pact Analysis of Damping Rsistors in Dampd Typ Doubl Tund Filtr on Ntwork Harmonic pd R.Madhusudhana Rao Assistant Profssor, Elctrical and Elctronics Dpartmnt V R Siddhartha Enginring Collg, Vijayawada, AP, India. Mrutyunjay Mohanty Snior Enginr, R&D Dpartmnt Powr Rsarch & Dvlopmnt Consultants Pvt. Ltd., Bngaluru, Karnataka, India. Vmula Mahsh Vra Vnkata Prasad M.Tch Studnt, Elctrical and Elctronics Dpartmnt V R Siddhartha Enginring Collg, Vijayawada, AP, India. Abstract: - In rcnt yars th usag of powr lctronics quipmnt and non-linar lmnts incrasd in various aras of powr systm. Powr systms contain considrabl lvls of harmonics which cannot b ignord furthr bcaus thr is considrabl ffcts on powr systm quipmnt du to th harmonics. Th filtrs ar usful to liminat harmonics and provid ractiv powr compnsation. Doubl tund filtr is th typ of passiv filtrs hav bn widly using in Industris and HVDC stations. This papr proposd th dsign procdur for th paramtrs of th dampd typ doubl tund filtr basd in th tund frquncis and paralll rson frquncy and ractiv powr dmand and voltag of th ntwork. This papr dals with th ffct of damping rsistors connctd in diffrnt configurations on th ntwork impd.to find th paramtrs a program has bn dvlopd in MATLAB-2015b. Th prform of th filtr paramtrs ar vrifid by using MiPowr 9.1. Kywords: Harmonics, Mitigation tchniqus, Harmonic distortion, Doubl tund passiv filtrs, Dampd rsistors. I. INTROUDCTION With th growing usag of nonlinar loads and powr lctronic quipmnt in th powr systm thr is a grat concrn about powr quality issus particularly harmonic distortion. Th harmonic distortions in th voltag and currnt wavforms in th powr systm ar incrasing continuously du to ths nonlinar quipmnt. Ths harmonics may produc undsirabl ffcts on various typ of quipmnt which ar prsnt in powr systm and communication systms[l]-[4]. So it is vry important to rduc th harmonic contnt produc by nonlinar to avoid th damag of th utility quipmnt. To liminat harmonics so many tchniqus ar proposd. Filtr dsign is th most old and popular mitigation tchniqu usd in industris. Th In this papr passiv filtrs dsign mainly dampd typ doubl tund filtr is dsign is prsntd. Th stimation of doubl tund filtr paramtrs from th two paralll singl tund filtr bank is proposd in [7].In this papr algorithm-2 is adoptd from [8] and algorithm-1is adoptd from [6]. II. BASIC DOUBLE TUNED FILTER Passiv filtrs ar th circuits with R, L and C lmnts connctd in diffrnt ways to liminat dsird harmonics by providing an altrnativ path to th harmonic currnts. This passiv filtr tchniqu is much popular, simpl and asir than th advd harmonic rduction tchniqus lik PWM static VAR compnsators and magntic flux compnsation, Activ filtrs. Singl tund (ST) filtrs, Doubl tund (DT) filtrs, and C-typ filtrs ar diffrnt typ of passiv filtrs. Doubl tund filtr is combination of on sris rsonant circuit and on paralll rsonant circuit and it is usd to liminat two harmonic frquncis at a tim. Gnrally To liminat two harmonic frquncis at a tim thn two ST filtrs ar rquird. Th quivalnt Volum 8 Issu 3 Jun 2017 148 ISSN: 2319-1058
