Research On Key Technology Of Active Power Control System In The Wind Farm

As the most important form of clean energy resource, wind power has developed rapidly. The capacity is growing at fast rate and wind power is taking more and more proportion in power supplies. Obviously, the effective control of output power in large-scale wind farm, together with the grid scheduling system, should be more and more important for wind power development. Therefore, active power control has become an urgent problem for the wind farm grid connection. This article has mainly studied on the power control theory of wind farm, the implementation of active power control in wind farms and wind turbines, the control algorithm of wind turbine and the stability of active power control. Some specific measures are included:1. In order to resist the volatility and uncontrollability of output power, the relationship between wind farm and power scheduling has been analyzed when a wind farm is connected to the grid and a wind farm active power optimization control strategy based on ultra-short-term power prediction is studied. Besides, a wind turbine power ultra-short-term prediction method with variable time scale is proposed. This prediction method is utilized in the wind farm active power optimization control strategy to adjust the wind turbine output power and improve the control accuracy. Furthermore, on one hand, an optimal control algorithm for wind farm active power reduction is presented to minimize the number of shutting down wind turbines when decreasing the output power, on the other hand, an optimal control algorithm for wind farm active power increasement is presented to minimize and maximize the number of starting wind turbines when lifting the output power.2. A wind farm communication network structure based on WiMAX and an intelligent wind turbine control strategy based on Multi-Agent are studied. The main research works are included in analyzing the WiMAX communication network architecture, designing different protocols to meet the requirements of data transmission and studying the multi-agent based intelligent control strategy to make the wind turbines more stable and reliable under the control of active power. 3. Considering the stability of wind turbine control based on the wind farm active power control and the wind turbine operation characteristics in different work states, a wind turbine global control strategy of rotating speed with load torque optimization control strategy is presented to improve the performance of the wind turbine rotating speed in different work states. In addition, considering the serious chaotic property of wind generator in the low-speed status, a wind generator adaptive Backstepping control algorithm is proposed.4. In order to utilize the studied wind turbine control strategies in 3, a stability analysis method for wind turbine is proposed.Based on the above works, an active power control system is designed and has been applied in a wind farm located in Inner Mongolia. The field experimental results show that the designed control system could reduce the active power error and improve the stability of the wind farm active power output.