Procngs of h Worl Congrss on Engnrng an Compur Scnc 7 WCECS 7, Ocobr 46, 7, San Francsco, USA PSS Tunng of h Combn Cycl Powr Saon by Nural Nwork E. L. F. Danl, F. M. F. Souza, J. N. R. a Slva Jr, J. A. o Nascmno, J. C. T. Campos, M. Falcucc an L. H. S. C. Barro Absrac Ths papr prsns a paramr molng o Powr Sysm Sablzrs (PSS) usng MLP an RBF nural nworks. Th applcaon of nural nworks n PSS ams o mprov h ynamc sably of lcrc powr sysms by rucng h machn lromchanc ampng oscllaon whn a surbanc occurs. Accorng o h currn plan oprang conons, h PSS paramrs ar auomacally ajus by h nural nwork n sns o gv a sasfacory conrol. Th obsrv prformanc for h propos approach s s n smulaons, usng a nonlnar ynamc mol of nfn bus machnyp. Th rsuls show ha s possbl o mprov h powr sysm ynamc prformanc wh h nw molng. In Trms Combn Cycl Plans, Dynamc Sably, Powr Sysm Sablzr, PSS, RBF, MLP. I. INTRODUCTION Th lcromchancal oscllaons of low fruncy, whn baly amp, hy ar harmful o h lcrcal sysm, bcaus ha hy can caus h loss of synchronsm of h gnraors. Th us of Powr Sysm Sablzrs (PSS) for h mprovmn of h ynamc sably of h powr sysms has rcv bggr anon n h las yars []. Th ajusmns of h paramrs us n hs conrollrs ar rmn hrough a lnar mol of h sysm aroun a nomnal opraon pon. Howvr, h prformanc of h convnonal PSS gras whn a chang n s opraon pon occurs []. Som chnus such as aap conrol hav bn proposals as soluon of h problm [5], [6]. Howvr, h mos of aap conrols s bas on paramrs nfcaon on h sysm mol n ral m, bu consums much m. Robus conrol chnus, fuzzy logc an PSS sgn bas on Lyapunov also ar ohr alrnavs o ra h problm [7], [8], [9]. Howvr, hr rsponss ar slow an ral m applcaons ar lm. E. L. F. Danl (warlnnon@gmal.com), F. M. F. Souza (francsmarry@yahoo.com.br), J. N. R. a Slva Jr (nlorjunor@yahoo.com.br), J. A. o Nascmno (alma@.ufc.br), J. C. T. Campos (ls@ufc.br), L. H. S. C. Barro (lbarro@.ufc.br) ar wh h Elcrcal Engnrng Dparmn, Fral Unvrsy of Cará, Foralza CE, ZIP 645576, Posal Co 6, BRA. M. Falcucc (mal: mfalcucc@nsabr.com.br) s wh h Foralza Thrmolcrc Cnral Gnraon (CGTFENDESA), Caucaa CE, ZIP 66, Posal Co 7, BRA. In hs papr wo molng forms for PSS s paramrs usng nural nworks ar proposals: MLP Mul Layr Prcpron an RBF Raal Bass Funcon. Th us of a nural nwork for paramrs ajusmn bcoms possbl h praccal mplmnaon of h mho an h paramrs auacy for ffrn opraon pons. Th nural nwork avanag s n h vrs of opraons pons snc opras wh nac aa an no oal fn suaons. II. SYSTEM S DESCRIPTION Th man for nrgy gnraon n o h consumpon plac coms growng smula by h publc an govrnmnal prssur for h nrgy mar vrsfcaon, currnly cnr n h hyraulc gnraon. Th ncnv for nw lcrc nrgy gnraon sourcs conrbu o ncras h us of h naural gas. Th hrmolcrc plans ar bnf by h combn cycl chnology ha br us h naural gas avanag an consunly o ncras h ncom of hm. A combn cycl hrmolcrc plan has assocas o h sam plan gas urbns an sam urbn gnrang lcrc nrgy. Th hrmolcrc n suy possss an nsall powr of 3,7MW, bng compos for: () wo gas urbns, ach on wh nomnal powr of,8mw, () on sam urbn wh nomnal powr of 3,MW, () wo bolrs of ha rcovry, (I) wo gnraors of 33,8MA an (v) a gnraor wh nomnal powr of 47MA. Th procss s na wh amosphrc ar bng suck for h combuson urbns comprssors. Ar s abl, m wh h naural gas, an afr ha hs mur s burn. Ths procss orgnas gass wh hgh mpraurs an prssurs ha ar sn for h