大规模双馈风电机组参与调频的电网自适应低频减载策略
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摘要
大规模风电参与惯性控制和一次调频会对电网频率特性产生显著影响,而现有的低频减载方法尚未考虑该影响,可能引起频率轨迹失真和负荷切除不合理问题。鉴于此,以双馈型风电机组为例,研究将风电虚拟惯性响应时变特性参数和一次调频响应系统模型融入低频减载过程的方法,提出了改进低频减载策略和负荷切除决策模型。首先,通过求解含风电虚拟惯性响应的电网等效惯量(具有时变特性)、检测频率变化率,计算低频减载首轮起动时刻的实时功率缺额。然后,定量表征风电一次调频及负荷调节效应先抵消部分的实时功率缺额,剩余功率缺额则由自适应低频减载策略分批切除。最后,理论研究及算例分析结果表明,所提低频减载改进策略和模型能更客观地反映电网频率特性,负荷切除量明显更小,体现了大规模风电参与调频对低频减载的有益影响。
The frequency characteristics of power grid will be notably impacted by large-scale wind power participating in inertial control and primary frequency regulation(PFR).These factors,which may cause frequency trajectory distortion and unreasonable load shedding,have not been considered in the existing under-frequency load shedding(UFLS)methods.Therefore,taking doubly-fed induction generator(DFIG)wind turbines as an example,the method for integrating the inertial response time-varying characteristic parameters and the PFR response system model into the process of UFLS is studied.Meanwhile,an improved UFLS strategy and load resection decision are proposed.Firstly,by solving the grid equivalent inertia(contain the virtual inertial response of wind farm)with time-varying characteristics and detecting the rate of change of frequency,the real-time power shortage is calculated at the first-time starting moment of UFLS.Then,some shortages of realtime power are offset by quantitatively characterizing the PFR of wind power and the effect of loads regulation,and the remaining power deficit is removed by an adaptive UFLS strategy.Finally,it can be observed from the theoretical research and simulations that the frequency characteristics of the grid can be reflected more objectively by using the proposed UFLS improvement strategy,and the amount of load removal is much smaller.This phenomenon reflects the beneficial effects of large-scale wind power participating in frequency regulation on UFLS.
The frequency characteristics of power grid will be notably impacted by large-scale wind power participating in inertial control and primary frequency regulation(PFR).These factors,which may cause frequency trajectory distortion and unreasonable load shedding,have not been considered in the existing under-frequency load shedding(UFLS)methods.Therefore,taking doubly-fed induction generator(DFIG)wind turbines as an example,the method for integrating the inertial response time-varying characteristic parameters and the PFR response system model into the process of UFLS is studied.Meanwhile,an improved UFLS strategy and load resection decision are proposed.Firstly,by solving the grid equivalent inertia(contain the virtual inertial response of wind farm)with time-varying characteristics and detecting the rate of change of frequency,the real-time power shortage is calculated at the first-time starting moment of UFLS.Then,some shortages of realtime power are offset by quantitatively characterizing the PFR of wind power and the effect of loads regulation,and the remaining power deficit is removed by an adaptive UFLS strategy.Finally,it can be observed from the theoretical research and simulations that the frequency characteristics of the grid can be reflected more objectively by using the proposed UFLS improvement strategy,and the amount of load removal is much smaller.This phenomenon reflects the beneficial effects of large-scale wind power participating in frequency regulation on UFLS.
引文
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[13]李世春,邓长虹,龙志君,等.风电场等效虚拟惯性时间常数计算[J].电力系统自动化,2016,40(7):22-29.LI Shichun,DENG Changhong,LONG Zhijun,et al.Calculation of equivalent virtual inertial time constant of wind farm[J].Automation of Electric Power Systems,2016,40(7):22-29.
[14]李世春,黄悦华,王凌云,等.基于转速控制的双馈风电机组一次调频辅助控制系统建模[J].中国电机工程学报,2017,37(24):7077-7086.LI Shichun,HUANG Yuehua,WANG Lingyun,et al.Modeling primary frequency regulation auxiliary control system of doubly fed induction generator based on rotor speed control[J].Proceedings of the CSEE,2017,37(24):7077-7086.
[15]胡杰,余贻鑫.电力系统动态等值参数聚合的实用方法[J].电网技术,2006,30(24):26-30.HU Jie,YU Yixin.A practical method of parameter aggregation for power system dynamic equivalence[J].Power System Technology,2006,30(24):26-30.
[16]昆杜拉.电力系统稳定与控制[M].北京:中国电力出版社,2002.KUNDUR P.Power system stability and control[M].Beijing:China Electric Power Press,2002.
[17]杨冠城.电力系统自动装置原理[M].北京:中国电力出版社,2007.YANG Guancheng.Principle of automatic system of power system[M].Beijing:China Electric Power Press,2007.
[18]国家能源局.电力系统自动低频减负荷技术规定:DL/T 428-2010[S].2011.National Energy Administration.Regulations of power system automatic underfrequency load shedding technical:DL/T428-2010[S].2011.
[19]杨德友,蔡国伟.减载控制灵敏度及其在广域低频保护中的应用[J].电力自动化设备,2016,36(3):124-128.YANG Deyou,CAI Guowei.The sensitivity of load shedding control and its application in wide-area low frequency protection[J].Electric Power Automation Equipment,2016,36(3):124-128.
