DYNAMIC REACTIVE POWER COMPENSATION FOR WIND FARMS

Transcription

1 DYNAMIC REACTIVE POWER COMPENSATION FOR WIND FARMS Battu Duga Sowjanya, Motukui Devika Rani 2 MTech tudent, Electical and Electonic Engineeing, PVPSiddhatha intitute of technology, AP, India 2 Aitant pofeo, Electical and Electonic Engineeing, PVPSiddhatha intitute of technology, AP, India Eail: battuowjanya02@gailco, devikaothukui@gailco 9 Abtact: Wheneve thee i a gid fault, the DFIG unit abob cetain aount of eactive powe fo the gid, which caue the gid voltage to dop futhe and effect the noal gid integation Hence a fact device i neceay fo the copenation of eactive powe in the yte and alo fo the aintenance of yte voltage within the ange Thi pape analye the gid integated doubly fed induction geneation (DFIG) and the feaibility to ipove it dynaic voltage level by uing eactive powe copenation device duing fault condition In thi pape the eactive powe vaiation duing fault condition fo wind fa with wind tubine potection ae analyzed and the eactive powe i copenated uing a fact device With the copenation of eactive powe, the eactive powe taniion fo the gid to the wind fa can be educed and the teinal voltage at the wind tubine can be ipoved Thi pape i iulated uing MATLAB iulink Keywod: SVC, DFIG, Wind tubine potection, Dynaic eactive powe copenation I INTRODUCTION Now-a-day thee i oe deand fo the powe a the conuption of powe i inceaing datically in all the aea of the wold But the conventional eouce ae not ufficient to eet thi deand So the wold i aiing to eet the deand with the help of enewable eouce A a ouce of enewable and clean enegy, wind powe ha dawn oe people attention, and cuently it poee the laget developent potential in the wold Wind tubine integation to the gid i an ipotant apect fo the lage-cale utilization of wind enegy Wind tubine ainly conit of two type One i induction geneato (IG) and the othe i doubly fed induction geneato (DFIG) In thee DFIG i one of the ain type of wind tubine DFIG can adjut the fequency, aplitude and phae of the oto voltage though the oto-ide convete with fou quadant to contol it opeating condition, o that DFIG can un with high efficiency of wind enegy conveion within a wide ange of wind peed[]-[5] The inceaing penetation of wind enegy, with it chaacteitic of high inteittency and uncetainty, into taditional powe gid, ha bought a huge challenge to the opeation and dipatching of powe gid[6] In ode to handle thi difficulty, any countie have developed tandad fo lage-cale wind powe integation, and equied that wind tubine hould have been equipped with Low Voltage Ride Though (LVRT) capability[7][8] Reactive powe play an ipotant ole in the powe yte tability In ode to aintain the voltage within the liit eactive powe copenation i neceay Wheneve thee i a gid fault the wind tubine daw eactive powe fo the gid In ode to aintain the yte table, the wind tubine need to be tipped The fequent occuence of wind tubine tipping not only bing a lot of touble to wind powe copanie, but alo poe a theat to the ecuity of the powe gid [9] Duing evee gid fault, the wind tubine ut be able to eain gid connected within a pedefined tie peiod, o that the intability tatu of powe gid cannot be exacebated Upon the gid equieent, wind tubine can quickly upply eactive powe to the gid to ait the egulation and tabilization of gid voltage accoding to the agnitude of gid voltage ag, when the gid voltage ditubance ha been eliinated, the apid ecovey of it active powe to the gid i equied [0]&[] In ode to copenate the eactive powe a fact device i connected to the yte SVC can dynaically change value of the hunt capacito and eactance In anothe wod, it can dynaically change the SVC output of eactive powe [2] It alo can contol voltage of the bu connected to SVC and even that of bue which need eote contol Siulation eult in thi pape how that SVC play an ipotant ole in uppoting eactive powe and voltage of wind tubine duing fault condition II CHARACTERISTIC ANALYSIS OF DFIG DFIG conit of wind tubine, echanical taniion yte, induction geneato, convete and it contol yte; pitch angle contol yte, etc The baic tuctue i hown in Fig Fig Stuctue of DFIG Vol, Iue 5, Sep-205

