Transient Stability Assessment of the Ugwuaji Transmission System Under a Single Line-to-Ground Fault Condition

Abstract

This study presents a rigorous transient stability assessment of the Ugwuaji Transmission Station following a single line-to-ground (SLG) fault. Employing dynamic simulation techniques, the research evaluates critical system parameters to determine the stability limits of the connected synchronous generator. A key outcome is the identification of a Critical Clearing Time (CCT) of 2.49 seconds for the fault scenario under investigation. The results demonstrate that the fault induces significant transients, including a voltage sag to 0.54 pu and oscillatory behavior in rotor angle and electrical power. However, the analysis confirms the system's inherent resilience, as all parameters exhibit well-damped responses and return to a stable operating point post-fault clearance. The findings underscore the criticality of protection system coordination and provide a technical basis for ensuring the Ugwuaji bus's reliability within the national grid.