A Comparative Study of 5-Bus and 14-Bus Systems with UPFC: A Power Flow Perspective

Controlling power flow in modern power systems can be made more flexible using the recent developments in power electronics, and computing and control technology. The Unified Power Flow Controller (UPFC) is a Flexible AC Transmission System (FACTS) device that can control all the three system variables, namely, line reactance, magnitude and phase angle difference of voltage across the line. This leads to sufficient improvement in power transfer and reduction in power loss. The performance of UPFC depends on proper control setting achievable through a power flow analysis program. This paper presents a method to control the settings of UPFC (Feng and Nagan, 1999) through a modified Newton-Raphson-based load flow calculation. The proposed algorithm is developed to calculate the control setting of UPFC and the power flow between the lines after the load flow is converged. Case studies were performed on IEEE 5-bus and 14-bus systems to observe the effectiveness of the proposed method.