增强型调速器对中国云南电网超低频振荡影响分析
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摘要
云南电网在部分水电机组中采用增强型调速器,会引发超低频振荡,并严重威胁异步电网频率安全。为揭示水电机组增强型调速器影响云南电网频率的原因,通过对系统频率偏差从不同方向穿越一次调频死区时的动力学行为进行理论计算和时域仿真,论证了增强型调速器在水电机组一次调频死区附近没有稳定平衡点,且当系统频率偏差缓慢穿回一次调频死区时,在超低频段引入约90°的相位滞后,进而降低系统频率安全稳定裕度。最后借助小扰动分析工具计算了包含水轮机、调速器、发电机模型的单机系统特征根,通过对比仿真,说明增强型调速器不仅与水锤效应在超低频段有相似的负阻尼效应,还是引发超低频振荡的扰动源头之一,使超低频振荡持续且无法衰减。
Enhanced governors are adopted in some hydroelectric units in Yunnan power grid, which causes the ultra-low frequency oscillation and threatens the frequency stability of power grid seriously. In order to reveal why the enhanced governors of hydroelectric units affect the frequency of Yunnan power grid of China, the theoretic calculation and time-domain simulation are conducted on dynamic behaviors when the system frequency difference across the dead zone of primary frequency regulation from different directions. It is demonstrated that the enhanced governor does not have a stable equilibrium point near the dead zone of primary frequency regulation of hydroelectric generator, and when the system frequency difference slowly passes back to the dead zone, a phase lag of about 90 degrees is introduced in ultra-low frequency band, thus reducing the safe and stable margin of the system frequency. Finally, the eigenvalues of a single-machine system including hydro turbine, governor and generator models are calculated with the aid of small disturbance analysis tools. Through the comparative simulation, it is shown that the enhanced governor not only has similar negative damping effect with the water hammer in ultra-low band, but also is the one of the disturbance sources of ultra-low frequency oscillation, which keeps ultra-low frequency oscillation continuous and unable to attenuate.
Enhanced governors are adopted in some hydroelectric units in Yunnan power grid, which causes the ultra-low frequency oscillation and threatens the frequency stability of power grid seriously. In order to reveal why the enhanced governors of hydroelectric units affect the frequency of Yunnan power grid of China, the theoretic calculation and time-domain simulation are conducted on dynamic behaviors when the system frequency difference across the dead zone of primary frequency regulation from different directions. It is demonstrated that the enhanced governor does not have a stable equilibrium point near the dead zone of primary frequency regulation of hydroelectric generator, and when the system frequency difference slowly passes back to the dead zone, a phase lag of about 90 degrees is introduced in ultra-low frequency band, thus reducing the safe and stable margin of the system frequency. Finally, the eigenvalues of a single-machine system including hydro turbine, governor and generator models are calculated with the aid of small disturbance analysis tools. Through the comparative simulation, it is shown that the enhanced governor not only has similar negative damping effect with the water hammer in ultra-low band, but also is the one of the disturbance sources of ultra-low frequency oscillation, which keeps ultra-low frequency oscillation continuous and unable to attenuate.
引文
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[7] 卢勇,贺祥飞,刘友宽,等.云南电网水电机组参与一次调频改进方案[J].电力系统自动化,2006,30(21):86-89.LU Yong,HE Xiangfei,LIU Youkuan,et al.Primary frequency control strategy of hydro power unit for Yunnan power network[J].Automation of Electric Power Systems,2006,30(21):86-89.
[8] 高翔.现代电网频率控制技术[M].北京:中国电力出版社,2010:182.GAO Xiang.Frequency control technology of modern power grid[M].Beijing:China Electric Power Press,2010:182.
[9] 文峰,贾光辉.自动控制理论[M].北京:中国电力出版社,2002.WEN Feng,JIA Guanghui.Automatic control theory[M].Beijing:China Electric Power Press,2002.
[10] 戴忠达.自动控制理论基础[M].北京:清华大学出版社,1991.DAI Zhongda.Basis of automatic control theory[M].Beijing:Tsinghua University Press,1991.
[11] 倪以信,陈寿孙,张宝霖.动态电力系统的理论和分析[M].北京:清华大学出版社,2002.NI Yixin,CHEN Shousun,ZHANG Baolin.Theory and analysis of dynamic power system[M].Beijing:Tsinghua University Press,2002.
