基于实时计算光伏系统等效阻抗的自适应距离保护
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摘要
由于过渡电阻倾斜角θ的大小取决于光伏电站等效阻抗的值,传统保护中针对光伏等效阻抗XN的求解存在较大误差,导致距离保护整定结果存在着一定的误差。基于此,在光伏并网的系统中发生故障时,文中通过分析负荷阻抗与光伏系统输出的故障电流之间的关系,利用协方差方法推导出光伏系统实时等效阻抗值,从而可以得到更准确的故障距离,提高了保护性能。文中利用PSCAD/EMTDC搭建了光伏并网模型,并用MATLAB计算出光伏系统的等效阻抗和故障距离,结果表明文中所提出的自适应距离保护方法极大地提高了测量阻抗的准确性。
Since the results of fault component analysis show the tilt angle θ of transition resistance,which is decided totally by the equivalent impedance of PV power station in traditional protection schemes. However,the XNevaluated by the least square method in traditional protection schemes has large error,which leads to a certain error in distance protection setting result. In order to solve this problem,this paper analyzes the relationship between the load impedance and the fault current provided by PV system firstly,and then,the real-time equivalent impedance value of the PV system is derived by the principle of covariance,so as to obtain a more accurate fault distance and improve the protection performance. The model of the grid-connected PV system is built in PSCAD/EMTDC and the equivalent impedance and fault distance of the PV is calculated in the MATLAB. The simulative results show that this proposed method can improve the accuracy of the measured impedance greatly.
Since the results of fault component analysis show the tilt angle θ of transition resistance,which is decided totally by the equivalent impedance of PV power station in traditional protection schemes. However,the XNevaluated by the least square method in traditional protection schemes has large error,which leads to a certain error in distance protection setting result. In order to solve this problem,this paper analyzes the relationship between the load impedance and the fault current provided by PV system firstly,and then,the real-time equivalent impedance value of the PV system is derived by the principle of covariance,so as to obtain a more accurate fault distance and improve the protection performance. The model of the grid-connected PV system is built in PSCAD/EMTDC and the equivalent impedance and fault distance of the PV is calculated in the MATLAB. The simulative results show that this proposed method can improve the accuracy of the measured impedance greatly.
引文
[1]丁明,王伟胜,王秀丽,等.大规模光伏发电对电力系统影响综述[J].中国电机工程学报,2014,34(1):2-14.Ding Ming,Wang Weisheng,Wang Xiuli.A Review on the Effect of Large-scale PV Generation on Power Systems[J].Proceedings of the CSEE,2014,31(1):2-14.
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[3]杨明,周林,张东霞,等.考虑电网阻抗影响的大型光伏电站并网稳定性分析[J].电工技术学报,2013,28(9):214-223.Yang Ming,Zhou Lin,Zhang Dongxia,et al.Stability,Analysis of Large-Scale Photovoltaic Power Plants for the Effect of Grid Impedance[J].Transactions of China Electrotechnical Society,2013,28(9):214-223.
[4]周林,张密,居秀丽,等.电网阻抗对大型并网光伏系统稳定性影响分析[J].中国电机工程学报,2013,33(34):34-41.Zhou Lin,Zhang Mi,Ju Xiuli,et al.Stability analysis of large-scale photovoltaic plants due to grid impedances[J].Proceedings of the CSEE,2013,33(34):34-41.
[5]张前进,周林,解宝.针对电网阻抗的大型光伏并网系统稳定性分析与提高策略[J].电力系统自动化,2017,41(21):127-132.Zhan Qianjin,Zhou Lin,Xie Bao.Analysis and improvement strategy of large-scale grid-connected Photovoltaic system considering grid impedance[J].Automation of Electric Power Systems,2017,41(21):127-132.
[6]周林,张密,杨明,等.考虑电网阻抗影响的LCL型并网逆变器控制策略[J].太阳能学报,2015,36(9):2146-2151.Zhou Lin,Zhang Mi,Yang Ming,et al.Controller design of three-phase inverter with LCL filter considering the grid impedance[J].Acta energiae solaris sinica,2015,36(9):2146-2151.
[7]陈新,张旸,王赟程.基于阻抗分析法研究光伏并网逆变器与电网的动态交互影响[J].中国电机工程学报,2014,34(27):4559-4567.Chen Xin,Zhang Yang,Wang Yuncheng.A study of dynamic Interaction between PV Grid-connected Inverters and Grid Based on the Impedance Analysis Method[J].Proceedings of the CSEE,2014,34(27):4559-4567.
[8]陈权,李令冬,王群京,等.光伏发电并网系统的仿真建模及对配电网电压稳定性影响[J].电工技术学报,2013,28(3):241-247.Chen Quan,Li Lingdong,Wang Qunjing,et al.Simulation Model of Photovoltaic Generation Grid-Connected System and Its Impacts on Voltage Stability in Distribution Grid[J].Transactions of China Electrotechnical Society,2013,28(3):241-247.
[9]竺庆茸,李晗,等.含光伏的主动配电网非对称故障条件下对并网点电压影响的研究[J].电测与仪表,2019,56(4):101-106.Zhu Qingrong,Li Han,et al.Research on active distribution network and network effects on non symmetrical voltage fault conditions with PV[J].Electrical Measurement&Instrumentation,2019,56(4):101-106.
[10]沈冰,何奔腾.基于阻抗轨迹估计的自适应相间距离继电器[J].中国电机工程学报,2007,27(31):71-76.Shen Bing,He Benteng.A novel adaptive distance protection based on impedance locus estimation[J].Proceedings of the CSEE,2007,27(31):71-76.
