Harmonics Measurement In Computer Laboratory And Design

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(IJACSA) International Journal of Advanced Computer Science and Applications,Vol. 8, No. 12, 2017Harmonics Measurement in Computer Laboratory andDesign of Passive Harmonic Filter using MATLAB1Muhammad Usman Keerio, 2Muhammad Shahzad Bajwa, 3Abdul Sattar Saand and 4Munwar Ayaz memonDepartment of Electrical Engineering QUEST NawabshahSindh, PakistanAbstract—In this paper the harmonics measurement forcomputer loads is analyzed and passive filters are designed formitigating those harmonics. The filters are designed to meet theIEEE standard 519-1992 which is recommended for harmoniccurrent limits. Personal computers are non-linear loads thatgenerate harmonics due to non-sinusoidal current present atentrance of power supply. In this work the personal computers inlaboratory are taken as domestic load and harmonics generatedby them cannot be ignored which are simulated usingMATLAB/Simulink. The purpose is developing analyticalmethod for the design of the passive harmonic filter that absorbscurrent harmonics caused by computer loads. The findings ofthis study would be supportive to make the source current freefrom harmonics thereby reducing the THD. Simulation results ofproposed design method of passive filters shows attractive resultsfor harmonic reduction with profit of upgrade of power factor.Design of passive harmonic filters by using non active power canbe simple cost effective solution for systems.It is significant as it represents the total power that must beavailable to provide power to the load, though just a part ofthis is of useful power S VI. For harmonic supply S P jQ V I (cosφ j sin φ), In this active power P V I cosφ andthe reactive power Q V I sin φ. The cosine of the phaseangle φ between the applied voltage and the current is calledthe power factor. Pf cos P/S. In case of non-sinusoidalsignals the influence of so called distortion power H or D isincluded this consists of unequal harmonics of current andvoltage [9]-[12].Keywords—Power Quality (PQ); personal computers; TotalHarmonic Distortion (THD); passive filter; MATLAB/SimulinkI.INTRODUCTIONIn AC power supply systems, current waveform isdistorted and harmonics are created due to usage of non-linearloads that reduces the quality of power [1], [2]. That causesenormous fault occurrence and monetary losses toward powersupply system. Harmonics effect in AC power system isincreasing day by day [3], [4]. Harmonics due to personalcomputers loads has particular attention to power quality (PQ)because personal computers are frequently concentrated in amassive group and produces harmonics [5], [6].A. Personal Computers(PC’s)Personal computers are non-linear loads to AC system.Switch Mode Power Supply (SMPS) used in computersgenerate harmonics. For nonlinear load, non-linear flow ofcurrent is created because of dc-link capacitor in power supply[7]. Fig. 1 shows personal computer equivalent SMPS circuitmodel.Fig. 1. Equivalent SMPS circuit model of PC.The powers active, reactive and distortion are connectedby a relation .Geometric sum of reactiveand distortion powers is equal to non-active power . Distortion power has raised increasing interest with the expansion of non-linear loads [13].The function representation of mentioned powers is shown inFig. 2 and 3.B. Relation between Active Power, Reactive Power, ApparentPowerWe use the following terms to describe power flow into asystem, active power P [Watt], reactive power Q [VoltAmpere reactive] and apparent power S S [VA]. Forsinusoidal waveform P, Q and S can be writtenas . Apparent power S is the product of rmsvalues of current I and applied voltage V [8].Fig. 2. Power vector configuration (linear loads).240 P a g ewww.ijacsa.thesai.org

(IJACSA) International Journal of Advanced Computer Science and Applications,Vol. 8, No. 12, 2017Fig. 3. Power vector configuration (non-linear loads).The paper is organized as follows: Section I presents theintroduction of non-linear load and harmonic distortion,Section II presents the methodology of research work,Section III presents the result of measurement of harmonicdistortion for computer laboratory, Section IV present thesimulation of system for proposed filter design and discussionabout obtained results and Section V concludes the paper.Fig. 5. Experimental setup of PQA with main supply.The features of PQA are as shown in Fig. 6 to 8.II. METHODOLOGYHarmonic distortion depends upon electronic elementsused in appliance‟s circuitry. Numbers of nonlinear residentialloads are increasing day by day; therefore harmonics causedby these loads cannot be neglected. There are many techniquesto reduce harmonics but economic and maintenance points ofview there have necessity to select best compensation method.The design attempts to comply with the IEEE Standard 5191992 recommended harmonic limits applied to the currentharmonic limits [14]-[17].Fig. 6. Features of PQA.In this section, measurement of harmonics values andpower quantities obtained from power quality analyzer (PQA)device for computer laboratory. In this work total 24 PC‟s arejoined to the AC supply system are shown in Fig. 4 and 5 andall obtained measurements are written in Tables I and II.PC’s data: Power supply of ATX type 220V P-4 cpu-3.00GHz, Monitor (CRT)-17 Inch, 256 MB of RAM, Power range140w-200w.Fig. 7. Recorded data in PQA.Fig. 4. View of computer laboratory in electrical department QUESTNawabshah.Fig. 8. Experimental data collected using PQA.241 P a g ewww.ijacsa.thesai.org

