Application of TRIZ Thinking Method to Unified Power Flow Controllers by Converting into DPFC and FSO-DPFC

This paper introduces an innovative and creative systematic thinking method based on TRIZ thinking technique which can improve the performance of unified power flow controllers (UPFC). This new device is called distributed power flow controller (DPFC). The difference between UPFC and DPFC lies in exchanging three-phase series converter with single-phase converters that are distributed along the transmission line. This is based on one of the 40 principles of TRIZ innovative thinking technique, called segmentation. The basic changes, occurring in the DPFC, compared to UPFC are eliminating common DC-link between the series and shunt converters, and replacing three-phase series converters with single-phase series converter. These changes, lead to more economic and more reliable system. Similar to UPFC, the DPFC adjusts line impedance, transmission angle and bus voltage simultaneously. The DPFC design procedure based on differences with UPFC is described and DPFC advantages in mitigation of transmission line voltage sag and fluctuation are shown; while in some cases, simulation results of using UPFCs, DSTATCOM, TCSC and SVC indicate voltage sags. Finally, this paper introduceس one innovatively DPFC called fuzzy self-organized DPFC (FSO-DPFC) to solve the most important problem of DPFC. DPFC series converter with and without FSO controller (FSO-DPFC) are simulated. The simulation results of using FSO-DPFC, compared to traditional DPFC, shows more system ability to mitigate disturbances in the central controller signals.