基于权重系数校正的火储两阶段联合调频方法

Two-stage Frequency Regulation Method for Energy Storage Coordinated with Thermal Power Unit Based on Weight Coefficient Correction

随着不确定性可再生能源大规模并网,电网频率特性日益复杂。传统火电机组具有响应时间长、无法准确跟踪指令等问题,亟须利用储能提高火电机组参与自动发电控制(automatic generation control,AGC)调频时的调节性能。首先,针对调频考核规则,建立调频性能指标数学模型,并考虑火储系统出力特性,结合改进层次分析法校正调频子指标权重系数,以此构建以调频性能最优为目标的第一阶段优化模型;在此基础上,为了减少储能荷电状态(state of charge,SOC)越限和深度充放情况,以储能SOC偏差最小为目标构建第二阶段优化模型。仿真验证表明:所提的两阶段调频方法能够提高火储联合系统的调频性能和调频收益,同时有效减少储能深度充放情况和工作寿命损耗,提高储能辅助调频服务的可持续性。

With the large-scale uncertain renewable energy connected to the grid,the frequency characteristics of the power grid are increasingly complex.Plagued by long response times and the inability to accurately track frequency regulation commands,traditional thermal power units call for urgent improvement in the performance of its participation in frequency regulation of automatic generation control(AGC)of thermal power by use of energy storage.Therefore,firstly,the mathematical model of frequency regulation performance index is established according to frequency regulation assessment rules.Besides,considering the output characteristics of the energy storage system,combined with the improved analytic hierarchy process to correct the weight coefficient of the frequency regulation sub index,the first-stage optimization model aiming at the optimal AGC performance is constructed.On this basis,in order to reduce the limit crossing and storage depth charging&discharging cases at the state of charge(SOC),the second-stage optimization model is constructed in order to minimize the SOC deviation.The simulation verification shows that the two-stage frequency regulation method proposed in this paper can improve the frequency regulation performance and benefits of the system of energy storage coordinated with thermal power unit,while reducing the energy storage in-depth charging&discharging cases and working life loss,thus improving the sustainability of frequency regulation auxiliary service of energy storage.