杆塔冲击接地阻抗的有限元分析
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摘要
电力系统的运行经验表明,大多数输电线路事故是由雷击输电线路或杆塔引起跳闸所致。经由输电线路杆塔接地体流入大地的雷电流可达数十甚至上百千安,此时接地体周围土壤出现非线性火花放电现象。为了提高输电线路耐雷水平,降低雷击故障率,考虑实际工况下土壤非线性火花放电效应进行杆塔接地体参数计算对降低杆塔接地电阻的优化设计至关重要。文中基于电磁场理论,考虑土壤中的火花效应特性,采用有限元数值计算方法建立了仿真模型,实现了高幅值冲击接地电流下接地体入地散流过程的模拟。研究表明,该仿真模型与试验结果偏差小于10%;随着雷电流幅值的升高,冲击接地阻抗降低且有饱和趋势;接地体阻抗随雷电流频率增大而增大。
Operating experiences of power system shows that most of accidents occurred at transmission lines were caused by lightning. The lightning current flowing through tower grounding electrode can be dozens or even hundreds thousands amps, which leads to non-linear spark effect in the soil around the electrode. In order to improve the lightning prevention of transmission lines, it is necessary to take the non-linear spark effect into consideration in the simulation of tower grounding electrode, which is essential for the design. In this article, a new model based on Maxwell differential equations is built and finite element method is used to calculate the model by COMSOL-multiphysics software. Also, the non-linear sparking discharge phenomenon in soil is considered. With this model, a grounding electrode simulation with a high amplitude can be done. The results show that the deviation between the simulation model and the experiment result is less than 10%. With the increase of the amplitude of the lightning current, grounding impedance decline and will be saturated. The grounding impedance increases with the increase of the lightning frequency.
Operating experiences of power system shows that most of accidents occurred at transmission lines were caused by lightning. The lightning current flowing through tower grounding electrode can be dozens or even hundreds thousands amps, which leads to non-linear spark effect in the soil around the electrode. In order to improve the lightning prevention of transmission lines, it is necessary to take the non-linear spark effect into consideration in the simulation of tower grounding electrode, which is essential for the design. In this article, a new model based on Maxwell differential equations is built and finite element method is used to calculate the model by COMSOL-multiphysics software. Also, the non-linear sparking discharge phenomenon in soil is considered. With this model, a grounding electrode simulation with a high amplitude can be done. The results show that the deviation between the simulation model and the experiment result is less than 10%. With the increase of the amplitude of the lightning current, grounding impedance decline and will be saturated. The grounding impedance increases with the increase of the lightning frequency.
引文
[1]何金良,曾嵘,电力系统接地技术[M].北京:科学出版社,2007.HE Jinliang, ZENG Rong. Grounding technology of power system[M]. Beijing:Science Press, 2007.
[2]关根志.高电压工程基础[M].北京:中国电力出版社,2003.GUAN Genzhi. High voltage engineering fundamental[M].Beijing:China Electric Power Press, 2003.
[3]谢云云,薛禹胜,王昊昊,等.电网雷击故障概率的时空在线预警[J].电力系统自动化,2013,37(17):44-51.XIE Yunyun, XUE Yusheng, WANG Haohao, et al. Spacetime early'warning of power grid fault probability by lightning[J]. Automation of Electric:Power Systems, 2013, 37(17):44-51.
[4]向东.降低贵州南中牵110 kV输电线路杆塔接地电阻的方法研究[D].重庆:重庆大学,2004.XIANG Dong. Study on the method of reducing the grounding resistance of 110 kV transmission line tower insouth guizhou[D]. Chongqing:Chongqing University, 2004.
[5]李超.山岩地区利用杆塔基础降低杆塔接地电阻的方法研究[D].长沙:长沙理工大学,2008.LI Chao. Study on the method of reducing grounding resistance of tower by using tower foundation in mountainous area[D]. Changsha:Changsha University of Science&Technology, 2008.
[6]邓长征,周文俊,魏绍东,等.电感效应与火花效应对接地体及其周围土壤雷电冲击特性的影响分析[J].高电压技术,2015,41(1):56-62.DENG Changzheng, ZHOU Wenjun, WEI Shaodong, et al.Influence analysis of inductance effect and spark effect on lightning impulse characteristics of grounding conductors and its ambient soil[J]. High Voltage Engineering, 2015,41(1):56-62.
[7]程杨.杆塔接地装置的仿真计算与测量研究[D].武汉:华中科技大学,2012.CHENG Yang. Simulation and measurement of tower grounding device[D]. Wuhan:Huazhong University of Science and Technology, 2012.
[8] HEIMBACH M,GRCEV L D. Grounding system analysisin transients program applying electromagnetic filedapproach[J]. IEEE Transactions on Power Delivery, 1997, 12(1):186-193.