2 20 The atheatical odel of the DFIG yte unde ynchonou otating coodinate yte can be etablihed Whee u d, u q, u d, u q epeent the d, q axi coponent of tato and oto voltage, epectively, i d, i q, i d, i q the d, q axi coponent of tato and oto cuent L, L, L ae elf and utual inductance of tato and oto, R, R ae the eitance of tato and oto, ω i the ynchonou efeence fae otating peed ω, i the electical angula velocity of oto and p i the diffeential opeato u u u u d q d q = R ωl (ω ω )L ω L R (ω ω )L R ω L (ω ω )L Accoding to the definition of oto flux: ψ d = L i d + L i d ωl (ω ω )L R i i i i d q d q () (2) ψ q = L i q + L i q (3) Though the deivation of equation () and by defining the tato flux a d-axi of otating efeence fae, that i, et ψ q = 0 and ω = ω ω then ubtitute equation (2) & (3nto equation () to get: pefoance of the DFIG yte can be ipoved by the PI contolle and feed fowad copenation of voltage When the gid fault occu, the yte voltage dop, then the DFIG unit need to abob a cetain aount of eactive powe fo the gid, which caue the gid voltage to decline futhe and affect the noal gid integation Theefoe, the equieent on the LVRT capability of DFIG i uch highe SVC, a tatic eactive powe copenation device, ha good dynaic chaacteitic, and can quickly povide eactive powe uppot to the yte to eet the deand and alo to aintain the voltage of yte within a cetain ange III CHARACTERISTIC ANALYSIS OF SVC The dialog box etting of the pogaable voltage ouce odule paaete ae hown a follow: at 0 econd, the voltage aplitude change fo 0pu to 097pu; at 04 econd, fo 097pu to 03pu, at 07 econd, the voltage aplitude ecove fo 03, to 0pu The ated capacity of SVC i 200MVA, and the adjutent of eactive powe ange fo -00Mva to 200Mva, while the contol ode of SVC i voltage egulation, whee Vef=0pu, X=003, Kp=0, Ki=300 The tudied yte ued in the iulation i hown in fig 2 u d =(L d L2 )pi L d + i d ω (L d L 2 L q + L L d (4) L 2 u q = (L d L 2 L d +ω L L ψ d L )pi q + i q + ω (L d (5) Equation (4) and (5) how that feed fowad copenation of oto voltage can ealize the decoupling contol of the geneato The odel of feed fowad copenation e d and e q i hown a follow: e d =ω (L L2 L q L L d (6) e q = ω (L L 2 L d ω L L ψ d (7) Fo equation (4), (5), (6) and (7), the elationhip of voltage and cuent can be deived a: ω (L L2 L d L L d = i d + u d (8) ω (L L2 L q L L d = i q + u q (9) The deivation of the teady-tate atheatical odel of the DFIG yte how that the inne cuent contol Fig2 Chaacteitic iulation of SVC Fig3 Voltage of SVC duing fault condition Fig4 Reactive powe output of SVC duing fault condition Vol, Iue 5, Sep-205

3 2 The voltage and eactive powe cuve of SVC fo the ocillocope afte the copletion of the iulation ae hown in Fig3 and Fig4 At 0 econd, the upply voltage dop to 097pu uddenly and the pot voltage of SVC coepondingly decline to 097pu aound, then SVC end eactive powe (about 03*200Mva=62 MVAR) to the yte, o that the voltage i etoed to 099pu At thi oent one TSC ha been put into opeation, but becaue TSC only ha two opeation ode, on and off, the capacitive eactive input i dicete If the capacity of a TSC i oe than 62 MVAR, the TCR i on to abob oe of the capacitive eactive powe At 04 econd, the upply voltage uddenly ie to 03pu, the pot voltage of SVC coepondingly ie to 03pu aound, SVC abob eactive powe