A new method of STATCOM controlling for harmonic mitigation and power factor correction

Abstract

This paper presents a control algorithm of 3ph STATic synchronous COMpensator (STATCOM). The algorithm depends on the accurate reference currents extraction from only the nonlinear load current spectrum in frequency domain using Fast Fourier Transfer (FFT). Then the determined harmonics and reactive compo-nents of load current are added together to form the compensating reference signals, the PI controllers then generate signals which control the Pulse Width Modulation (PWM) method. The simulation of the study is car-ried out under MATLAB/Simulink environment to show the usefulness of this control algorithm with nonlinear dynamic loads. It determines exactly the phase shift between the power system current and source voltage using only load current measurement. It is also able to calculate accurately the harmonics presence in source current. Various simulation results are presented with many modes of operation of dynamic nonlinear reactive loads. The results show a perfect damping of harmonics and reactive power compensating. The current Total Harmonic Distortion (THD) maintains the IEEE STD 519 Standard and power factor is almost 1, the STATCOM also has a fast dynamic response for transients.