Research On Reactive Power And Voltage Coordinated Control In Wind Farm Based On DFIG And STATCOM

Under the background of gradual depletion of traditional fossil fuels and the increasingly serious environmental pollution, wind power as the highest technical maturity, the most widely used new energy power generation has been considerable development in recent years. However, with the increase of wind power capacity, the effect of large-scale wind power on the safe and stable operation of the power system is also growing,wherein the reactive power and voltage issue has become a constraint of wind power integration to be solved.Choosing double-fed wind farm for the study object, this papergives a detail analysis of the control capability of DFIG based on DIgSILENT, and then proposes improved dual PWM converter control policy, making the unit can participate in the steady-state and transient reactive power control; and then selects the DFIG wind farm with STATCOM for the study, to take advantage of DFIG variable capacity as the goal, proposes a sub-mode windfarm reactive power and voltage coordinated control strategy.The main work is summarized as follows:(1 Establishes the simulation model of DFIG. Based on the basic structure and operating principle of DFIG, establishesthe mathematical model of DFIG, and builds the control system simulation model of wind turbine and double-fed induction motor using DIgSILENT/Power Factory simulation software, laying the foundation for the subsequentsimulation analysis of DFIG operating characteristics.(2) Proposesan improved dual PWM converter control strategy and study the reactive power and voltage control ability in the strategy. By optimizing the RSC control strategy, in the premise of keeping active power output,take full advantage of the unit’s adjustable reactive power capacity, achieving the reactive power compensation in steady-state; With the Crowbarprotection action signal,by optimizing the GSC control strategy,achieve the reactive power supportfor the emergency in transient condition;The validity of the strategy has been proved in simulation.(3) Proposes a sub-mode windfarm reactive power and voltage coordinated control strategy based on DFIG and STATCOM.Selecting the DFIG wind farm with STATCOM for the study,making usingDFIG’s reactive adjustable capacitypreferentially, reducing dynamic reactive power compensation capacity as the goal,put forward a coordinated control strategy, achieving the coordination of RSC、GSC and STATCOM. The validity of the control strategy has been proved in simulation.