Study On System Frequency Control Considering Wind And Aluminum Joint Participatio

With the continuous promotion of large-scale integration of new energy and the "dual carbon" strategy,traditional power system frequency adjustment faces problems such as slow response and low ramp rate.In the era of new power systems,new energy units represented by wind power play an important role in grid frequency regulation.However,due to natural conditions,wind power output has random and fluctuating characteristics,which can easily cause power imbalance in the system.Therefore,it is necessary to fully tap new frequency regulation resources.With the concept of "smart grid" proposed,heavy industry loads represented by high-energy-consuming electrolytic aluminum have significant potential for regulation due to their large thermal storage capacity,which is of great significance for improving the flexibility and stability of the power system.Based on the above background,this paper conducts a comparative in-depth study on load frequency control(LFC)of the power system from three aspects: modeling of frequency regulation resources on both sides of the source and load,improvement of load frequency controller,and wind-aluminum joint participation in frequency regulation control strategy,focusing on the structural characteristics of the two-region interconnected system and the demand for system frequency stability.The main research work of this paper is as follows:(1)A two region interconnected power grid model with frequency modulation resources on both sides of the source and load has been established.The unit model of the power system is the foundation for achieving interconnected regional frequency regulation.Based on a detailed analysis and discussion of the frequency characteristics of the power system,a reheat steam turbine unit and its governor,load,and tie line model considering nonlinear factors have been established;At the same time,the frequency characteristics and mathematical models of new frequency modulation resources represented by double fed induction generators(DFIG)and electrolytic aluminum loads on both sides of the power system source and load were analyzed and described.(2)A fractional order PID controller based on particle swarm optimization has been designed.In order to cope with possible random disturbances in the system,a fractional order PID controller(FOPID)based on Particle Swarm Optimization(PSO)optimization was designed.The controller aims to suppress system frequency fluctuations as its control objective.By inputting an Area Control Error(ACE)signal and using an improved Oustaloup filter approximation method,better approximation performance can be achieved in the full frequency band.The original ITAE index evaluation function is also improved,resulting in better dynamic performance in parameter optimization;At the same time,in order to improve the performance of the FOPID controller,the PSO algorithm is used to optimize the controller parameters to achieve better control performance.Finally,the designed controller is simulated and verified through an example.(3)A wind aluminum joint participation frequency control strategy has been proposed.In response to the current practical needs of insufficient frequency regulation capacity and weak system inertia in the power system,a control strategy for collaborative participation of frequency regulation resources on both sides of the source and load is proposed.This strategy includes improving virtual inertia control for wind turbines and precise load reduction for electrolytic aluminum plants based on self saturated reactors.In terms of wind turbine control strategy,a fast active power support method based on improved virtual inertia control has been proposed,which can effectively increase the participation of the Wind Energy Conversion System(WECS)in existing frequency regulation,better respond to various working conditions and load demands,and significantly improve the frequency response ability of wind turbines;In terms of electrolytic aluminum load reduction to support grid frequency regulation,a dual closed-loop control strategy is proposed based on the fast current stabilization control characteristics of self saturated reactors to reduce active power consumption and assist in grid frequency regulation.This strategy utilizes the characteristics of high thermal density,large thermal inertia,and easy control of electrolytic aluminum load to achieve precise and rapid load reduction,significantly improving system frequency stability;Finally,based on the regional interconnected system and with the goal of suppressing system frequency fluctuations,the two types of frequency modulation resources were controlled in parallel.The rationality and effectiveness of the proposed source load collaborative control strategy were verified through simulation analysis.