Abstract—This paper deals with Unified Power Quality Conditioners (UPQC’s), which aim at the integration of series-active and shunt-active filters. The main purpose of a UPQC is to compensate for voltage flicker/imbalance, reactive power, negative-sequence current, and harmonics. In other words, the UPQC has the capability of improving power quality at the point of installation on power distribution systems or industrial power systems. This paper presents a modified Synchronous-Reference Frame (SRF)-based control method to Shunt active filter and Instantaneous PQ (IPQ) theory based control technique for series active filter to compensate Power-Quality (PQ) problems through a three-phase four-wire Unified PQ Conditioner (UPQC) under unbalanced and distorted load conditions. The proposed UPQC system can improve the power quality at the point of common coupling on power distribution systems under unbalanced and distorted load conditions. The simulation results based on Matlab/Simulink are discussed in detail in this paper.

Index Terms—Unified Power Quality Conditioner (UPQC), Phased Locked Loop (PLL), Active Power Filter (ACP), Synchronous Reference Frame (SRF)

Cite: P Ramya and C N Arpitha, "REDUCTION OF THD IN POWER SYSTEM USING GENERALIZED UPQC," International Journal of Electrical and Electronic Engineering & Telecommunications, Vol. 2, No. 4, pp. 47-56, October 2013.