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Stress-thermal aging properties of silicone rubber used for cable accessories and electric-thermal-stress multiple fields coupling simulation

Li Guo-Chang Guo Kong-Ying Zhang Jia-Hao Sun Wei-Xin Zhu Yuan-Wei Li Sheng-Tao Wei Yan-Hui

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Stress-thermal aging properties of silicone rubber used for cable accessories and electric-thermal-stress multiple fields coupling simulation

Li Guo-Chang, Guo Kong-Ying, Zhang Jia-Hao, Sun Wei-Xin, Zhu Yuan-Wei, Li Sheng-Tao, Wei Yan-Hui
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  • During the long-term operation of a cable, the electrical field, high temperature, and interface stress may age or deteriorate the silicon rubber (SIR) insulation of the cable accessories, affecting the combined electrical-thermal-force performance of the accessories, and easily causing discharge faults. In this work, the electrical-thermal-force properties of silicone rubber for cable accessories under thermal aging and combined force-thermal aging are studied experimentally and numerically. The changes and mechanisms of physical and chemical properties, electrical properties, thermal properties and mechanical properties of silicone rubber are tested and compared before and after aging. The changes of electric, thermal and force field of cable accessories, caused by the change of SIR material parameters under different aging time and aging form, are further simulated. The experimental results show that the crosslinking degree and molecular motion system of SIR will change with the deepening of the aging degree, which will change the electrical-thermal-force properties of the material to different degree. After aging, large agglomeration protrudes and small cavities appear in SIR section, and the damage is more serious under force-thermal aging. The relative dielectric constant first decreases and then increases with the aging time increasing. The volume resistivity, breakdown strength and flashover voltage all first increase and then decrease. The thermal conductivity first increases and then decreases with aging time increasing. In addition, with the increase of aging time, the tensile strength and elongation at break decrease gradually. Considering the change of properties after aging, the destruction of SIR material by force-thermal aging is more serious. The simulation results show that under the two aging modes, the maximum electric field strength at the stress cone root of the cable accessories first increases and then decreases with the increase of time. The electric field strength at the stress cone root of the cable accessories, caused by the force-thermal aging, changes little, maintaining about 2.2 kV/mm. The difference in temperature between the inside and the outside of the insulation layer is obvious under different aging degree, and the temperature difference shows a first decreasing and then increasing trend under both aging modes, and the maximum temperature gradient is 9.15 ℃. The interface stress at the stress cone root decreases from 0.263 to 0.230 MPa, which is about 12.5% lower. This work has guiding significance in evaluating the insulation performance and analyzing the fault of distribution cable accessories.
      Corresponding author: Wei Yan-Hui, Weiyhui@126.com
    • Funds: Project supported by the National Natural Science Foundation of China (Grant No. 52107154).
    [1]

    Zhang Z P, Zhao J K, Zhao W, Zhong L S, Hu L X, Rao W B, Zheng M, Meng S X 2022 High Voltage 5 69Google Scholar

    [2]

    Li Z R, Zhou K, Meng P F, Yuan H, Wang Z K, Chen Y D, Li Y, Zhu G Y 2021 High Voltage 7 802Google Scholar

    [3]

    Wang X, Wang C, Wu K, Tu D M, Liu S, Peng J K 2014 IEEE Trans. Dielectr. Electr. Insul. 21 5Google Scholar

    [4]

    Liu Y, Wang X 2019 IEEE Trans. Dielectr. Electr. Insul. 26 2027Google Scholar

    [5]

    Du B X, Han T, Su J G 2014 IEEE Trans. Dielectr. Electr. Insul. 21 503Google Scholar

    [6]

    Wei Y H, Zhang J H, Li G C, Hu K, Nie Y J, Li S T, Hao C C, Lei Q Q 2023 IEEE Trans. Dielectr. Electr. Insul. 30 359Google Scholar

    [7]

    周远翔, 张征辉, 张云霄, 朱小倩, 黄猛 2022 电工技术学报 37 4474Google Scholar

    Zhou Y X, Zhang Z H, Zhang Y X, Zhu X Q, Huang M 2022 Trans. Chin. Electrotech. Soc. 37 4474Google Scholar

    [8]

    程子霞, 刘杰, 张云宵, 周远翔, 张灵, 沙彦超 2019 高电压技术 45 470Google Scholar

    Cheng Z X, Liu C, Zhang Y X, Zhou Y X, Zhang L, Sha Y C 2019 High Voltage Eng. 45 470Google Scholar

    [9]

    王若丞, 贺云逸, 康洪玮, 王昭, 金海云 2021 高电压技术 47 3181Google Scholar

    Wang R C, He Y Y, Kang H W, Wang Z, Jin H Y 2021 High Voltage Eng. 47 3181Google Scholar

    [10]

