In order to solve the problem of insufficient frequency modulation of thermal power units caused by large-scale new energy power grid connection,we proposed an optimal control strategy for thermal power units to maintain power grid frequency stability assisted by energy storage based on the characteristics of fast response of energy storage batteries.By analyzing energy storage dead zone and thermal power unit dead zone,the frequency deviation is divided into three regions with these two dead zones as the boundary.According to the frequency modulation requirements of each region and the advantages of virtual droop control and virtual inertia control,we adopted different strategies to sup-press the deterioration of frequency deviation and its change rate to the greatest extent.Considering the energy storage capacity,we adopted the optimized logistic function to adjust the unit power coefficient(i.e.,droop and inertia coef-ficients)to prevent SOC from reaching the off-limit region too quickly.Finally,we used Matlab/Simulink to simulate the step load disturbance and continuous load disturbance.The results show that the control strategy can not only re-duce the output power of thermal power unit,but also significantly suppress the deterioration rate of frequency devia-tion,reduce the time of frequency stability and improve the stability of the system.
关键词
一次调频/虚拟下垂控制/虚拟惯性控制/荷电状态/储能系统
Key words
primary frequency/modulation virtual droop control/virtual inertial control/state of charge/energy stor-age system
维普
万方数据