Energy Storage Configurations With Multi-timescale Flexibility Resources

With the rapid development of renewable energy in recent years,while alleviating the shortage of fossil energy and reducing environmental pollution,its volatility and randomness also bring flexibility problems to the power system.Especially in the new energy grid with high external power supply ratio,the shortage of local adjustable power supply and the unadjustable external power supply aggravate the problem of insufficient flexibility of the system,and how to ensure the flexibility of the system has become an urgent problem to be solved.Faced with this problem,many scholars have studied the feasibility of new energy units and energy storage equipment to provide flexible support for power grid.Based on the existing research,this paper studies the optimization problem of energy storage allocation and existing flexible resources to improve power grid flexibility,and proposes an energy storage allocation model considering multi-time scale flexible resources.Firstly,based on the quantification of the frequency support problem,the critical thermal power generation ratio is proposed and verified by simulation.In this work,firstly,after the new energy is connected to the power grid on a large scale,the inertia support and primary frequency modulation support requirements of the power grid are introduced,and the frequency support constraints of the system are quantified to obtain the inertia support constraints and primary frequency modulation support constraints of the power grid as theoretical support for subsequent research.On this basis,considering the inertia support demand of new energy power grid under high external power receiving ratio,the critical value of thermal power generation ratio,that is,the critical thermal power generation ratio,which can meet the inertia support requirements of power grid,is theoretically deduced.Secondly,this paper establishes a energy storage configuration planning model considering multi-time scale flexible resources.In this work,the feasibility of allocating energy storage and matching with existing flexible resources to improve the flexibility of power grid is studied.Considering the existing models of energy storage and wind turbines participating in frequency support,taking the allocation cost of hybrid energy storage as the objective function and considering the active power constraints of power grid at different time scales,an energy storage allocation model considering flexible resources at multiple time scales is established.Finally,the influence of inertia on stability,the theoretical derivation of critical thermal power generation ratio and the simulation model of energy storage configuration are verified.The simulation example of critical thermal power generation ratio theory is based on PSASP7.61.04,and the modified EPRI-36 bus system is adopted.The example shows that the simulation results are consistent with the derivation of the critical thermal power generation ratio in this paper,which verifies the theoretical derivation of the critical thermal power generation ratio in this paper.Using Python3.10 as the platform and Gurobi9.5 as the modeling tool,the model proposed in this paper is modeled and solved in 5 minutes.The solution results show that the hybrid energy storage configuration can effectively improve the flexibility of power grid,meet the active power requirements of power grid at different time scales,reduce the critical thermal power generation ratio of the system to a certain extent,and achieve the effect of ensuring the safe operation of the system.