Estimation and Minimization of Harmonics in IEEE 13 Bus Distribution System

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2 Estmton nd Mnmzton of Hrmons n IEEE 13 us Dstruton System G.R Kumr M.Teh Student (PE&ED) MIST, Sthuplly M.Loky ssstnt Professor n EEE Dept. MIST, Sthuplly T.Vjy Mun ssstnt Professor n EEE Dept. NRI Insttute of Tehnology strt power qulty prolem ours due to the nonstndrd oltge, urrent or frequeny ths result n flure of user equpments. So the present work s to dentfy the promnent onerns n ths re nd hene the mesures tht n enhne the qulty of the power re reommended. Hrmon nlyss of the dstruton system s essentl to study the ehour of equpments onneted n the nonsnusodl system enronment for desgnng nd optml loton of flters. In ths pper, IEEE 13us dstruton system s onsdered for nlyss of hrmons. Hrmon nlyss of the system ges the hrmon spetrum nd THD of urrents nd oltges t rous uses. Mtgton of hrmons s performed y smulton usng sngle tuned, doule tuned, retne oneport flters. omprte nlyss of flter performne s presented. The smulton study show tht the est performne of the flter s otned when postoned t/ner the nonlner lod uses. The dstruton system model s smulted y usng MTL SIMULINK erson R29 softwre wth stt nd djustle speed dres s lods. 1. Introduton Now dy s eletr dstruton system s prt of n eletr system etween the ulk power soure or soures nd the onsumer s sere swthes. One of the most power qulty prolems tody s oltge sg/swell. The oltge sg/swell mgntude s rnged from hlf yle to one mnute. Voltge sgs re one of the most ourrng power qulty prolems. For n ndustry oltge sgs our more often enduser equpment s the mn power qulty prolems. [1] Hrmon urrents use ddtonl lne losses nd stry losses n trnsformers. Wtthour meter error s often onern. t hrmon frequenes, the meter my regster hgh or low dependng on the hrmons present nd the response of the meter to these hrmons. The prolems used y hrmon urrents re oerlodng of neutrls, oerhetng of trnsformers, nusne trppng of rut rekers, oer stressng of power ftor orreton ptors nd skn effets[4][6]. nlyss s ommonly done to predt dstorton leels for ddton of new hrmon produng lod or ptor nk. The generl proedure s to frst deelop model tht n urtely smulte the hrmon response of the present system nd then to dd model of the new ddton [6][8]. In ths pper, modellng of SD s proded nd desgn of rous psse flters nd shunt te flter s presented. IEEE 13us system model s smulted n PSD/EMTD s se study nd hrmon nlyss s performed. Performne of flters n ompenstng urrent nd oltge hrmons s tested y smulton for rton of lod nd optml loton of flter n the dstruton system s suggested. THDs of urrent nd oltge re used s hrmon ndes n ths pper. Senstty nlyss s lso performed to nlyze the effet of flter prmeter rton on THDs t rous uses.. 2. Power Qulty n Power Dstruton System Most of the more mportnt nterntonl stndrds defne power qulty s the physl hrtersts of the eletrl supply proded under norml opertng ondtons tht do not dsrupt or dstur the ustomer s proesses. Therefore, power qulty prolem exsts f ny oltge, urrent or frequeny deton results n flure or n d operton of ustomer s equpment. Howeer, t s mportnt to note tht the qulty of power supply mples slly oltge qulty nd supply rellty. Voltge qulty prolems reltes to ny flure of equpment due to detons of the lne oltge from ts nomnl hrtersts, nd the supply rellty s hrterzed y ts dequy (lty to supply the lod), seurty (lty to wthstnd sudden dsturnes suh s system fults) nd llty (fousng espelly on long nterruptons). 1

