Frequency Control Strategy For Power Systems With High Penetration Of Wind Power

With the development of social modernization,energy crisis and environmental pollution have brought more and more challenges to the sustainable development of society.Therefore,the development and utilization of renewable energy has been highly valued by all countries in the world.Wind power generation has an important position in the field of renewable energy because of its abundant resources,large scale development,short construction period and so on.It is an important research topic to improve the frequency control strategy of the interconnected power grid in order to adapt to the large-scale wind power access.Therefore,this paper focuses on the frequency control of wind power interconnected power system,which includes two aspects:wind turbine active participation in system frequency modulation and improvement of load frequency control of interconnected power grid.The main work of this paper includes:In order to eliminate the impact of rotor speed recovery process of the conventional kinetic energy control on the frequency response,an improved frequency control strategy for doubly-fed induction generator(DFIG)based wind turbines based on rotor kinetic energy control is proposed.The proposed improvement scheme can realize the active control of the rotor speed recovery start time,and the frequency drop process caused by the speed recovery is controlled to occur after the frequency is stable.Thus,the adverse effect caused by the speed of the rotor speed recovery process after the release of the rotor kinetic energy is eliminated.Simulation results show that the proposed method can effectively improve the performance of DFIG-based wind turbines participating into frequency regulation.In order to improve the design of the integer-order PID load frequency controller to meet the wind power access,a fractional-order PID load frequency controller for interconnected power grid with wind power is designed,and the parameters of the controller are optimized by PSO algorithm.The simulation results show that the controller has good dynamic response and anti-jamming capability.Compared with the integer-order PID load frequency controller,the fractional-order PID load frequency controller can better deal with the nonlinearity and uncertainty in the load frequency control.The fractional PID load frequency controller can effectively eliminate the negative influence to the interconnected power grid frequency control which caused by the uncertainty of wind power output,and provide a new solution for the load frequency control of wind power interconnected power grid.In order to improve the anti-parameter perturbation ability of load frequency controller,a load frequency controller for interconnected power grid with wind power is designed based on sliding mode control.The simulation results show that the load frequency controller based on sliding mode control has better control performance than the integer PID load frequency controller,which can better solve the load frequency control problem of wind power interconnected power grid.Compared with the fractional-order PID load frequency controller,the load frequency controller based on sliding mode control has better anti-parameter perturbation ability.The theoretical research and simulation results show that it is reasonable and effective to improve the frequency control strategy of wind power interconnected power grid from the two aspects of wind turbine active participation in system frequency modulation and improvement of load frequency control of interconnected power grid.which is helpful to improve the wind power interconnected power grid frequency stability control ability,and can provide a powerful guarantee for the safe and stable operation of wind power interconnected power grid.