[9] GRCEV L D. Comeputer analysis of transient voltages in large grounding systems[J]. IEEE Transaction on Power Delivery, 1996,11(2):815-823.
[10] NEKHOUL B, GUERIN C, LABIE P, et al. A finite elementmethod for calculating the electromagnetic fieldsgenerated by substation grounding systems[J]. IEEE Transactions on Magnetics, 1995, 31(3):2150-2153.
[11] HABJANIC A,TRLEP M. The simulation of the soil ionization phenomenon around the grounding system by the finite element method[J]. IEEE Transactions on Magnetic, 2006,42(4):867-870.
[12] GERI A, VECA G M, GARBAGNATI E, et al. Non-linear behaviour of ground electrodes under lightning surge currents:computer modelling and comparison with experimental results[J]. IEEE Transactions on Magnetic, 1992,28(2):1442-1445
[13]杨琳,吴广宁,曹晓斌.变电站接地网暂态建模方法[J].电网技术,2012,36(5):161-165.YANG Lin, WU Guangning,CAO Xiaobin. A transient modeling approach of substation grounding grid[J]. Power System Technology, 2012, 36(5):161-165.
[14] TANABE K, Novel method for analyzing dynamic behavior of grounding systems based on the finite-difference time-domain method[J]. IEEE Power Engineering Reviwe, 2001,21(9):55-57.
[15]李景丽,袁涛,杨庆,等.考虑土壤非线性的接地网有限元分析[J].高电压技术,2011,37(1):249-256.LI Jingli, YUAN Tao,YANG Qing,et al. Analysis of grounding grid by finite element method in consideration of soil nonlinear characteristics[J]. High Voltage Engineering, 2011,37(1):249-256.
[16]齐磊,崔翔,李慧奇.变电站接地网的频域有限元方法[J].中国电机工程学报,2007,27(6):62-66.QI Lei, CUI Xiang, LI Huiqi. Finite element modeling of the substation grounding grids in frequency domain[J]. Proceedings of the CSEE, 2007, 27(6):62-66.
[17]甘艳,阮江军,陈允平,等.考虑自身电阻率的地网接地性能分析计算[J].高电压技术,2002,28(10):13-15.GAN Yan, RUAN Jiangjun, CHEN Yunping, et al. Calculation of performance of grounding grid under the consideration of the resistivity of grounding[J]. High Voltage Engineering, 2002, 28(10):13-15.
[18]冯慈璋,马西奎.工程电磁场导论[M].北京:高等教育出版社,2000.FENG Cizhang, MA Xikui. Introduction of engineering electro-magneticfields[M].Beijing:Higher Education Press,2000.
[19] VISACRO S, SOARES A, HEM:A model for simulation of lightning-related engineering problems[J]. IEEE Transactions on Power Delivery, 2005,20(2):1026-1028.
[20]朱时阳,袁涛,朱彬.分层土壤中接地装置冲击散流特性的有限元分析模型[J].电网技术,2014,38(8):2304-2309.ZHU Shiyang, YUAN Tao,ZHU Bin. Finite element model of impulse dispersing characteristics of grounding equipment in layered soil[J]. Power System Technology, 2014,38(8):2304-2309.
[21]司马文霞,李晓丽,袁涛.考虑土壤非线性特性的接地网冲击特性分析方法[J].中国电机工程学报,2009,29(16):127-132.SIMA Wenxia,LI Xiaoli, YUAN Tao. Analysis of grounding grid impulse characteristics in frequency domain in consideration of soil non-linear characteristic[J]. Proceedings of the CSEE, 2009, 29(16):127-132.
[22] ZENG R, GONG X, HE J,et al. Lightning impulse performances of grounding grids for substations considering soil ionization[J]. IEEE Transactions on Power Delivery, 2008,23(2):667-675.
[2]关根志.高电压工程基础[M].北京:中国电力出版社,2003.GUAN Genzhi. High voltage engineering fundamental[M].Beijing:China Electric Power Press, 2003.
[3]谢云云,薛禹胜,王昊昊,等.电网雷击故障概率的时空在线预警[J].电力系统自动化,2013,37(17):44-51.XIE Yunyun, XUE Yusheng, WANG Haohao, et al. Spacetime early'warning of power grid fault probability by lightning[J]. Automation of Electric:Power Systems, 2013, 37(17):44-51.
[4]向东.降低贵州南中牵110 kV输电线路杆塔接地电阻的方法研究[D].重庆:重庆大学,2004.XIANG Dong. Study on the method of reducing the grounding resistance of 110 kV transmission line tower insouth guizhou[D]. Chongqing:Chongqing University, 2004.
[5]李超.山岩地区利用杆塔基础降低杆塔接地电阻的方法研究[D].长沙:长沙理工大学,2008.LI Chao. Study on the method of reducing grounding resistance of tower by using tower foundation in mountainous area[D]. Changsha:Changsha University of Science&Technology, 2008.