    Zhang Y Y, Deng Y K, Wei W C, Xu W C, Zha J W 2023 Cellulose 30 5321Google Scholar

    [11]

    王佩龙 2011 电线电缆 10 1Google Scholar

    Wang P L 2011 Electric Wire Cable 10 1Google Scholar

    [12]

    李国倡, 李雪静, 刘明月, 魏艳慧, 雷清泉, 周自强, 胡列翔, 王少华 2022 高压电器 58 31Google Scholar

    Li G C, Li X J, Liu M Y, Wei Y H, Lei Q Q, Zhou Z Q, Hu L X, Wang S H 2022 High Voltage Appar. 58 31Google Scholar

    [13]

    Du B X, Zhang M M, Han T, Zhu L W 2016 IEEE Trans. Dielectr. Electr. Insul. 23 104Google Scholar

    [14]

    Zuidema C, Kegerise W, Fleming R, Welker M, Boggs S 2011 IEEE Electr. Insul. Mag. 4 45Google Scholar

    [15]

    方春华, 刘浩春, 任志刚, 郭卫, 李景, 张帅, 周雨秋 2019 高压电器 55 65Google Scholar

    Fang C H, Liu H C, Ren Z G, Guo W, Li J, Zhang S, Zhou Y Q 2019 High Voltage Appar. 55 65Google Scholar

    [16]

    Barber K, Alexander G 2013 IEEE Electr. Insul. Mag. 29 27Google Scholar

    [17]

    周远翔, 张云霄, 张旭, 刘睿, 王明渊, 高胜友 2014 高电压技术 40 979Google Scholar

    Zhou Y X, Zhang Y X, Zhang X, Liu R, Wang M Y, Gao S Y 2014 High Voltage Eng. 40 979Google Scholar

    [18]

    Kashi S, Varley R, De Souza M, Al-Assafi S, Di Pietro A, De Lavigne C, Fox B 2018 Polym. Plast. Technol. Eng. 57 1687Google Scholar

    [19]

    Ito S, Hirai N, Ohki Y 2020 IEEE Trans. Dielectr. Electr. Insul. 27 722Google Scholar

    [20]

    杜伯学, 苏金刚, 徐航, 韩涛 2016 中国电机工程学报 36 6627Google Scholar

    Du B X, Su J G, Xu H, Han T 2016 Proc. CSEE 36 6627Google Scholar

    [21]

    刘昌, 惠宝军, 傅明利, 刘通, 侯帅, 王晓游 2018 高电压技术 44 518Google Scholar

    Liu C, Hui B J, Fu M L, Liu T, Hou S, Wang X Y 2018 High Voltage Eng. 44 518Google Scholar

    [22]

    王成江, 郭鸣锐, 张扬, 曾洪平, 张婧, 祝梦雅 2022 绝缘材料 55 94Google Scholar

    Wang C J, Guo M R, Zhang Y, Zeng H P, Zhang J, Zhu M Y 2022 Insul. Mater. 55 94Google Scholar

    [23]

    祝贺, 何峻旭, 郑亚松, 曹煜锋, 郭维 2023 电工技术学报 139 65Google Scholar

    Zhu H, He J X, Zheng Y S, Cao Y F, Guo W 2023 Trans. Chin. Electrotech. Soc. 139 65Google Scholar

    [24]

    Wei W C, Chen H Q, Zha J W, Zhang Y Y 2023 Front. Chem. Sci Eng. 17 991Google Scholar

  • 图 1  试样制备与老化试验流程图

    Figure 1.  Flow chart of specimen preparation and aging test.

    图 2  老化后SIR试样断面微观形貌图 (a) 0 h空白对照组; (b) 热老化720 h; (c) 热老化2160 h; (d) 力-热老化720 h; (e) 力-热老化2160 h

    Figure 2.  Microscopic morphology of the section of the aged SIR specimens: (a) Unaged 0 h; (b) thermal aging 720 h; (c) thermal aging 2160 h; (d) force-thermal aging 720 h; (e) force-thermal aging 2160 h.

    图 3  老化后SIR试样FTIR图谱 (a) 热老化SIR试样FTIR图谱变化规律; (b) 力-热老化SIR试样FTIR图谱变化规律

    Figure 3.  FTIR spectra of the aged SIR specimens: (a) Changes of FTIR spectra of heat-aged SIR samples; (b) changes of FTIR spectra of force-thermal aging SIR samples.

    图 4  老化后SIR试样相对介电常数 (a) 热老化SIR试样介电常数变化; (b)力-热老化SIR试样介电常数变化

    Figure 4.  Relative permittivity of the aged SIR specimens: (a) Changes in dielectric constant of SIR samples after thermal aging; (b) changes in the dielectric constant of SIR samples during strength-thermal aging.