[12] 魏守平.水轮机调节[M].武汉:华中科技大学出版社,2009.WEI Shouping.Hydraulic turbine regulation[M].Wuhan:Huazhong University of Science and Technology Press,2009.
[13] SCHLEIF F,WHITE J.Damping for the Northwest-Southwest tieline oscillations—an analog study[J].IEEE Transactions on Power Apparatus and Systems,1966,85(12):1239-1247.
[14] 水轮机调节系统并网技术导则:DL/T 1245—2013[S].北京:国家能源局,2013.Technical guide for hydraulic turbine regulating system in grid:DL/T 1245—2013[S].Beijing:National Energy Administration,2013.
[15] 沈丛奇,归一数,程际云,等.快动缓回一次调频策略[J].电力系统自动化,2015,39(13):158-162SHEN Congqi,GUI Yishu,CHENG Jiyun,et al.A primary frequency regulation control strategy with fast-moving and delayed-returning technology[J].Automation of Electric Power Systems,2015,39(13):158-162.
[16] 陈帝伊,杨朋超,马孝义,等.水轮机调节系统的混沌现象分析及控制[J].中国电机工程学报,2011,31(14):113-120.CHEN Diyi,YANG Pengchao,MA Xiaoyi,et al.Chaos of hydro-turbine governing system and its control[J].Proceedings of the CSEE,2011,31(14):113-120.
[17] 凌代俭,沈祖诒.水轮机调节系统的非线性模型、PID控制及其Hopf分岔[J].中国电机工程学报,2005,25(10):97-102.LING Daijian,SHEN Zuyi.The nonlinear model of hydraulic turbine governing systems and its PID control and Hopf bifurcation[J].Proceedings of the CSEE,2005,25(10):97-102.
[18] 凌代俭,沈祖诒.考虑饱和非线性环节的水轮机调节系统的分岔分析[J].水力发电学报,2007,26(6):126-131.LING Daijian,SHEN Zuyi.Bifurcation analysis of hydro-turbine governing system with saturation nonlinearity[J].Journal of Hydroelectric Engineering,2007,26(6):126-131.
[19] 陈磊,路晓敏,陈亦平,等.利用暂态能量流的超低频振荡在线分析与紧急控制方法[J].电力系统自动化,2017,41(17):9-14.DOI:10.7500/AEPS20161208004.CHEN Lei,LU Xiaomin,CHEN Yiping,et al.Online analysis and emergency control of ultra-low frequency oscillations using transient energy flow[J].Automation of Electric Power Systems,2017,41(17):9-14.DOI:10.7500/AEPS20161208004.
[20] 曹程杰,莫岳平,刘洁.基于Matlab模块化模型的水轮发电机组仿真研究[J].电力系统保护与控制,2010,38(2):68-71.CAO Chengjie,MO Yueping,LIU Jie.Research of hydro generating units based on modularized model of Matlab[J].Power System Protection and Control,2010,38(2):68-71.
[21] 方红庆,陈龙,李训铭.基于线性与非线性模型的水轮机调速器PID参数优化比较[J].中国电机工程学报,2010,30(5):100-106.FANG Hongqing,CHEN Long,LI Xunming.Comparisons of optimal tuning hydro turbine governor PID gains based on linear and nonlinear mathematical models[J].Proceedings of the CSEE,2010,30(5):100-106.
[22] 何常胜,董鸿魁,翟鹏,等.水电机组一次调频与 AGC 典型控制策略的工程分析及优化[J].电力系统自动化,2015,39(3):146-151.HE Changsheng,DONG Hongkui,ZHAI Peng,et al.Engineering analysis and optimization on typical control strategy of primary frequency modulation and automatic generation control of hydropower units[J].Automation of Electric Power Systems,2015,39(3):146-151.
[23] 潘学萍,鞠平,卫志农,等.水力系统对低频振荡的影响[J].电力系统自动化,2002,26(3):24-27PAN Xueping,JU Ping,WEI Zhinong,et al.The influence of hydraulic system on low frequency oscillation[J].Automation of Electric Power Systems,2002,26(3):24-27.
[24] 陈磊,路晓敏,陈亦平,等.多机系统超低频振荡分析与等值方法[J].电力系统自动化,2017,41(22):10-15.DOI:10.7500/AEPS20170528001.CHEN Lei,LU Xiaomin,CHEN Yiping,et al.Analysis of Ultra-low-frequency oscillations in multi-machine system and equivalent method[J].Automation of Electric Power Systems,2017,41(22):10-15.DOI:10.7500/AEPS20170528001.
