Research On Cross-Regional Reserve Sharing In Interconnected System With High Wind Power Penetration

Leveraging on technology upgrading and policy support,the wind power industry in China has experienced leap-forward development in the past decade.The new and cumulative installed wind power capacity of China have ranked first in the world for many years,whereas the level of wind power accommodation has failed to achieve the world's forefront.The existing utilization of wind power in China is mainly based on large-scale centralized development mode.The volatility and uncertainty of wind power have led to a surge in spinning reserve requirements.However,affected by intrinsic resource constraints and wind power crowding,the flexibility resources such as pumped storage and hydro power are scarce in regions with significant wind power penetration.Furthermore,CHP units account for the majority of the newly installed thermal units in these regions,which leads to further insufficiency of spinning reserve during heating seasons.The increasing difficulty for local reserve to meet the demand of full-scale wind accommodation has become a main reason for wind curtailment.Therefore,in order to promote wind power integration and sustain further development,it is of great significance to study the solution to tackle with the lack of reserve capacity in regions with high wind power penetration.With the construction of China's AC and DC UHV and inter-provincial tie-lines,it is possible to coordinate the use of multi-region flexibility in the large-scale interconnected power system.Mainly based on multi-region coordinated scheduling and inter-regional reserve sharing,this paper studies the coordination strategy of reserve capability in the interconnected power system,which solves the reserve insufficiency problem in regions with high wind power penetration.Furthermore,the reserve sharing cost is considered in the cross-regional reserve sharing model for the practicality of proposed method.Firstly,in order to estimate spinning reserve requirements in wind power integrated power system,this paper deduces the function description between loss of load probability and up reserve,as well as the functional description between wind curtailment probability and down reserve,considering wind power uncertainty,load fluctuation and generation unit failures.Then,a method to determine reserve demand based on above two reliability indices is given,laying foundation for the research of multi-region coordinated scheduling and cross-regional reserve sharing.Secondly,aiming at the reserve insufficiency problem in regions with high wind power penetration,a cross-regional coordination scheduling model adaptable to various tie-lie operating modes is established,the model achieves the optimized allocation of reserve through coordinated multi-region units and tie-lines scheduling.The simulation results demonstrate the effectiveness of the proposed method in solving reserve inadequacy for regions with high wind penetration.The influence mechanism and scope of application of the proposed method on region reserve capability are also analyzed.Finally,considering the lack of coordination scheduling strategy based upon independent reserve sufficed within each own region,this paper proposes a cross-regional reserve sharing scheme based upon the principle that regions sufficient in reserve provide reserve assistant for regions insufficient in reserve,the additional cost caused by cross-regional reserve sharing is also taken into account in this paper.Hence,a cross-regional reserve sharing model considering reserve sharing cost is established,the effectiveness of the model in solving reserve insufficiency within one region is demonstrated in case study.The comparative analyses of different reserve sharing schemes indicate the necessity of considering reserve sharing cost.This paper also analyses the impact of reserve sharing cost on reserve sharing decisions.