06-02-2017, 07:01 PM
13-02-2017, 11:19 AM
The flexible alternating current transmission system (FACTS), called Distributed Power Flow Controller (DPFC). The DPFC is derived from the Unified Power Flow Controller (UPFC). The DPFC can be considered as an UPFC with a common DC link removed. The active energy exchange between the branch and serial converters, which is through the common DC link in the UPFC, now passes through the transmission lines to the third harmonic frequency. The DPFC uses the distributed concept FACTS (D-FACTS), which consists of using multiple small-size single-phase converters instead of a single large three-phase series inverter in the UPFC. The large number of serial converters provides redundancy, thus increasing system reliability. Because the D-FACTS converters are single-phase and floating with respect to the ground, high-voltage insulation between the phases is not required. Consequently, the cost of the DPFC system is lower than that of the UPFC. The DPFC has the same control capability as the UPFC, which includes the adjustment of the line impedance, the angle of transmission and the bus voltage. The principle and the analysis of the DPFC are presented in this work and the corresponding experimental results that are realised in a scaled prototype are shown.