[25] 黄伟,段荣华,江崇熙,等.多机系统超低频振荡稳定分析与调速器参数优化[J].电力系统自动化,2018,42(21):185-191.DOI:10.7500/AEPS20180215003.HUANG Wei,DUAN Ronghua,JIANG Chongxi,et al.Stability analysis of ultra-low frequency oscillation and governor parameter optimization for multi-machine system[J].Automation of Electric Power Systems,2018,42(21):185-191.DOI:10.7500/AEPS20180215003.
[2] 刘春晓,张俊峰,陈亦平,等.异步联网方式下云南电网超低频振荡的机理分析与仿真[J].南方电网技术,2016,10(7):29-34.LIU Chunxiao,ZHANG Junfeng,CHEN Yiping,et al.Mechanism analysis and simulation on ultra-low frequency oscillation of Yunnan power grid in asynchronous interconnection mode[J].Southern Power System Technology,2016,10(7):29-34.
[3] 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(增刊1):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(Supplement 1):74-78.
[4] 余一平,闵勇,陈磊,等.周期性负荷扰动引发强迫功率振荡分析[J].电力系统自动化,2010,34(6):7-11.YU Yiping,MIN Yong,CHEN Lei,et al.Analysis of forced power oscillation caused by continuous cyclical load disturbances[J].Automation of Electric Power Systems,2010,34(6):7-11.
[5] 路晓敏,陈磊,陈亦平,等.电力系统一次调频过程的超低频振荡分析[J].电力系统自动化,2017,41(16):64-70.DOI:10.7500/AEPS20161208002.LU Xiaomin,CHEN Lei,CHEN Yiping,et al.Ultra-low-frequency oscillation of power system primary frequency regulation[J].Automation of Electric Power Systems,2017,41(16):64-70.DOI:10.7500/AEPS20161208002.
[6] 付超,柳勇军,涂亮,等.云南电网与南方电网主网异步联网系统试验分析[J].南方电网技术,2016,10(7):1-5.FU Chao,LIU Yongjun,TU Liang,et al.Experiment and analysis on asynchronously interconnected system of Yunnan power grid and main grid of China southern power grid[J].Southern Power System Technology,2016,10(7):1-5.
[7] 卢勇,贺祥飞,刘友宽,等.云南电网水电机组参与一次调频改进方案[J].电力系统自动化,2006,30(21):86-89.LU Yong,HE Xiangfei,LIU Youkuan,et al.Primary frequency control strategy of hydro power unit for Yunnan power network[J].Automation of Electric Power Systems,2006,30(21):86-89.
[8] 高翔.现代电网频率控制技术[M].北京:中国电力出版社,2010:182.GAO Xiang.Frequency control technology of modern power grid[M].Beijing:China Electric Power Press,2010:182.
[9] 文峰,贾光辉.自动控制理论[M].北京:中国电力出版社,2002.WEN Feng,JIA Guanghui.Automatic control theory[M].Beijing:China Electric Power Press,2002.
[10] 戴忠达.自动控制理论基础[M].北京:清华大学出版社,1991.DAI Zhongda.Basis of automatic control theory[M].Beijing:Tsinghua University Press,1991.
[11] 倪以信,陈寿孙,张宝霖.动态电力系统的理论和分析[M].北京:清华大学出版社,2002.NI Yixin,CHEN Shousun,ZHANG Baolin.Theory and analysis of dynamic power system[M].Beijing:Tsinghua University Press,2002.
[12] 魏守平.水轮机调节[M].武汉:华中科技大学出版社,2009.WEI Shouping.Hydraulic turbine regulation[M].Wuhan:Huazhong University of Science and Technology Press,2009.
[13] SCHLEIF F,WHITE J.Damping for the Northwest-Southwest tieline oscillations—an analog study[J].IEEE Transactions on Power Apparatus and Systems,1966,85(12):1239-1247.
[14] 水轮机调节系统并网技术导则:DL/T 1245—2013[S].北京:国家能源局,2013.Technical guide for hydraulic turbine regulating system in grid:DL/T 1245—2013[S].Beijing:National Energy Administration,2013.