fo the yte (about 03*200Mva=62Mva), o that the voltage i down to 0pu, while TCR i on and TCS i off At 07 econd, the voltage i etoed to 0pu The iulation eult how that SVC can achieve the bet copenation effect within 00 whethe the yte voltage i low o high Two cenaio have been ued to veify the ole of SVC to uppot eactive powe on the powe gid Scenaio : 60% voltage ag occu to the gid 330kV yte Scenaio 2: 60% voltage ag occu to the gid 330kV yte and SVC i connected to 35kV bu V ANALYSIS OF DYNAMIC REACTIVE POWER COMPENSATION DURING FAULT CONDITION FOR THE WIND FARM A Siulation eult of cenaio : Duing 45 ~ 45 econd, the teinal voltage, cuent, active powe, eactive powe and othe cuve of DFIG unit ae hown in Fig6(a) Fig6(g) IV SIMULATION MODEL AND SYSTEM PARAMETERS A wind fa with the capacity of 63MW, 42 et of 5MW unit, i connected to a 330kV powe gid, by 35/0kV and 0/330kV tep-up tanfoe The yte fequency i 50Hz, and the wind tubine teinal voltage i 690V In the wind tubine odel in MATLAB, the following potection ae conideed: ) AC unde voltage potection: poitive equence voltage eache 075pu, delay 0 econd, wind tubine tip 2) AC ove voltage potection: poitive equence voltage eache pu, delay 0 econd, wind tubine tip 3) DC ove voltage potection: DC voltage eache 2500V, delay 000 econd, wind tubine tip 4) Unde Speed potection: peed eache 03pu, delay 5 econd, wind tubine tip 5) Ove Speed potection: peed eache 5pu, delay 5 econd, wind tubine tip 6) AC ove cuent potection: poitive equence cuent eache pu, delay 5 econd, wind tubine tip The cuve of noal opeation without failue how the yte tat-up i coplete in about 45 econd At 45 econd, the unit opeate tably, and a 60% voltage ag i applied to the 330kV yte duing 45~45 econd The iulation odel of yte i hown in Fig5 Fig6(a) Active powe output of DFIG Fig6(b) Reactive powe output of DFIG Fig6(c) Angula velocity of DFIG Fig6(d) Pitch angle of DFIG Fig5 Siulation odel of yte Vol, Iue 5, Sep-205

4 22 Fig6(e) DC voltage of DFIG Fig7(b) Reactive powe output of DFIG Fig6(f) Voltage of 690V bu Fig7(c) Angula velocity of DFIG Fig6(g) Cuent of 690V bu At 45 econd, the DFIG unit tip due to unde voltage potection action, a hown in Fig6(a), and the active powe of the unit i 0 Duing the voltage ag, the unit abob cetain aount of eactive powe fo the gid, a hown in Fig6(b) and the axiu of DC voltage eache 2200V, a hown Fig6(e) Fig6(c) how the elationhip between electoagnetic toque and peed of the wind tubine The abolute value of electoagnetic toque deceae with the voltage ag, becaue the flux deceae with the voltage ag, the electoagnetic toque i educed But the input echanical toque of the wind tubine i contant, which caue the peed of the wind tubine to inceae A the wind inceae the pitch angle i adjuted to contol the tubine a hown in Fig6(d) The voltage of 690V bu dop to 038pu, and the cuent inceae to 3~4 tie of ated value duing the voltage ag, a hown in Fig6(f) and Fig6(g) ep B Siulation eult of cenaio 2: With SVC connecting to the 35kV bu, unde voltage potection of the wind tubine i not activated, o the wind tubine can eain gid integation duing the voltage ag Fig7(d) Pitch angle of DFIG Fig7(e) DC voltage of DFIG Fig7(f) Voltage of 690V bu Fig7(g) Cuent of 690V bu Fig7(a) Active powe output of DFIG The active powe of the unit ecove apidly afte the ecovey of gid voltage, a hown in Fig7(a) and the Vol, Iue 5, Sep-205

