Research On Primary Frequency Regulation Of Hybrid Energy Storage Participating In Photovoltaic Power Station

Photovoltaic power generation has the characteristics of randomness and volatility,and there is no inertia through power electronic grid-connection.Largescale grid-connection of photovoltaic power generation brings huge challenges to the frequency safety and stability of power system.Flywheel energy storage has high cycle times,fast response speed,and large charge and discharge power in short time.Lithium battery energy storage has high energy density and long energy release time.The two complementary participation in PV primary frequency regulation can effectively improve the active support capacity of PV to the safety and stability of power grid frequency.Therefore,this paper studies the capacity optimization allocation method based on ICEEMDAN hybrid energy storage to participate in PV primary frequency modulation,and determines the best configuration scheme of flywheel and lithium battery,proposed a hybrid energy storage participating in PV primary frequency regulation control strategy including energy storage primary frequency regulation adaptive coordination control and frequency deviation allocation module.The performance of primary frequency modulation in multiple disturbance scenarios is improved The main research work and achievements of this paper are as follows:(1)The frequency modulation models of flywheel energy storage and lithium battery energy storage are established.A primary frequency modulation model of photovoltaic power station with a frequency response layer is established,and the response performance of the model under three extreme frequency disturbances is verified by simulation.(2)The power requirements of primary frequency regulation of photovoltaic power stations are analyzed.Aiming at the complementary characteristics of flywheel energy storage and lithium battery energy storage,a capacity optimization allocation method based on ICEEMDAN decomposition involving hybrid energy storage in primary frequency regulation of photovoltaic power stations is proposed.In this method,photovoltaic primary frequency regulation demand power is decomposed and reconstructed into high frequency and low frequency components,which are used as frequency regulation instructions of flywheel and lithium battery energy storage respectively.Taking the net income of photovoltaic and energy storage system as the objective function,a hybrid energy storage capacity optimization configuration model was established,which included primary frequency regulation income,initial energy storage investment and replacement cost,and frequency regulation deficit penalty cost.In order to avoid falling into the local optimal solution,hybrid particle swarm optimization algorithm based on hybridization was selected.Finally,based on the actual operation data of a photovoltaic power station in Shanxi,a numerical example analysis was carried out to verify the effectiveness of the hybrid energy storage capacity optimization configuration model,which has certain investment reference significance.(3)In view of the different characteristics of the main control modes of primary frequency regulation,the frequency variation characteristics of primary frequency regulation process,and the influence of energy storage SOC on the operating life of energy storage,the adaptive coordination control of primary frequency regulation of energy storage was proposed.At the same time,considering the different characteristics of flywheel and lithium battery energy storage,a frequency deviation allocation module is designed.The simulation results show that under the three scenarios of load step disturbance,continuous random disturbance and intermittent photovoltaic power output disturbance,compared with no energy storage and droop control strategy,the proposed strategy can effectively improve the primary frequency modulation effect of photovoltaic power station,the frequency fluctuation range is smaller,and the frequency stability is greatly improved.At the same time,the frequency modulation pressure of thermal power unit in single region power system is alleviated.