多馈入交直流系统电压稳定分析
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摘要
随着社会的进步和经济发展,对电力的需求越来越大。我国能源与生产力发展不均衡的基本国情,决定了能源资源大规模、大范围优化配置势在必行。直流输电以其在大容量、长距离输电上的优势得到了快速的发展。随着西电东送和全国联网的发展,在我国的南方电网和华东电网已经出现了多馈入交直流系统,对多馈入交直流系统进行更深入的安全评价,对系统的安全稳定运行具有十分重要的意义。
本文介绍了直流输电的优缺点以及国内外直流工程的发展概况。通过查阅国内外大量的文献资料,重点论述了交直流输电系统电压稳定问题的研究现状,特别是针对多馈入交直流输电系统的电压稳定问题进行深入的研究。交流和直流的相互作用在很大程度上取决于交流系统与所连直流系统容量的相对大小,即短路比指标。基于短路比的电压稳定分析广泛地应用在学术界和工程界中,它为系统的规划提供了一个参考依据。针对传统短路比无法考虑多馈入交直流系统中各直流的相互影响,只能适用单馈入交直流系统,因此提出新的多馈入短路比定义迫在眉睫。目前学术界对多馈入短路比的定义没有统一的标准,本文追本溯源,通过理论分析推导了两种多馈入短路比的计算方法,统一了目前学术界已有的对多馈入短路比的定义。在此基础上,本文推导了多馈入临界短路比和临界有效短路比的函数关系式,提出了划分多馈入交直流系统强弱的标准。针对弱交流系统,从无功功率的角度提出改善系统运行的措施。通过分析多馈入最大直流功率与多馈入电压稳定因子间的关系,证明了多馈入短路比用于多馈入交直流系统电压稳定分析的可行性。最后,本文通过多馈入短路比对多馈入交直流系统的运行进行评估,通过理论和算例仿真研究了多馈入弱交流受端的动态过电压、谐波谐振、电压稳定等问题,证明了利用多馈入短路比指标判别多馈入交流系统强弱的有效性,对规划有着重要的指导意义。
With the development of society and economy, it has a much higher demand on power. The distribution of energy source and the unbalance of regional economic development make optimizing energy distributing configuration necessary. Owing to the fact that High Voltage Direct Current transmission has advantages in large capacity and long distance, HVDC has developed rapidly. As electricity transmission from West to East and nationwide power network interconnection has been developed, multi-infeed HVDC (MIDC) connected to one AC system has emerged in South China Power Grid and East China Power Gird. It has important meaning of safety evaluating for MIDC system.
The thesis introduces advantages and disadvantages of HVDC transmission, and makes a survey of HVDC transmission projects both in domestic and abroad. By referring to lots of documents, the thesis classifies and analyzes methods of voltage stability for AC/DC system, especially for multi-infeed HVDC system. The interaction of AC and DC depends on the capacity of DC compared with AC, namely short current ratio (SCR). The voltage stability analysis based on SCR is widely used in academic circles and engineering circles. It can provide reference basis for system planning. Because traditional SCR can't take interaction of DCs into account, it is extremely urgent to propose a new evaluating way for MIDC system. At present, there are not unified standards for multi-infeed SCR. The thesis defines multi-infeed SCR by formula derivation and theoretical analysis, and proves two calculation methods . Further more, the multi-infeed critical SCR is derived, and the thesis proposes the judgment standard of weak MIDC system. For weak MIDC system, it advises measures to improve system stability. In addition, the thesis discusses the relationships between multi-infeed maximal available power and multi-infeed voltage sensitivity factor. It is proved that MSCR can indicate the voltage stability of multi-infeed HVDC system. Further more, the thesis uses MSCR to analyze weak MIDC operation problems, for example, transient over-voltage, harmonic resonance, voltage stability. By simulations, it can prove indices correctly, and can make contribution to system planning.