[2]MAURICIO J M,MARANO A,GOMEZ-EXPOSITO A,et al.Frequency regulation contribution through variable-speed wind energy conversion systems[J].IEEE Transactions on Power Systems,2009,24(1):173-180.
[3]周天沛,孙伟.高渗透率下变速风力机组虚拟惯性控制的研究[J].中国电机工程学报,2017,37(2):486-496.ZHOU Tianpei,SUN Wei.Study on virtual inertia control for DFIG-based wind farms with high penetration[J].Proceedings of the CSEE,2017,37(2):486-496.
[4]LEE J,MULJADI E,SORENSEN P,et al.Releasable kinetic energy-based inertial control of a DFIG wind power plant[J].IEEE Transactions on Sustainable Energy,2015,7(1):1-10.
[5]宋兆欧,刘俊勇,刘友波,等.计及动态修正的自适应广域低频减载[J].电力自动化设备,2014,34(4):95-100.SONG Zhao’ou,LIU Junyong,LIU Youbo,et al.WAMS-based adaptive UFLS considering dynamic correction[J].Electric Power Automation Equipment,2014,34(4):95-100.
[6]RUDEZ U,MIHALIC R.Monitoring the first frequency derivative to improve adaptive underfrequency load-shedding schemes[J].IEEE Transactions on Power Systems,2011,26(2):839-846.
[7]李常刚,刘玉田,邱夕兆.基于暂态频率偏移安全性的低频减载方案优化[J].电力系统自动化,2013,37(4):51-56.LI Changgang,LIU Yutian,QIU Xizhao.Optimization of under-frequency load shedding schemes based on transient frequency deviation security[J].Automation of Electric Power Systems,2013,37(4):51-56.
[8]徐泰山,李碧君,鲍颜红,等.考虑暂态安全性的低频低压减载量的全局优化[J].电力系统自动化,2003,27(22):12-15.XU Taishan,LI Bijun,BAO Yanhong,et al.Optimal parameter-setting of under-frequency and under-voltage load shedding for transient security[J].Automation of Electric Power Systems,2003,27(22):12-15.
[9]蔡国伟,孙正龙,王雨薇,等.基于改进频率响应模型的低频减载方案优化[J].电网技术,2013,37(11):3131-3136.CAI Guowei,SUN Zhenglong,WANG Yuwei,et al.Optimization of under frequency load shedding scheme based on improved system frequency response model[J].Power System Technology,2013,37(11):3131-3136.
[10]汤奕,邓克愚,孙华东,等.智能家电参与低频减载协调配合方案研究[J].电网技术,2013,37(10):2861-2867.TANG Yi,DENG Keyu,SUN Huadong,et al.Research on coordination scheme for smart household appliances participating underfrequency load shedding[J].Power System Technology,2013,37(10):2861-2867.
[11]孙毅,李泽坤,刘迪,等.可控负荷参与低频减载的动态集群优化控制策略[J].中国电机工程学报,2018,38(7):1913-1921.SUN Yi,LI Zekun,LIU Di,et al.An optimization control strategy for intelligent UFLS using dynamically aggregated controllable loads[J].Proceedings of the CSEE,2018,38(7):1913-1921.
[12]李顺,廖清芬,唐飞,等.高风电渗透率下的自适应低频减载策略研究[J].电网技术,2017,41(4):1084-1090.LI Shun,LIAO Qingfen,TANG Fei,et al.Adaptive underfrequency load shedding strategy considering high wind power penetration[J].Power System Technology,2017,41(4):1084-1090.
[13]李世春,邓长虹,龙志君,等.风电场等效虚拟惯性时间常数计算[J].电力系统自动化,2016,40(7):22-29.LI Shichun,DENG Changhong,LONG Zhijun,et al.Calculation of equivalent virtual inertial time constant of wind farm[J].Automation of Electric Power Systems,2016,40(7):22-29.
[14]李世春,黄悦华,王凌云,等.基于转速控制的双馈风电机组一次调频辅助控制系统建模[J].中国电机工程学报,2017,37(24):7077-7086.LI Shichun,HUANG Yuehua,WANG Lingyun,et al.Modeling primary frequency regulation auxiliary control system of doubly fed induction generator based on rotor speed control[J].Proceedings of the CSEE,2017,37(24):7077-7086.
[15]胡杰,余贻鑫.电力系统动态等值参数聚合的实用方法[J].电网技术,2006,30(24):26-30.HU Jie,YU Yixin.A practical method of parameter aggregation for power system dynamic equivalence[J].Power System Technology,2006,30(24):26-30.
[16]昆杜拉.电力系统稳定与控制[M].北京:中国电力出版社,2002.KUNDUR P.Power system stability and control[M].Beijing:China Electric Power Press,2002.
[17]杨冠城.电力系统自动装置原理[M].北京:中国电力出版社,2007.YANG Guancheng.Principle of automatic system of power system[M].Beijing:China Electric Power Press,2007.
[18]国家能源局.电力系统自动低频减负荷技术规定:DL/T 428-2010[S].2011.National Energy Administration.Regulations of power system automatic underfrequency load shedding technical:DL/T428-2010[S].2011.
[19]杨德友,蔡国伟.减载控制灵敏度及其在广域低频保护中的应用[J].电力自动化设备,2016,36(3):124-128.YANG Deyou,CAI Guowei.The sensitivity of load shedding control and its application in wide-area low frequency protection[J].Electric Power Automation Equipment,2016,36(3):124-128.