调速系统频率模态对电网低频振荡的影响
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摘要
随着调速系统技术的不断发展,调速系统对电网低频振荡(low frequency oscillation,LFO)的影响越来越引起人们的关注。现有理论研究表明,调速系统不仅会影响电网LFO阻尼特性,还会向电网引入一个独特的比LFO频率更低的振荡模态,该文称为频率模态,该模态会在调速系统动作时出现。该文首先采用转矩分析理论研究了调速系统对电网LFO阻尼特性的影响。然后以4机2区域系统为例,重点分析了频率模态的特点及其对LFO的影响,分析结果表明:频率模态是调速系统自身的一种控制模态,其阻尼比主要受调速比例–积分–微分控制器的参数影响;考虑到调速系统动作死区影响,在系统发生LFO且调速系统使该LFO阻尼为负的情况下,当频率模态阻尼较强时,电网功率LFO发散后会逐渐变为等幅振荡;而当频率模态阻尼较弱,电网功率LFO将会呈现出类似"拍频"的特性。最后,通过某实际互联电力系统仿真验证了上述分析结果的有效性。
With the technique development of the governor system, the influence of governor system on low frequency oscillations(LFOs) has attracted more and more attention. The current research shows that the governor system not only can influence the damping characteristics of LFOs, but also will introduce a special very low frequency mode into the power system. This mode, called by frequency mode, has lower frequency than LFOs and would appear when the governor system is performed. In this paper, the influence of governor system on the damping characteristics of LFOs was investigated by using the torque analysis theory. Then the feature of the frequency mode and its influence on LFOs were mainly analyzed base on a 4-machine 2-area system. The analysis results show that frequency mode is a control mode of governor system and its damping ratio is significantly influenced by the parameters of the governor proportional integral derivative(PID) controller. When the governor system makes the damping ratios of LFOs become negative and the dead band is taken into account, the system LFO will gradually become equispacing oscillation if the damping ratio of the frequency mode is relatively strong, while the power LFO will appear like a beat frequency oscillation if the damping ratio of the frequency mode is relatively weak. Finally, simulation results of a practical inter-connected power system validate the effectiveness of the analysis results above.
With the technique development of the governor system, the influence of governor system on low frequency oscillations(LFOs) has attracted more and more attention. The current research shows that the governor system not only can influence the damping characteristics of LFOs, but also will introduce a special very low frequency mode into the power system. This mode, called by frequency mode, has lower frequency than LFOs and would appear when the governor system is performed. In this paper, the influence of governor system on the damping characteristics of LFOs was investigated by using the torque analysis theory. Then the feature of the frequency mode and its influence on LFOs were mainly analyzed base on a 4-machine 2-area system. The analysis results show that frequency mode is a control mode of governor system and its damping ratio is significantly influenced by the parameters of the governor proportional integral derivative(PID) controller. When the governor system makes the damping ratios of LFOs become negative and the dead band is taken into account, the system LFO will gradually become equispacing oscillation if the damping ratio of the frequency mode is relatively strong, while the power LFO will appear like a beat frequency oscillation if the damping ratio of the frequency mode is relatively weak. Finally, simulation results of a practical inter-connected power system validate the effectiveness of the analysis results above.
引文
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[15]王茂海,孙昊.强迫功率振荡源的在线定位分析技术[J].中国电机工程学报,2014,34(34):6209-6215.Wang Maohai,Sun Hao.An analysis method for forced power oscillation source detection[J].Proceedings of the CSEE,2014,34(34):6209-6215(in Chinese).
[16]李文锋,李莹,周孝信,等.基于WAMS的电力系统功率振荡分析与振荡源定位(2)力矩分解法[J].中国电机工程学报,2013,33(25):47-53.Li Wenfeng,Li Ying,Zhou Xiaoxin,et al.Power system oscillation analysis and oscillation source location based on WAMS part 2:method of torques decomposition[J].Proceedings of the CSEE,2013,33(25):47-53(in Chinese).
[17]Grenier M E,Lefebvre D,Van Cutsem T.Quasi steady-state models for long-term voltage and frequency dynamics simulation[C]//2005 IEEE Russia Power Tech.St.Petersburg:IEEE,2005:1-8.
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[19]Mantzaris J C,Metsiou A,Vournas C D.Analysis of interarea oscillations including governor effects and stabilizer design in south-eastern Europe[J].IEEE transactions on Power Systems,2013,28(4):4948-4956.
[20]Pico H V,Mc Calley J D,Angel A,et al.Analysis of very low frequency oscillations in hydro-dominant power systems using multi-unit modeling[J].IEEE Transactions on Power Systems,2012,27(4):1906-1915.
[21]Cebeci M E,Karaa?a?U,T?r O B,et al.The effects of hydro power plants’governor settings on the stability of turkish power system frequency[OL].Turkey,ELECO Conf,2007[2015-04-02].http://www.emo.org.tr/ekler/ad6635f33710af6_ek.pdf.
[2]朱方,赵红光,刘增煌,等.大区电网互联对电力系统动态稳定性的影响[J].中国电机工程学报,2007,27(1):1-7.Zhu Fang,Zhao Hongguan,Liu Zenghuang,et al.The influence of large power grid interconnected on power system dynamic stability[J].Proceedings of the CSEE,2007,27(1):1-7(in Chinese).
[3]刘取.电力系统稳定性及发电机励磁控制[M].北京:中国电力出版社,2007:136-154.Liu Qu.Power system stability and excitation control[M].Beijing:China Electric Power Press,2007:136-154(in Chinese).
