A study on utilizing d-statcom to improve voltage profile in electrical distribution networks

Radial distribution networks, particularly in rural areas with a high penetration of inductive loads such as agricultural irrigation motors, face significant voltage regulation and power quality challenges. The high inrush currents drawn by these motors during startup, combined with the high line impedance, lead to severe voltage sags at the far end of the feeders, often exceeding standard tolerance limits. The primary objective of this thesis is to investigate the effectiveness of a Distribution Static Synchronous Compensator (D-STATCOM), a modern Voltage Source Converter (VSC)-based FACTS device, in improving the voltage profile and correcting the power factor in such weak distribution networks. To achieve this objective, a typical radial distribution network representing a rural area with high agricultural loads was modeled using the DIgSILENT PowerFactory software. The dynamic behavior of the system was examined through timedomain simulations, wherein motor loads were sequentially started. The system's performance was then comparatively analyzed for two main scenarios: with the DSTATCOM connected (compensated case) and without it (uncompensated case). The simulation results demonstrate that the D-STATCOM, with its millisecond-level fast response, effectively mitigates the voltage sags caused by motor starting through instantaneous reactive power injection. It is proven that with the integration of the device, the voltage profile across all nodes of the network is stabilized within acceptable limits, and the overall system power factor is significantly improved. This study concludes that D-STATCOM presents a superior and effective solution compared to conventional methods for enhancing power quality and ensuring voltage stability, particularly in weak rural networks with dynamic load characteristics. The application of this technology is foreseen to reduce the need for costly infrastructure upgrades.