Concurrent Real and Reactive Power Flow Enhancement using UPFC in a Power Transmission System
The paper presents simultaneous control of real and reactive power flow in a transmission network with the use of unified power flow controller (UPFC).The UPFC Provides multi-functional flexibility to solve many problems of power deliver industry. The UPFC is a combination of SSSC and STATCOM which provides concurrent real and reactive series line compensation without using external electrical energy source. The UPFC is used here to improve power transmission capability by means of unconstrained series voltage injection, transmission line voltage, impedance, load angle or alternatively the real and reactive power flow in the transmission line. This paper also deliberates the UPFC with Two Voltage Source Models (VSM). The VSM is developed in Newton Raphson (N-R) Load flow algorithm. MATLAB/SIMULINK based studies are carried out for IEEE 5-bus, IEEE 14-bus and IEEE 30- bus systems showing the power flow enhancements with and without connection of UPFC. The VSM Model of UPFC along with N-R Method for these networks allows a bi-directional flow of real power between series output terminals of the SSSC and the shunt output terminals of STATCOM.