rsponsbl urbn for convrng h hrmal nrgy no mchancs. Th connc lcrc gnraor o h urbn s al convrs h nrgy mchancs no lcrc. Th procss, unl hs sag, s characrz as smpl cycl nrgy gnraon. Afr h panson of h gass, hy ar sn for h rcovry bolrs, whr wll ak avanag h ha of h ho gass procng from h gas urbns o gnra h vapor ha wll pu no moon h sam urbn. Whn lavng h urbn, h sam s conns an rurns for h rcovry bolrs, closng h cycl. Ths urbn convrs h sor nrgy no h sam n hgh prssur an mpraur n roaon nrgy, whch s ransform no lcrc nrgy for ISBN:978988986764 WCECS 7
Procngs of h Worl Congrss on Engnrng an Compur Scnc 7 WCECS 7, Ocobr 46, 7, San Francsco, USA h gnraor. Fg. rprsns h machn of smplf form. Th volag rgulaor conrols h gnraor s caon sysm so ha h gnra volag an h racv powr vary h sr on n accoranc wh. Th purpos of h Sablzr s o us h gnraor s caon sysm br o rgula h powr oscllaons, ncrasng h gnraor s sably an mprovng h ransmsson sysm as a whol []. Th PSS opras by gnraor s rgulaor of volag, nfluncng s ajusmn pon. Th consans 4, 5 an 6 rprsn rspcvly: h magnz ffc of a roor angl varaon δ, wh consan volag fl E FD ; h rmnal volag varaon T for a roor angl varaon, wh flow concana n h rc consan al an h rmnal volag varaon wh h varaon of, for consan roor angl. Δ 4 E f c 3 (4) Ecaon Sysm Rgulaor Sablzr ( )[( ) snγ R cosγ ]} Turbn Saor Δ Δ δ Toru Fg.. Machn s rprsnaon n block agrams. Δ 5 c { [ R cosγ ( )... (5) III. CONENTIONAL MODELING OF PARAMETERS Th sablzr s paramrs ar ajus makng us of h lnar mol of 3 r orr foun n lraur an shown n Fg.. Th mol s bas on a machn connc on an nfn bus hrough uvaln mpanc aroun a f pon of opraon []. Through hs convnonal mol h paramrs for vrs opraon pons ar gon, ha wll form a nonlnar s o b us as bas for ranng of h nural nworks n h boarng proposal n hs work. Th mol s uaons ar prss n funcon of h consans o 6. Th Euaon () rprsns h lcrc oru varaon, T E, for a varaon δ n h roor s angl, wh flow concana n h rc consan al,. ΔT c Rsn I { [ δ ( )cos γ] I sn R ( )[( ) γ cos Th Euaon () prss h lcrc oru varaon T E for a varaon of h flow concana n h rc al, wh angl of h consan roor δ. ΔT δ c Δ { R I[ R ( ) Th followng rm, n (3), rprsns h mpanc facor. 3 ]} () () [ ( )( )] (3) γ]}... snγ ]} ( Δ 6 c Δ δ [ ( ) cosγ R snγ )] R (6) [ R ( )( ] (7) Bng: nfn bus volag. volag ha fns h al poson an ha suppls h oru angl nal valu. δ nal oru angl. rc al racanc. rc al ransory racanc. uaraur al racanc. uaraur al ransory racanc. crcu s propr racanc of h roor s ron. γ amanc angl srs uvaln lss h oru angl. I currn componn n h uaraur al. rmnal volag s componn of h gnraor n h uaraur al n h machn s rfrnc. rmnal volag s componn of h gnraor n h rc al a machn s rfrnc. ISBN:978988986764 WCECS 7
Procngs of h Worl Congrss on Engnrng an Compur Scnc 7 WCECS 7, Ocobr 46, 7, San Francsco, USA gnraor s rmnal volag n prmann rgmn (absolu valu). ΔT m 3 s 3To ΔE f Δ Hs 6 4 377 s Δ δ Fg.. Machn nfn bus blocks agram. 