impds of two singl-tund filtrs nar thir rson frquncis ar practically th sam as th basic doubl tund filtr configuration. C a C b L a L b Figur.1. Two paralll singl tund filtrs Figur.2.Doubl tund filtr Th basic doubl tund filtr is practically qual to th paralll brh of two singl tund filtrs. Hnc th calculation of doubl tund filtr paramtrs has bn don by quating th impd of basic doubl tund filtr and paralll connction of two singl tund filtrs. Th total impd of th paralll connction of two singl tund filtrs has bn writtn as Th total impd of th basic doubl tund filtr has bn writtn as By quating (1) and (2), th sris brh paramtrs ( ) and paralll brh paramtrs ( ) of th doubl tund filtr can b xprssd as (3) (1) (2) (4) (5) Whr ar th paramtrs of two individual singl tund filtrs. By using (3), (4), (5), (6) th paramtrs of th filtrs ar tund for th particular harmonic ordr with particular ractiv powr and bus voltag. From th abov dsign it is not possibl to choos th particular paralll rsonant frquncy.so a mthod is proposd in [8] to dtrmin th paramtrs of th doubl tund filtr by choosing th dsird paralll rson. III. ALTERNATIVE DESIGN OF DOUBLE TUNED FILTER BY CHOOSING THE PARALLEL RESONANCE FREQUENCY In convntional dsign procdur of filtr which is prviously xplaind in sction II thr has bn no choic to choos th intrmdiat frquncy btwn intrstd tund frquncis. If any harmonic frquncy btwn th two slctd tund frquncis is causing svr harmonic injctions into th systm ths harmonic contnts can b minimizd by rducing th filtr impd at that frquncy. Bcaus normally at paralll rson frquncy th impd is vry high. An altrnativ approach has bn dsignd to shift th paralll rson point to rduc th harmonic contnt. Th procdur to dtrmin th paramtrs using paralll rson frquncy has bn xplaind in this papr. From th basic doubl tund filtr th impd of th sris and paralll circuits ar rspctivly Whr ω is th angular frquncy and th sris rsonant frquncis of th sris and paralll circuits rspctivly Volum 8 Issu 3 Jun 2017 149 ISSN: 2319-1058 (6) (7) (8) (9)
Intrnational Journal of Innovations in Enginring and Tchnology (IJIET) Sris rsonant frquncy (10) Paralll rsonant frquncy (11) Whn th sris circuit impd ( ) is capacitiv and whn th sris circuit impd is inductiv. Whn th paralll circuit impd ( ) is inductiv and whn th paralll circuit impd ( ) is capacitiv Z p da nc Z Ind ucti v Cap acit iv p da nc In du cti v ω (a) In p C du da ap cti nc ac v iti Ca pa cit iv Ca pa cit iv ω In du cti v ω (b) (c) Figur.3. (a) Charactristics of th sris brh of doubl tund filtr (b) Charactristics of th paralll brh of doubl tund filtr (c) Charactristics of th doubl tund filtr Th total impd of th basic doubl tund filtr is (12) Th total Thvinin impd of doubl tund filtr at th tund frquncis is zro (13) (14) Lt ar th roots of abov quation, thn (15) (16) (17) From (16), th obtaind rlations ar (18) (19) Bsids filtring th harmonic currnt, th doubl tund filtr has anothr prform of supplying th ractiv compnsation powr. If th ntwork fundamntal ratd voltag is V, and th fundamntal ractiv powr supplid by th filtr is Q, thn th impd of th filtr at fundamntal frquncy is (20) (21) (22) By using th valu thn simply, obtain th rmaining paramtrs typ doubl tund filtr ar.finally th paramtrs of dampd (23) Volum 8 Issu 3 Jun 2017 150 ISSN: 2319-1058
