A comparative Study of Low-Voltage Ride-Through (LVRT) Control of Grid-Interfaced Doubly-Fed Induction Generator (DFIG)

Due to the fast increase in energy of modern human being the desire for the clean renewable energy is increasing day by day.Electrical power generation from wind is promising source.But due to the large combination of wind forms in electrical power grid the stability and security are key issues for the electrical power engineers.Amongst the required grid codes for the power utilities LVRT is very important.According to LVRT the wind form should act as conventional power plant and connect to grid for some particular time to provide stability to grid at normal and fault time.In this paper we have developed a LVRT strategy for control of active, reactive power and DC link voltage of the variable speed wind turbine.The test bed system is 9 MW DFIG wind turbine attached to 120KV grid system by 30KM long 25 KV transmission line.The modelling and simulation is done by using MATLAB/SIMULINK.The control system is implemented by using PI controller using vector or field oriented control.The LVRT strategies implemented on test bed model are (STFCL), DC chopper, Rotor Crowbar and Hybrid strategy with using RSC control, GSC control and pitch control mechanisms.The hybrid strategy provides excellent solution for LVRT of DFIG wind turbine by controlling power (active and reactive) and voltage of DC link.The results of hybrid strategy during symmetrical fault is best and well suited to the LVRT requirements as compared of STFCL, DC chopper and crowbar.