    图 5  老化后SIR试样体积电阻率变化

    Figure 5.  Volume resistivity variations of the aged SIR specimens.

    图 6  老化后SIR试样击穿场强变化 (a) 热老化SIR试样击穿场强变化; (b) 力-热老化SIR试样击穿场强变化

    Figure 6.  Breakdown strength variations of the aged SIR samples: (a) Change of breakdown field strength of thermally-aged SIR samples; (b) changes in breakdown field strength of force-thermal aging SIR samples.

    图 7  老化后SIR试样导热系数 (a) 热老化SIR试样导热系数变化; (b) 力-热老化SIR试样导热系数变化

    Figure 7.  Thermal conductivity of the aged SIR specimens: (a) Changes of thermal conductivity of SIR samples during thermal aging; (b) changes in thermal conductivity of SIR samples during force-thermal aging.

    图 8  老化后SIR试样拉伸强度变化

    Figure 8.  Tensile strength variations of the aged SIR specimens.

    图 9  老化后SIR试样断裂伸长率变化

    Figure 9.  Elongation at break variations of the aged SIRspecimens.

    图 10  橡胶材料拉伸应力-应变曲线及 Yeoh 拟合曲线

    Figure 10.  Tensile stress-strain curve and Yeoh fitting curve of rubber materials.

    图 11  电缆附件最大畸变电场随时间的变化

    Figure 11.  Variation of the maximum electric field of the cable accessory with time.

    图 12  最大电场强度随老化时间变化

    Figure 12.  Variation of the maximum electric field with aging time.

    图 13  电缆附件温度场分布

    Figure 13.  Temperature field distribution of the cable accessories.

    图 14  应力锥根部温度与内外侧温差随老化时间变化

    Figure 14.  Variation of the stress cone root temperature and temperature difference with aging time.

    图 15  电缆附件界面压力分布

    Figure 15.  Interface stress distribution of the cable accessory.

    图 16  电缆附件界面压力随过盈量变化

    Figure 16.  Interface stress variation with the interference.

    图 17  应力锥根部界面压力随老化时间变化

    Figure 17.  Stress cone root interface stress variation with the aging time.

    表 1  老化后SIR试样击穿场强的αβ

    Table 1.  Breakdown strength α and β of SIR specimens after aging.

    老化时间/h热老化力-热老化
    α/(kV·mm–1)βα/(kV·mm–1)β
    025.4926.2025.4926.20
    16825.8348.9826.3917.50
    72026.4841.3326.4837.82
    144026.9523.2727.5120.89
    216025.8323.3025.4534.53
    DownLoad: CSV

    表 2  老化后SIR试样闪络电压变化

    Table 2.  Flashover voltage variations of aged SIR specimens.

    老化时间/h老化类型
    热老化/kV力-热老化/kV
    06.256.25
    1686.396.52
    7207.366.84
    14405.765.55
    21605.555.31
    DownLoad: CSV

    表 3  Yeoh 模型拟合参数

    Table 3.  Fitting parameters of Yeoh model.

    材料类型Yeoh模型拟合参数/MPa
    C10C20C30
    空白对照0.212.21×10–4–4.11×10–7
    DownLoad: CSV

    表 4  老化后SIR试样Yeoh模型参数

    Table 4.  Yeoh model parameters of the aged SIR specimens.

    老化类型 C10 C20/10–4 C30/10–6
    空白对照 0.21 2.12 –0.411
    热老化 168 h 0.23 2.24 –0.913
    热老化 720 h 0.25 0.356 –1.81
    热老化 1440 h 0.32 8.26 –5.30
    热老化 2160 h 0.25 1.45 –0.224
    力-热老化 168 h 0.22 1.63 –0.644
    力-热老化 720 h 0.26 4.59 –2.48
    力-热老化 1440 h 0.31 7.03 –4.82
    力-热老化 2160 h 0.24 1.75 –1.53
    DownLoad: CSV
    Baidu
  • [1]

    Zhang Z P, Zhao J K, Zhao W, Zhong L S, Hu L X, Rao W B, Zheng M, Meng S X 2022 High Voltage 5 69Google Scholar

    [2]

    Li Z R, Zhou K, Meng P F, Yuan H, Wang Z K, Chen Y D, Li Y, Zhu G Y 2021 High Voltage 7 802Google Scholar

    [3]

    Wang X, Wang C, Wu K, Tu D M, Liu S, Peng J K 2014 IEEE Trans. Dielectr. Electr. Insul. 21 5Google Scholar

    [4]

    Liu Y, Wang X 2019 IEEE Trans. Dielectr. Electr. Insul. 26 2027Google Scholar

    [5]

    Du B X, Han T, Su J G 2014 IEEE Trans. Dielectr. Electr. Insul. 21 503Google Scholar

    [6]