3 Power qulty prolems re ommon n most of ommerl, ndustrl nd utlty networks. Nturl phenomen, suh s lghtnng re the most frequent use of power qulty prolems. Swthng phenomen resultng n oslltory trnsents n the eletrl supply, for exmple when ptors re swthed, lso ontrute sustntlly to power qulty dsturnes. lso, the onneton of hgh power nonlner lods ontrutes to the generton of urrent nd oltge hrmon omponents. etween the dfferent oltge dsturnes. tht n e produed, the most sgnfnt nd rtl power qulty prolems re oltge sgs due to the hgh eonoml losses tht n e generted. Shortterm oltge drops (sgs) n trp eletrl dres or more senste equpment, ledng to ostly nterruptons of produton. For ll these resons, from the onsumer pont of ew, power qulty ssues wll eome n nresngly mportnt ftor to onsder n order to stsfy good produtty. On the other hnd, for the eletrl supply ndustry, the qulty of power delered wll e one of the dstngushng ftor for ensurng ustomer loylty n ths ery ompette nd deregulted mrket. To ddress the needs of energy onsumers tryng to mproe produtty through the reduton of power qulty relted proess stoppges nd energy supplers tryng to mxmze opertng profts whle keepng ustomers stsfed wth supply qulty, nnote tehnology prodes the key to osteffete power qulty enhnements solutons. Howeer, wth the rous power qulty solutons lle, the oous queston for onsumer or utlty fng prtulr power qulty prolem s whh equpment prodes the etter soluton. 3. Rete Power n Voltge Regulton 3.1 Voltge Dsturnes Voltge sg or dp represent oltge fll to.1 to.9 p.u. nd exstng for less thn one mnute nd oltge swell s the rse n oltge of greter thn 1.1 p.u. nd exsts for less thn one mnute. 3.2 Voltge ontrol y Rete Power ompenston Frst, we onsder n unompensted lne. The urrent drwn y the lod depends on the lod tself nd the lne oltge. The urrent engenders the oltge drop n the trnsformer nd the lne retne. It results n the derese n trnsmsson oltge V T nd dstruton oltge V D. Fgure 1.1 shows the etor dgrm of sngle lod entre onneted to unompensted lne. The oltge drop n the lne mnly depends on the urrent tken y the lod s well s the resstne nd ndutne n the lne. Fgure 1.1 Unompensted Lnes wth Sngle Lod Fgure 1.2 ompensted Lnes wth Sngle Lod It n lso e seen tht the ngle etween the oltge nd the urrent s plyng mjor role n mntnng the oltge. Let us onsder the supply oltge s E. Now due to the oltge drops I R nd I X the lod oltge s V. It s possle to rng V=E, just y mkng the urrent to led so tht the etor dgrm wll get modfed s shown n fgure 1.2..e y the use of shunt ompenston (ether t the trnsmsson lne or t the dstruton lne) the oltge t the lod end n e regulted. 4. Model of djustle Speed Dres (SD) SDs onsst of n nduton motor suppled y rle oltge dered from onerters. Hene, the SD onssts of three mjor omponents; the frst s the front end, whh s usully 6 or 12 pulse retfer. The seond s the nerter stge tht onerts the generted D oltge to ontrollle frequeny nd oltge to ontrol the speed of the motor. The lst stge s the D lnk (shunt ptor) tht ouples the two mn stges nd help n redung the rpples of the D oltge n se of VSI nd PWM topologes. The frontend retfer njets hrmon urrents nto the supply system due to ts swthng proess. The nerter ntrodues ddtonl rpples n the D lnk urrent, whh n turn penetrtes nto the supply sde nd hene ontrutes for hrmons. Lke ll other nonlner nd swthng lods, SDs were normlly represented y hrmon urrent njeton. The 2

4 mgntude of these hrmon urrents ws tken to e equl to (1/n)th of the fundmentl frequeny urrent for the nth hrmon. ut ths method mples does not onsder the nterton etween the urrent nd the oltge hrmons generted y the dee. Ths mght led to the wrong estmton of the system dstorton leel. In order to ommodte these ntertons whle lultng the system dstorton, the SD model together wth the system wll e represented n the tmedomn to urtely ount for the hrmon ntertons. whh s ether low pss or nd pss flter. Ths type of flter s the smplest to desgn nd the lest expense to mplement. The onfgurton of sngle tuned flter s depted n Fg The mjor rter n desgnng the flter, s the seleton of proper ptor sze tht ges resonle power ftor t fundmentl frequeny. The ptor retne lue, X nd rete power reltonshp s gen y, where kvp s the lneto lne rted oltge of the ptor nd MVr s the rete power