(24) In ordr to dsign th filtr has bn calculatd initially from th known quantitis lik ntwork voltag, ractiv powr rquird for th ntwork and tund frquncis.,, ar has to b calculatd according to (22-25). (25) IV. DAMPED TYPE DOUBLE TUNED FILTER Th basic doubl tund filtr Thvnin impd is almost pur inductiv or capacitiv in natur ovr th whol frquncy rang. If th systm impd is approximatly qual in magnitud and conjugat to th impd of th filtr at som harmonic frquncis, as a rsult th ntwork rson will occur. Du to this rson phnomnon th harmonic currnts bing svrly amplifid with th harmonic ovr voltag of th componnts in th filtr and in powr systm. To prvnt such a phnomnon, damping rsistors ar addd to basic typ of doubl tund filtr in diffrnt ways to obtain th diffrnt configurations of dampd typ doubl tund filtrs. Th charactristics and th prform of dampd typ doubl tund filtr will chang with rspct to th placing of damping rsistor. Figur.4. Dampd typ doubl tund filtr Diffrnt configuration of dampd typ doubl tund filtr has bn formd by insrting th dampd rsistor at diffrnt position in basic doubl tund filtr as showd in Figur.4.th various typs of dampd typ doubl tund filtr configurations has bn xplaind in sction-v. Th procdur to dtrmin th paramtrs of dampd typ doubl tund filtr is xplaind in a stp by stp procss as follows. Stp 1 START Stp 2 Choos th typ of filtr and Rad th Input Data Q, V, Stp 3 Slct tund frquncis Such that th magnitud of impd should b minimum Stp 4 Lt and Stp 5 Calculat using (22), (23), (24), and (25). Stp 6 Find th tund frquncis and from frquncy scan plot Stp 7 Find and Stp 8 Find maximum valu btwn and.and tak it as prcssion ( ) Stp 9 Chck th condition Stp 10 If YES Go to Stp14 Stp 11 If No Go to Stp12 Stp 12 Calculat Stp 13 Go to stp 4 Stp 14 Validat th prform of th filtr Stp 15 STOP From th abov procdur a program has bn dvlopd in MATLAB softwar to calculat filtr paramtrs accuratly. Th filtr paramtr valus and prform and impact of th dsignd filtrs ar xplaind in dtail in sction V. Volum 8 Issu 3 Jun 2017 151 ISSN: 2319-1058
V. CASE STUDY To analys th diffrnt doubl tund filtrs a tst cas is takn from [5]. Th tst systm showd in Figur.5 consisting of 220kV gnrator having short circuit capacity of 4000 MVA X/R ratio as 20 and 100 MVA, 220kV/33kV stp down transformr having % impd as 14 and X/R ratio is 10. This tst systm consisting linar load of 20MW and nonlinar load (adjustabl spd motor driv) of 25MW installd at 33kV bus.100 MVA & 60Hz ar considrd as th bas quantitis. A Shunt capacitor having a rating of 8.4 MVAR is also installd at th 33kV bus. Th harmonic sourc in this cas study is a standard diod rctifir supplying 25 MW on th dc sid. Th harmonic contnt injctd by th diod rctifir is tabulatd in Tabl.1. Th Harmonic analysis is carrid out using MiPowr softwar, with th load modlld as frquncy dpndnt Ract and constant Rsist (paralll combination) to find out impact of harmonic causd by diod rctifir. Th prform of th dsignd dampd typ doubl tund filtrs has bn vrifid by using MiPowr softwar. A frquncy scan plots has bn plottd for vry configuration of filtr. Tabl.1. Harmonic currnts injctd by diod rctifir at 33kV bus Harmonic ordr 5 7 11 13 17 19 Harmonic currnt(amps) 87.68 62.22 39.59 33.23 25.45 23.33 33 kv Bus 220 kv Bus G Gnrator Supply Voltag=220V Short circuit capacity= 4000MVA X/R ratio =20 Transformr Yg - Yg Powr rating=100mva Voltag rating=220kv/33kv % pd = 14 X/R ratio =10 Shunt Capacitor 8.4 MVAR Linar Load P=20MW Q=15MVAR ASD P=25 MW Fi lt Filtr I h Harmonic Sourc Ordr Harmonic currnt (I h) 5 87.68 7 62.22 11 39.59 13 33.23 17 25.45 19 23.33 Figur.5. IEEE -319 Tst systm for harmonic analysis Th rsults obtaind by prforming th harmonic analysis on tst systm without filtr and with th filtrs hav bn tabulatd and also th variation of charactristics of diffrnt typ of filtrs with rspct to th variation in paralll rson frquncy also has bn xplaind in this sction. By prforming th harmonic analysis using MiPowr for th tst systm without any filtr th rsults ar tabulatd in Tabl 2. Tabl.2.Harmonic distortion at 33kV bus without filtrs % Voltag harmonic distortions at 33kV bus without filtr Harmonic ordr Total 5 7 11 13 17 19 Harmonic distortion 12.1820 5.7409 8.8072 5.1726 2.8747 1.3365 1.0335 From th Tabl.2 th harmonic distortions injctd by 5 th, 7 th, 11 th ordr ar dviating as pr [1]. To liminat ths harmonic it is ncssary to dsign th filtr. This work is mainly focusd on th diffrnt configurations of th dampd typ doubl tund filtr. Hr th filtrs ar dsignd for 5 th and 11 th ordr harmonics th ractiv powr has bn takn as 8.4Mvar to dsign th harmonic filtrs which is prviously supplid by capacitor. Th filtrs ar dsignd at 33kV bus voltag. Th filtr paramtrs for diffrnt configurations obtaind through MATLAB programming using algorithm proposd in sction-v is tabulatd in Tabl 3. Th damping rsistor valu should b vry high if th rsistor is connctd in paralll to th filtr componnts, and th valu of th Volum 8 Issu 3 Jun 2017 152 ISSN: 2319-1058
rsistor should low if th rsistor is connctd in sris with filtr lmnts. In ordr to satisfy ths conditions in this papr th rsistor valus for diffrnt configuration of dampd typ doubl filtrs ar tabulatd in tabl.3. Tabl.3.Th Dampd rsistor valus considrd in diffrnt configurations of th dampd typ doubl tund filtr Filtr typ 1 2 3 4 5 6 Damping Rsistor valu(ohm) 500 500 500 0.2 R 1=500,R 2=500 R 1=500,R 2=250 Th dsignd paramtrs of th dampd typ doubl filtr by varying th paralll rson frquncy in btwn 5 th and 11 th harmonic ordr frquncis ar tabulatd in tabl.4. Tabl.4.Filtr paramtrs of diffrnt configuration of filtrs Filtr paramtrs Doubl tund filtr (5 th,11 th ) Dampd typ Doubl tund filtr(5 th,11 th ) L 1(Hnry) 0.0047762 0.0057315 0.0075226 0.0095525 0.011821 C 1(Farad) 1.9967-05 1.9886-05 1.9789-05 1.9723-05 1.9677-05 L 2(Hnry) 0.0036369 0.0041249 0.0040827 0.0032613 0.0018618 C 2(Farad) 4.7187-05 3.4812-05 2.6929-05 2.6635-05 3.7792-05 Th voltag harmonic distortions limits aftr installation basic doubl tund filtr is tabulatd in Tabl.5. Tabl.5. pact of basic doubl tund filtr on 33kv bus % Voltag harmonic distortions on 33 kv bus Total 5 7 11 13 17 19 5.3784 0.0001 4.799 0 0.9755 1.5043 1.6378 From th Tabl it is undrstand that th 5 th and 11 th ordr harmonics ar liminatd aftr installation of basic typ doubl tund filtr at 33kV bus. pd R Harmonic numbr Figur.6. Filtr (1) Figur.7.Charactrstics of Filtr (1) Th filtr-1 has bn formd by insrting th dampd rsist in paralll with th paralll brh of simpl doubl tund filtr. Th charactristics of Filtr (1) dampd typ doubl tund filtr will dpnd upon th rsistor R valu 1. if R=0 thn th rsist brh is short circuitd and th dampd typ doubl tund filtr will act as singl tund filtr at som rsonant frquncy, this rsonant frquncy will dpnd up on th modlld sris filtr lmnts of dampd typ doubl tund filtr. 