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.

In the family of Flexible AC Transmission Systems (FACTS) controllers, the distributed power flow controller (DPFC) can control powerfully all the system's parameters like bus voltages magnitude, transmission angle, and line impedances with high redundancy and a wide range of compensation. In this paper, IEEE-14 bus IEEE-30 bus, and IEEE-118 bus systems are taken for the testing of the proposed approach. The optimal placement of the series and shunt converters of the DPFC is decided by the most critical bus and most critical line associated with that bus respectively. The sizing of the DPFC is decided based on the minimization of active power losses of the systems. The loss function is considered an objective function and the limits of the bus voltages magnitudes, bus voltage angles, thermal limits of the lines, and level of compensation of the DPFC are taken as the system's constraints. To solve complex problems in various fields, meta-heuristic optimizations are more popular. Among the meta-heuristic optimizers, the jellyfish optimizer is one that is based on the behavior of jellyfish in the ocean. The optimization of the objective function with constraints has been solved by time-varying acceleration coefficients (TVAC) particle swarm optimization (PSO), artificial bee colony (ABC), genetic algorithm (GA), and metaheuristic optimizer jellyfish methods. Results show that all the optimization techniques provide solutions with minimum losses. Among these methods, the solution of the jellyfish optimizer has the lowest active power losses, highest convergence rate, less number of iterations, and also takes less computational time.