Application Of Mixed Reactive Power Compensation In Wind Farm

In the deteriorating environment and the increasing demand for energy today, clean energy has received unprecedented attention.Because of wind power has lots of advantages and its development is more perfect than other clean energy, wind power capacity has increased rapidly along with the promotion of clean energy. However, with a large number of wind farms interconnectted with the power grid, the stability of the grid had been damage to a certain extent.For example, random wind leads the fluctuations of wind power output, if the grid can not get enough of the reactive power compensation, then the voltage prone to bias, or even cause voltage flicker. Thus reactive power compensation of power quality is vital.In the article, firstly the wind speed model in wind farm, aerodynamic model and the wind turbine shaft model was introduced and analyzed, and the mathematical model of wind turbine induction generator-based group has been deduced, and gives its control diagram.Then the basic structure STATCOM has been introduced and the working principle of STATCOM has been analyzed, and a detailed analysis and derivation of its mathematical model has been duuced, and the differential equations group with constant coefficients of STATCOM has been received on a rotating coordinate system.Finally in accordance with the equations presented,the current indirect control strategy and control block diagram has been plotted.Finally, strategy is consisted of several original switching capacitor banks with static synchronous compensator(STATCOM) compensate reactive power together, which can compensate for switching capacitor banks for reactive power by the line of the integer part, and static synchronous compensator remainder compensation.In response to this more complex mix of compensation strategy,the appropriate control strategies should be given and simulation models by PSCAD / EMTDC should be built.In the steady and transient state respectively,several wind farms compensation under operating conditions were simulated,analyzed and compared to verify the rationality and effectiveness of the mixing of reactive power compensation strategy.