TIET KitM NANG LI/0NG Q
Giai pliap SIJI dung nang iildng tiieu qua trong cac dgng cd dien xoay chieu dung trong cong ngiiiep
Trjnh Van Hung
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dng CO dien l i thiet bj dien co hpc giiip chuyen dien n i n g thanh co ning. Co n i n g nay duoc sif dung de, quay banh cdng t i c cua bom, quat hoac quat day, chay m i y nen, nang vat lieu,... Cac ddng co dien duoc sii dung trong dan dung (may xay, khoan, quat gid) va trong cdng nghiep. Ddi khi ddng co dien dupe gpi la"siic ngua"ciia nganh cdng nghiep vi ude tfnh, ddng co sii dung khoing 70% ciia toan bd tai dien trong nganh cdng nghiep. Chinh vi vay viec tim g i i i phap de n i n g cao hieu qua Slf dung cac ddng co nay se cd y nghTa to Idn trong viec tiet kiem dien ning, giam g i i thanh sin pham va t i n g tinh canh tranh ciia doanh nghiep.
I. Ton that trong dong co ctlen xoay chieu
Cd 2 loai ddng co thudng diing trong cdng nghiep:
ddng CO ddng bp (DB) va ddng co khdng ddng bd (KDB).
Ddng co KDB la ddng co thdng dung nhit, duoc sif dung cho cac thiet bj khic nhau trong cdng nghiep. Sd di loai ddng ca niy thdng dung nhU v i y la vi chiing cd thiet ke ddn g i i n , re tien v i de bao tri, cd the ndi tnic tiep vdi ngudn xoay chieu 3 pha. Tdn that cd the thay ddi t i i 2%- 20%. Bang 1 cho tha'y cac loai tdn that d mdt ddng co khdng ddng bd (KDB).
Bang 1. Cac loai tdn that dDCKDB Loai ton that
Ton that co djnh hoac ton that do loi thep
Ton that bien doi: ton that stato Ton that bien doi: ton that roto Tdn that do ma sat va quan lai Tdn that ccf khf cCia dpng cd
Phan tram ton that toan phan (100%)
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Trong q u i trinh lam viec, de g i i m tdn that va hieu q u i lam viec ciia ddng co thi viec n i n g cao hieu suit cho ddng co ddng vai trd quan trpng. Hieu suit ciia ddng co duoc xic djnh bdi tdn that ben trong chi cd the g i i m bang each thay ddi thiet ke ddng co va dieu kien van hinh. Hieu suit ciia ddng co cd the djnh nghia la "ty sd ciia cdng suit dau ra hiifu dung ciia ddng co vdi cdng suit d i u ra toan phan." Cic yeu td i n h hudng den hieu suit ciia ddng cd bao gdm:
TTJ 2» 38 5S~
Motor Rating (kVW)
425 Sbo
Hinh 2. So sanh giOfa dpng co hieu suat cao va dong ccf chuan - Lao hda: ddng co mdi hoat ddng hieu q u i hon.
- Cdng suit. Vdi phan Idn cac thiet bj, hieu suit ciia ddng CO tang khi lam viec d cdng suat djnh miic
Tdc dp. Cac ddng co tdc dp cao hon thudng hieu qua hon
- Loai. Vf du nhU, ddng co Idng sde thudng hieu q u i hon ddng co cd vanh trUOt.
- Nhiet dp. Dpng co cd quat lam mat hieu q u i hon so vdi ddng cd cd Idp b i o ve chdng am (SPDP)
- Quan lai ddng ca cd the lam giim hieu suit
-Tii ddng cO, dUpc md ta nhU sau: GiCfa hieu suit va t i i ciia ddng co cd mdi lien he rd rang vdi nhau. Cic nha sin xuit thiet ke ddng co van hanh d miic t i i 50-100% va hieu qua nhat d miic t i i 75%. Nhung khi t i i giim xudng dUdi miic 50%, hieu suit se giim rat nhanh. Van hanh ddng co dudi 50% miic t i i cung cd t i c ddng tUOng tii, nhUng nhe hon ddi vdi he sd cdng suit. Hieu suit ciia ddng co cao va he sd cdng suit g i n bang 1 l i miic van hinh hieu q u i mong mudn v i giiip giim chi phf ciia toan bd day chuyen chii khdng chi rieng vdi ddng co. Vi ly do tren, khi dinh gia ket q u i hoat ddng cua mdt ddng co, cin xac djnh c i t i i v i hieu suit. 6 hau het cic nude, cac nha sin xuit phii ghi rd hieu suit day t i i tren phin ghi cic thdng sd (nhin) ciia ddng cd. Tuy nhien, vdi mdt ddng cd van hanh trong mdt thdi gian dai, thudng rit khd xic djnh hieu suit vi phan nhin miy ciia ddng co bj mat di hoac bj son de len tren.
