| With the deepening of the carbon peaking and carbon neutrality goals and the reform of China’s power system,the intrinsic characteristics of the new power system have been continuously highlighted.First of all,its energy resources are balanced in time and space,with a larger spatial scale and a smaller time scale.Secondly,a large number of new energy sources are continuously connected to the power grid,and the inherent volatility and uncertainty of new energy power generation and the low inertia of the power system make the operating characteristics of the power system more complex and changeable,and it is difficult for traditional frequency regulation units to meet the frequency regulation demand under the increasing penetration rate of new energy.When the power grid containing large-scale new energy is disrupted by shock load,it will seriously affect the frequency stability of the system.In recent years,Battery Energy Storage System(BESS)has become an important frequency regulation resource with its rapid,precise output and high climbing rate to improve the frequency regulation performance of regional power grids under the situation of high penetration rate of new energy.With China’s continuous attention to energy storage and the leading advantages in power grid construction and dispatching,the configuration of energy storage in the power grid is bound to become an important frequency regulation means of the new power system.Based on this background,in order to better promote the application of energy storage in the field of power system frequency regulation,it is of great value to study how to make full use of existing battery energy storage resources to participate in frequency regulation of single-region power grids and multi-regional interconnected power grids.In the above context,this thesis takes single-area power grid and multi-area interconnected power system with battery energy storage as the research object,and studies the control strategy of battery energy storage in frequency regulation of single-region power grid and multi-regional interconnected power grid,the main contents are as follows:(1)Firstly,the mechanism of the Load Frequency Control(LFC)of power system is analyzed,and on this basis,the dynamic element model of power grid frequency regulation is established,including the governor model of thermal power plants,steam turbine model,generator-load model and tie-lines model.Secondly,the operation mechanism of energy storage participating in frequency regulation in the power system is analyzed,and the battery energy storage model that can reflect the frequency regulation characteristics of battery energy storage is established.Finally,on the basis of considering the nonlinear factors that cannot be ignored in the actual power grid,the load frequency control model of power system with battery energy storage is established,which lays a foundation for studying the control strategy of battery energy storage participating in frequency regulation in single-region power grid and multi-regional interconnected power grid.(2)Aiming at the problem of coordinated allocation of frequency regulation power instruction in frequency regulation control strategy,a two-tier distributed coordinated control strategy for battery energy storage to participate in single-region power grid load frequency control is proposed.In the upper layer,based on the Area Control Error(ACE)signal,the State of Charge(SOC)management and the technical characteristics of different frequency modulation power sources are comprehensively considered to complete the coordinated distribution of the frequency regulation signal between energy storage and traditional units.In the lower layer,considering the operation economy optimization needs of the energy storage system,the operating cost model of energy storage frequency regulation is established,and the distributed energy storage is coordinated and controlled based on the distributed consistent algorithm,so as to realize the refined management of their respective output and complete the response to the frequency regulation demand signal.The simulation results show that the proposed control strategy can give full play to the technical characteristics of different frequency regulation power sources,while improving the frequency regulation effect of single-area power grid,excessive loss of energy in the energy storage system can be avoided to realize continuous operation of the energy storage system.(3)For the multi-regional interconnected power system,a distributed load frequency control strategy of multi-regional interconnected power system with the participation of battery energy storage is proposed.On the basis of clarifying the topology of multi-regional interconnected power grid,this strategy first divides the system into several subsystems by region,and designs the Distributed Model Predictive Control(DMPC)structure of multi-regional interconnected power system with battery energy storage;Secondly,based on the load frequency control model of power system with battery energy storage established in Chapter 2,the construction of the state space model of multi-regional interconnected power system with the participation of battery energy storage is completed.Then,based on the principle of DMPC,the DMPC controller is designed with the comprehensive index composed of output prediction error and control increment of each region as the optimization goal,and the Alternating Direction Method of Multipliers(ADMM)is used to solve it.Finally,the effectiveness and feasibility of the design scheme in the thesis are verified through the comparative analysis of the simulation results. |