(IJACSA) International Journal of Advanced Computer Science and Applications,Vol. 8, No. 12, 2017III. MEASUREMENT RESULTS OF PQAA. Experimental Results of Current and Voltage Waveforms(Fig. 9)C. Experimental Results of Individual Harmonics, when (24)PCs are Tied to AC Supply (Fig. 11)(a)(a)(b)Fig. 9. (a): For One PC, (b):For Twenty four PC.(b)B. Experimental Results of Active Power, Reactive Power,Apparent Power, Power Factor and Displacement PowerFactor Values (Fig. 10)(c)(a)(d)(b)Fig. 10. (a): For One PC, (b): For Twenty four PC.242 P a g ewww.ijacsa.thesai.org

(IJACSA) International Journal of Advanced Computer Science and Applications,Vol. 8, No. 12, 2017D. Experimental Results of Average, Maximum and Minimumof THDi (Fig. 12)(e)(a)(f)(b)Fig. 12. (a): For 1, (b): For 24.E. Experimental Results of Voltage Distortion (Fig. 13)(g)(a)(h)Fig. 11. (a): 1st harmonic, (b): 3rd harmonic, (c): 5th harmonic, (d): 7thharmonic, (e): 9th harmonic, (f): 11th harmonic, (g): 13th harmonic, (h): 15thharmonic.(b)Fig. 13. (a): For 1 PC, (b): For 24 PC.243 P a g ewww.ijacsa.thesai.org

(IJACSA) International Journal of Advanced Computer Science and Applications,Vol. 8, No. 12, 2017TABLE I.PQA MEASURED RESULTSNo. of )PowerFactorDisplacementPower tpowerCrest factorfor currentCrest factorfor 422.22-0.80-0.994.24k-3.41k2.52k2.01.3TABLE II.PQA MEASURED EESULTS OF IHDI ,THDI,THDV1No. of% 3rd% 5th% 7th% 9th% 11th% 13th% 05.82.53.7TABLE III.IV. SIMULATION OF EQUIVALENT SMPS OF PCThe parameters used for this system are given in Table IIIand equivalent SMPS of PC is simulated using MATLABsoftware by Simulink library as shown in Fig. 14.VsIsfRsysLsys% THDi% THDv5.466.31.60.455.94.3CIRCUIT PARAMETERS USED FOR SIMULATION OFEQUIVALENT COMPUTER POWER SUPPLY220 v10.65 A50Hz1Ω1mHCRVfH100uF25 Ω0.8 v3rd,5th,7th,9thContinuouspowerguiScope RsysLsysi- AimCR v-vmvs-BUniversal BridgeFig. 14. Simulation of equivalent SM.Fig. 15. Input supply current without passive filter.244 P a g ewww.ijacsa.thesai.org

(IJACSA) International Journal of Advanced Computer Science and Applications,Vol. 8, No. 12, 2017Fig. 16. Input supply voltage without passive filter.signal rmsIrms3Continuous2047VScope 2Active powerPQpowerguisignal rmsIScope-851Active & ReactivePowerVrms2Reactive powerRsysLsysi -ismRL Asignal rms10 .65Irms1vs v-CIrmsProductvsmsignal rmsR2344Irms2220-BVrms1Scope 1VrmsUniversal BridgeFig. 17. Simulation of proposed model for passive filter design.The 3rd, 5th, 7th, 9th and 11th harmonic component are highin magnitudes. So these harmonic components are to bemitigating during this research work. Fig. 15 and 16 show thesupply current and supply voltage prior to installation ofpassive filter, the current and voltage harmonic distortion(THDi and THDv) are found to be 35.79 % and 0.38 %respectively. So IEEE limits for THDi distortion limits areviolated while THDv is found under standard limit.3) Supply voltage (rms) Vs in volts4) Harmonic order h Number5) Quality Factor QL NumberSteps to calculate values of C, L and R for single tunedfilter.A. Design of Single-Tuned Passive FilterQuantities required for the filter design:1) Non active power N in VAr2) Supply frquency f in Hz3.245 P a g ewww.ijacsa.thesai.org