De do hieu suit ciia ddng co, c i n ngit t i i va dem ddng cd den bd phin kiem tra de thiic hien mdt sd kiem tra. Ket q u i ciia nhiing lan kiem tra duoc so sinh vdi thdng sd hoat ddng chuan cua ddng co do nha sin xuit cung cap. Trong trUdng hop khdng the n g i t ddng co khdi
Dien A Dth' sdhg
E] TIET KIEM NANG Ll/GfNG
tai, cd the liy gia trj tUOng ddi ve hieu suit trong b i n g cung cap cic gia trj tuong ddi cua hieu suit ddng co.
2. Cac g\i\ phap nang cao hieu suat va giam tdn that trong dong cor KDB
2.1 Thay dong cof tieu chuan bang dong cof hieu suat cao
Ddng co hieu suit cao duoc thie't ke chuyen dung de t i n g hieu suit hoat ddng so vdi ddng cd tieu chuan. Cic cai tien thiet ke t i p trung vao viec lam g i i m tdn that ben trong ddng co, bao gdm viec sir dung thep silic cd tdn that sat tlf t h i p hon, Idi dai hon (de t i n g chat kich hoat), d i y day hdn (de g i i m trd khing), l i thep mdng hon, khoing trdng khdng khf giufa stato va rdto nhd hdn, sCr dung ddng thay cho cic thanh nhdm trong rdto, cic vdng dem tdt hdn va quat nhd hon.... Ddng co hieu suit cao cd d i i cdng suit thie't ke va miic day tai rdng. Hieu suit cao hdn ddng CO tieu chuan tif 3% tdi 7% nhU cho trong hinh 2. Bang 2 dUa ra cac g i i i phap c i i tien thudng dUpfc sif dung trong thiet ke ddng cd hieu suit cao.
Do p h i i thuc hien cac giai phap c i i thien hoat ddng ciia ddng co, chi phf cua ddng co hieu suit cao cao hon chi phf cCia ddng co tieu chuin. Phan chi phi cao hon se duoc hoan vdn r i t nhanh nhd g i i m chi phf van hanh, nhat la vdi cac ling dung mdi hoac thay the cic ddng cd het thdi han Slf dung. NhUng thay the cic ddng cd dang dung ma chUa het thdi gian sir dung bang cac ddng co hieu suit cao khdng p h i i liic nao cung k h i thi ve mat tai chfnh, va vi viy, chiing tdi de xuat chi thay nhufng ddng co n i y bang ddng CO hieu suit cao khi nhufng ddng co nay hdng.
Bang 2. NhCfng khu viTc nang cao hieu suat of dong CO hieu suat cao
Khu vUc tdn that dien 1. Sat tlf
2. Stato I^R
3 Rdto I^R
4 Ma sat va q u i n d i y 5.Tdn that rd
Nang cao hieu suat
- Sii dung thep t i m mdng hon vi tdn t h i t Idi sat t h i p hon se giiip g i i m tdn that ddng xoiy.
- Ldi dai hdn se c i n sii dung nhieu thep hdn trong thiet ke, lam giam tdn that nhd g i i m mat dp tCf thdng sinh ra.
- SCf dung bd dan Idn hdn bang ddng giiip t i n g dien tich tiet dien ciia cic cudn d i y trong stato. Nhd v i y lam giam trd khing (R) ciia cudn d i y va g i i m tdn t h i t do cudng dp ddng dien (1)
- Dung nhufng thanh dan rdto Idn hdn de t i n g tiet dien, nhd v i y g i i m trd khing dan (R) va tdn that do cUdng dp ddng (1) - Slf dung thiet ke quat tdn t h i t t h i p giam tdn t h i t do chuyen djch khdng khi - SCr dung thiet ke tdi Uu v i quy trinh kiem soit chit luong chat che de g i i m thieu tdn that rd
2.2 Giam mufe non tai (va tranh siir dung ddng co qua Idfn)
Nhu d i g i i i thfch d p h i n 3, non t i i se lam t i n g tdn t h i t , g i i m hieu suit va he sd cdng suit cua ddng co. Non t i i cd the la nguyen n h i n phd bien n h i t khien ddng co hoat ddng khdng hieu qua, vi mdt sd ly do sau:
- Nha sin x u i t thiet bj cd xu hudng sCr dung he sd an t o i n (he sd d i i truf cdng suit) Idn hon khi chon ddng co.
