Research On The Technology Of Improving The Reactive Power And Regulating Ability Of Doubly - Fed Wind Turbine

The increase of the proportion of wind power is a new challenge to the existing power system. In view of the present doubly-fed wind type hair machine always run at a constant for a power factor, many scholars on the proposed new expectations. In doubly-fed fan reactive power and active power decoupling, back-to-back converter is adopted to form the doubly-fed fan has good reactive power and active power control independently.Doubly-fed fan when wind speed is lower than the rated wind speed, the active power rating has not been achieved, the residual capacity of generator totally has the ability of auxiliary power grid voltage regulation. In this paper, the doubly-fed wind generator, back-to-back converter has carried on the detailed mathematical modeling. Secondly analyses the influence on voltage stability of wind farms with regulating ability, and based on the reactive power limit analysis doubly-fed fan, in the active and reactive power decoupling control theory is put forward on the basis of the wind generator reactive power of voltage difference and no difference of the two kinds of strategy adjustment. Under the condition of the investment is proposed using a small amount of auxiliary converter with fixed capacity of capacitor group and the inductance of the auxiliary circuit to increase the doubly-fed wind generator reactive power capacity method. Assist device in the case of investment is not big, can make the reactive power capacity of doubly-fed fan triple (reactive power capacity based on the fan itself), and can achieve STACOM smooth and fine adjustment effect of voltage.Improved fan, the author of this paper also puts forward the corresponding wind farm reactive power control strategy, and finally to establish the validation model based on MATLAB/Simulink, the experiment verified under the condition of the voltage deviation is not big, the improved fan can be very good to participate in power grid voltage regulation; Failure in power grid voltage drop is very severe cases, the improved fan Crowbar protection circuit, the network side converter with auxiliary converter control capacitor can provide reactive power support for fault during the power grid, the compensation in the low voltage across the fan to absorb reactive power, help to power grid voltage recovery rate, improve the ability of the low pressure of the fan through.