Nghiên cứu thiết kế chế tạo máy biến áp siêu cao áp 450000kVA 500 225 35 kv

NGHIEN CIJU THIET KE CHE TAO MAY BIEN AP SI^U CAO AP 450.000 kVA-50Q/225/35 kV KS NGUYEN THj NGUYET Cong ty CP Che tao Thiet bi dien Dong Anh Dien nang dong vai tro rat quan do! vdi sti phat trien cua nen kinh te quoc dan, he thong dien la "mach mau" cung cap nang luang nudi moi hoat dong kinh te xa hoi, phuc vu ddi sdng, dam bao an ninh quoc phong cho moi quoc gia Dien nang tii nguon den nofi tieu thu thiTdng phai bien doi qua nhieu cap dien ap, do tong cong suat cac may bien ap thudng bang khoang 5-7 lan tong cong suat cac may phat dien d nUofc ta hien nay, mac du dien nang phat trien vdi tdc binh quan 15% mot nam nhufng nhu cau ve dien tang khoang 18%, do tinh trang cung khdng du cau se cdn keo dai Ngoai viec tap trung xay dUng cac loai ngudn dien, he thdng truyen tai va phan phdi dien cung can duTofc dau tu phat trien Nha nudc da xay dung chien luac ndi dja hda san pham thiet bj dien, dd Viet Nam phai lam chu viec thiet ke, che tao thiet bj dien cd dien ap den 220 kV I NHU'NG THUAN LOl VA KHO KHAN Cdng ty CP Che tao Thiet bi dien Ddng Anh (EEMC) da tUng budc lam chu cdng nghe, che tao cdng cac may bien ap 110 kV, 220 kV Thanh cdng cua viec nghien cUu, thiet ke che tao cac may bien ap da thuc day dpi ngO can bd ky thuat cua cdng ty nghien cUu sUa chUa phuc hoi, tien den nghien cUu thiet ke che tao cdng May bien ap sieu cao ap 500 kV Day la sU thay doi ve chat bdi vl che tao thiet bj dien tU 220 kV chuyen sang 500 kV la thach thUc to Idn ve ca ly thuyet, bf quyet cdng nghe ma dpi ngu can bd ky thuat phai tap trung giai quyet Doi vdi cac nudc cd nen cdng nghiep phat trien dang quan tam den van de thiet ke che tao may bien ap cd cdng suat Idn, dien ap cao den 750 va 1000 kV, cdn ddi vdi may bien ap 500 kV the gidi da di trUdc chung ta hon 30 nam TU nudc ta cd he thdng dien 500 kV tat ca cac may bien ap 500 kV deu phai nhap ngoai Mpi cdng viec lap dat, bao dudng phai thue chuyen gia nUdc ngoai dam nhiem Doi vdi ngUdi Viet Nam viec thiet ke, che tao cac thiet bj 30 Tijf dpng hoa / 4, 2011 dien ap sieu cao la nhiem vu "bat kha khang" Nam 2005, mdt loat may bien ap 216.000 kVA- 500/15,75 kV cua nha may Thuy dien lALY bj sU co, gay thiet hai Idn cho nganh dien cung nhu nen kinh te Viet Nam Tap doan Dien lUc Viet Nam (EVN) da giao cho EEMC nghien cUu sUa chufa phuc hdi cac to may Luc bay gid may bien ap lALY la san pham 500 kV mdi, cd dac thu ket cau phUc tap, trinh cdng nghe cao, tham ehf can bd ky thuat cua EEMC cung chua hieu gl ve may 500 kV Tuy nhien vdi tinh than quyet tam cao, khao khat lam chu cdng nghe d trinh dp the gidi, EEMC da dang ky cdng trinh NCKH cap Bp, nham nghien cUu sUa chOfa, phuc hdi cac to may bien ap SU cdng cua viec sUa chUa cac to may bien ap 500 kV da giup nganh dien hoan toan chu ddng viec van hanh he thdng dien 500 kV, va cung tU dd may bien ap 500 kV khdng cdn la "bat kha khang" ddi vdi can bd ky thuat Viet Nam nUa SU thanh cdng cua de tai, cang lam tang uy tin cua EEMC nganh dien cung nhu ca nUdc, va ddng thdi md co hdi cho viec nghien cUu che tao may IS Research on manufaturing design of ultra-highvoltage transformer 450.000kva-500/225/35kV This article focuses on introducing the research on manufaturing