FUZZY LOGIC-BASED UNIFIED POWER QUALITY CONTROLLER FOR ENHANCEMENT OF POWER SYSTEM STABILITY

The paper deals with a Unified Power Quality Conditioner (UPQC), which aims at the integration of series and shunt active power filters for enhancement of power system stability. The proposed UPQC
consists of two independent active filters, each with its own dc link, a device known as "OPEN UPQC". The OUPQC is connected to a low voltage grid supplying industrial loads, mainly AC drives. Two controllers are proposed for operating the UPFC, namely a PI controller and fuzzy logic controller FLC. The fault ride through (FRT) ability of the FLC-based UPQC is investigated and compared with the FRT of a PI-based UPQC. This scheme also helps in maintenance cost saving and individual dealing with each customer. The comparison for each type of faults considered included time taken for fault recovery, harmonic level in waveforms, active and reactive power consumption, and system power factor. Also, switching the positions of the shunt and series devices is investigated to conclude the optimum connection status.