Compensation of the electrical mains by means of unified power flow controller (UPFC)-comparison of three control methods

Many papers on FACTS generally or UPFC devices particularly are available nowadays. Most of them use these new devices as phase controllers in the transmission lines, in order to control the power flow in the mains. But, UPFC is capable of controlling the power flow by acting over three basic electrical parameters which are line voltage, impedance and electrical angle. So, the main objective of this paper is to compare these three power flow control approaches. Three comparison points are aimed which are the limitation of each approach in term of line active power correction, the UPFC device power rating and finally the impact over the reactive power circulation in the controlled line. With respect to these comparison, one can choose the best control parameter among voltage, impedance or electrical angle, according to the envisaged application. After a basic theoretical study on power flow control by UPFC, the numerical simulations using SABER are realized in order to validate, through a simple case, the obtained results. Moreover, as these compensations are mainly realized by the series part of UPFC, the contribution of the shunt part in reactive compensation is also considered in the simulations.