[15] 沈丛奇,归一数,程际云,等.快动缓回一次调频策略[J].电力系统自动化,2015,39(13):158-162SHEN Congqi,GUI Yishu,CHENG Jiyun,et al.A primary frequency regulation control strategy with fast-moving and delayed-returning technology[J].Automation of Electric Power Systems,2015,39(13):158-162.
[16] 陈帝伊,杨朋超,马孝义,等.水轮机调节系统的混沌现象分析及控制[J].中国电机工程学报,2011,31(14):113-120.CHEN Diyi,YANG Pengchao,MA Xiaoyi,et al.Chaos of hydro-turbine governing system and its control[J].Proceedings of the CSEE,2011,31(14):113-120.
[17] 凌代俭,沈祖诒.水轮机调节系统的非线性模型、PID控制及其Hopf分岔[J].中国电机工程学报,2005,25(10):97-102.LING Daijian,SHEN Zuyi.The nonlinear model of hydraulic turbine governing systems and its PID control and Hopf bifurcation[J].Proceedings of the CSEE,2005,25(10):97-102.
[18] 凌代俭,沈祖诒.考虑饱和非线性环节的水轮机调节系统的分岔分析[J].水力发电学报,2007,26(6):126-131.LING Daijian,SHEN Zuyi.Bifurcation analysis of hydro-turbine governing system with saturation nonlinearity[J].Journal of Hydroelectric Engineering,2007,26(6):126-131.
[19] 陈磊,路晓敏,陈亦平,等.利用暂态能量流的超低频振荡在线分析与紧急控制方法[J].电力系统自动化,2017,41(17):9-14.DOI:10.7500/AEPS20161208004.CHEN Lei,LU Xiaomin,CHEN Yiping,et al.Online analysis and emergency control of ultra-low frequency oscillations using transient energy flow[J].Automation of Electric Power Systems,2017,41(17):9-14.DOI:10.7500/AEPS20161208004.
[20] 曹程杰,莫岳平,刘洁.基于Matlab模块化模型的水轮发电机组仿真研究[J].电力系统保护与控制,2010,38(2):68-71.CAO Chengjie,MO Yueping,LIU Jie.Research of hydro generating units based on modularized model of Matlab[J].Power System Protection and Control,2010,38(2):68-71.
[21] 方红庆,陈龙,李训铭.基于线性与非线性模型的水轮机调速器PID参数优化比较[J].中国电机工程学报,2010,30(5):100-106.FANG Hongqing,CHEN Long,LI Xunming.Comparisons of optimal tuning hydro turbine governor PID gains based on linear and nonlinear mathematical models[J].Proceedings of the CSEE,2010,30(5):100-106.
[22] 何常胜,董鸿魁,翟鹏,等.水电机组一次调频与 AGC 典型控制策略的工程分析及优化[J].电力系统自动化,2015,39(3):146-151.HE Changsheng,DONG Hongkui,ZHAI Peng,et al.Engineering analysis and optimization on typical control strategy of primary frequency modulation and automatic generation control of hydropower units[J].Automation of Electric Power Systems,2015,39(3):146-151.
[23] 潘学萍,鞠平,卫志农,等.水力系统对低频振荡的影响[J].电力系统自动化,2002,26(3):24-27PAN Xueping,JU Ping,WEI Zhinong,et al.The influence of hydraulic system on low frequency oscillation[J].Automation of Electric Power Systems,2002,26(3):24-27.
[24] 陈磊,路晓敏,陈亦平,等.多机系统超低频振荡分析与等值方法[J].电力系统自动化,2017,41(22):10-15.DOI:10.7500/AEPS20170528001.CHEN Lei,LU Xiaomin,CHEN Yiping,et al.Analysis of Ultra-low-frequency oscillations in multi-machine system and equivalent method[J].Automation of Electric Power Systems,2017,41(22):10-15.DOI:10.7500/AEPS20170528001.
[25] 黄伟,段荣华,江崇熙,等.多机系统超低频振荡稳定分析与调速器参数优化[J].电力系统自动化,2018,42(21):185-191.DOI:10.7500/AEPS20180215003.HUANG Wei,DUAN Ronghua,JIANG Chongxi,et al.Stability analysis of ultra-low frequency oscillation and governor parameter optimization for multi-machine system[J].Automation of Electric Power Systems,2018,42(21):185-191.DOI:10.7500/AEPS20180215003.