5 Δ (P) an racv powr (Q) an h oupus ar h PSS s paramrs. Th aanmn of hs aa was gav hrough h sablzr s convnonal mol, as shown n Fg. 3. Tabl. Daa of nranc of h nural ns. Inpus Oupus P Q T T 7.5.9.3 8..354.39 3 8.8.98.48 4 9..639.64 5 9.6.469.346 6 9.8.3834.45 7.3398.478 8.363.53 9 9.9.86.567 9.7.686.64 I. POWER SYSTEM STABILIZER A Powr Sysms Sablzr (PSS) s an lmn, or group of lmns, ha suppls an aonal npu o h rgulaor o mprov h powr sysms ynamc prformanc. Th man funcon of h cononal sgnal o h PSS s n s o compnsa h sysm s lay o b conroll [9]. Th phas compnsaon s ralz hrough by h us of funcons lalag ha suppls phas avanc on h scal of nrs fruncy. Th agram of Fg. 3 rprsns h sablzr. Th frs block rprsns gan, h scon block s a flr washou o lmna rrors n h npu sgnal, an h hr block s a crcu lalag wh m consans T an T. w rf Fg. 3. PSS s blocks Dagram. Tabl rprsns h aa ha wll b us as bas for nural nwork s ranng. Th npus mnon h acv powr E f. MODELING BY NEURAL NETWORS Two algorhms ha bn mplmn, Nural Nwork RBF, ha s compos for an hn layr an a oupu layr, an h Nural N MLP, ha possss wo hn layrs. Th savanag of us a sablzr s convnonal mol ar n h fac of h paramrs ajusmn o b lm o only on opraon pon, wh jus sablsh fruncy, wha can bcom an nffcn ampng ou of hs pon. Th RBF mplmnaon s compos for a hn an oupu layr. Dffrnly of h MLP, whr ach nuron fns a sparaon plan [3], h RBF fns on crcl n h npu spac hrough a Gaussan funcon. Anohr ffrnc bwn hs ns s h fac of h MLP o us nrnal proucs, whl h RBF uss sancs. In h vlop n, wh ach npu aa has bn assoca a spcfc cnr. In hn nuron acvaon s rmn by a nonlnar funcon of h sanc bwn h npu vcor an a rfrnc vcor. Th RBF has a smpl archcur, conssng wo layrs of wghs (W E an W S ), whr h frs on conans h raal bass funcons paramrs an h scon form lnar combnaons of h funcon s raal bas acvaons o gnra h oupu [4]. I s ran n wo pros, wh h funcons of raal bas bng rmn frs for nosuprvs chnus, usng for ISBN:978988986764 WCECS 7
Procngs of h Worl Congrss on Engnrng an Compur Scnc 7 WCECS 7, Ocobr 46, 7, San Francsco, USA npu aa an h scon layr (wghs), bng lar rmn for suprvs lnar mhos (lnar funcon), of fas convrgnc. Th analyz nural nworks ar compos for h npus an oupus n accoranc wh Tabl. Th nural nwork paramr ajusmn s shown n Fg. 4. avanag n o us h paramrs ajusmn usng nural nworks for h bggs ampng, n rmn of h paramrs gon hrough h convnonal mol. Tabl. Nural nwork s valaon aa. INPUT OUTPUT MLP OUTPUT RBF P Q T T T T 55 9.7.45.377.44.4 95 9.8.79.579.76.588 9.4.55.584.67.67 Fg. 4. Sysm s blocks agram wh h nural nwork s ncluson. 8,5 5,8 3,,3 Dsgn Paramrs Usful Tunng Paramrs Whou PSS Th of nural nwork s nrpolaon capacy s a usful characrsc o h ra problm, onc ha h abl us o sor h paramrs valus T an T n ffrn pons opraon woul b nsv u o nfny of pons sua bwn wo pons. Ths nural nworks ably has bcom hm usful for h molng of nonlnar sysms. Snc h s of opraons pons foun n Tabl s nonlnar. Th nural nworks mos sgnfcan characrsc s h ably o approach any connus nonlnar funcon of a sr corrcon gr. I. RESULTS AND DISCUSSION Th machn s mahmacal mol an h conrollrs was ncorpora o h program Transory Analyss Elcromchancal (ANATEM), n whch smulaons ha bn carr hrough ha ha srv for h aabas composon us n h ranng an nural nworks valaon. Nural nworks MLP an RBF ha bn projc for convrgnc wh mamum rror of.. Th MLP prsn convrgnc n raons an h RBF n 8 raons. Th aa gon for h ns ar n Tabl. I was appl a sp of % n h loa an smula h sysm n hr suaons was appl Fg. 5: () whou h sablzr, () usng h sablzr ajus n fl an () usng h sablzr wh projc paramrs. As can b vrf by h curvs, h sysm whou h sablzr s vry oscllaory, wha can ak h loss of machn s synchronsm. Wh h PSS can b obsrv h 97,5 94,8 9, 7,8 8,5 9, 9,9,6,3, Tm (s) Fg. 5. Comparson bwn fl valus an calcula for % of loa. 96,5 94,9 93,3 9,8 9, 88,6 87, Nural Nwork Tunng F Paramrs 7,8 8,5 9, 9,9,6,3, Tm (s) Fg. 6. Comparson bwn nural nwork unng an calcula f paramrs for % of loa appl n 9%. 