INVESTIGATION AND ANALYSIS OF HARMONIC POLLUTION IN INDUSTRIAL AND CMMERCIAL POWER SYSTEMS

Abstract

Modern electrical distribution systems arc employing a large number or non-linear loads due to the development of semiconductor technology. This arises from the need that facilities want to increase efficiency and productivity of their systems. Among these non-linear loads arc large 1 \SDs, arc furnaces, etc in industrial power systems and computers, Printers, UPSs. electronic and magnetic ballast iluoresccnt lighting , used in modern offices and commercial buildings. The widespread and growing use of these loads has greatly increased the flow of harmonic currents on facility distribution systems and has created a number of problems such as overheated transformers , motors, conductors, and neutral wires; nuisance breaker trips: and vo I tagc distortion . So the effects of harmonics within the system and their impact on the utility and neighboring loads needs to be examined before any complaints arc made, equipment is damaged. or production is lost. This research investigates and analyzes the harmonic distortion levels in L V electrical networks. For the purpose of this research two facilities have been selected, one is industrial power system and the other is commercial power system . HIOKl 3196 Power quality analyzer was used to assess and evaluate the harmonic distortion level in the first site and simulation technique. using DlgSILENT PowerFactory, was used for the second facility. At the end. measurement and simulation results have been compared with standards, possible causes analyzed and harmonic effects, particularly additional losses in distribution transformers have been esti ma t ed. Resul t s o r the research include the vol tage and current distortion l evels in the industria l site bci ng within IEEE standards, but the current and voltage distortion l e vels in the commerc i al site were found to exceed the standard limits . It was found that trans former load losses can increase by up to 126% under harmonic load currents. By looking at the harmonic-related losses in a speci fic electrical system, energy costs have also been qua n ti fi ed . The an al y s i s sh owed tha t co s t s d u e to l osses re l ated to harmonics may be more than three fold the cost o f losses w i t h no h a rm onics . One o f the most economic and effective ways to mitigate harmonics in power systems is through the use of harmonic shunt passive fil ters . ln this thesis a singl e- tuned m u lt i ­ branch filter was designed as a mitigation techni que and observed to reduce the harmonicdistortion levels to acceptable v a l ues.