5 23 eactive powe i hown in Fig7(b) The angula velocity i a ooth cuve, a hown in Fig7(c) and the pitch angle eain contant a thee i no change in wind peed a hown in Fig7(d) The voltage of 690V bu dop to 045pu, ipoved 0035pu copaed to cenaio, a hown in Fig7(f) The cuent ecove to be noal afte fluctuation, a hown in Fig7(g) Each vaiable can etoe tability afte 05 econd of fluctuation SVC povide eactive powe to the yte duing 45~45 econd, and play an ipotant ole fo uppoting gid voltage V CONCLUSION Thi pape analye the dynaic eactive powe copenation duing fault condition fo wind fa with wind tubine potection Baed on the analyi of dynaic chaacteitic of SVC and the etablihent of a 63MW wind fa yte odel, thi pape how that SVC ha good dynaic chaacteitic When a SVC i connected to a wind fa, it can upply eactive powe coenuate with the capacity of SVC fo the wind fa, o that the eactive powe taniion fo the gid to the wind fa can be educed When evee voltage ag occu in the gid ide, SVC i able to adjut the output eactive powe dynaically to help ebuilding the teinal voltage of wind tubine and play an ipotant ole in uppoting gid voltage To cetain extent, it i alo able to ipove the fault ide though capability of wind tubine On the othe hand, it hould be noted that, thee ae cetain etiction fo the uppoting ole played by SVC: If the voltage ag of the yte i too evee, then the eactive powe copenation of SVC will be inufficient to let the wind tubine eain gid integation REFERENCES [] Zhong Ling, Song Xiao fang, Chang Kang, Xue feng, Meng Zhaojun Dynaic eactive powe copenation duing fault condition fo wind fa with the conideation of wind tubine potection effect Intenational Confeence on Sutainable Powe Geneation and Supply (SUPERGEN 202), IET, 202 [2] Hong liang, ZHAO Haixiang, CHI Yongning, et al Requieent fo LVRT Capability of Wind Tubine Geneato in Powe Syte, Powe yte technology, 2007, 3(7):79-82 [3] Yan Gangui, Wang Maochun, Mu Gang, et al Modeling of Gid-Connected Doubly-Fed Induction Geneato fo Reactive Powe Static Regulation Capacity Study, Tanaction of China Electotechnical Society, (7) [4] Cae C Connecting Wind Fa to the Gid-what You Need to Know, Vancouve, Canada: 2006 [5] LI Mei, LI Jianlin, ZHAO Bin, et al Copaion of Repone of Wind Tubine with DFIG duing Diffeent Gid Voltage Dip, High Voltage Engineeing, 2008, 34(4): [6] LIANG Liang, LI Jianlin, XU Honghua, Reactive Powe Contol Stategy fo Doubly-Fed Induction Wind Powe Geneation Syte Unde Fault in Powe Netwok, Powe yte technology, 2008,32():70-73 [7] ZHANG Xianping, Study on Low Voltage Ride Though fo Diect-dive VSCF Wind Powe Syte High-powe convete technology, 200(4):28-3 [8] HU Shuju, LI Jianlin, XU Honghua Analyi on the Low-voltage-ide-though Capability of Diect-dive Peanent Magnetic Geneato Wind Tubine, Autoation of electic powe yte, 2007, 3(7):73-77 [9] LI Jianlin, XU Honghua Wind powe yte low voltage ide though technology, China achine pe, 2008 [0] Wang jing, Weng guoqing, Zhang youbin Siulation and application of powe yte baed on MATLAB/SIMULINK, Xi an Univeity of Electonic Science and Technology pe, 2008 [] CUI Yang, YAN Gangui, MENG Lei, et al Analyi on Abnoal Diconnection of Doubly Fed Induction Geneato Wind Tubine Fo Powe Gid and It Deand on Reactive Powe, Powe yte technology, 20,35():58-63 [2] Naain G Hingoani, Lazlo Gyugyi, Undetanding FACTS: Concept and Technology of Flexible AC Taniion Syte About Autho: Battu Duga Sowjanya eceived the BTech degee in Electical and Electonic Engineeing fo Velagapudi Raakihna Siddhatha Engineeing College in 202 and he i cuently puuing MTech in Powe Syte Contol and Autoation at Paad V Potlui Siddhatha Intitute of Technology He eeach include Gid integation of Wind enegy yte Motukui Devika Rani eceived the BTech degee in Electical and Electonic Engineeing fo JNTU Hydeabad in 2003 and eceived the MTech degee in Powe Electonic fo JNTU Kakinada in 20 Peently he i woking a an Aitant Pofeo in Electical and Electonic Engineeing depatent at Paad V Potlui Siddhatha Intitute of Technology He eeach aea include Powe Electonic and it application to Powe yte Vol, Iue 5, Sep-205