基于动态下垂系数与SOC基点的储能一次调频控制策略

Primary frequency regulation control strategy of energy storage based on dynamic droop coefficient and SOC reference

为高效利用储能资源满足电网一次调频需求,提出一种基于动态下垂系数与动态SOC基点(Dynamic Droop Coefficient and Dynamic Reference of SOC,DDC&DRSOC)的储能一次调频控制策略。提出以电网调频死区为分割边界将储能调频过程划分为调频阶段与SOC恢复阶段:在调频阶段,以SOC和最大频率偏差为控制量自适应调整储能出力深度以防止储能SOC的饱和或殆尽;在SOC恢复阶段,首先提出适应负荷变化的动态SOC恢复基点调整方法,然后提出兼顾SOC恢复需求与电网承受能力的储能出力确定方法,最后设计双层模糊控制器实现动态SOC基点值和储能出力值的确定。提出3个评价指标评估一次调频效果与SOC维持效果。以某区域电网为例,在阶跃负荷扰动和连续负荷扰动下验证了所提策略的有效性。仿真结果表明所提策略SOC维持效果较对比策略提高9%,调频效果提高4%。

In order to efficiently use Energy Storage System(ESS)to meet the Primary Frequency Regulation(PFR)needs of the power grid,a control strategy for ESS based on dynamic droop coefficient and dynamic SOC reference is proposed.It is proposed to divide the ESS frequency regulation process into frequency regulation stage and SOC recovery stage with the frequency dead zone of power system as the boundary.In the frequency regulation stage,the SOC and the maximum frequency deviation are used as control variables to adaptively adjust the output of ESS to prevent the SOC from exceeding the limit.In the SOC recovery stage,first,the dynamic SOC restoration reference adjustment method that adapts to load changes is proposed.Then,a method for determining the output power of ESS that takes into account the SOC recovery requirement and the power grid affordability is proposed.Finally,a double-layer fuzzy controller is designed to determine the dynamic SOC restoration reference and the power of the ESS.Three evaluation indicators are proposed to evaluate the frequency regulation effect and SOC maintenance effect.Taking a certain regional power grid as an example,the effectiveness of the proposed strategy is verified under step load disturbance and continuous load disturbance.The simulation result shows that the SOC maintenance effect and frequency regulation effect of the proposed strategy is 9%and 4%higher than the comparison strategy,respectively.