Power System Optimal Dispatch Method For Inertia And Frequency Response Reserve Demand

In recent years,clean and renewable energy represented by wind power has developed rapidly,which plays an important role in alleviating the energy crisis.However,with the continuous improvement of wind power penetration,the uncertainty of wind power output and the low inertia characteristics of wind turbines to the grid bring challenges to the stable operation of the grid.At the same time,the load side frequency modulation resources are relatively diversified,with high degree of uncertainty,and the frequency modulation response ability of various resources is different.Therefore,in order to give full play to the ability of wind power and load to participate in frequency regulation and improve the operation stability of power system,it is of great significance to further carry out the research on power system optimal scheduling method for inertia and frequency regulation reserve demand..This paper mainly studies the optimal scheduling model of the source load reserve frequency response reserve resources integration into the system,and the main work is summarized as follows:(1)In order to meet the challenge of low inertia support to the stable operation of power system,the inertia demand of wind power and load participating in frequency response is quantified,and the minimum inertia demand constraints of power system with wind power and load participating in frequency response are constructed.Firstly,according to the low inertia characteristics of wind turbine to the grid,the principle of synchronous inertia and wind power virtual inertia is studied.The minimum inertia demand under severe power loss is calculated and the minimum inertia demand constraint is constructed to ensure the frequency stability of large-scale wind power after it is connected to the power system.Secondly,according to the frequency regulation of load on power system,the motion equation of synchronous generator is deduced again.The minimum inertia demand of power system with load participating in frequency response is quantified reasonably when the system is in power shortage.The relevant constraints of power system inertia demand for load participation frequency response are constructed.Finally,the simulation results show that the proposed model and method can reasonably determine the minimum inertia demand under the condition of high power shortage and improve the inertia response capability of the system.(2)Aiming at the high-order uncertainty of wind power,a two-stage robust unit combination model is established to represent the probability distribution value of wind power prediction error based on the normal cloud model,and to combine the feasible region of 1-norm and norm conditions to constrain the probability of wind power prediction error.Meanwhile,considering the characteristics of low frequency response capability of high permeability wind power system,the dynamic frequency response model of wind power participating in frequency response is considered comprehensively in the optimization model.The time-domain optimization and frequency control are combined.Through the analysis of time-frequency domain,the whole process constraint of "inertia support frequency lowest point quasi steady-secondary frequency response" is derived to meet the inertia and frequency regulation of each stage Spare demand for.Based on this,the proposed model is mixed with integer linearization,and the column and constraint generation algorithm are used to solve the problem.The optimization cut can effectively reduce the complexity of the solution.The simulation results show that the proposed model and method can effectively improve the frequency response ability of the system and ensure the safe and economic operation.(3)In order to determine the reserve reasonably,the response delay and communication delay of load are carefully considered,and the high-order dynamic frequency response model of unit and load is coupled.Aiming at the problem of time-frequency conversion,the delay time constant is replaced equivalently,and the reserve constraint of "inertia-primary frequency regulation-secondary frequency regulation" is derived.At the same time,aiming at the aggregate power oscillation of air-conditioning,the equilibrium constraint of air-conditioning operation state is constructed,which is incorporated into the quantitative model of air-conditioning frequency regulation capacity in each scheduling period,and the scheduling potential of air-conditioning load in each scheduling period is quantified,which is integrated into the dynamic frequency response power constraint of air-conditioning load.Based on this,the unit commitment model is constructed by considering the constraints of unit,wind power and frequency regulation,and the mixed integer linearization is used to solve the model.Finally,the simulation results show that the proposed model and method can reserve the spare resources reasonably and ensure the safe and economic operation of the system.