-Thiet bj thudng dUcrc suf dung non tai. Vidu nhu cac nha san xuat m i y cdng cu dUa ra hieu suat djnh miic cua ddng CO cho mufe day t i i . Tren thiic te, ngudi sCr dung rit ft khi can mufe cdng suit 100%, dan den viec thiet bj van hanh d miic non t i i trong p h i n Idn thdi gian.
- Nhufng ddng cd Idn hdn dUdc liia ehpn de giiip duy tri dau ra d mufe mong mudn ke c i khi dien i p dau vao thap mdt cich bat thudng.
- Nhufng dpng co Idn dUOc lUa ehpn cho nhufng iing dung c i n md men khdi ddng cao nhUng nhufng ddng CO nhd hon duoc thiet ke cho md men cao cd the phu hop hon.
Nen Ilia chon ky cdng suit cua ddng co diia tren danh gia chi tiet ve mufe t i i . NhUng khi thay mdt ddng co qua Idn bang mdt ddng cd khac nhd hon, cung can phii tfnh den hieu suit tiem nang dat dUpfc. Nhufng ddng co Idn hon vdn cd hieu suit thiet ke cao hon ddng co nhd hdn. Vi viy, nhin chung chung tdi khdng de xuat thay the dpng cd hoat ddng d miic 60 - 70% cdng suit hoac cao hon. Mat khic, khdng cd nguyen t i e cufng nhac trong viec liia ehpn ddng CO va can danh g i i tiem ning tiet kiem diia tren tifng trudng hop. Vi du nhU, neu mdt ddng co nhd hdn la ddng CO hieu suit cao va ddng co dang dung khdng phii la ddng co hieu suit cao, thi cd the c i i thien hieu suit.
Neu nhufng ddng co ludn hoat dpng d mufe tai dudi 40% cdng suit thiet ke, cd the i p dung mdt phUdng phap hieu q u i v i khdng tdn kem la dau sao. Viec thay ddi tii kieu dau tam giac tieu chuan sang dau sao chi gdm viec d i u lai d i y tai hop dau diy. Van hinh d dang ndi sao se lam g i i m dien i p theo he sd'V3'. 0 dang ndi sao, ddng cd se g i i m cdng suit, nhUng nhufng die tinh lam viec nhU ham cCia t i i se khdng thay ddi. Vi viy, ddng co ndi sao se cd hieu suit va he sd cdng suit cao hdn khi hoat ddng d mufe day t i i so vdi khi hoat ddng d mufe khdng diy tai theo ndi tam giic. Tuy nhien, van hanh ddng cO ndi sao chi cd the Slf dung cho cic ufng dung vdi yeu c i u ty sd md men/
tdc dp t h i p khi t i i giam. Ngoii ra, nen trinh chuyen sang ndi sao neu ddng co duoc ndi vdi thiet bi sin xuit cd sin luong phu thudc v i o tdc dp cua ddng cd (vi tdc dp ciia ddng CO g i i m khi ndi sao). Vdi nhOng thiet bj c i n md men ban d i u cao va yeu cau md men khi hoat ddng thap, cd the sCf dung bd khdi ddng Y/ D de cd the d i p ufng dUdc yeu cau md men ban d i u cao.
2.3 Chon cong suat dong co cho tiii thay ddi Cac ddng cO cdng nghiep thudng hoat dpng d nhiifng dieu kien t i i thay ddi do cic yeu c i u cCia qua trinh. Mdt
24 Dien & Ddi sdhg
TIET KIEM NANG LI/0NG Q
kinh nghiem thiic te trong tinh hudng nay la lifa ehpn ddng CO diia tren mufe tai cao nhit. NhUng nhU viy thi sCf dung ddng co se tdn kem hon vi nd chi hoat ddng d cdng suit tdi da trong nhufng giai doan ngan, va se cd nguy co ddng co bj non t i i .
