Application Research Of SVC In Grid-connected Wind Farm

With the use of wind power systems and the increase of grid-connected capacity,problems such as low power factor and voltage fluctuations have a serious impact on the safe and stable operation of the power grid.Therefore,the research of reactive power compensation technology in wind farms is of great significance.In this paper,the grid-connected constant-speed constant-frequency wind power generation system is analyzed.The software and hardware design of Static Var Compensation(SVC)system is carried out.The compensation effect of SVC in wind farm is simulated and analyzed.Firstly,the constant-speed constant-frequency wind power generation system is modeled,and the voltage stability of the power generation system and the wind speed and short-circuit fault disturbance are analyzed.Secondly,the structure and compensation principle of TCR+FC type SVC are expounded,and the compensation characteristics,harmonic characteristics and filtering methods are analyzed.The estimation of system reactive power compensation capacity and the selection and calculation of main current parameters are carried out according to the grid-connected wind power system.The detection and calculation methods of voltage,current,reactive power and susceptance based on instantaneous reactive power theory are expounded.The dynamic disturbance characteristics of SVC compensator are analyzed,and the control strategy of control system is studied.Then design the hardware circuit and software part of the SVC control system.The hardware circuit includes AC voltage and current sampling,low-pass filtering,phase-locked frequency multiplication,thyristor triggering and protection circuit;the software part includes main program module,AD sampling program module,zero-crossing detection module,digital filtering module,digital PI control module,TCR The firing angle calculation module generates a module by detecting a voltage zero-crossing delay and a trigger pulse.Finally,based on the system parameters,the wind power grid-connected system and the SVC system were simulated and modeled by MATLAB platform.The wind power grid-connected system is simulated and analyzed under the condition of wind speed disturbance and three-phase fault disturbance.The simulation results show that SVC has a good regulation effect on voltage fluctuation and reactive power variation,provides real-time for wind power grid-connected system.Dynamic compensation.Effectively improve the stability of the system voltage.