Coordinated Control Strategy Of Wide-area Cluster Wind-ESS System

With sustained development and the scale expansion of wind power,its own volatility and intermittence will affect the output power quality in the process of paralleling in grid,which leads to high output power fluctuation,and affects the stability of the grid.At the same time,because of the influence of wind speed and geography,the wind power output will cause the wind power output inconsistent and the cluster system instable.The energy storage system responds quickly,and it can provide a solution for voltage drop and power fluctuation in the process of wind power integration.In this paper,from three aspects of the single unit,wind farm to the cluster system,the control strategy puts forward to maintaining the stable of the system operation and resolving the problems in the process of grid connection.The main work is as follows:(1)Research on low voltage ride through control strategy for doubly fed wind turbines equipped with supercapacitors.At first,constructed the system model of the wind turbine supercapacitor and the grid side converter,and the coordinated control strategy based on the grid side converter and the super capacitor DC/DC converter is put forward,and the specific control method of the converter is given.Based on the proposed control strategy,the charge or discharge of the supercapacitor is used to maintain the voltage stability of the DC side,and the grid side converter provides reactive compensation to ensure that the wind turbine has a low voltage crossing capability at the condition of the voltage falls when power grid voltage has dropped.(2)Research on the active power control strategy to smooth the output of wind farms based on the lithium battery.Firstly,establishing The equivalent model of lithium battery,and then proposing the power smoothing control strategy of the wind farm power storage system based on(State of Charge,SOC)regulation of lithium battery based on the moving average method.The control strategy is based on the state of charge and charge of the lithium battery and the state of charge and discharge.The fuzzy controller is designed to control the output power of the lithium battery,and the output power of the wind farm is smoothed.It is proved by simulation that the control strategy can realize the smooth need of the active power of the wind farm.At the same time,it can calculate the state of charge of the lithium battery in real time,and keep the lithium battery working in the safe and stable situation.(3)Research on the coordinated power control strategy of cluster wind power in the fixed area.It is designed a hierarchical control structure of cluster system and proposed a control method based on priority method to adjust the cluster system’s output power.The force control sequence is determined based on the control performace index,and the coordinated control strategy of the cluster wind water fire is given.Finally,the cluster system model is built,and the effectiveness of the control strategy is verified through the simulation.