Mdt Ilia ehpn khic la ehpn cdng suit cua ddng co diia tren dd thi t i i cua mdt thiet bj cu the. Dieu niy cd nghia la cdng suit ddng co dupc ehpn thap hon mdt chut so vdi mufe t i i cao n h i t v i ddng co cd the bj qua t i i trong mpt thdi gian ngan. Cd the i p dung each niy vi nha sin x u i t thiet ke ddng cd vdi mot he sd q u i t i i (thudng la cao hon t i i djnh mufe la 15%) de d i m b i o viec thing thoing ddng CO hoat ddng qua t i i se khdng gay ra nhifng hdng hdc d i n g ke. Nguy co Idn n h i t la viec ddng co bj qua nhiet, dieu nay se i n h hUdng den tudi thp va hieu suit cCia ddng co, tang chi phi van hanh. Mdt tieu chf liia ehpn cdng suit ciia ddng co la s i f t i n g nhiet dp trung binh tfnh theo trpng sd trong chu ky lam viec thiic te khdng dUpc cao hon miic tang nhiet dp khi van hanh d che dp d i y t i i lien tuc (100%). Qua nhiet cd the xay ra trong nhifng trudng hcfp sau:
-Thay ddi Idn ve t i i , nhU thudng xuyen tat/bit hoac t i i ban dau cao
Thudng xuyen v i / h o i c bj qua t i i trong mdt thdi gian dai
- Khi nang lam mat ddng co bj han che, vf du nhU d dp cao Idn, trong mdi trudng ndng hoac khi ddng co bj bao kin hoac b i m ban.
Khi t i i ddng co thay ddi nhieu trong mdt thdi gian, cd the sir dung phuong phap dieu khien tdc dp ciing vdi viec ehpn cdng suit ddng co thich hop.
2.4 Nang cao chat li/tfng dien
Hieu suit ciia ddng cd thudng bj i n h hUdng nhieu bdi chat lupfng ciia dien dau vio. Chat lupng dien d i u vao do dien i p thiic te va tan sd so vdi gia trj djnh miifc quyet djnh. Slf dao ddng ve dien ap va tan sd qua mufe so vdi gia trj cho phep cd t i c ddng d i n g ke den hieu suat cua ddng CO. Bing 6 neu len nhufng i n h hudng chung do sii dao ddng cua dien i p va t i n sd ddi vdi hoat ddng cua ddng Cd. Slf m i t c i n bang dien i p cd the i n h hudng nhieu den hieu suit cua ddng co, x i y ra khi cac pha ciia ddng co ba pha khdng c i n bang. Dieu niy thudng xiy ra do dien i p c i p cho cic pha khic nhau. Cung cd the la do kfch thudc d i y d he thdng p h i n phdi khac nhau. Vf du ve t i c ddng cua mat can b i n g dien i p ddi vdi hieu suit cua ddng cd cho trong b i n g 3.
Oien i p ciia mdi pha trong he thdng ba pha phii can b i n g , ddi xufng v i chenh nhau 120°. Cin duy tri c i n b i n g pha trong khoing 1% de t r i n h lam hdng ddng co va khdng duoc b i o h i n h bdi n h i sin xuit. Mdt sd yeu td cd the i n h hUdng den c i n b i n g dien i p : t i i mdt pha chi lay d mdt pha, kfch thudc d i y c i p khic nhau, hoac sif cd mach. SU m i t c i n b i n g n i y se lam t i n g tdn t h i t he thdng va g i i m hieu suit ddng co.
2.5 Quan lai
Mdt v i n de phd bien trong cac doanh nghiep cdng nghiep l i q u i n lai cic ddng co bj chay. Sd luong cac ddng CO q u i n lai d mdt sd doanh nghiep chiem hon 50% toan bd ddng co. Cung cd khi quan lai can t h i n se giup duy tri hieu suit ciia ddng cd d miifc nhu trudc nhung phan Idn la quan lai lam giam hieu suit. Quin lai cd the i n h hUdng den mdt sd yeu td dan den giim hieu suit ciia ddng co:
q u i n khdng dung thiet ke va bien dang ranh, lam giam k h i nang each dien v i tang nhiet dp ddng co qua miifc cho phep. Chang han, khi gia nhiet de bdc cac day quin cu, vat lieu cich dien cd the bj hu hai, lam tang tdn t h i t do ddng dien xoiy. Mdi thay ddi d khoang trdng khf giOa rdto va stato cd the i n h hUdng den he sd cdng suit va md men d i u ra.