of the ptor. The flter ptne s then lulted usng (3) s The hrmons njeted y the nerter s mnly dependent on the nerter topology nd the motor hrtersts. Therefore, the SD n e modeled wth ommon three phse rdge onerter rut together wth D lnk rut nd hrmon urrent soure to represent the nerter nd the motor s shown n Fg. 2. The D lnk ptor n se of VSI nd the D ndutor n se of SI n lok the propgton of the hrmons generted from the nerter sde from enterng the system [7]. Ths onluson lls for smple representton of the onerter nd the motor olletely y D urrent soure nsted of hrmon urrent soure. The dret urrent nto nerter n e estmted from the motor lod s (1). where f s the fundmentl frequeny. (4) s then used to otn the retor lue of the flter. where n s the hrmon order to whh the flter s tuned. The lue of the resstne R determnes the qulty ftor (Q) of the flter nd s equl to the rto of the ndute or pte retne, t resonne, to the resstne. Typl lues of Q rnge from 15 to 8 for flters used n ndustrl nd ommerl ppltons [12]. 5. Desgn of Psse Flters Psse hrmon flters redue dstorton y dertng hrmon urrents n low mpedne pths. Psse flters re desgned to e pte t fundmentl frequeny, so tht they re lso used for produng rete power requred y onerters nd for power ftor orreton. 5.1 Sngle Tuned Flter The most ommon type of shunt psse flters used n hrmon mtgton s the sngle tuned flter (STF) Fgure 5.1 Sngle Tuned Flter 5.2 Doule Tuned Flter The doule tuned flter (DTF) onssts of seres L rut nd prllel RL rut. The s onfgurton of DTF s shown n elow Fg If f1 nd f2 re the two tunng frequenes, oth the seres rut nd the prllel rut re tuned to pproxmtely the men geometr frequeny f m = f 1 f 2. 3

5 Dsrete, Ts = 5e5 s. us4 ThreePhse Seres RL rnh11 ThreePhse Seres RL rnh us1 ThreePhse us2 Trnsformer (Two Wndngs) ThreePhse Seres RL rnh2 us5 ThreePhse Seres RL rnh1 ThreePhse Trnsformer (Two Wndngs)6 Fgure 5.2 Doule Tuned Flter DTF n e used to flter two hrmon omponents smultneously. ompred to the STF wth the sme performne, DTF hs few dntges suh s only one retor s sujeted to full lne oltge, ts losses re muh lower nd the mpedne mgntude t the frequeny of the prllel resonne s lower nd smller spe needed. ThreePhse Trnsformer (Two Wndngs)1 ThreePhse Seres RL rnh3 us6 us3 ThreePhse Trnsformer (Two Wndngs)7 us8 ThreePhse Seres RL rnh6 us9 ThreePhse Trnsformer (Two Wndngs)3 us1 ThreePhse Trnsformer (Two Wndngs)4 us12 ThreePhse Seres RL rnh8 us11 ThreePhse Trnsformer (Two Wndngs)5 us13 ThreePhse Seres RL rnh12 6. IEEE 13 us Dstruton System prtl IEEE 13us [9] medum oltge ndustrl dstruton system feedng dfferent types of ndustrl nd ommerl lods shown n Fg. 6 s onsdered for hrmon nlyss. The system trnsformer nd feeder dt [8] re gen n Tles I nd II. The system s fed from utlty supply t 69kV t us 4 nd lol genertor of 13.8 kv opertng t us 1. power ftor orreton ptor rted of 6 kvr s onneted t the pont of ommon ouplng (P) t us 3. Two hrmon produng lods nmely the djustle speed dres of 2 hp eh re serng the ustomers t us 7 nd us 1. ThreePhse Seres RL rnh5 us7 Susystem1 I3 From I7 From1 I9 From2 I1 From3 ThreePhse Seres RL rnh4 Sope Sope1 V3 From4 V7 From5 V9 From6 V1 From7 ThreePhse Seres RL rnh7 Sope2 Sope3 Susystem2 ThreePhse Seres RL rnh9 ThreePhse Seres RL rnh1 Fgure 7.1 Smulnk Model of IEEE 13 us Dstruton System g D motor equlent rut Id Mux Synhronzton Voltges 1 Thyrstor onerter Vd V V V lph_deg pulses lok Synhronzed 6Pulse Genertor & Vd Id & Id_ref Sope Mux PI urent Regultor 5 Fgure 6 Sngle lne dgrm of IEEE 13 us Dstruton System 7. Smulnk Model of Test System 1 1 s Id_Referene 9 Fgure 7.2 Smulnk Model of SD 8. Smulton Results 4

6 Mg (% of Fundmentl) Mg (% of Fundmentl) Fgure 8.1 urrent t us 3 & 7. Fgure 8.4 Voltge t us 9 & 1. Seleted sgnl: 6 yles. FFT wndow (n red): 2 yles Tme (s) Fundmentl (6Hz) = 28.52, THD= 28.72% Fgure 8.1 urrent t us 9 & Hrmon order Fgure 8.5 THD t us 1 wthout flter (28.72%). Seleted sgnl: 6 yles. FFT wndow (n red): 2 yles Tme (s).3 Fundmentl (6Hz) = 87.21, THD=.34% Fgure 8.3 Voltge t us 3 & Hrmon order Fgure 8.6 THD t us 1 wth sngle tuned flter (.34%). 5

