考虑储能调频死区与荷电状态的一次调频策略

为更好改善电网频率特性,发挥储能电池辅助调频作用及快速响应优势,提出考虑储能调频死区和荷电状态(State of Charge,SOC)的电网一次调频自适应控制策略。基于对电网幅频特性的分析,设置储能调频死区小于传统机组调频死区,使储能先于传统机组快速响应负荷扰动,有效平抑频率波动。通过分析虚拟惯性控制在一次调频过程中的出力特点,提出正反向虚拟惯性控制,使储能在整个调频过程中出力方向始终与频率恢复方向一致,降低频率恶化速度,促进频率恢复。在此基础上,提出储能电池综合控制方法：在传统机组调频死区内,储能采用下垂控制;传统机组参与调频后,储能采用下垂与正反向虚拟惯性相结合的控制方式,并根据频率偏差和SOC实时调整二者的控制系数及出力比重,有效避免电池过充过放。最后在MATLAB/Simulink平台搭建含储能的区域电网一次调频模型,在不同工况下仿真验证了所提策略的有效性。

Primary Frequency Regulation Strategy Considering Dead Band and State of Charge of Energy Storage

In order to improve the frequency characteristics of the grid, make better use of battery energy storage and its advantages of rapid response in frequency regulation, an adaptive control strategy for primary frequency regulation of power grid considering dead band of energy storage and its state of charge (SOC) is proposed. Based on the analysis of the grid"s amplitude-frequency characteristics, the frequency regulation dead band of energy storage is set to be inside that of conventional generator, so that energy storage can respond to load disturbances more quickly than conventional generators and effectively smooth frequency fluctuations. By analyzing the output characteristics of virtual inertial control, positive/negative virtual inertial control is proposed, thus the direction of energy storage output power is always consistent with the frequency recovery direction during the entire regulation process, reducing the speed of frequency deterioration and promoting frequency recovery. On this basis, a comprehensive control method for energy storage battery is proposed: in conventional generators frequency regulation dead band, energy storage adopts droop control; when conventional generators participates in regulation, energy storage adopts a control method combining droop and positive/negative virtual inertial control, and both control coefficient and output proportion are adjusted according to the frequency deviation and SOC, avoiding overcharge and overdischarge of batteries effectively. Finally, a primary frequency regulation model of regional power grid with energy storage batteries was built on MATLAB/Simulink platform, and the effectiveness of the proposed strategy was verified through simulations under different working conditions.