本文介绍了直流输电的优缺点以及国内外直流工程的发展概况。通过查阅国内外大量的文献资料,重点论述了交直流输电系统电压稳定问题的研究现状,特别是针对多馈入交直流输电系统的电压稳定问题进行深入的研究。交流和直流的相互作用在很大程度上取决于交流系统与所连直流系统容量的相对大小,即短路比指标。基于短路比的电压稳定分析广泛地应用在学术界和工程界中,它为系统的规划提供了一个参考依据。针对传统短路比无法考虑多馈入交直流系统中各直流的相互影响,只能适用单馈入交直流系统,因此提出新的多馈入短路比定义迫在眉睫。目前学术界对多馈入短路比的定义没有统一的标准,本文追本溯源,通过理论分析推导了两种多馈入短路比的计算方法,统一了目前学术界已有的对多馈入短路比的定义。在此基础上,本文推导了多馈入临界短路比和临界有效短路比的函数关系式,提出了划分多馈入交直流系统强弱的标准。针对弱交流系统,从无功功率的角度提出改善系统运行的措施。通过分析多馈入最大直流功率与多馈入电压稳定因子间的关系,证明了多馈入短路比用于多馈入交直流系统电压稳定分析的可行性。最后,本文通过多馈入短路比对多馈入交直流系统的运行进行评估,通过理论和算例仿真研究了多馈入弱交流受端的动态过电压、谐波谐振、电压稳定等问题,证明了利用多馈入短路比指标判别多馈入交流系统强弱的有效性,对规划有着重要的指导意义。
With the development of society and economy, it has a much higher demand on power. The distribution of energy source and the unbalance of regional economic development make optimizing energy distributing configuration necessary. Owing to the fact that High Voltage Direct Current transmission has advantages in large capacity and long distance, HVDC has developed rapidly. As electricity transmission from West to East and nationwide power network interconnection has been developed, multi-infeed HVDC (MIDC) connected to one AC system has emerged in South China Power Grid and East China Power Gird. It has important meaning of safety evaluating for MIDC system.
The thesis introduces advantages and disadvantages of HVDC transmission, and makes a survey of HVDC transmission projects both in domestic and abroad. By referring to lots of documents, the thesis classifies and analyzes methods of voltage stability for AC/DC system, especially for multi-infeed HVDC system. The interaction of AC and DC depends on the capacity of DC compared with AC, namely short current ratio (SCR). The voltage stability analysis based on SCR is widely used in academic circles and engineering circles. It can provide reference basis for system planning. Because traditional SCR can't take interaction of DCs into account, it is extremely urgent to propose a new evaluating way for MIDC system. At present, there are not unified standards for multi-infeed SCR. The thesis defines multi-infeed SCR by formula derivation and theoretical analysis, and proves two calculation methods . Further more, the multi-infeed critical SCR is derived, and the thesis proposes the judgment standard of weak MIDC system. For weak MIDC system, it advises measures to improve system stability. In addition, the thesis discusses the relationships between multi-infeed maximal available power and multi-infeed voltage sensitivity factor. It is proved that MSCR can indicate the voltage stability of multi-infeed HVDC system. Further more, the thesis uses MSCR to analyze weak MIDC operation problems, for example, transient over-voltage, harmonic resonance, voltage stability. By simulations, it can prove indices correctly, and can make contribution to system planning.
引文
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[2].蔡泽祥,朱浩骏,白雪峰,倪以信.多馈入直流输电系统的动态特性及稳定控制与分析.华北电力大学学报,2004,31(5).
[3].赵畹君.高压直流输电工程技术,北京:中国电力出版社,2004.
[4].中国电力科学研究院.多回直流馈入系统特有机理研究,2004.12
[5].Prabha Kundur.Power System Stability and Control.北京:中国电力出版社,2002.
[6].华东电网2020年目标网站安全稳定校核,中国电力科学研究院,2002.
[7].韩祯祥,徐政.直流输电中的多馈入问题[J].加入WTO后中国电机工程科技发展的机遇与挑战学术研讨会.
[8].马尔柯维奇.张钟俊译.动力系统及其运行情况.电力工业出版社,1956.
[9].Charles Concordia.Voltage Instability:Definition And Concepts.Venice,Florida,1987.
