Research On Frequency Regulation Strategy Of Wind Power In Power System

Wind power generation unit and system installed capacity increasesceaselessly in China; the grid in the wind power is becoming more and more highpermeability. The current wind turbines generally take the optimal power outputstrategy on power system frequency, lack of support, easy to cause the systemfrequency pollution. December30,2011promulgated national standards" windpower technology regulations"(GB/T19963-2011), although the wind turbinegrid-connected operation frequency range of norms, but also relates to the activepower control problems, but have not yet been clear wind farm in the gridfrequency specific requirements. In this paper the doubly-fed induction generator(DFIG) type of wind turbine and wind farm to participate in a moderate powersystem frequency regulation strategies related issues, with a view to the highpermeability grid wind power in the power system frequency control to providetechnical support.Wind power in the power system frequency regulation process, in order tomeet the demand, usually have to make DFIG load reduction operation.Therefore, this paper firstly research DFIG sub-optimal power active powerretention strategy, the purpose is to enable both the wind farm economic loss andDFIG to meet the system frequency regulation capacity requirements at the sametime. Study on primary and secondary frequency control active power reservedmanner, the tracking curve segment processing strategy, and on the basis ofsystem of wind frequency control capacity requirements and a wind farm maywithstand the economic loss of two constraint parameter tuning. The wind speedis higher than the threshold wind velocity, DFIG retained part of active power,retention value according to the speed range rate setting, and on the basis ofconventional unit speed droop, properly on the DFIG relaxation. At the sametime, according to our country on power system frequency deviation of theprovisions, setting reserved power margin of DFIG for taking frequency control.Then, research on the DFIG primary frequency control. On the comparativeanalysis of the speed control method and optimal power rotating speed controlmethod on the basis of this paper, suboptimal power rotating speed controlmethod and increase the pitch angle control link, make the DFIG a more stablefrequency control effect.The DFIG participation system secondary frequency control, the strategy forthe comprehensive utilization of pitch angle control and suboptimal power operation mode is presented. Pitch angle adjustment is a mechanical process,change is relatively slow, but can meet the control requirements of secondaryfrequency control. Considering the practical requirements, this paper uses DFIGactual characteristic, the pitch angle and the output power function relationshipbetween simplified properly, effectively reduces the control order. DFIGparticipated in the primary and secondary frequency control joint, simulationresults show that, this strategy can make the DFIG to complete the task of thefrequency control.Finally, studies the wind electric field frequency control strategy, as well aswind electric field receiving secondary frequency control after an instruction toset task allocation mechanism, proposed one kind based on the load of real-timemonitoring and forecasting data, according to the fluctuating component targetedactivation of the corresponding frequency modulation optimization method, andaccording to the field of wind power generator. Condition difference and timedelay operation condition prediction, to adjust the weight allocation is optimized,so that the wind farm in the control of economic losses, at the same time tocomplete the assigned task power frequency control.In this paper, the research help to improve wind turbine primary andsecondary frequency control method, the control strategy can take into accountthe two requirements: frequency control ability and the economic operation ofthe unit, the wind frequency modulation strategy optimization, further reducingthe wind farm power waste, make economy improved; secondary frequencycontrol task in wind farm distribution of the differential strategy, so that the windfarm secondary frequency control task can be successfully completed.This paper is supported by the National High Technology Research andDevelopment Program Project (863Program)(NO.2011AA05A105) andNational Natural Science Foundation of China (NO.50877014).