Voltage profile enhancement by fuzzy controlled MLI UPFC

► We designed UPFC fuzzy logic controller under PSCAD. ► The controller is built up using three dimensional matrices. ► The parameters of the controller can be changed for different applications. ► We used seven level diode clamped multilevel inverter. ► The controller is used for enhancing voltage profile of a TL. A fuzzy logic controlled multi-level inverter based unified power flow controller system is used in a transmission line to maintain voltage profile and protect/compensate against over-voltages, under-voltages, sags and swells. The controller is designed as a stand-alone module and tested in PSCAD-EMTDC environment. The results show that the controller is robust and can rapidly maintain voltage stability under different load conditions.