55, 53,83 5,67 5,5 5,33 49,7 48, F Paramrs Nural Nwork Tunng 7,8 8,5 9, 9,9,6,3, Tm (s) Fg. 7. Comparson bwn nural nwork unng an calcula f paramrs for % of loa appl n 5%. Fgurs 6 an 7 show h unng nflunc for wo opraon pons. As h calcula f paramr for nomnal powr movs away from h sam on, h paramrs unng for h nural nworks bcoms mor mporan. ISBN:978988986764 WCECS 7
Procngs of h Worl Congrss on Engnrng an Compur Scnc 7 WCECS 7, Ocobr 46, 7, San Francsco, USA 6,5 59,8 57,67 56,5 54,83 53,4 5, F Paramrs 7,8 8,5 9, 9,9,6,3, Tm (s) Fg. 8. Comparson bwn MLP an RBF unng an calcula f paramrs for % of loa appl n 55%. capabl conrollrs aanmn of auomacally aap h ffrn opraon pons, wha vlop h oscllaons ampng. Th smulaons ha provn ha h ampng of h ajus machn for f paramrs spols as soon as opraon conon movs away from h sablsh opraon pon. In comparson, h nural nworks ha prsn goo aa rapolaon, hrfor clln valus for h paramrs ha bn foun whn a loa of % o h sysm was appl. Fgurs 8, 9 an us h unng of Tabl n h MLP an RBF valaon propos, bcaus h pons ar ou of h s of ranng an show h capacy of h ns n nrpolang an surpassng gvn.,3 99,8 98,3 96,8 95, 93,7 9, F Paramrs 8, 8,3 8,5 8,8 9, 9,3 9,5 Tm (s) Fg. 9 Comparson bwn nural nworks unng MLP an RBF an calcula f paramrs for % of loa appl n 95%. 8,5 5,6,7 9,8 6,8 3,9, Whou PSS 7,8 9,5,,9 4,6 6,3 8, Tm (s) Fg. Comparson bwn MLP an RBF unng an sysm whou ESP appl n %. ACNOWLEDGMENT Th auhors hank h Foralza Thrmolcrc Powr plan CGTF, company of h ENDESA group, o h Naonal Avc Scnfc an Tchnologcal Dvlopmn CNP, h Supror Lvl Prfcon Coornaon Saff CAPES an h Rsarch Suppor Founaon FUNCAP for h suppor chncan an fnancng h rsarch. REFERENCES [] P. M. Anrson A. A. Foua, (994) Powr Sysm Conrol an Sably, IEEE, Nw York. [] P. unur, (994) Powr Sysm Sably an Conrol, McGrawHll, Nw York. [3] A. M. Sharaf, T. T. L H. B. Goo, (993) Nural Nwork Bas Powr Sysm Sablzrs, IEEE Trans. PWRS, pp. 88646. [4] M. A. Abo Y. L. AblMag, (997) Raal Bass Funcon Nwork Bas Powr Sysm Sablzrs for Mulmachn Powr Sysms, IEEE Trans PWRS, pp. 7834. [5] A. Ghanra, O. P. Malk G.S. Hop, (988) A slfunng conrollr for h conrol of mulmachn powr sysms, IEEE Trans. PWRS, vol. 3, no. 3, pp. 657. [6] D. Xa G. T. Hy, (983) Slfunng conrollr for gnraor caon conrol, IEEE Trans. PAS, vol., pp. 877885. [7] A. Swarcwcz. WróblwskaSwarcwcz, () Robus Powr Sysm Sablzr, IEEE Poro Powr Tch Confrnc, pp. 783739, Poro. [8] N. S. D. Arrfano,. A. Olvra R. A. Ramos, (4) Dsgn an Applcaon of Fuzzy PSS for Powr Sysms Subjc o Ranom Abrup araons of h Loa, Amrcan Conrol Confrnc, ol II, pp. 859, Boson. [9] S. Robak, J. W. Balk J. Machowsk, () Comparson of ffrn conrol srucurs for lyapunovbas powr sysm sablzr, IEEE Powr Inusry Compur Applcaons, pp. 934, Balmor. II. CONCLUSION Th soluons ha prsn sasfacory rsul. Howvr, h carr hrough ss ha shown ha h RBF applcaon convrg mor uckly han h carr hrough wh h MLP. Th Gaussans unng cnrs o ach npu of h s ranng bcam h sysm convrgnc fass. Wh only 8 raons for h ajusmns h aanmn of a suffcnly ncssary approach was possbl. Th man avanag obsrv wh h us of nural nworks n h paramrs molng of h PSS was h ISBN:978988986764 WCECS 7