DPFC design procedure - a case study using the KEPCO UPFC as an example

The Distributed Power Flow Controller (DPFC) is a new device within the FACTS family. It is emerged from the UPFC and has relatively low cost and a high reliability. The DPFC consists of two types of converters that are in shunt and series connected to grids. The common dc link between the shunt and the series converters is eliminated. The active power exchange between the shunt and series converters that is through the common dc link in the UPFC, is now though the transmission line at the 3rd harmonic frequency. The DPFC has the same control capability and the UPFC that is to adjust the line impedance, the transmission angle and the bus voltage simultaneously. Additionally, the DPFC has a lower cost due to the small rating of the series converters and a higher reliability due to the redundancy. In this paper, the design procedure of the DPFC is presented. A series of steps and corresponding equation to determine the major parameters of the DPFCns are given and explained. A case study is presented which is using the KEPCO UPFC as an example. This paper ends with the comparisons between the DPFC and UPFC solutions considering the weight, cost and reliability.