Enhancement of Power Quality by Multi ? Connected Distributed Power Flow Controller (MC-DPFC)

This paper presents a new component within the Flexible AC Transmission System (FACTS) family, called Distributed Power Flow Controller (DPFC) capable of simultaneous compensation for the voltage and current in multi bus system. DPFC is derived from the UPFC with an eliminated common DC link. In this configuration one shunt voltage source converter and two or more series voltage source converters exist. The system can be applied to adjacent feeders to compensate for supply-voltage and load current imperfections on the main feeder. The active power exchange between the shunt and series converters, which is through the common dc link in the UPFC, is now through the transmission lines at the third-harmonic frequency. The DPFC can be designed with multiple single phase series converters (DFACTS) and one three phase shunt converter. The reliability of the DPFC system is further improved by the use of multiple single phase series converters with the adapted control schemes. The DPFC having much control capability like UPFC, however at much reduced cost and an improved reliability. The DPFC has the same control capability as the UPFC, which comprises the adjustment of the line impedance, the transmission angle, and the bus voltage. The principle and analysis of the DPFC are presented. The case study contains a DPFC sited in a single-machine infinite bus power system including two parallel transmission lines, which simulated in MATLAB/ Simulink and the results validate the DPFC ability to improve the power quality