Minimization of Total Harmonic Distortion Introduced by Distributed Generation in a Distribution Network using Unified Power Quality Conditioner

Abstract

Distributed generation (DG) systems have become very popular in recent times as à
solution to the ever-increasing demand for more energy caused by man’s continuous
quest for a better life. This is due to the obvious advantages of distributed generation,
which include the elimination of the time and cost associated with the building of
transmission systems. Regardless of the advantages of distributed generation, they still
introduce some power quality problems into the network, of which harmonics appear
to be the most prevalent. In this paper the level of harmonics introduced by solar (DG)
sources is investigated and the unified power quality conditioner (UPQC) is proposed
as a means of reducing these harmonics introduced by the presence of distributed
generation sources. From IEEE 519 standard, the Voltage Total Harmonic Distortion
(VTHD) should not exceed the 5% limit, but the VTHD obtained from Otovwodo
network without the introduction of DG and UPQC was 13.09% – 22.59%. Also,
Voltage Individual Harmonic Distortion (VIHD) should not exceed 3% as per IEEE
519 standard but was found in the range 10.79% - 17.45% in Otovwodo network
before the introduction of DG. Harmonic load flow results of DG integrated network
in the ETAP 16.0 software environment indicate an increase in Voltage Total
Harmonic Distortion (VTHD) to values within the rang 15.60% - 24.37%. However,
when the UPQC was introduced into the DG integrated network VTHD was found to
reduce drastically to values within the range 1.81% - 4.86%. Thus, significantly
improving the power quality of the Otovwodo Distribution Network.