Research On High Voltage Ride Through Of DFIG Based On STATCOM

With introduce the Wind Turbine System,we could see the hope to solve the pollution problems,and in terms of energy structure no longer simplification,the wind power is more aligned with the energy sustainable development.However,with the Large-scale wind power connected into the power systems no only given us the opportunities,but also brought us the greatest challenge have even faced.Wind power grid failure more frequent,which put forward higher technical requirements on power system.During the grid failure,the Wind Power,not like the conventional energy such as Thermal Power and Hydro power,unable to support voltage and frequency for grid system.After the Wind Turbine off-grid,which might cause voltage and frequency fluctuations,threat to the safe and stable operation of grid system.At present,domestic and overseas focus on the research of wind power generation connected grid only landing on the part of wind turbine Low Voltage Ride Through,the wind turbine High Voltage Ride Through part not give too much attention.However,past many high voltage accidents show,compared to voltage drop fault voltage swell fault hazard is more serious.Therefore,an effective solution to solve the high voltage fault off-grid is imperative under the situation.In this paper,through the analysis of the DFIG under grid voltage symmetrical swells transient,gives the fault voltage from symmetry dropped to overcompensation,symmetrical voltage swells of the stator flux linkage process.Meanwhile,when the grid voltage swells,at present most mainstream wind turbines are equip with crowbar protection circuit action response results,and on the platform of MATLAB simulation and analysis of the active power,reactive power and electromagnetic torque fluctuations under the crowbar protection circuit,simulation results show that in the crowbar protection circuit the wind power generator active power, reactive power and the electromagnetic torque fluctuation is more intense,which illustrate that the crowbar protection circuit can’t alone make the wind turbines complete through the highvoltage,should work in with hardware or control strategy.Besides,made quantitative analysis about the rotor voltage and current of DFIG under the symmetrical grid voltage swells,through analysis of the result of theoretical value and the MATLAB simulation values are compared,comparing the analysis theoretical accuracy.In this paper proposed achievement of DFIG high voltage ride through scheme based on STATCOM through analysis of the symmetrical grid voltage swell the wind turbine dynamic characteristics and the transient process.In the symmetrical grid voltage swells the STATCOM equipment absorbing excess system containing capacitive power of wind power system and inductive compensation reactive power support system to continue running with the grid by control strategy.In the simulation platform of MATLAB / Simulink to build simulation model and simulation,simulate the DFIG with or without the STATCOM in the grid voltage symmetrical swells,and comparing the results,the results show that when the grid voltage swell the STATCOM can not only ensure wind turbine generator continue running with the grid,but also can timely to grid faults provide certain perceptual reactive and assist fast voltage recovery.