Frequency Regulation And Optimal Operation Model With Risk Aversion Of Wind-storage System

The proportion of renewable energy sources which is environmental but uncertain and difficult to adjust in the power system is rising rapidly,which brings great challenges to the frequency security and stability of the power system.Under the guidance of the current policies about renewable energy and energy storage,how renewable energy with energy storage to participate in the frequency regulation of the power system has become a key concern in the field of renewable energy.It is of great significance to study the coordinated control strategy and economic optimization of frequency regulation for renewable energy and energy storage combined system.Comparing differences of frequency regulation between novel and traditional power system in terms of interconnection structure,inertia demand&frequency regulation characteristics and active power&frequency dynamic process after disturbance.This paper analyzes reasons of the low inertia of novel power system and the differences between inertia response and frequency regulation.The advantages and disadvantages of renewable energy active power control technology are compared.This work ensure that renewable energy and energy storage participate in the frequency regulation effectively and feasible.In the field of inertia response and primary frequency regulation of wind-storage system,the inertia support power of wind power is derived from the perspective of kinetic energy transformation.The frequency signal is added to VSG in order to achieve quantitative correlation between mechanical frequency of rotor and power grid frequency.Kinetic energy sensitivity constraints are set and translated into frequency sensitivity constraints of wind turbine inertia support power.The inertia response strategy of wind turbine is proposed.An energy storage frequency regulation model is adopted,which is supplemented by inertia support and dominated by primary frequency regulation.An adaptive regulation strategy of virtual inertia coefficient and virtual droop coefficient is designed based on SOC feedback.Simulation results show that the wind-storage system can effectively improve the safety and stability of power grid frequency by adopting proposed strategies.In the field of secondary frequency regulation and generation scheduling of wind-storage system,studying wind-storage system participates in both AGC and generation scheduling.Considering wind power deviation,the AGC power strategy of energy storage is proposed.The deviation of the wind-storage system is assessed by setting the nonlinear ladder deviation penalty coefficient in the balanced market.The tail risk contained in the loss caused by the deviation is measured by CVaR.Random scenarios of wind power and AGC signals are generated by Monte-Carlo and reduced by fast forward method respectively,and scenarios are combined by cartesian product.A day-ahead optimization model for maximizing the total expected return of the wind-storage system is established.A risk avoidance factor that could reflect the risk acceptance degree of decision-makers is introduced.Simulation results show that the proposed strategies and models can effectively avoid the risk of wind-storage system market participation and reduce generation deviation.In order to promote the application of the proposed strategy and model,the economics of wind-storage system participating in inertia service and different decision makers participating in frequency regulation service are verified from the perspective of auxiliary service market.The participation of renewable energy and energy storage in grid frequency regulation is conducive to strengthening the dominant position and ability of renewable energy in the novel power system and promoting the transition from the traditional power system to a more environmental,efficient and reliable novel power system.