Research On Fast Estimation Model And Mechanism Of Power System Frequency Response Integrated With Large Scale Wind Farms

Wind power has become the cleanest and fastest growing new energy generation in the world.China's megawatt scale wind power base is being gradually connected.With the increasing of wind power penetration,the inertia of the power system will gradually decrease and primary frequency modulation ability will gradually decrease,which will weaken the actual power system frequency response,even threaten the system's safe and stable operation.Therefore,the influence of large-scale wind power grid to power system frequency response and rapid assessment model with wind power system frequency response have an important theoretical and practical significance for high penetration of wind power system planning and operation.For the frequency response of power system connected with large-scale wind farm,the following two aspects are studied:(1)Power system planning and operation are to evaluate frequency response behavior of power system containing large-scale wind power.The current evaluation method of frequency response behavior of power system with large-scale wind power mainly relies on the establishment of a detailed electromechanical transient model for time domain simulation.However,the time domain simulation of the detailed electromechanical transient model with large-scale wind power is very time-consuming,which leads to the low efficiency of the system frequency response behavior evaluation.According to the above problem,this paper proposes a power system frequency response rapid assessment model with high wind penetration and explains in detail parameters equivalent polymerization method and error analysis method of the proposed frequency response model.Subsequently,IEEE 10 machine 39 node model was adopted to contrast and analyze the frequency response behavior of the detailed electromechanical transient model and the proposed rapid evaluation model.The results show that the calculation efficiency of the proposed model in MATLAB is several orders of hundred magnitude higher than that of the detailed electromechanical transient model in PSS/E and the accuracy of the analysis results is available.It is of great significance to the operation and planning of the power system.(2)For wind power units participating in the power system frequency modulation scene,The analytical formula of power system frequency response important indexes is derived,such as the initial decline rate of power system frequency,the lowest frequency,steady state frequency and steady state transition time.Research results show that the wind power units participating in virtual inertia control and droop control are helpful to improve the frequency response characteristics of the power system,but the different frequency modulation modes of wind power units have different contribution to the frequency response indexes of the power system.The virtual inertia control is used to improve the frequency conversion rate,the droop control is used to improve the lowest frequency and steady-state frequency.