大规模光伏并网系统谐振机理及稳定性分析
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摘要
在弱电网下或者装机容量增加时,大规模光伏并网系统易引发谐波谐振,危及光伏电站的正常稳定运行。针对上述问题,以大规模光伏并网系统为研究对象,分别从系统阻尼、闭环控制等角度揭示了大型光伏电站和电网之间的谐振机理。研究结果表明:LCL滤波器自身的有源阻尼策略并不会导致大规模光伏并网系统引发谐振,引发谐振的关键因素在于并网逆变器自身的稳定裕度。电网阻抗、装机容量、系统参数设计、控制策略等因素的综合效应可以使并网逆变器在某一特定条件下运行到临界稳定状态附近而引发谐振,谐振将导致入网电流在相应谐振频段产生大量谐波。如果稳定裕度进一步减小,系统将逐步由谐振状态过渡到振荡、发散等不稳定状态。仿真与实验结果验证了理论分析的正确性。
Under weak grid conditions or when the capacities of photovoltaic(PV) power plants increase, a large-scale grid-connected PV system will easily cause harmonic resonance, which endangers the normal and stable operation of PV power plants. In consideration of the above problems, the large scale grid-connected PV system is taken as the research object in this paper, and the resonance mechanism between the large scale PV power plant and grid is revealed from aspects including system damping and closed loop control. Theoretical analysis indicates that the active damping strategy for the LCC filter itself will not cause harmonic resonance to the system, and the key factor is the stability margin of the grid-connected inverter. The combined effect of factors, such as grid impedance, plant capacity, design of system parameters, and control strategy, can make the grid-connected inverter run in a critical stable state under a specific condition and further cause harmonic resonance, producing a large amount of harmonics in the corresponding resonance frequency band. With further shrinking of the stability margin, the system will gradually transit from the resonance state to the unstable states of oscillation and divergence. Simulation and experimental results validated the theoretical analysis.
Under weak grid conditions or when the capacities of photovoltaic(PV) power plants increase, a large-scale grid-connected PV system will easily cause harmonic resonance, which endangers the normal and stable operation of PV power plants. In consideration of the above problems, the large scale grid-connected PV system is taken as the research object in this paper, and the resonance mechanism between the large scale PV power plant and grid is revealed from aspects including system damping and closed loop control. Theoretical analysis indicates that the active damping strategy for the LCC filter itself will not cause harmonic resonance to the system, and the key factor is the stability margin of the grid-connected inverter. The combined effect of factors, such as grid impedance, plant capacity, design of system parameters, and control strategy, can make the grid-connected inverter run in a critical stable state under a specific condition and further cause harmonic resonance, producing a large amount of harmonics in the corresponding resonance frequency band. With further shrinking of the stability margin, the system will gradually transit from the resonance state to the unstable states of oscillation and divergence. Simulation and experimental results validated the theoretical analysis.
引文
[1]赵争鸣,雷一,贺凡波,等.大容量并网光伏电站技术综述[J].电力系统自动化,2011,35(12):101-107.Zhao Zhengming,Lei Yi,He Fanbo,et al.Overview of large-scale grid-connected photovoltaic power plants[J].Automation of Electric Power Systems,2011,35(12):101-107(in Chinese).
[2]黄伟,董旭柱,雷金勇,等.大容量分布式光伏并网对配电网综合影响分析[J].电力系统及其自动化学报,2016,28(11):44-49.Huang Wei,Dong Xuzhu,Lei Jinyong,et al.Integrated impact of large-capacity distributed photovoltaic on power grid[J].Proceedings of the CSU-EPSA,2016,28(11):44-49(in Chinese).
[3]李自鹏,陆畅,沈攀,等.光伏电站接入对电能质量的影响及其对策措施研究[J].电源学报,2015,13(5):1-9.Li Zipeng,Lu Chang,Shen Pan,et al.Research on effect of grid-connected PV station on power quality and countermeasures[J].Journal of Power Supply,2015,13(5):1-9(in Chinese).
[4]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):1-14.Ding Ming,Wang Weisheng,Wang Xiuli,et al.A review on the effect of large-scale PV generation on power systems[J].Proceedings of the CSEE,2014,34(1):1-14(in Chinese).
[5]张笠君,汪飞,郭慧,等.微电网谐振建模与抑制方法的研究现状[J].电源学报,2016,14(2):52-62.Zhang Lijun,Wang Fei,Guo Hui,et al.Research status of resonance modeling and suppressionin in microgrid[J].Journal of Power Supply,2016,14(2):52-62(in Chinese).
[6]谢宁,罗安,马伏军,等.大型光伏电站与电网谐波交互影响[J].中国电机工程学报,2013,33(34):9-16.Xie Ning,Luo An,Ma Fujun,et al.Harmonic interaction between large-scale photovoltaic power stations and grid[J].Proceedings of the CSEE,2013,33(34):9-16(in Chinese).
[7]Liserre M,Teodorescu R,Blaabjerg F.Stability of photovoltaic and wind turbine grid-connected inverters for a large set of grid impedance values[J].IEEE Transactions on Power Electronics,2006,21(1):263-272.
[8]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(in Chinese).
[9]Agorreta J L,Borrega M,Lopez J,et al.Modeling and control of N-paralleled grid-connected inverters with LCL filter coupled due to grid impedance in PV plants[J].IEEE Transactions on Power Electronics,2011,26(3):770-785.
[10]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].Transaction of China Electrotechnical Society,2013,28(9):214-223(in Chinese).
