含风电的双馈抽水蓄能机组协调调频策略

Coordinated frequency modulation strategy of doubly fed pumped storage units with wind power

双馈抽水蓄能机组解耦控制使得其转子无法响应系统频率变化。为提高双馈抽水蓄能机组参与系统调频能力,提出一种转子动能与导叶开度协调控制的控制策略。首先建立水泵水轮机和双馈电机的数学模型,分析双馈抽水蓄能机组进行导叶开度寻优的过程。其次在水泵水轮机的导叶开度控制中加入频率控制环节,同时根据机组可用转子动能整定可变调差系数,确保机组转速始终运行在安全范围内。最后结合两种控制的调频优势,依据频率变化协调两种控制参与调频的比例系数,实现二者平滑切换。在含风机的系统中仿真分析,结果表明所提控制策略在抽水蓄能机组发电、电动工况下均能够提高机组频率响应能力和电网的风电消纳能力。

The decoupling control of a doubly fed pumped storage unit makes its rotor unable to respond to a change of system frequency.To improve the ability of the storage unit to participate in system frequency modulation,a control strategy of coordinated control of rotor kinetic energy and guide vane opening is proposed.First,the mathematical models of pump turbine and doubly fed generator are established,and the optimization process of guide vane opening of the storage unit is analyzed.Secondly,the frequency control link is added to the guide vane opening control of the pump turbine,and the variable difference adjustment coefficient is set according to the available rotor kinetic energy of the unit.This ensures that the unit speed always operates within the safe range.Finally,combined with the frequency modulation advantages of the two controls,the proportional coefficients of the two controls participating in frequency modulation are coordinated according to the frequency change,so as to realize smooth switching between the two.In the system with wind turbine,the simulation results show that the proposed control strategy can improve the frequency response capacity of the unit and the wind power consumption capacity of the power grid under the power generation and electric conditions of the pumped storage unit.