2. If R is finit valu thn thn th impd of th dampd typ doubl tund filtr will b in th ordr of that R valu. Th valu of R must b chosn lik it should b mor. 3. If R is infinit thn th rsist brh is opn circuit thn it will act as a simpl doubl tund filtr. From figur.7. It is clar that impd of filtr (1) is in ordr of R=500 ohms at vry ordr of paralll rson frquncy 7 th, 8 th, 9 th and 10 th. So it is concludd that impd of filtr (1) is on th ordr of R at ω p. Th voltag harmonic distortions aftr installation of filtr (1) by slcting th intrstd paralll rson frquncy ar tabulatd in Tabl.6. Volum 8 Issu 3 Jun 2017 153 ISSN: 2319-1058
Tabl.6. pact of filtr (1) on 33kV bus %voltag harmonic distortions by changing th paralll rson Paralll rson frquncy ordr Total 5 th ordr 7 th ordr 11 th ordr 13 th ordr 17 th ordr 19 th ordr 7 4.7037 0.23 3.8137 0.056 1.1619 1.692 1.8199 8 4.4836 0.1455 3.076 0.1473 1.5074 1.9848 2.0944 9 4.6367 0.0725 2.7176 0.2991 1.8848 2.2452 2.3292 10 4.9306 0.0201 2.5097 0.519 2.2893 2.4726 2.5274 Filtr (2) is formd by insrting th damping rsistor in doubl tund filtr as shown in figur.8. R pd Harmonic numbr Figur.8. Filtr (2) Figur.9.Charactrstics of Filtr (2) For filtr (2) th rsist (R) valu has bn chosn 500 ohms to satisfy th rlation.th impd th impd taks 500 ohms as asymptotic lin whn is mor than 11 th ordr frquncy.it has bn concludd that In filtr (2) th impd taks R as asymptotic lin whn is mor than.th voltag harmonic distortions aftr installation of filtr (2) is tabulatd in Tabl.7. Tabl.7. pact of filtr (2) on 33kV bus %voltag harmonic distortions by changing th paralll rson Paralll rson frquncy ordr Total 5 th ordr 7 th ordr 11 th ordr 13 th ordr 17 th ordr 19 th ordr 7 4.7237 0.6291 3.8163 0.0609 1.1545 1.6723 1.7946 8 4.4857 0.6324 3.0665 0.0613 1.4964 1.9575 2.0599 9 4.6154 0.6365 2.7021 0.0617 1.8681 2.2093 2.2851 10 4.8737 0.6393 2.491 0.062 2.263 2.4277 2.4739 Filtr (3) is formd by insrting th damping rsistor in doubl tund filtr as shown in figur.10. R pd Harmonic numbr Figur.10. Filtr (3) Figur.11.Charactrstics of Filtr (3) Volum 8 Issu 3 Jun 2017 154 ISSN: 2319-1058
Th impd of th filtr(c) rachs th infinit valu at ach and vry ordr of paralll rson frquncy 7 th, 8 th, 9 th and 10 th. Th impd of filtr (c) at but th impd abov is in th ordr of R. Th voltag harmonic distortions aftr installation of filtr (3) is tabulatd in Tabl.8. Tabl.8. pact of filtr (3) on 33kV bus % voltag harmonic distortions by changing th paralll rson Paralll rson frquncy ordr Total 5 th ordr 7 th ordr 11 th ordr 13 th ordr 17 th ordr 19 th ordr 7 4.7024 0.108 3.8405 0.2292 1.1507 1.666 1.7886 8 4.4647 0.183 3.0872 0.387 1.4879 1.9484 2.0516 9 4.6142 0.2929 2.7156 0.6071 1.8549 2.1996 2.2767 10 4.9237 0.4437 2.4967 0.8925 2.2501 2.4209 2.4682 Filtr (4) is formd by insrting th damping rsistor in doubl tund filtr as shown in figur.12. R pd Harmonic numbr Figur.12. Filtr (4) Figur.13.Charactrstics of Filtr (4) Th damping rsistor valu in Filtr (D) is vry lss bcaus th rsistor is connctd in sris with th ractiv lmnt. Filtr (D) bhavs as a high pass filtr. Th voltag harmonic distortions aftr installation of filtr (3) is tabulatd in Tabl.9. Tabl.9.pact of filtr (4) on 33kV bus %voltag harmonic distortions by changing th paralll rson Paralll rson frquncy ordr Total 5 th ordr 7 th ordr 11 th ordr 13 th ordr 17 th ordr 19 th ordr 7 4.6774 0.2478 3.7758 0.2824 1.1596 1.6863 1.8145 8 4.4851 0.0377 3.0826 0.1831 1.5053 1.9831 2.0928 9 4.64 0.0183 2.7207 0.362 1.8824 2.2436 2.3278 10 5.0222 0.0102 2.5096 1.1025 2.2852 2.4709 2.5261 Filtr (5) is formd by insrting th damping rsistor in doubl tund filtr as shown in figur.14. R 1 pd R 2 Harmonic numbr Figur.14. Filtr (5) Figur.15.Charactrstics of Filtr (5) Volum 8 Issu 3 Jun 2017 155 ISSN: 2319-1058