[11]许德志,汪飞,毛华龙,等.多并网逆变器与电网的谐波交互建模与分析[J].中国电机工程学报,2013,33(12):64-71.Xu Dezhi,Wang Fei,Mao Hualong,et al.Modeling and analysis of harmonic interaction between multiple grid-connected inverters and the utility grid[J].Proceedings of the CSEE,2013,33(12):64-71(in Chinese).
[12]He Jinwei,Li Yunwei,Bosnjak D,et al.Investigation and active damping of multiple resonances in a parallel-inverter based microgrid[J].IEEE Transactions on Power Electronics,2013,28(1):234-246.
[13]胡伟,孙建军,马谦,等.多逆变器并网系统谐振特性分析[J].电力自动化设备,2014,34(7):93-98.Hu Wei,Sun Jianjun,Ma Qian,et al.Resonant characteristics of multi-inverter grid-connection system[J].Electric Power Automation Equipment,2014,34(7):93-98(in Chinese).
[14]孙振奥,杨子龙,王一波,等.光伏并网逆变器集群的谐振原因及其抑制方法[J].中国电机工程学报,2015,35(2):418-425.Sun Zhenao,Yang Zilong,Wang Yibo,et al.The cause analysis and suppression method of resonances in clustered grid-connected photovoltaic inverters[J].Proceedings of the CSEE,2015,35(2):418-425(in Chinese).
[15]张兴,余畅舟,刘芳,等.光伏并网多逆变器并联建模及谐振分析[J].中国电机工程学报,2014,34(3):336-345.Zhang Xing,Yu Changzhou,Liu Fang,et al.Modeling and resonance analysis of multi-paralleled grid-tied inverters in PV systems[J].Proceedings of the CSEE,2014,34(3):336-345(in Chinese).
[16]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(in Chinese).
[2]黄伟,董旭柱,雷金勇,等.大容量分布式光伏并网对配电网综合影响分析[J].电力系统及其自动化学报,2016,28(11):44-49.Huang Wei,Dong Xuzhu,Lei Jinyong,et al.Integrated impact of large-capacity distributed photovoltaic on power grid[J].Proceedings of the CSU-EPSA,2016,28(11):44-49(in Chinese).
[3]李自鹏,陆畅,沈攀,等.光伏电站接入对电能质量的影响及其对策措施研究[J].电源学报,2015,13(5):1-9.Li Zipeng,Lu Chang,Shen Pan,et al.Research on effect of grid-connected PV station on power quality and countermeasures[J].Journal of Power Supply,2015,13(5):1-9(in Chinese).
[4]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):1-14.Ding Ming,Wang Weisheng,Wang Xiuli,et al.A review on the effect of large-scale PV generation on power systems[J].Proceedings of the CSEE,2014,34(1):1-14(in Chinese).
[5]张笠君,汪飞,郭慧,等.微电网谐振建模与抑制方法的研究现状[J].电源学报,2016,14(2):52-62.Zhang Lijun,Wang Fei,Guo Hui,et al.Research status of resonance modeling and suppressionin in microgrid[J].Journal of Power Supply,2016,14(2):52-62(in Chinese).
[6]谢宁,罗安,马伏军,等.大型光伏电站与电网谐波交互影响[J].中国电机工程学报,2013,33(34):9-16.Xie Ning,Luo An,Ma Fujun,et al.Harmonic interaction between large-scale photovoltaic power stations and grid[J].Proceedings of the CSEE,2013,33(34):9-16(in Chinese).
[7]Liserre M,Teodorescu R,Blaabjerg F.Stability of photovoltaic and wind turbine grid-connected inverters for a large set of grid impedance values[J].IEEE Transactions on Power Electronics,2006,21(1):263-272.
[8]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(in Chinese).
[9]Agorreta J L,Borrega M,Lopez J,et al.Modeling and control of N-paralleled grid-connected inverters with LCL filter coupled due to grid impedance in PV plants[J].IEEE Transactions on Power Electronics,2011,26(3):770-785.
[10]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].Transaction of China Electrotechnical Society,2013,28(9):214-223(in Chinese).
[11]许德志,汪飞,毛华龙,等.多并网逆变器与电网的谐波交互建模与分析[J].中国电机工程学报,2013,33(12):64-71.Xu Dezhi,Wang Fei,Mao Hualong,et al.Modeling and analysis of harmonic interaction between multiple grid-connected inverters and the utility grid[J].Proceedings of the CSEE,2013,33(12):64-71(in Chinese).
[12]He Jinwei,Li Yunwei,Bosnjak D,et al.Investigation and active damping of multiple resonances in a parallel-inverter based microgrid[J].IEEE Transactions on Power Electronics,2013,28(1):234-246.
[13]胡伟,孙建军,马谦,等.多逆变器并网系统谐振特性分析[J].电力自动化设备,2014,34(7):93-98.Hu Wei,Sun Jianjun,Ma Qian,et al.Resonant characteristics of multi-inverter grid-connection system[J].Electric Power Automation Equipment,2014,34(7):93-98(in Chinese).
[14]孙振奥,杨子龙,王一波,等.光伏并网逆变器集群的谐振原因及其抑制方法[J].中国电机工程学报,2015,35(2):418-425.Sun Zhenao,Yang Zilong,Wang Yibo,et al.The cause analysis and suppression method of resonances in clustered grid-connected photovoltaic inverters[J].Proceedings of the CSEE,2015,35(2):418-425(in Chinese).
[15]张兴,余畅舟,刘芳,等.光伏并网多逆变器并联建模及谐振分析[J].中国电机工程学报,2014,34(3):336-345.Zhang Xing,Yu Changzhou,Liu Fang,et al.Modeling and resonance analysis of multi-paralleled grid-tied inverters in PV systems[J].Proceedings of the CSEE,2014,34(3):336-345(in Chinese).
[16]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(in Chinese).