Harmonic simulation of distribution transformers due to the connection groups

As one of the most important factors for electricity energy, the power quality are thedeviations which are occuring on voltage, current and frequency quantities. Harmonics whichis the most important part of the power quality, development of technology with necessity andincreasing useage of power electronics and semi conductor devices, is coming to existance animportant problem.Harmonics as the distortions of sine wave form that cause with useage of transformers,generators, motors like iron nucleus electric machines, rectifiers and the other nonlineerdevices loosing of sine property of electrical systems. These loads as injecting harmonics tothe system, damage electrical plants connected consumer equipments and bring not workingcompletely.For year of 2010, according to the estimations % 50 of produced power will be controlledwith semi conductors, thus this nonsinüsoidal formation is becoming the meaning of useageof more power correction capacitors in the industry. With decreasing of resonance frequency,power system are becoming more sensitive case to the nature frequency and more affectedsituation off harmonic currents which are produced by these loads. For harmonic event, this isan enough proof to state that it is the most important power quality problem today andtomorrow increasing to be taken with an importance.In this study the effects of Dyn1, Dyn11 and Yyn connection groups of distributiontransformers to the harmonic phenomenon are targeted and for different cases in a MV/LVsystem with nonlinear load composition modelled with MATLAB Simulink, this effectsviewed.Key words: Power quality, power system harmonics, modelling power system harmonicswith MatLab Simulink, harmonic standards, IEEE 519-1992, harmonic sources, harmonicfiltering, distribution transformers and harmonics.JURY:1. Yrd. Doç. Dr. Aslan NAN (Supervisor) Date: 11.10.20052. Prof. Dr. Fahrettin ASLAN Page: 1343. Doç. Dr. Osman KILIÇ