Based On Renewable Energy Power System Load Frequency Control

With the process and development of industrialization,fossil energy has been depleted and renewable energy sources(RES)are connected to the grid on a large scale,and the power generation end of modern power system shows a diversified development trend,and there are many types and quantities of loads.However,traditional load frequency control(LFC)methods cannot meet the needs of modern power systems.In the process of energy transformation,in order to rationally plan RES and improve its utilization,electric vehicles have been vigorously developed as representatives.The concept of electric vehicle to power system(Vehicle-to-grid,V2G)has been proposed,which has given electric vehicles a new meaning in the power system.Electric vehicles can not only assist the frequency regulation of the power system,but also serve as a small energy storage unit,but after the electric vehicle is connected to the grid,the LFC has to consider more factors.Secondly,photovoltaic power generation has no pollution,sufficient sources and other characteristics in the power system penetration rate is getting higher and higher,in 2020 statistics,it is expected that in2050,photovoltaic power generation will become the largest power generation energy.The development of energy storage system is another factor promoting the development of RES,photovoltaic energy storage integration reduces the phenomenon of curtailment and greatly improves the utilization rate of photovoltaic energy.Like electric vehicles,the random and intermittent nature of photovoltaic systems is seriously affecting the safe and stable operation of the power system.In order to eliminate the frequency fluctuation caused by the above,this thesis the LFC of electric vehicles and photovoltaic auxiliary power generation systems,including the following:1)According to the power supply and charging characteristics of electric vehicles and the operation characteristics of photovoltaic power generation systems,an energy storage system for frequency regulation of power systems is added to the traditional single-area thermal power unit LFC model;Finally,the tie line model is introduced to establish the LFC model of multi-regional power system.2)For the LFC system containing electric vehicles,the influence of the state of electric vehicles as a power source and load on the system frequency is considered separately.In order to further fit the actual situation,the disturbance of the white noise simulation system is added to the photovoltaic power generation model,and the communication delay between electric vehicles,photovoltaic power generation and traditional LFC systems and the delay between generator and motor are considered respectively.For the two multi-source interconnected LFC system models with strong randomness,in order to achieve the coordinated control of multi-regional power system,the corresponding controller is designed by sliding mode control method for the established LFC model,and the simulation analysis is carried out.From the results,it can be seen that the designed controller realizes the cooperation of various subsystems,which is conducive to the control of the system frequency.3)LFC analysis was carried out for renewable energy island operation.Different types of energy have different environmental constraints,and the controller is designed with the idea of model predictive control,and information transmission is carried out through various energy subsystems to achieve different types of energy collaborative control.Through the analysis of simulation results,under the action of the controller,the frequency of different energy outputs can be stabilized and controlled,which improves the stability of the power system to a certain extent.