    Wei Y H, Zhang J H, Li G C, Hu K, Nie Y J, Li S T, Hao C C, Lei Q Q 2023 IEEE Trans. Dielectr. Electr. Insul. 30 359Google Scholar

    [7]

    周远翔, 张征辉, 张云霄, 朱小倩, 黄猛 2022 电工技术学报 37 4474Google Scholar

    Zhou Y X, Zhang Z H, Zhang Y X, Zhu X Q, Huang M 2022 Trans. Chin. Electrotech. Soc. 37 4474Google Scholar

    [8]

    程子霞, 刘杰, 张云宵, 周远翔, 张灵, 沙彦超 2019 高电压技术 45 470Google Scholar

    Cheng Z X, Liu C, Zhang Y X, Zhou Y X, Zhang L, Sha Y C 2019 High Voltage Eng. 45 470Google Scholar

    [9]

    王若丞, 贺云逸, 康洪玮, 王昭, 金海云 2021 高电压技术 47 3181Google Scholar

    Wang R C, He Y Y, Kang H W, Wang Z, Jin H Y 2021 High Voltage Eng. 47 3181Google Scholar

    [10]

    Zhang Y Y, Deng Y K, Wei W C, Xu W C, Zha J W 2023 Cellulose 30 5321Google Scholar

    [11]

    王佩龙 2011 电线电缆 10 1Google Scholar

    Wang P L 2011 Electric Wire Cable 10 1Google Scholar

    [12]

    李国倡, 李雪静, 刘明月, 魏艳慧, 雷清泉, 周自强, 胡列翔, 王少华 2022 高压电器 58 31Google Scholar

    Li G C, Li X J, Liu M Y, Wei Y H, Lei Q Q, Zhou Z Q, Hu L X, Wang S H 2022 High Voltage Appar. 58 31Google Scholar

    [13]

    Du B X, Zhang M M, Han T, Zhu L W 2016 IEEE Trans. Dielectr. Electr. Insul. 23 104Google Scholar

    [14]

    Zuidema C, Kegerise W, Fleming R, Welker M, Boggs S 2011 IEEE Electr. Insul. Mag. 4 45Google Scholar

    [15]

    方春华, 刘浩春, 任志刚, 郭卫, 李景, 张帅, 周雨秋 2019 高压电器 55 65Google Scholar

    Fang C H, Liu H C, Ren Z G, Guo W, Li J, Zhang S, Zhou Y Q 2019 High Voltage Appar. 55 65Google Scholar

    [16]

    Barber K, Alexander G 2013 IEEE Electr. Insul. Mag. 29 27Google Scholar

    [17]

    周远翔, 张云霄, 张旭, 刘睿, 王明渊, 高胜友 2014 高电压技术 40 979Google Scholar

    Zhou Y X, Zhang Y X, Zhang X, Liu R, Wang M Y, Gao S Y 2014 High Voltage Eng. 40 979Google Scholar

    [18]

    Kashi S, Varley R, De Souza M, Al-Assafi S, Di Pietro A, De Lavigne C, Fox B 2018 Polym. Plast. Technol. Eng. 57 1687Google Scholar

    [19]

    Ito S, Hirai N, Ohki Y 2020 IEEE Trans. Dielectr. Electr. Insul. 27 722Google Scholar

    [20]

    杜伯学, 苏金刚, 徐航, 韩涛 2016 中国电机工程学报 36 6627Google Scholar

    Du B X, Su J G, Xu H, Han T 2016 Proc. CSEE 36 6627Google Scholar

    [21]

    刘昌, 惠宝军, 傅明利, 刘通, 侯帅, 王晓游 2018 高电压技术 44 518Google Scholar

    Liu C, Hui B J, Fu M L, Liu T, Hou S, Wang X Y 2018 High Voltage Eng. 44 518Google Scholar

    [22]

    王成江, 郭鸣锐, 张扬, 曾洪平, 张婧, 祝梦雅 2022 绝缘材料 55 94Google Scholar

    Wang C J, Guo M R, Zhang Y, Zeng H P, Zhang J, Zhu M Y 2022 Insul. Mater. 55 94Google Scholar

    [23]

    祝贺, 何峻旭, 郑亚松, 曹煜锋, 郭维 2023 电工技术学报 139 65Google Scholar

    Zhu H, He J X, Zheng Y S, Cao Y F, Guo W 2023 Trans. Chin. Electrotech. Soc. 139 65Google Scholar

    [24]

    Wei W C, Chen H Q, Zha J W, Zhang Y Y 2023 Front. Chem. Sci Eng. 17 991Google Scholar

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Publishing process
  • Received Date:  28 November 2023
  • Accepted Date:  23 December 2023
  • Available Online:  23 January 2024
  • Published Online:  05 April 2024

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