7 9. onluson In ths pper, method for plement for dfferent types of flter n IEEE 13 us dstruton system for estmton nd mnmzton of hrmons s presnted. Two types of flters (Sngle tuned flter & doule tuned flter) he een modeled. The THD s lulted efore the flter onneted nd fter the flter onneted. 1. Referenes [1] IEEE Gude for pplton nd Spefton of Hrmon Flters, IEEE Std [2] IEEE Workng Group on Power System Hrmons, Power System Hrmons: n oerew, IEEE Trns. on Power pprtus nd Systems, Vol. PS12, No. 8, ugust [3] J. rllg,. Nedn, M.L.V. Lso, M.., P. Snhez, The Hrmon Domn: Frme of Referene for Power System Hrmon nlyss, IEEE Trns. On Power Systems, Vol. 1, No. 1, Fe 1995 pp [4] Wlter. Mlsowsk, llen rdley, Hrmons n Power Systems, Eletrl Eletrons Insulton onf., Sept. 1995, pp [5] Gregory W. Mssey, Estmton Methods for Power System Hrmon Effets on Power Dstruton Trnsformers, IEEE Trns. on Industry ppltons, Vol. 3, No. 2, Mr/prl 1994, pp [6] J.. Ds, Psse Flters Potentltes nd Lmts, IEEE Trns. On Industry ppltons, Vol. 4, No. 1, Jn/Fe. 24, pp [7] T.K. delgll, E.F. ElSdny nd M.M.. Slm, Implementton of Dfferent Mtgton Tehnques for Redung Hrmon Dstorton n Medum Voltge Industrl Dstruton System, Trns. nd Dstruton onf. nd Exposton, Vol. 1, 28 th Ot.2nd No. 21, pp [8] E.F. ElSdny, Effeteness of Dfferent Flterng Methodologes n Hrmon Dstorton Mtgton, ndn onf. on Eletrl nd omputer Engg., Vol. 2, 13th 16th My 21, pp [9] S.W. Mddlekuff,.J. Eel nd.. Jensen, Usng Hrmon Smulton to Elute Fltywde Hrmon Mtgton, IEEE Power Engneerng Soety Summer Meetng, Vol. 2, 16th2th July 2, pp [1] PoT heng, YungFu Hung nd hung hun Hou, New Hrmon Suppresson Sheme for Threephse Four Wre Dstruton Systems, 21, pp [11] Mohmed S.. Dhdh, N.Mrun, S. Mhmod nd N.Khn, Sngle Phse te Power Flter for Hrmon Mtgton n Dstruton Power Lnes, Pro. 23 Ntonl Power nd Energy onf., ng, Mlys, pp [12] J.M. Mz rteg, M. urgos Pyn nd. Izquerdo Mthell, Power Ftor orreton nd Hrmon Mtgton n Industry, IEEE Industry ppltons onf. 2, Vol. 5, 812th Ot. 2, pp [13] IEEE Reommended Prte for Eletr Power Dstruton for Industrl Plnts, IEEE Std [14] S.N..L. Yousf, M.Z.. Wnk nd. Mohmed, Implementton of Dfferent Psse Flter Desgns for Hrmon Mtgton, Pro. 24 Ntonl Power nd Energy onf., Kullmpur, Mlys, No. 24, pp [15] E.F. ElSdny, M.M.. Slm nd.y. hkhn, Reduton of Voltge nd urrent Dstorton n Dstruton Systems wth Nonlner Lods usng Hyrd Psse Flters, IEE Pro. Gener, Trnsm nd Dstr, Vol. 145, No. 3, My 1998, pp uthor s Profle G.R Kumr reeed helor s Degree n Eletrl & Eletrons Engneerng from Mother Teres Insttute of Sene & Tehnology, Sthuplly, Ind n 27. He worked s ssstnt Professor n Deprtment of Eletrl Engneerng, Sr Srth Insttute of Engneerng & Tehnology from June 27 to ugust 21. He presently peruses hs M.Teh n Power Eletrons & Eletr Dres n Mother Teres Insttute of Sene & Tehnology, Sthuplly. Hs res of nterest nlude Network nlyss, ontrol Systems nd Power Eletrons. Mr.M.Loyk ws orn n He grduted from KKTIY UNIVERSITY, n Tehnologl Unersty, Hyderd n the yer 211. He s presently workng s ssstnt Professor n the Deprtment of Eletrl nd Eletrons Engneerng t Mother Teres Insttute of Sene nd Tehnology, ndhr Prdesh,Ind. the yer 25. He reeed M.Teh degree from Jwhrll Nehru T.Vjy Mun ws orn n 1986 n Ind. He reeed the helor s Degree n Eletrl & Eletrons Engneerng from MIST, Sthuplly, Ind n 27. He reeed the Mster s Degree n Power & Industrl Dres from NET, Vjywd, Ind n 21. He worked s ssstnt Professor n SSIET, Nuzd, Ind from 27 to 21. He presently s workng s ssstnt Professor n Deprtment of Eletrl & Eletrons Engneerng, NRI Insttute of Tehnology, grpll, Ind. He pulshed three Interntonl Journls nd one ntonl onferene. Hs reserh nterests nlude FTS, Power Eletrons, Dstruton System nd Power System nlyss. 6