Impact of Reactive Current Injection by Islanding Detection Techniques on the Voltage Quality of Distributed Generation

Many active islanding detection techniques uses current injection through q-axis current controller of grid side converter (GSC) for islanding detection of distributed generation (DG). This paper studies the impact of injection of current on voltage quality of DG. The voltage quality of the DG is investigated by measuring the total harmonic distortion (THD) of voltage at the point of common coupling (PCC). The THD curves are plotted to suggest and help in selecting the amplitude and frequency of q-axis injection current for designing the q-axis injection current based islanding detection technique (IDT). The studies are carried out on a partial converter based small wind energy system on per unit basis to have generalized conclusions. Computer simulations are carried out in MATLAB.