[4]Rogers G.Power system oscillations[M].US:Springer,2000:129-130.
[5]Kundur P.Power system stability and control[M].New York:Mc Graw-Hill,1994:278-279.
[6]王官宏,陶向宇,李文峰,等.原动机调节系统对电力系统动态稳定的影响[J].中国电机工程学报,2008,28(34):80-86.Wang Guanhong,Tao Xiangyu,Li Wenfeng,et al.Influence of turbine governor on power system dynamic stability[J].Proceedings of the CSEE,2008,28(34):80-86(in Chinese).
[7]苏寅生.南方电网近年来的功率振荡事件分析[J].南方电网技术,2013,7(1):54-57.Su Yinsheng.Analysis on the CSG’s power oscillation events in recent years[J].Southern Power System Technology,2013,7(1):54-57(in Chinese).
[8]张利娟,陈庆国,陈海焱,等.调速系统恶化阻尼的机理分析及其改进措施[J].水电能源科学,2005,23(3):9-11.Zhang Lijuan,Chen Qingguo,Chen Haiyan,et al.Mechanism analysis for negative damping caused governing system and its improvement measure[J].Water Resources and Power,2005,23(3):9-11(in Chinese).
[9]刘春晓,张俊峰,李鹏,等.调速系统对南方电网动态稳定性的影响研究[J].中国电机工程学报,2013,33(Z1):74-78.Liu Chunxiao,Zhang Junfeng,Li Peng,et al.Influence of turbine governor on dynamic stability in China Southern Grid[J].Proceedings of the CSEE,2013,33(Z1):74-78(in Chinese).
[10]翁洪杰,徐衍会,王珍珍.汽轮机调速系统对电网低频振荡的影响[J].南方电网技术,2014,8(3):83-86.Weng Hongjie,Xu Yanhui,Wang Zhenzhen.The impact of steam-turbine governor system on the low frequency oscillation of power grids[J].Southern Power System Technology,2014,8(3):83-86(in Chinese).
[11]徐衍会,王珍珍,翁洪杰.一次调频试验引发低频振荡实例及机理分析[J].电力系统自动化,2013,37(23):119-124.Xu Yanhui,Wang Zhenzhen,Weng Hongjie.A low frequency oscillation event caused by primal frequency modulation test and its mechanism analysis[J].Automation of Electric Power Systems,2013,37(23):119-124(in Chinese).
[12]徐衍会,贺仁睦,韩志勇.电力系统共振机理低频振荡扰动源分析[J].中国电机工程学报,2007,27(17):83-87.Xu Yanhui,He Renmu,Han Zhiyong.The cause analysis of turbine power disturbance inducing power system low frequency oscillation of resonance mechanism[J].Proceedings of the CSEE,2007,27(17):83-87(in Chinese).
[13]竺炜,周有庆,谭喜意,等.电网侧扰动引起共振型低频振荡的机制分析[J].中国电机工程学报,2009,29(25):37-42.Zhu Wei,Zhou Youqing,Tang Xiyi,et al.Mechanism analysis of resonance-type low-frequency oscillation caused by networks side disturbance[J].Proceedings of the CSEE,2009,29(25):37-42(in Chinese).
[14]盛锴,刘复平,刘武林,等.汽轮机阀门流量特性对电力系统的影响及其控制策略[J].电力系统自动化,2012,36(7):104-109.Sheng Kai,Liu Fuping,Liu Wulin,et al.Influence of steam turbine valve discharge characteristics on power systems and its control strategy[J].Automation of Electric Power Systems,2012,36(7):104-109(in Chinese).
[15]王茂海,孙昊.强迫功率振荡源的在线定位分析技术[J].中国电机工程学报,2014,34(34):6209-6215.Wang Maohai,Sun Hao.An analysis method for forced power oscillation source detection[J].Proceedings of the CSEE,2014,34(34):6209-6215(in Chinese).
[16]李文锋,李莹,周孝信,等.基于WAMS的电力系统功率振荡分析与振荡源定位(2)力矩分解法[J].中国电机工程学报,2013,33(25):47-53.Li Wenfeng,Li Ying,Zhou Xiaoxin,et al.Power system oscillation analysis and oscillation source location based on WAMS part 2:method of torques decomposition[J].Proceedings of the CSEE,2013,33(25):47-53(in Chinese).
[17]Grenier M E,Lefebvre D,Van Cutsem T.Quasi steady-state models for long-term voltage and frequency dynamics simulation[C]//2005 IEEE Russia Power Tech.St.Petersburg:IEEE,2005:1-8.
[18]Vournas C D,Mantzaris J C.Application of QSS modeling to stabilizer design for interarea oscillations[J].IEEE transactions on Power Systems,2010,25(4):1910-1917.
[19]Mantzaris J C,Metsiou A,Vournas C D.Analysis of interarea oscillations including governor effects and stabilizer design in south-eastern Europe[J].IEEE transactions on Power Systems,2013,28(4):4948-4956.
[20]Pico H V,Mc Calley J D,Angel A,et al.Analysis of very low frequency oscillations in hydro-dominant power systems using multi-unit modeling[J].IEEE Transactions on Power Systems,2012,27(4):1906-1915.
[21]Cebeci M E,Karaa?a?U,T?r O B,et al.The effects of hydro power plants’governor settings on the stability of turkish power system frequency[OL].Turkey,ELECO Conf,2007[2015-04-02].http://www.emo.org.tr/ekler/ad6635f33710af6_ek.pdf.