(IJACSA) International Journal of Advanced Computer Science and Applications,Vol. 8, No. 12, 20174. L 5. R 2.Here to avoid from using a trial-and-error approach forsingle tune filter design, non-active power is considered asdesign parameter and proposed MATLAB/Simulink model fordoing this calculation is as shown in Fig. 17 and variouspower obtained from this proposed model is written as shownin Table IV.TABLE IV. 47.68 Ω 3.P(W)2047W 5. R 16.8mH 0.1058 Ω Similarly follows the same steps ,in this paper four singletuned passive filter has been designed such as 3rd,5th,7th and 9thand the values of all passive tuned filter can be shown inTable V.Q(VAr)-851VarNow we can use below equation to computes the nonactive power needs in Var as follows: 66.79uF 5.29 Ω 4. L VARIOUS POWERS OBTAINED WITH PROPOSED MODELS(VA)2344 TABLE V.DESIGNED 3RD, 5TH , 7TH AND 9TH PASSIVE FILTERrdFor 5thHarmonicRΩ0.0352C72.19uFL5.61MhFor 3HarmonicR Ω 0.1058C66.79uFL16.8mH N 1141.98 VarNow we can calculate values of required passive harmoniccomponent filter as follows.For 3rd Harmonic filterFor 7thHarmonicRΩ0.01778C73.6uFL2.808mHFor rguiScopei -Rsys AimLsysC v-3rd5th7thR9thvmvs-BUniversal BridgerdthFig. 18. Simulation model of equivalent computer power supply using 3 ,5 ,7th and 9th harmonic filter.Selected signal: 10 cycles. FFT window (in red): 1 cycles2000-20000.050.1Time (s)0.150.2Mag (% of Fundamental)Fundamental (50Hz) 311 , THD 0.07%0.050.040.030.020.010012345678Harmonic order910111213Fig. 19. Input supply voltage with passive filter.246 P a g ewww.ijacsa.thesai.org

