Comparing a Multi-Terminal High Voltage Direct Current and Unified Power Flow Control for Short Circuit Level Reduction in Iraqi 400 Kv Grid

The demand for electricity has increased significantly in recent years; yet, the transmission and distribution networks are unable to meet unrestrained demands because of resource constraint. Losses in power lines exacerbate the unfavorable conditions for maximum power transfer. Recent decades have seen a rise in the use of FACTS and High Voltage Direct Current transmission in power systems due to its many advantages, which include reduced short circuit level (SCL), enhanced voltage profiles, reduced network power losses, and enhanced system reliability and safety. The paper presents a comparing study of the effectiveness of Unified Power Flow Control (UPFC) and Multi-Terminal High Voltage Direct Current (MT-HVDC) transmission in reducing short circuit current and network power losses for the Iraqi Super High Voltage (ISHV) grid. Modeling of Unified Power Flow Control and Multi-Terminal High Voltage Direct Current transmission is carried out using the Power System Simulator for Engineering (PSS/E) version 32 Package Program. The integration of multi-terminal HVDC transmission to the system resulted in a considerable decrease in short circuit levels and network power losses for the majority of buses in the system, as well as a reduction in the loading on the transmission lines in the southern region of Iraqi Super High Voltage grid, As a result, the South’s network performance will improve, hence improving Iraq’s electrical power system. Furthermore, when compared to installing a UPFC, the results showed that multi-terminal HVDC transmission reduces short circuit levels more efficiently.