Tuy nhien, neu thifc hien cac bien p h i p thfch hpp, cd the duy tri hieu suit ciia ddng co sau khi quan lai, va trong mdt sd trudng hpp cd the cai thien hieu suit nhd thay ddi thiet ke quin. Sif dung d i y vdi tiet dien Idn hon, kfch thudc ranh q u i n thfch hpp se giup giim tdn t h i t stato v i t i n g hieu suit. Tuy nhien, nen duy tri thiet ke ban dau ciia ddng CO khi quan lai, trif khi cd ly do die biet lien quan den tai can thiet ke lai.
Cd the de dang danh gia t i c ddng ciia viec quan lai vdi hieu suit va he sd cdng suit cua ddng co neu biet duoc tdn that khdng tai ciia ddng cotrUdc va sau khi quan lai. Thdng tin ve tdn that khdng tai va tdc dp khdng tai cd the tim dMc trong tai lieu gidi thieu ve ddng co khi mua.
Mdt chi sd cho mufe dp thanh cdng khi quan lai la so sanh giUa ddng dien khdng tai va trd khang ciia stato d mdi pha ciia ddng coquan lai vdi ddng khdng t i i va trd khing ciia stato ban dau vdi cung miifc dien ap. Khi quan lai ddng CO, can lUu y den cac yeu td sau:
Chon hing dugc cap chiifng nhan ISO 9000 hoac hing la dai dien ciia Hiep hdi djch vu ve dien (Electrical Apparatus Service Association).
- Ddng co cd cdng suit nhd hon 40 HP v i d i sir dung dUdc hon 15 nam (nhit l i nhUng ddng co d i dUOc quan lai) thudng cd hieu suit thap hon nhieu so vdi loai ddng cd hieu suit cao hien dang cd tren thj trUdng. Tdt nhit la nen thay. Va tdt nhit la nen thay nhiing ddng cO khdng chuyen dung cd cdng suit nhd hon 15 HP
- Neu chi phf quin lai vUOt q u i 50% - 65% so vdi g i i cua mdt ddng co hieu suit cao mdi, nen mua ddng co mdi. Dp tin cay va hieu suit cao hon se nhanh chdng bii lai phan g i i chenh hon.
2.6 Dieu chinh he sd cdng suat bing each lap tu bu Nhu d i lUu y d tren, DCKDB cd die tfnh l i he sd cdng suit nhd hon 1, dan tdi hieu suit t o i n phin thap hon (vi chi phf van hinh tdng cao hon) ciia he thdng dien nha miy.
Tu bu d i u song song vdi ddng cd dupe sif dung de ning cao he sd cdng suitTu bu khdng giiip t i n g he sd cdng suit ciia b i n t h i n ddng co ma giiip t i n g he sd cdng suit cua he thdng phit dan dien. Lpi fch ciia viec dieu chinh he sd cdng suit bao gdm giim cdng suit phin khing v i cdng
Dien A Ddi sdhg
E] TIET KIEM NANG Ll/tfNG
suit bieu kien (va nhd v i y g i i m tien dien cho nhu cau sif dung), g i i m tdn t h i t nhiet I^R tieu hao tren d i y dan trudc tu bu (nhd vay g i i m chi phf sif dung n i n g lUdng), g i i m sut i p tren dudng d i y (nhd v i y giiip dieu chinh dien i p ) v i t i n g hieu suit toan phan ciia toan bd he thdng dien.
Kfch cd ciia tu bu phu thudc vao cdng suit phan khing khdng t i i 6 ddng co. Kich thudc ciia tu bii khdng nen vUpt qua 90% cdng suit p h i n khing khdng t i i ciia ddng CO vi nhufng tu bu Idn hon se dan den dien i p cao lam chiy dpng co. Chi cd the xic djnh duoc kVAR ciia ddng cd nhd kiem tra khdng tai ciia ddng co. Mdt cich khic l i sir dung he sd cdng suit dien hinh d cac ddng co tieu chuin de xic djnh kich cd ciia tu bu.
