شبيه سازي يك جبران كننده توان راكتيو با ساختار FC/TCR براي بهبود كيفيت توان كوره هاي قوس الكتريكي

چكيده انگليسي :

Simulation of a Static Var Compensator with FC TCR Structure for Power Quality Improvement of Electrical Arc Furnaces Mohammad Nazari Vanani m nazari@ec iut ac ir Date of Submission 2013 21 09 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisors Ahmad GhaderiAbstractElectric arc furnaces are used in steel plants to melt and retrieve metals especially iron Thesefurnaces melt scraps using the heat which is made by electric arc Due to the nature of electric arcand melting process these devices make some problems like unbalanced voltage and current voltage and current harmonics voltage fluctuations and low power factor Some issues like voltagestabilization power factor adjustment and harmonics filtering should be addressed in order tooptimize the electric power of arc furnaces in steel plants Static VAR Compensator is a goodsolution to reduce the power quality problems caused by electric arc furnaces In this thesis the effectiveness of Static VAR compensator on improvement of electric arc furnacespower quality was studied by simulating of 63KV line of Mobarakeh Steel Plant To do so different models of electric arc furnaces was studied Because the most important factor inaccuracy of electric arc is the voltage current curve exponential hyperbolic model which has closecharacteristics to the arc real characteristics was chosen for this simulation In this modelunbalanced voltage and current and voltage flicker were applied randomly and it was shown thatthe behavior of electric arc model was near to real electric arc in Mobarakeh Steel Plant StaticVAR compensator structure and its operations were also studied With respect to the producercompany information the simulated compensator and proportional integral PI control coefficientsare tuned by trial and error as the respond time of constant zero error and flicker compensationbecome less than a cycle Finally the 63KVA line in Mobarakeh Steel Plant was simulated using the model of electric arcand Static VAR compensator To make the model more accurate the real values of Transformer andlines impedance was used The results were studies while the thyristor controlled reactor TCR isin and out of the control range and these results were compared with the practical results Theresults show while TCR is working within the control range it can improve the electric arcfurnaces power quality factors such as voltage and current unbalance and voltage fluctuations Thecurrent total harmonic distortion THD was reduced from 3 7 to 1 3 and compensator busvoltage THD was reduced from 2 2 to 1 1 The increase of electric arc furnaces numbersincreases the consumed reactive power and as a result the compensator is unable to compensatethe voltage and current unbalance and voltage fluctuations and only increase the supply powerfactor with a constant value So the loads connected to the compensator bus will face thesefluctuations constantly In this case the percentage of harmonic distortion of the whole current wasreduced from 3 to 0 5 and the percentage of the harmonic distortion of the whole bus voltage ofcompensator was reduced from 4 2 to 1 2 Keywords Electric Arc Furnace Fixed Capacitors Static Reactive Compensator ThyristorControlled Reactor

نظري واناني، محمد

شبيه سازي يك جبران كننده توان راكتيو با ساختار FC/TCR براي بهبود كيفيت توان كوره هاي قوس الكتريكي

خازن هاي ثابت , سلف كنترل شونده با تريستور