Flexible D-STATCOM performance as a flexible Distributed Generation in mitigating faults

This paper proposes a flexible D-STATCOM (Distribution Static COMpensator) and its new controller system, that be able to both mitigate all types of faults and operate as a Distributed Generation (DG), when it supplies power to sensitive loads while the main utility source is disconnected (i.e. it is under islanded operating condition). Thus D-STATCOM operates same as a flexible DG (FDG) and consequently, it is called Flexible D-STATCOM (FD-STATCOM). This paper validates the performance of FD-STATCOM system to mitigate power quality problems and improve distribution system performance under all types of system related disturbances and system unbalanced faults, such as Line-to-Line (LL) and Double Line to Ground (DLG) faults and supplies power to sensitive loads under islanding condition. In this paper, the 12-pulse D-STATCOM configuration with IGBT is designed and the graphic based models of the D-STATCOM are developed using the PSCAD/EMTDC electromagnetic transient simulation program. The reliability and robustness of the control schemes in the system response to the voltage disturbances caused by LL and DLG faults and islanded operating condition are obviously proved in the simulation results.