Research On Power Control Strategy Of Wide Area Wind Farm Clusters

In recent years,with the large-scale access of wind power in the power system and the continuous improvement of wind power penetration rate,the issue of large-scale wind power integration to the power system has become more and more prominent in terms of active frequency and reactive power regulation voltage.It is impossible to meet the requirements of system stability only relying on the traditional power supply for grid performance control,and it is urgent to have the ability of wind power to coordinate with traditional power sources to participate in power system performance control.Wind farms in the cluster are close to each other in space and are closely connected with each other,therefore,they can be connected together into a grid through clustered transformer substations.These wind farms can be coordinated and controlled as a whole with the centralized transformer substations.This control mode will effectively improve the wind power output of the cluster,reduce network losses and enhance voltage stability.Therefore,it is very important to study the power control strategy of wide-area wind power clusters.The main works are as follows:(1)Analyzing the typical topological structure of the wind farm,dividing the wind farms based on the Jensen model of the wake effect,then using the modified capacity-weighted equivalent method to set up the wind farm equivalently model.Simulating on PSCAD software,it is verified that the multi-machine equivalent is more accurate than the stand-alone equivalent model.(2)Based on the principle of layering,wind farm cluster's active power control system is designed.In order to maximize the use of real-time coordinated control of wind farm cluster and achieve rational allocation of capacity between wind farms,a dynamic real-time control model of wind power cluster is established,it based on dynamic priority sorting method and multi-objective multi-constrained optimization algorithm.(3)The wind farm cluster's active power optimization allocation method based on genetic algorithm is adopted.This method maximizes the active power output of the wind farm cluster and minimizes the line loss as control targets.It will avoid frequent start-stops of wind turbines as a constraint,and take into account the influence of short-term power prediction errors.Taking an actual wind farm cluster in China as an example to verify the effectiveness and feasibility of the method.(4)Taking into account the coordination between wind farms within a cluster and between wind farms and aggregating substations,a coordinated reactive-voltage control strategy for wind farm cluster is proposed,specifically including the voltage optimization control strategy for wind farm cluster,the voltage overrun control strategy for wind farm cluster and wind power convergence transformer substation's reactive voltage coordination control strategy,and verify it with simulation analysis.The simulation results of the example show that the voltage level of the wind farm cluster has been significantly improved by adopting the strategy proposed in this paper,and the network loss in the wind farm cluster area has also been significantly reduced.The test results has verified the correctness and effectiveness of the reactive power and voltage coordinated control strategy.