Th rsist (r 1 ) valu for filtr(5) has bn takn as 500ohm in ordr to satisfy th rlation of, th impd of th filtr(5) is limitd to th rsist valus at 11 th ordr and abov 11 th ordr.it is concludd that Filtr (5) has limitd impd at and also abov. Th voltag harmonic distortions aftr installation of filtr (5) is tabulatd in Tabl.10. Tabl.10.pact of filtr (5) on 33kV bus %voltag harmonic distortions by changing th paralll rson Paralll rson frquncy ordr Total 5 th ordr 7 th ordr 11 th ordr 13 th ordr 17 th ordr 19 th ordr 7 4.6942 0.3335 3.8137 0.282 1.1518 1.6658 1.7884 8 4.4781 0.3248 3.0749 0.5195 1.4899 1.9481 2.0514 9 4.6564 0.3624 2.7116 0.8548 1.8569 2.1994 2.2765 10 5.0076 0.4624 2.4963 1.2703 2.2506 2.4209 2.4681 Filtr (6) is formd by insrting th damping rsistor in doubl tund filtr as shown in figur.16. R 1 pd R 2 pd of filtr (F) is limitd to 250 ohms which is th lowr valu of R 1 and R 2 both at frquncy ordr 7 th, 8 th, 9 th and 10 th and abov 11 th ordr. Hnc it is concludd that th pd filtr (6) is limitd to th lowr valu of R 1 and R 2 both at and abov ω 2. Th voltag harmonic distortions aftr installation of filtr (6) is tabulatd in Tabl.11. Tabl.11. pact of filtr (6) on 33kV bus Harmonic numbr Figur.16. Filtr (6) Figur.17.Charactrstics of Filtr (6) %voltag harmonic distortions by changing th paralll rson Paralll rson frquncy ordr Total 5 th ordr 7 th ordr 11 th ordr 13 th ordr 17 th ordr 19 th ordr 7 4.7619 1.0377 3.7723 0.1703 1.153 1.6712 1.7938 8 4.5262 0.8936 3.0457 0.3446 1.493 1.9558 2.0587 9 4.6679 0.7674 2.6936 0.6189 1.8631 2.2077 2.2841 10 4.9725 0.6758 2.489 0.9803 2.2593 2.427 2.4735 As pr [1] th voltag individual harmonic distortion limits for 33kV bus should b 3%. Th voltag individual harmonic distortion limits causd by th 5 th and 11 th harmonics has bn liminatd with th usag of basic doubl tund filtr. By adding a dampd rsistor to th doubl tund filtr th total voltag harmonic distortion is furthr rducd as compard to basic doubl tund filtr. It is concludd that with th variation of th paralll rson frquncy ordr in btwn th 5 th and 11 th th harmonic contnt producd by th intrmdiat harmonics i.., 7 th harmonic is also rducd and as a rsult th total harmonic contnt in th tst systm is also rducd. Th individual voltag harmonic distortions du 7 th ordr harmonic also significantly rducd by incrasing th paralll rson frquncy ordr from 7 th to 10 th. VI. CONCLUSION An algorithm to dtrmin th paramtrs of diffrnt configurations of doubl tund filtrs is proposd in this papr. With th proposd algorithm th intrmdiat harmonic btwn th tund frquncis also rducd by changing th paralll rson frquncis. Th variation in th charactristics of dampd typ doubl tund filtr by varying th damping rsist is also xplaind brifly in this papr. Volum 8 Issu 3 Jun 2017 156 ISSN: 2319-1058
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