2.7 Tang cUdng bao tri
Phan Idn cac Idi ciia ddng co duoc lam bang thep silic hoac thep c i n ngudi cacbon t h i p , cic d i e tinh ve dien khdng thay ddi d i n g ke theo thdi gian. Tuy nhien, b i o tri kem cd the lam g i i m hieu suit ddng co theo thdi gian v i dan den hoat ddng khdng tin cay ciia ddng cd. Vi du nhU bdi tron khdng thfch hdp se lam tang ma sit d c i ddng CO va thiet bj truyen dpng. Ma sat t i n g lam t i n g nhiet dp ddng CO, dan den tdn t h i t l i m t i n g trd khang trong ddng CO. Dieu kien mdi trUdng xung quanh cung cd anh hudng tdi hieu suit cua dpng co. Vf du nhu nhiet dp q u i cao, q u i nhieu bui, mdi trUdng i n mdn va dp am cd the lam hdng Idp cich dien; ufng suit cd hpc do tai bien ddi theo chu ky cd the g i y lech true. De duy tri hieu suit ciia ddng cd, can thifc hien b i o tri thfch hop. Danh muc cac hoat ddng b i o tri phu hpp bao gdm:
- Thudng xuyen kiem tra hao mdn d cic d true v i vd ddng CO (de g i i m tdn t h i t do ma sit) va kiem tra bui, chat ban d cic dudng thdng gid ciia ddng co (de dam b i o sU t h o i t nhiet)
- Kiem tra dieu kien t i i de d i m b i o ddng co khdng bj q u i tai hoac non tai. Thay ddi d t i i ddng co do dUpfc la d i u hieu ve sii thay ddi cua t i i , c i n tim hieu nguyen nhan ciia thay ddi nay.
Bdi tron thich hpp. Cic nha sin xuat thudng de x u i t cich thifc va thdi diem c i n bdi trdn ddng co. Bdi tron khdng chuan se gay ra nhifng true trie d i neu d tren. Bdi trdn q u i mufe can thiet cung se g i y ra nhufng true trie, vi du nhu dau hoac md dU thCfa d cic d true ciia ddng co se chiy vao ddng co va t h i m vao cich dien, lam hdng hoac g i y nguy co chiy ddng cd.
- Ojnh ky kiem tra dp ddng true ciia ddng co v i phan duoc truyen ddng lap vdi true ddng co. Lech true se nhanh chdng l i m hdng true v i d true, lam hdng ddng cd va phan dan dpng.
- Chac chin rang day dan va tii dien cd cdng suit va dupc lap dat thich hdp. Thudng xuyen kiem tra cac tiep xiic tren ddng co va thiet bi khdi ddng de d i m bao chiing sach v i chit.
- D i m b i o thdng gid thich hop v i gifl sach dudng l i m m i t de t h o i t nhiet, giam tdn t h i t . Tudi thp ciia each
dien trong ddng co cung cd the keo dai: cuf mdi mfle t i n g 10 C vugt q u i nhiet dp van hanh cho phep cua ddng co, thdi gian tdi khi ddng cd p h i i q u i n lai g i i m di mdt nfla.
2.8 Dieu khien tdc do of DCKDB
Theo truyen thdng, ddng co mdt chieu dugc sfl dung khi cd yeu cau ve thay ddi tdc dp. NhUng do cic han che cua ddng co mdt chieu ( d i g i i i thich d p h i n 2), ddng cd xoay chieu n g i y cang dugc sfl dung nhieu hon trong cic flng dung ddi hdi thay ddi tdc dp. C i ddng co ddng bd v i DCKDBdeu phu hgp vdi dieu khien thay ddi tdc dp.
Vi ddng co cam flng l i ddng co khdng ddng bd, thay ddi tan sd cung c i p cd the lam thay ddi tdc dp. Cach thflc dieu khien d mdt ddng co cu the phu thudc vao mdt sd yeu td nhfl chi phi dau tU, dp tin ciy t i i va cac yeu cau dieu khien d i e biet khac. Dieu nay ddi hdi p h i i xem xet chi tiet cic d i e tinh t i i , cic dfl lieu q u i khfl ve dieu khien q u i trinh, cic d i e diem yeu c i u cua he thdng dieu khien tdc dp, cic chi phi tien dien va chi phf dau tU. Cic die tfnh cua t i i (giii thfch trong p h i n 1) la d i e biet quan trpng ddi vdi viec quyet djnh cd nen thiic hien dieu khien tdc dp hay khdng. Tiem nang tiet kiem dien cao nhat ddi vdi bp dieu khien bien tdc -VSD thudng l i d cic flng dung cd md men thay ddi, vf du nhu bdm li t i m va quat. Vdi cac thiet bj nay, cdng suit yeu cau ti le bic ba vdi tdc dp. Tii cd md men cd djnh cung phii hgp vdi VSD.
