Research On Siulation Of Large-Scale Grid-Connected Wind Farm

Exploitation and utilization of wind power have significance to energy developing and environment improving. Wind power will be rapidly developed in China, and fund allocated on wind power development will increase year by year. For the sake of improving the efficiency of wind energy, all kinds of research for wind turbine generator system will be widely developed all over the world.Wind power is unstable,and generally most wind farms are located in weak grid. Large-scale wind farm will become mainstream in future wind industry. But as the scale of wind farm increases, more importance should be attached to the stability problems brought by connection to power system. Wind generator system includes 2 types,constant-speed constant-frequency system and variable-speed constant-frequency system. As variable-speed wind generators have the superiority of keeping system stable,they have been replacing the constant-speed wind generators and becoming mainstream wind generators in the world. Furthermore, for local power system,wind farm is an uncertain factor,so the scale of wind farm it can receive is limited.This paper sets a view to the mutual influence between wind generator and power system,and does some research on the problems brought by large grid-connected wind farm aimed at actual situation in China through two points of generator control strategy choice and power system connecting analysis. In the point of generator control strategy choice,this paper sets cage asynchronous generator and doubly-fed induction generator as research objects,and emphasizes the superiority in which aspect variable-speed wind generator system keeps power system more stable. In the point of power system connecting analysis,the paper analyses the maximum power injection of wind farm from static and dynamic stability points, with the intention of seeking methods to improve the wind farm's stability. These methods include choosing variable-speed wind system,connecting wind farm to high voltage power system and increasing spare capability for power system.