[10].Carson W.Taylor.Power System Voltage Stability,北京:中国电力出版社,2002
[11].IEEE Committee Report.Voltage Stability of Power Systems:Concepts,Analytical Tools,and Industry Experience.IEEE/PES 93TH0358-2-PWR,1990.
[12].CIGRE TF38.02.10.Modeling of Voltage Collapse Including Dynamic Phenomena.Electra,No.147,Apr.1993
[13].李兴源.高压在直流输电系统的运行和控制[M],北京:科学出版社,1998.
[14].傅旭,王锡凡.电力系统电压稳定性研究现状及其展望[J].电力自动化设备,2005,25(2).
[15].B Franken,G Andersson.Analysis of HVDC converter connected to weak ac system[J].IEEE Transactions on Power System.1990,5(1).
[16].Krishayya P C S,Adapa R,Holm M,etal.IEEE guide for planning DC links terminating at AC locations having low short-circuit cap- acities.partⅠ:AC/DC system interaction phenomena,partⅡ:planning guidelines[R].CIGRE and IEEE.
[17].周川梅,彭志炜.基于交直流并联系统P-V曲线的电压稳定性分析[J],贵州电力技术,2005(3).
[18].John Reeve,Edvina Uzunovic.study on power transfer capability of DC system incorporating AC load and a parallel AC line[J].IEEE Transactions on Power Delivery,1997,12(1).
[19].徐政.联于弱交流系统的直流输电特性研究之一:直流输电的输送能力[J].电网技术,1997,21(1).
[20].C.W.Taylor.Power System Voltage Stability[M].北京:中国电力出版社.2002.
[21].浙江大学发电教研组直流输电科研组.直流输电[M].北京:水利电力出版社,1985.
[22].John Reeve,Edvina Uzunovic.Study of Power Transfer Capability of DC[J].IEEE Transactions on Power Delivery,1997,12(1).
[23].高东峰.高压直流逆变端交流母线电压稳定性及负荷特性影响的研究(D).2005.
[24].Denis L H A,Andersson G,etal.Influence of load characteristics on the power/voltage stability of HVDC systems.I.Basic equations and rela- tionships[J].IEEE Transactions on Power Delivery,1998,13(4):1437-1444.
[25].Z.Y.Liu,J.Wen,M.X.Hen,L.Dong,H.Ding.Researches on the Load Representation of Hunan Power Grid ACDC System:2006 International Conference on Power System Technology.
[26].杨秀,郎鹏越,靳希.高压直流输电系统功率/电压静态稳定性的建模与分析.华东电力,2006,24(3).
[27].Paulo fischer de toledo,Bernt Bergdahl,Gunnar Asplund.Multiple Infeed Short Curcuit Ratio-Aspects Ralated To Multiple HVDC into One AC Network.
[28].J.B.Davies,Systems with multiple DC infeed WG.b4.41 report.
[29].Franken B.Analysis of HVDC converters connected to weak AC systems IEEE transaction on power system,1990,5(1):235-242.
[30].徐政.联于弱交流系统的直流输电特性研究之二:控制方式与电压稳定,电网技术,1997,21(3):1-4.
[31].Hammad A E,Kuhn W.A computation algorithm for assessing voltage stability at AC/DC interconnection IEEE Transactions on power system,1986,PWRS-I(1):209-216.
[32].B Franken,G Andersson.Analysis of HVDC converters connected to weak AC systems[J].IEEE Transactions on Power System.1990,5(1).
[33].L A S Pilotto,M Szechtman,A.E.Hammad.Transient AC voltage related phenomena for HVDC schemes connected to weak AC systems[J].IEEE Transactions on Power Delivery,1992,7(3).
[34].欧开建,任震.多馈入直流输电系统换流母线电压稳定性评估模型和算法[J].电力自动化 设备,2003,23(9):24-26.
[35].O.B.Nayak,et al.Control sensitivity indices for stability analysis of HVDC systems[J].IEEE Transactions on Power Delivery,1995,10(4).
[36].Dragan Jovcic,et al.Small signal analysis of HVDC-HVAC interactions[J]IEEE Transactions on Power Delivery,1999,14(2).
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