[11]张华中,朱玲玲,张洪涛,等.基于估算对侧电源阻抗的自适应距离保护算法[J].电力系统自动化,2011,35(12):70-75.Zhang Huazhong,Zhu Lingling,Zhang Hongtao,et al.Adaptive Distance Protection Algorithm Based on Estimation of contralateral Source Impedance[J].Automation of Electric Power System,2011,35(12):70-75.
[12]马静,马伟,闫新,等.基于阻抗复数平面的自适应距离保护方案[J].电网技术,2016,40(1):290-296.Ma Jing,Ma Wei,Yan Xin,et al.Impedance Complex Plane Based A-daptive Distance Protection Scheme[J].Power System Technology,2016,40(1):290-296.
[13]张尧,晁勤,李育强,等.基于过渡电阻倾斜角的光伏并网自适应距离保护[J].电力自动化设备,2016,36(1):30-34.Zhang Yao,Chao Qin,Li Yuqiang,et al.Adaptive distance protection based on tilt angle of transition resistance for grid-connected PV station[J].Electric Power Automation Equipment,2016,36(1):30-34.
[2]李斌,袁越.光伏并网发电对保护及重合闸的影响与对策[J].电力自动化设备,2013,33(4):12-17.Li Bin,Yuan Yue.Impact of grid-connected photovoltaic power generation on protection and reclose,and its countermeasures[J].Electric Power Automation Equipment,2013,33(4):12-17.
[3]杨明,周林,张东霞,等.考虑电网阻抗影响的大型光伏电站并网稳定性分析[J].电工技术学报,2013,28(9):214-223.Yang Ming,Zhou Lin,Zhang Dongxia,et al.Stability,Analysis of Large-Scale Photovoltaic Power Plants for the Effect of Grid Impedance[J].Transactions of China Electrotechnical Society,2013,28(9):214-223.
[4]周林,张密,居秀丽,等.电网阻抗对大型并网光伏系统稳定性影响分析[J].中国电机工程学报,2013,33(34):34-41.Zhou Lin,Zhang Mi,Ju Xiuli,et al.Stability analysis of large-scale photovoltaic plants due to grid impedances[J].Proceedings of the CSEE,2013,33(34):34-41.
[5]张前进,周林,解宝.针对电网阻抗的大型光伏并网系统稳定性分析与提高策略[J].电力系统自动化,2017,41(21):127-132.Zhan Qianjin,Zhou Lin,Xie Bao.Analysis and improvement strategy of large-scale grid-connected Photovoltaic system considering grid impedance[J].Automation of Electric Power Systems,2017,41(21):127-132.
[6]周林,张密,杨明,等.考虑电网阻抗影响的LCL型并网逆变器控制策略[J].太阳能学报,2015,36(9):2146-2151.Zhou Lin,Zhang Mi,Yang Ming,et al.Controller design of three-phase inverter with LCL filter considering the grid impedance[J].Acta energiae solaris sinica,2015,36(9):2146-2151.
[7]陈新,张旸,王赟程.基于阻抗分析法研究光伏并网逆变器与电网的动态交互影响[J].中国电机工程学报,2014,34(27):4559-4567.Chen Xin,Zhang Yang,Wang Yuncheng.A study of dynamic Interaction between PV Grid-connected Inverters and Grid Based on the Impedance Analysis Method[J].Proceedings of the CSEE,2014,34(27):4559-4567.
[8]陈权,李令冬,王群京,等.光伏发电并网系统的仿真建模及对配电网电压稳定性影响[J].电工技术学报,2013,28(3):241-247.Chen Quan,Li Lingdong,Wang Qunjing,et al.Simulation Model of Photovoltaic Generation Grid-Connected System and Its Impacts on Voltage Stability in Distribution Grid[J].Transactions of China Electrotechnical Society,2013,28(3):241-247.
[9]竺庆茸,李晗,等.含光伏的主动配电网非对称故障条件下对并网点电压影响的研究[J].电测与仪表,2019,56(4):101-106.Zhu Qingrong,Li Han,et al.Research on active distribution network and network effects on non symmetrical voltage fault conditions with PV[J].Electrical Measurement&Instrumentation,2019,56(4):101-106.
[10]沈冰,何奔腾.基于阻抗轨迹估计的自适应相间距离继电器[J].中国电机工程学报,2007,27(31):71-76.Shen Bing,He Benteng.A novel adaptive distance protection based on impedance locus estimation[J].Proceedings of the CSEE,2007,27(31):71-76.
[11]张华中,朱玲玲,张洪涛,等.基于估算对侧电源阻抗的自适应距离保护算法[J].电力系统自动化,2011,35(12):70-75.Zhang Huazhong,Zhu Lingling,Zhang Hongtao,et al.Adaptive Distance Protection Algorithm Based on Estimation of contralateral Source Impedance[J].Automation of Electric Power System,2011,35(12):70-75.
[12]马静,马伟,闫新,等.基于阻抗复数平面的自适应距离保护方案[J].电网技术,2016,40(1):290-296.Ma Jing,Ma Wei,Yan Xin,et al.Impedance Complex Plane Based A-daptive Distance Protection Scheme[J].Power System Technology,2016,40(1):290-296.
[13]张尧,晁勤,李育强,等.基于过渡电阻倾斜角的光伏并网自适应距离保护[J].电力自动化设备,2016,36(1):30-34.Zhang Yao,Chao Qin,Li Yuqiang,et al.Adaptive distance protection based on tilt angle of transition resistance for grid-connected PV station[J].Electric Power Automation Equipment,2016,36(1):30-34.