[6]邓长征,周文俊,魏绍东,等.电感效应与火花效应对接地体及其周围土壤雷电冲击特性的影响分析[J].高电压技术,2015,41(1):56-62.DENG Changzheng, ZHOU Wenjun, WEI Shaodong, et al.Influence analysis of inductance effect and spark effect on lightning impulse characteristics of grounding conductors and its ambient soil[J]. High Voltage Engineering, 2015,41(1):56-62.
[7]程杨.杆塔接地装置的仿真计算与测量研究[D].武汉:华中科技大学,2012.CHENG Yang. Simulation and measurement of tower grounding device[D]. Wuhan:Huazhong University of Science and Technology, 2012.
[8] HEIMBACH M,GRCEV L D. Grounding system analysisin transients program applying electromagnetic filedapproach[J]. IEEE Transactions on Power Delivery, 1997, 12(1):186-193.
[9] GRCEV L D. Comeputer analysis of transient voltages in large grounding systems[J]. IEEE Transaction on Power Delivery, 1996,11(2):815-823.
[10] NEKHOUL B, GUERIN C, LABIE P, et al. A finite elementmethod for calculating the electromagnetic fieldsgenerated by substation grounding systems[J]. IEEE Transactions on Magnetics, 1995, 31(3):2150-2153.
[11] HABJANIC A,TRLEP M. The simulation of the soil ionization phenomenon around the grounding system by the finite element method[J]. IEEE Transactions on Magnetic, 2006,42(4):867-870.
[12] GERI A, VECA G M, GARBAGNATI E, et al. Non-linear behaviour of ground electrodes under lightning surge currents:computer modelling and comparison with experimental results[J]. IEEE Transactions on Magnetic, 1992,28(2):1442-1445
[13]杨琳,吴广宁,曹晓斌.变电站接地网暂态建模方法[J].电网技术,2012,36(5):161-165.YANG Lin, WU Guangning,CAO Xiaobin. A transient modeling approach of substation grounding grid[J]. Power System Technology, 2012, 36(5):161-165.
[14] TANABE K, Novel method for analyzing dynamic behavior of grounding systems based on the finite-difference time-domain method[J]. IEEE Power Engineering Reviwe, 2001,21(9):55-57.
[15]李景丽,袁涛,杨庆,等.考虑土壤非线性的接地网有限元分析[J].高电压技术,2011,37(1):249-256.LI Jingli, YUAN Tao,YANG Qing,et al. Analysis of grounding grid by finite element method in consideration of soil nonlinear characteristics[J]. High Voltage Engineering, 2011,37(1):249-256.
[16]齐磊,崔翔,李慧奇.变电站接地网的频域有限元方法[J].中国电机工程学报,2007,27(6):62-66.QI Lei, CUI Xiang, LI Huiqi. Finite element modeling of the substation grounding grids in frequency domain[J]. Proceedings of the CSEE, 2007, 27(6):62-66.
[17]甘艳,阮江军,陈允平,等.考虑自身电阻率的地网接地性能分析计算[J].高电压技术,2002,28(10):13-15.GAN Yan, RUAN Jiangjun, CHEN Yunping, et al. Calculation of performance of grounding grid under the consideration of the resistivity of grounding[J]. High Voltage Engineering, 2002, 28(10):13-15.
[18]冯慈璋,马西奎.工程电磁场导论[M].北京:高等教育出版社,2000.FENG Cizhang, MA Xikui. Introduction of engineering electro-magneticfields[M].Beijing:Higher Education Press,2000.
[19] VISACRO S, SOARES A, HEM:A model for simulation of lightning-related engineering problems[J]. IEEE Transactions on Power Delivery, 2005,20(2):1026-1028.
[20]朱时阳,袁涛,朱彬.分层土壤中接地装置冲击散流特性的有限元分析模型[J].电网技术,2014,38(8):2304-2309.ZHU Shiyang, YUAN Tao,ZHU Bin. Finite element model of impulse dispersing characteristics of grounding equipment in layered soil[J]. Power System Technology, 2014,38(8):2304-2309.
[21]司马文霞,李晓丽,袁涛.考虑土壤非线性特性的接地网冲击特性分析方法[J].中国电机工程学报,2009,29(16):127-132.SIMA Wenxia,LI Xiaoli, YUAN Tao. Analysis of grounding grid impulse characteristics in frequency domain in consideration of soil non-linear characteristic[J]. Proceedings of the CSEE, 2009, 29(16):127-132.
[22] ZENG R, GONG X, HE J,et al. Lightning impulse performances of grounding grids for substations considering soil ionization[J]. IEEE Transactions on Power Delivery, 2008,23(2):667-675.