This work investigates the boost of steady-state stability of voltage using various Flexible Alternating Current Transmission Systems (FACTS) devices. A simulation study was conducted on the IEEE 14 Bus power grid applying PSAT ( Power System Analysis Toolbox) in MATLAB. The Unified Power Flow Controller (UPFC), Static Synchronous Series Compensator (SSSC), Thyristor Controlled Series Compensator (TCSC), Static VAR Compensator (SVC), and Static Synchronous Compensator (STATCOM) were among the FACTS devices that were examined.

The study focuses on the superior performance of the UPFC, emphasizing its effectiveness in improving the fluctuations limit of the power system. In contrast to other FACTS gadgets, the UPFC showed the greatest improvement in voltage stability, power flow control, and oscillation damping. It permits independent regulation of the phase angle and voltage, leading to better voltage regulation, system stability, and reduced active power losses.The results highlighted a 7.1 kW gain in power when comparing the system without FACTS devices to one with the UPFC, showcasing its positive impact on power flow and stability. Ultimately, the study concludes that the UPFC significantly outperforms other FACTS devices in maintaining system stability, especially under large disturbances, making it a more reliable solution for improving both transient and steady-state stability in power systems.