More and more large capacity wind power will be integrated into power system in the future,and certain technical challenges will emerge due to the fluctuation characteristics of wind power and the complex control of p...More and more large capacity wind power will be integrated into power system in the future,and certain technical challenges will emerge due to the fluctuation characteristics of wind power and the complex control of power electronic devices inside the wind turbines(e.g.,low voltage ride through(LVRT)).By comparing a wind power integration grid with a hydropower integration grid,the special transient phenomena caused by the wind power integration is studied and simulation results are presented.Furthermore,the potential impacts on the traditional protection are discussed.Results show that the special transient phenomena can decrease the sensitivity,reliability and operation speed of conventional protections.展开更多
Large-scale doubly-fed induction generator(DFIG)wind turbines are connected to the grid and required to remain grid-connection during faults,the short-circuit current contributed by the generation has become a signifi...Large-scale doubly-fed induction generator(DFIG)wind turbines are connected to the grid and required to remain grid-connection during faults,the short-circuit current contributed by the generation has become a significant issue.However,the traditional calculation methods aiming at synchronous generators cannot be directly applied to the DFIG wind turbines.A new method is needed to calculate the short-circuit current required by the planning,protection and control of the power grid.The short-circuit transition of DFIG under symmetrical and asymmetric short-circuit conditions are mathematically deduced,and the short-circuit characteristics of DFIG are analyzed.A new method is proposed to calculate the steady-state short-circuit current of DFIG based on the derived expressions.The time-domain simulations are conducted to verify the accuracy of the proposed method.展开更多
针对双馈风机经串补并网引发的次同步控制相互作用(sub-synchronous control interaction,SSCI)问题,提出一种有源电力滤波器(active power filter,APF)谐波补偿控制策略。基于双馈风机(doubly fed induction generator,DFIG)和串补输...针对双馈风机经串补并网引发的次同步控制相互作用(sub-synchronous control interaction,SSCI)问题,提出一种有源电力滤波器(active power filter,APF)谐波补偿控制策略。基于双馈风机(doubly fed induction generator,DFIG)和串补输电线路的等效阻抗电路,利用阻抗法分析了系统发生SSCI的原因和特性;设计有源电力滤波器,通过向有源电力滤波器内部控制器注入包含无功电流和振荡电流在内的谐波参考电流来抑制风电场的次同步控制相互作用,该谐波电流参考值可通过并网采样电流减去其有功电流获得,有功电流则通过对APF直流侧电压采用一阶自抗扰控制(active disturbance rejection control,ADRC)获得;仿真验证了所提APF补偿控制策略在抑制SSCI方面的可行性。展开更多
为解决双馈风力发电机(doubly-fed induction generator,DFIG)采用综合惯量控制时固有调速器的抑制作用,及转速恢复时系统频率二次跌落(secondary frequency dip,SFD)的问题,提出了基于模糊推算和动态控制的风储联合调频控制策略。首先...为解决双馈风力发电机(doubly-fed induction generator,DFIG)采用综合惯量控制时固有调速器的抑制作用,及转速恢复时系统频率二次跌落(secondary frequency dip,SFD)的问题,提出了基于模糊推算和动态控制的风储联合调频控制策略。首先分析了电力系统频率响应特性,揭示了输出功率抑制量(output power suppression amount,OPSA)与SFD的产生机理。其次在DFIG频率支撑阶段,基于系统频率指标对综合惯量控制系数进行模糊逻辑设计,减小OPSA影响并提升DFIG调频能力。然后在转速恢复阶段,根据DFIG转速变化动态计算储能有功功率参考值,调整储能输出以减小SFD,并设计变系数比例-积分(proportional-integral,PI)控制以平滑恢复储能荷电状态(state of charge,SOC)。最后,在MATLAB/Simulink中搭建风-储-火四机两区域电力系统仿真模型,验证了所提策略的有效性,保证了高风电渗透率电力系统的频率稳定性。展开更多
