A Distributed Power Flow Controller (DPFC) to Improve Power Quality

This paper represents a new dimension of the Flexible AC Transmission System (FACTS) called as Distributed Power-Flow Controller (DPFC). is a further development of the UPFC. The DPFC can be considered as a UPFC with an eliminated common dc link. The system consists of several low-power series converters and one shunt large-power converter without common dc link. Also new is that the power exchange between the shunt and series parts is through the existing transmission line at a harmonic frequency and the active power exchange between shunt and series is transmitted through the transmission line in the nth harmonic frequency, and has no disturbance to the fundamental component. The aim of this paper is to develop a new type of power-flow controlling device that offers the same control capability as the UPFC. This solution enables the Distributed series part of the separated UPFC to reduce the cost significantly and have a lot of extra benefits, such as higher reliability, convenient for installation and maintenance. Here the results of steady-state analysis of the separated UPFC are also presented.