(IJACSA) International Journal of Advanced Computer Science and Applications,Vol. 8, No. 12, 2017Selected signal: 10 cycles. FFT window (in red): 1 cycles40200-20-4000.050.1Time (s)0.150.2Fundamental (50Hz) 37.45 , THD 4.41%Mag (% of Fundamental)1.510.50012345678Harmonic order910111213Fig. 20. Input supply current with passive filter.Fig. 18 show simulation model of equivalent computerpower supply using designed filters. Fig. 19 and 20 show thesource voltage and source current after passive filterinstallation. THDv was reduced to 0.07% from 0.38% afterpassive filter installation, whereas THDi was reduced to4.41% from 35.79 % after passive filters installation accordingto IEEE limit.It can be noticed that before compensation, the inputsupply current is not sinusoidal (distorted) with r.m.s. (rootmean square) value of 14.26 ampere. The input source currentafter compensation by passive filter becomes nearly sinusoidalfrom the distorted wave. After compensation the sourcecurrent becomes sinusoidal with r.m.s value of 37.45 and inphase with the supply voltage.It is concluded that the harmonic distortion depends uponelectronic elements used in appliances circuitry. Numbers ofnonlinear residential loads are increasing day by day; thereforeharmonics caused by these loads cannot be neglected.Produced harmonics due to residential loads should beminimized. There are many techniques to reduce harmonicsbut economic and maintenance points of view there havenecessity to select best compensation method. Design ofpassive harmonic filters by using non active power can be thebetter and simple solution and cost effective systems. Bymeans of the simulation of proposed design method of passivefilters showed good results for harmonic reduction with profitof upgrade of power factor too.[2][3][5][6][7][8][9]V. CONCLUSION[1][4]REFERENCESM.Shahzad Bajwa, Aslam pervez Memon, Jamshed A.Ansari,M.Tarique Bhatti (2016), “ An Experimental Investigation Based onMathematical And Software Modeling of Total Harmonic Distortion inPersonal Computer ” , Bahria university journel of information andcommunication Technologies Vol.9 ,Issue 1 , pp.62-73.Kaushik Aryan and Varanasi Jyothi. (2014), „„Harmonic VoltageDistortions in Power Systems due to Non LinearLoads‟‟, InternationalJournal of Applied Power Engineering (IJAPE) , V. 3, No. 1, pp. 67-74.Memon Aslam P., Ahsan Zafar, M. Usman Keerio, Waqar Ahmad Adil,Asif Ali. A .(2014), „„Experimental Study and Analysis of HarmonicsGeneration in Uncontrolled and Controlled Rectifier Converters‟‟ ,International Journal of Scientific & Engineering Research (IJSER),V.5, 17]N.A. Abidullah, N.H. Shamsudin andA.R. Abdullah (2014)„„Experimental Evaluation for Power Quality Analysis System‟‟,Australian Journal of Basic and Applied Sciences, pp. 227-239.Saha Srijan, Das Suman, Nandi Champa.(2014) „„Harmonics Analysisof Power Electronics Loads‟‟, International Journal of ComputerApplications,V.92 ,No.10.pp.32-36.Lalotra Jyoti , Sharma Shavet and Saleem Khan .(2013) „„ Investigatethe Effect of Different Combination of Loads on Harmonic Distortion‟‟,International Journal of Advanced Research in Computer Science andSoftware Engineering , V.3,Issue. ankerRam.(2011),„„Estimating the Power Quality disturbance caused byPersonnel Computer‟‟,International Journal of Engineering Researchand Applications (IJERA) ,V. 1, Issue 3, pp.1034-1039.Liao Wei-Hsin, Shun-Chung Wang, Yi-Hua Liu.(2009) TLAB/SIMULINK‟‟,IEEE,PP.1-6.S. F. Mekhamer , A. Y. Abdelaziz ,S. M. Ismael .(2013),„„DesignPractices in Harmonic Analysis Studies Applied to Industrial ElectricalPower Systems‟‟ , Engineering Technology & Applied ScienceResearch (ETASR ) ,V. 3, No. 4,pp. 467-472.Haroon Farooq, Chengke Zhou and Mohamed Emad Farrag .(2012),„„Analyzing the Harmonic Distortion in a Distribution System Causedby the Non-Linear Residential Loads‟‟, International Journal of SmartGrid and Clean Energy , V. 2, No. 1, pp.46-51.Julio Barros, Matilde de Apraiz and Ramón I. Diego (2006) ,„„ Analysisof second order harmonic voltages in power systems , department ofElectronics and Computers.Moore Philip jand Iliana E. Portugués. (2003) ,„„The Influence ofPersonal Computer Processing Modes on Line Current Harmonics‟‟,IEEE Transactions on Power Delivery, V.18, NO. 4, pp.1363-1368.Grady W. Mack , Arshad Mansoor, Ewald F. Fuchs, Paola Verde andMichael Doyle.(2002), „„Estimating the Net Harmonic CurrentsProduced by Selected Distributed Single-Phase Loads: Computers,Televisions, and Incandescent Light Dimmers ‟‟IEEE ,pp.1090-1094.IEEE Power & Energy Society(2009),“ IEEE Recommended Practicefor Monitoring Electric Power Quality ‟‟ , IEEE Std 1159 -2009.Arnulfo B. de Vasconcellos, Dr., Marina S. C. de Carvalho, Acad.,Andrei M. Coimbra,Acad., Jéssica R. de Carvalho, Acad., Raul V. A.Monteiro, Esp. “Analysis of Tuned Filters for Mitigation of HarmonicCurrent Distortion of Air Conditioning Systems to Inverter” 2014 IEEE.Z. A. Memon, M. A. Uqaili and M. A. Soomro , “Experimental Analysisof Harmonic Mitigation Efforts of Three-Phase Six-Pulse Controller byUsing Pass Filters”, Mehran University Research Journal of Engineering& Technology, Volume 30, pp. 653-656.J. C. Das, "Passive Filters-Potentialities and Limitations", IEEETransactions on Industry Applications, Volume 40, pp. 232-241, 2004.247 P a g ewww.ijacsa.thesai.org

A. Personal Computers(PC’s) Personal computers are non-linear loads to AC system. Switch Mode Power Supply (SMPS) used in computers generate harmonics. For nonlinear load, non-linear flow of current is created because of dc-link capacitor in power supply [7]. Fig. 1 shows personal computer

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