With the rapid increase of wind farms,the grid code needs to be improved to meet the requirement of wind farms and enhance grid stability.Doubly-fed induction generators are largely used in wind turbines,but they are ...With the rapid increase of wind farms,the grid code needs to be improved to meet the requirement of wind farms and enhance grid stability.Doubly-fed induction generators are largely used in wind turbines,but they are very sensitive to grid disturbances.The voltage swell can be caused by switching on capacitor banks or switching off large loads,which may result in the reversal of the power flow in the grid convertor;the current may flow from the grid into the DC link,which may step up DC voltage,and result in large faults of rotor currents and instantaneous power oscillation.The grid reactive compensation devices can not have the automatic swithing function after the low voltage fault,which will result in local reactive power surplus,so some wind power generators will retreat from the grid under high voltage protection.展开更多
文摘More and more large capacity wind power will be integrated into power system in the future,and certain technical challenges will emerge due to the fluctuation characteristics of wind power and the complex control of power electronic devices inside the wind turbines(e.g.,low voltage ride through(LVRT)).By comparing a wind power integration grid with a hydropower integration grid,the special transient phenomena caused by the wind power integration is studied and simulation results are presented.Furthermore,the potential impacts on the traditional protection are discussed.Results show that the special transient phenomena can decrease the sensitivity,reliability and operation speed of conventional protections.
基金supported by State Key Laboratory of Power Transmission Equipment and System Security(No.2007DA10512711102,No.2007DA10512709202)Program of Introducing Talents of Discipline to Universities("111"Program)(No.B08036)the Fundamental Research Funds for the Central Universities(No.CDJXS11150026)
文摘Large-scale doubly-fed induction generator(DFIG)wind turbines are connected to the grid and required to remain grid-connection during faults,the short-circuit current contributed by the generation has become a significant issue.However,the traditional calculation methods aiming at synchronous generators cannot be directly applied to the DFIG wind turbines.A new method is needed to calculate the short-circuit current required by the planning,protection and control of the power grid.The short-circuit transition of DFIG under symmetrical and asymmetric short-circuit conditions are mathematically deduced,and the short-circuit characteristics of DFIG are analyzed.A new method is proposed to calculate the steady-state short-circuit current of DFIG based on the derived expressions.The time-domain simulations are conducted to verify the accuracy of the proposed method.
文摘为解决双馈风力发电机(doubly-fed induction generator,DFIG)采用综合惯量控制时固有调速器的抑制作用,及转速恢复时系统频率二次跌落(secondary frequency dip,SFD)的问题,提出了基于模糊推算和动态控制的风储联合调频控制策略。首先分析了电力系统频率响应特性,揭示了输出功率抑制量(output power suppression amount,OPSA)与SFD的产生机理。其次在DFIG频率支撑阶段,基于系统频率指标对综合惯量控制系数进行模糊逻辑设计,减小OPSA影响并提升DFIG调频能力。然后在转速恢复阶段,根据DFIG转速变化动态计算储能有功功率参考值,调整储能输出以减小SFD,并设计变系数比例-积分(proportional-integral,PI)控制以平滑恢复储能荷电状态(state of charge,SOC)。最后,在MATLAB/Simulink中搭建风-储-火四机两区域电力系统仿真模型,验证了所提策略的有效性,保证了高风电渗透率电力系统的频率稳定性。
文摘With the rapid increase of wind farms,the grid code needs to be improved to meet the requirement of wind farms and enhance grid stability.Doubly-fed induction generators are largely used in wind turbines,but they are very sensitive to grid disturbances.The voltage swell can be caused by switching on capacitor banks or switching off large loads,which may result in the reversal of the power flow in the grid convertor;the current may flow from the grid into the DC link,which may step up DC voltage,and result in large faults of rotor currents and instantaneous power oscillation.The grid reactive compensation devices can not have the automatic swithing function after the low voltage fault,which will result in local reactive power surplus,so some wind power generators will retreat from the grid under high voltage protection.