a. Dong co nhieu tdc do
Cic ddng co cd the dugc q u i n sao cho cd the van hanh d hai tdc dp, theo ty le 2:1. Ddng co cung cd the dugc quan vdi hai cudn d i y rieng biet, mdi cudn cho hai tdc dp, tdng cdng la 4 tdc dp. Ddng co nhieu tdc dp cd the dugc thiet ke cho cac flng dung c i n md men khdng ddi, md men thay ddi, hoac cdng suit d i u ra khdng ddi. Cic ddng co nhieu tdc dp phil hgp vdi cic flng dung can dieu khien tdc dp gidi han (2 hoac 4 tdc dp cd djnh thay vi thay ddi tdc dp trong mdt dai lien tuc). Cic ddng co loai nay khdng kinh te lam vi hieu suit t h i p hon so vdi ddng cd mdt tdc dp.
b. Bo dieu khien tdc do vd cap (VSDs)
Bd dieu khien tdc dp vd cap (VSDs) cdn gpi la bd bien t i n (inverter) cd k h i n i n g thay ddi tdc dp ddng co. Cic thiet bj n i y sin cd trong d i i tfl vai kW den 750 kW. Chiing dflgc thiet ke de dieu khien DCKDBtieu chuan v i cd the de dang lap d i t cho mdt he thdng san cd. Bd bien t i n thudng dugc b i n rieng vi ddng cd cd the d i cd san, nhUng cung cd the mua bd bien tan kem vdi ddng co. Khi tai thay ddi, bd dieu khien tdc do vd c i p hoac ddng co hai tdc dp cd the giam mfle tieu thu n i n g lugng d cic bdm li t i m va quat xudng 50% hoac hon.
Mdt bd dieu khien cO b i n bao gdm mdt bd bien tan thiic hien chuyen ddi tan sd tfl 50 Hz sang cic t i n sd v i dien i p thay ddi tuy theo yeu cau t i i . Tan sd thay ddi se dieu khien tdc dp cua ddng co tuong flng. Hien nay, cd ba kieu bien tan. Od la Bien t i n ddng ngudn (CSI), Bien tan dien i p bien thien (Wl), va Bien tan dieu bien dp rdng xung (PWM).
26 Dien & Ddi sdhg
TIET KIEM NANG LI/0NG Q
c. Bd dieu khien mdt chieu (DC)
^ Cdng nghe dieu khien mdt chieu la cdng nghe dieu khien tdc dp dien l i u ddi nhit. He thdng dieu khien bao gdm mdt ddng co mdt chieu v i mdt bd dieu khien.
Odng CO bao gdm cic cudn diy va phan flng. Cac cudn c i m can cd kich tfl mdt chieu de ddng co hoat dpng, thfldng la vdi mfle dien i p khdng ddi tfl bd dieu khien. Cic ndi mach phan flng dugc thUc hien qua chdi than va bd chuyen mach.
Tdc dp cua ddng co ty le thuin vdi dien i p cap. Bd dieu khien la bd chinh luu kieu cau dieu khien pha vdi cic mach logic de dieu chinh dien i p mdt chieu c i p cho phan flng cua ddng co.
Dieu khien tdc dp thflc hien nhd dieu chinh dien ap phan flng cua ddng co.Thdng thudng, mdt may phit tdc dupc lap kem de d i m b i o dieu chinh tdc dp chfnh xic. Miy phit tdc cd the lap tren ddng cd de phit cic tfn hieu phin hdi tdi bd dieu khien.
d. Bd dieu khien dong co xoay chieu rdto day quan (DCKDB CO vanh trUort)
Ddng co rdto d i y q u i n sfl dung mdt rdto cau tao die biet de cd the dieu khien tdc dp. Rdto ddng co gdm cic cudn diy dugc ning khdi ddng co bang cic vanh trugt tren true ddng CO. Cic cudn d i y dugc ndi vdi mach dieu khien, vdi cic bien trd lap ndi tiep vdi cic cudn day. Cd the dieu khien md men ddng CO bang cic bien trd nay. Cic ddng co rdto d i y quin phd bien nhat trong khoing tfl 300 HP (sfle ngfla) trd len.
