In this paper, we revise the power quality issues of grid connected synchronous generator(SG) based wind farm. Firstly, the model of wind energy conversion system(WECS) was modeled using MATLAB simulink. The system consists of turbine, gearbox, DFIG and converters. The total harmonic distortion (THD) index was used as performance index for both wind farm output voltage and current. THD was performed using Fast Fourier Transform(FFT) technique. Static synchronous compensator(STATCOM) and static var compensator(SVC) was applied for improving THD and therefore the system dynamic response.