. 上海: 上海交通大学, 2019. [20] 钟琼霞, 兰莉, 吴建东, 等. 交联副产物对交联聚乙烯中空间电荷行为的影响[J]. 中国电机工程学报, 2015, 35(11): 2903-2910. Zhong Qiongxia, Lan Li, Wu Jiandong, et al.The influence of cross-linked by-products on space charge behaviour in XLPE[J]. Proceedings of the CSEE, 2015, 35(11): 2903-2910. [21] 陈驰, 李佳兴, 王霞, 等. 交联聚乙烯试样中空间电荷输运特性的数值模拟[J]. 高电压技术, 2023, 49(1): 311-320. Chen Chi, Li Jiaxing, Wang Xia, et al.Numerical simulation of space charge transport characteristics in crosslinked polyethylene samples[J]. High Voltage Engineering, 2023, 49(1): 311-320. [22] 黄光磊, 李喆, 杨丰源, 等. 直流交联聚乙烯电缆泄漏电流试验特性研究[J]. 电工技术学报, 2019, 34(1): 192-201. Huang Guanglei, Li Zhe, Yang Fengyuan, et al.Experimental research on leakage current of DC cross linked polyethylene cable[J]. Transactions of China Electrotechnical Society, 2019, 34(1): 192-201. [23] 黄光磊. 直流电缆局部放电与泄漏电流特性及类型识别研究[D]. 上海: 上海交通大学, 2019. [24] 严有祥, 朱婷, 王蕾. 基于有限元法对±320 kV直流XLPE电缆中间接头电场与空间电荷的仿真计算[J]. 高电压技术, 2017, 43(11): 3591-3598. Yan Youxiang, Zhu Ting, Wang Lei.Simulation calculation of electric field and space charge in the joint of DC ±320 kV XLPE cable based on finite element method[J]. High Voltage Engineering, 2017, 43(11): 3591-3598. [25] 曹政钦, 石岩, 魏钢. 高电压技术[M]. 重庆: 重庆大学出版社, 2020. [26] 李进, 梁虎成, 杜伯学, 等. 基于双极性载流子输运模型的高压直流电缆附件绝缘EPDM/LDPE界面电荷的数值模拟[J]. 高电压技术, 2018, 44(5): 1443-1449. Li Jin, Liang Hucheng, Du Boxue, et al.Numerical simulation of interface charge behaviors between LDPE/EPDM for HVDC cable accessory insulation based on the bipolar charge transport model[J]. High Voltage Engineering, 2018, 44(5): 1443-1449. [27] 张灵, 陈健宁, 周远翔, 等. 聚合物绝缘空间电荷动力学的理论模型与数值仿真研究进展[J]. 中国电机工程学报, 2022, 42(8): 3037-3055. Zhang Ling, Chen Jianning, Zhou Yuanxiang, et al.Progress on theoretical models and numerical simulation of space charge kinetics in polymeric insulation[J]. Proceedings of the CSEE, 2022, 42(8): 3037-3055. [28] Liu Hongbo, Liao Ruijin, Zhu Qingdai, et al.Calculation of space charge density in negative corona based on finite-element iteration and sound pulse method[J]. IEEE Transactions on Magnetics, 2018, 54(3): 1-4. [29] 于弘洋, 周飞, 荆平, 等. 城市电网紧凑化输电增容技术探讨[J]. 智能电网, 2014, 2(8): 26-30. Yu Hongyang, Zhou Fei, Jing Ping, et al.Discussion of compact design and capacity increase technology of power transmission in urban power grid[J]. Smart Grid, 2014, 2(8): 26-30. [30] Lan Li, Wu Jiandong, Yin Yi, et al.Effect of temperature on space charge trapping and conduction in cross-linked polyethylene[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2014, 21(4): 1784-1791. [31] 刘士利, 李丛健, 沈方, 等. 交流XLPE电缆改为直流运行时空间电荷积累特性仿真[J]. 高电压技术, 2017, 43(11): 3576-3582. Liu Shili, Li Congjian, Shen Fang, et al.Simulation on the characteristics of space charge accumulation when converting the AC XLPE cable to DC operation[J]. High Voltage Engineering, 2017, 43(11): 3576-3582. [32] 陶文彪, 朱光亚, 宋述勇, 等. 交联聚乙烯中丛状电树枝的生长机制[J]. 中国电机工程学报, 2018, 38(13): 4004-4012, 4042. Tao Wenbiao, Zhu Guangya, Song Shuyong, et al.The growth mechanism of brush-type electrical tree in XLPE[J]. Proceedings of the CSEE, 2018, 38(13): 4004-4012, 4042. [33] Wang Haoyue, Wang Wei, Wu Feng, et al.Characteristics analysis of water needle induced electrical trees in XLPE[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2021, 28(6): 1988-1995. [34] 马鑫, 张怀垠, 吴继岩, 等. 温度对交联聚乙烯电缆尖刺缺陷局部放电特性的影响[J]. 高压电器, 2021, 57(5): 151-156. Ma Xin, Zhang Huaiyin, Wu Jiyan, et al.Effect of temperature on partial discharge characteristics of needle defects in cross-linked polyethylene cable[J]. High Voltage Apparatus, 2021, 57(5): 151-156.
2023, Vol. 38 