3. Cac giai phap lUa chgn
Phan nay dUa ra danh sach cic giai phap sfl dung nang lupng hieu q u i nhat ddi vdi ddng cd dien.
- Duy tri mfle dien i p cung c i p vdi bien dp dao ddng tdi da la 5% so vdi g i i trj danh djnh.
- Giim thieu sfl m i t c i n bang pha trong khoing 1% de tranh lam g i i m hieu suit ddng co
- Duy tri he sd cdng suit cao bang each lap tu bu d vj tri cang gan vdi ddng co cang tdt.
- Chpn cdng suit cua ddng co thich hop de trinh hieu q u i t h i p v i he sd cdng suit kem.
- D i m b i o mfle tai cua ddng co Idn hon 60%
- Ap dung chfnh sich b i o tri thfch hgp cho ddng cd.
- Sfl dung cic bd dieu khien tdc dp (VSD) hoac hai c i p tdc dp cho cic flng dung thich hgp.
-Thay cic ddng co hdng, q u i t i i hoac non t i i bang cic ddng cd hieu suit cao.
- Quan lai cic dpng co bj chiy tai cic djch vu ky t h u i t d i m b i o
-Tdi flu h o i hieu suit truyen ddng thdng qua b i o tri v i lip d i t dung cich cic true, xich, banh ring, bd truyen dai.
- Kiem soit nhiet dp mdi trfldng xung quanh de keo d i i tudi thp cich dien v i dp tin ciy cua ddng co, vi du nhfl t r i n h de ddng co dudi vdi anh n i n g mat trdi triic tiep, d i t ddng cd d nhflng khu vflc dugc thdng gid tdt v i gifl ddng co d tinh trang sach se.
- Bdi trdn ddng cOtheo chi djnh cua nha sin xuit va sfldung dau hoac md chat lugng cao de trinh bj nhiem ban hoac nude.
Hdi thao ve djch vu khach hang va tiet Iciem dien nang
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di t h i o "Djch vu khich hang va tiet kiem dien ning cua cic Cdng tyOien lUc Nhit Ban"td chflc tai Ha Ndi tfl ngay 4 - 7 / 1 0 la mdt trong nhflng hoat ddng thudng nien theo thda thuin hpp t i c gifla EVN va Trung t i m Thdng tin Oien Iflc Nhit Ban (JEPIC).FV2011JEPIC/eVN Sem omerServKzeandEntrg, S^..
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Cic hpc vien l i 50 c i n bd den tfl cic tdng cdng ty dien life, cdng ty dien lUc se cd co hdi nam bat dupe them nhflng thdng tin thiet thUe va hflu fch ve djch vu khich hang va TKD
Thdi gian qua, cung vdi viec thifc hien cic muc tieu sfl dung ning lugng tiet kiem v i hieu q u i ndi chung va sfldung dien tiet kiem ndi rieng, viec ning cao chit lugng cdng t i c djch vu khich hinh dugc EVN die biet quan t i m nhim xiy dUng hinh i n h , quing b i thuong hieu va ning cao uy tin hon nfla cua EVN ddi vdi khich hang sfl dung dien. Qua dd, tao diing hinh i n h ben vflng trong Idng khich hang theo phuong chim "Khich hing l i sUtdn tai cua chflng tdi".
Thdng qua cudc hdi t h i o niy, nhieu can bd den tfl cic Tdng cdng ty Oien Iflc, Cdng ty Oien lUc cd cd hdi nam bat dugc thdng tin cua cic cdng ty dien lUc Nhit Bin. Trao ddi hpc hdi, kinh nghiem, kien thflc vdi cic chuyen gia Nhit Bin ve nhflng v i n de lien quan den cdng t i c djch vu khich hang v i thifc hien tiet kiem dien. Hdi t h i o cung la djp t h i t chit hon nfla sU hieu biet, quan he hop t i c gifla EVN, JEPIC va cic cdng ty dien life Nhit Bin.
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