design of ultro-high-voltoge transformer 450.000kVA-500/225/35KV mode successfully for the first time in Vietnam and Southeast Asia by Engineer Nguyen Thi Nguyet, Dong Anh Electrical Equipment Manufacturing Joint Stock Company (EEMC) On July, 2010, the first unit of the focility uuas plated to celebrate 000 years of Thong Long-Hanoi n/ldy bien apSOOkV Idn dau tien che tao tai Viet Nan\ bien ap 500 kV sap tdi Phat huy nhUng cdng viec sUa chUa may bien ap 500 kV, nam 2008, EEMC da manh dan dang ky de tai NCKH cap Nha nUdc "Nghien cUu thiet ke, che tao to may bien ap 450.000 kVA-500 kV", vdi cac thdng sd ky thuat thda man tieu chuan lEC, tUdng dUOng vdi cac san pham cung loai cua cac nUdc tien tien Day la cdng trinh NCKH Idn nhat cua nganh Co dien Viet Nam tUtrUdc den Hien tren the gidi mdi chi cd hon chue pudc che tao dupe loai may bien ap sieu cao ap 500 kV Khac vdi viec thiet ke che tao May bien ap 110, 220 kV, nghien cUu thiet ke che tao to May bien ap 500 kV, cdng ty phai dau tU lai toan bp nha xUdng de dat tieu chuan quoc te ve: Dp am, dp sach cua khdng khf Oe phuc vu cho viec thU nghiem to may bien ap nay, nha nudc da dau tU nang cap Trung tam ThU nghiem dien Quoc gia hang tram ty ddng Cdng trinh nghien cUu thiet ke che tao may bien ap 500 kV da trd mpt thach thUc doi vdi nganh Co khf Dien luc Viet Nam ndi chung va EEMC ndi rieng Gia trj cdng trinh len tdi 120 ty VND ddi hdi ban lanh dao va toan the dpi ngu cdng nhan vien chUc cdng ty EEMC tap trung mpi ngudn lUc dam bao cho viec che tao cdng II TIEU CHUAN, THONG SO CHE TAO MAY BIEN APSOOKV May bien ap dUdc tfnh toan thiet ke, lUa chpn vat lieu phu kien, che tao va thU nghiem phu hpp vdi cac chi tieu thdng sd ky thuat theo tieu chuan: lEC - 60076 11.1 DIEU KIEN LAM VIEC: - Dp cao so vdi mUc nUdc bien - Nhiet dp mdi trudng tdi da -Nhiet dp mdi trudng trung blnh - Nhiet dp mdi trUdng thap nhat -Dp am cue dai - D p a m trung blnh -Khf hau - MUc dp d nhiem mdi trUdng : 1000m : 450C : SS^C : 0°C : 100% : 85% : Nhiet ddi : Nang (cap 3) Automation Today / 4, 2011 ol - Tdc dd gid du kien : 160km/h 11.2 CAC THONG SO KY THUAT CHINH: Kieu: pha, tru Loai may bien ap: pha, tru ngam dau, lam viee ngoai trdi Tan sd: 50Hz Dien apdanh djnh: Dien ap cudn cao ap (HV): 500/ x1,25% kV (dieu chinh dien ap dudi tai) , Dien ap cudn trung ap (MV):225/ kV(Cupn cao ap va trung ap dau tU ngau) Dien ap cudn ap (LV): 35 kV Cdng suat danh djnh (Cao/Trung/Ha): ONAN: 90.000/90.000/30.000 kVA ONAF: 112.500/112.500/37.500 kVA OFAF: 150.000/150.000/50.000 kVA Td ndi day: YNaOdll MUe each dien: Kieu lam mdt: D^ura Difin dp lam viec cue dai kV 550 Dien ap thii cao ap AC(kV) Dien dp chiu xung xet Ll' Gia trj'dinh (kV) 1550 170 Trung 4p (MV): 225 kV 245 Trung tfnh cao dp (HV) va trung ap (MV) Ha Sp (LV): 35kV 38.5 630 (cam ihtf., 200 Hz) 460 (cam (mg, 200 Hz) 70 38,5 70 Caodp(HV): 500 kV 950 N/A ONAN/ONAF/OFAF (lam mat tU nhien/quat cUdng bUe/bom dau eUdng bUe) Ddng dien ngan mach eua he thdng: 50 kA/2s -Phfa 500 kV: - Phfa 225 kV: 25 kA/2s -Phfa35kV: 20 kA/2s MUc tieng dn: Dudi 80 dB d khoang each m theo tieu chuan IEC-60551 Kha nang chju qua tai eua may bien ap: Theo tieu chuan IEC-60354 va phu hop vdi quy trinh van hanh MBA Gidi han dp tang nhiet dp: Ldp dau tren: 550C Cudn day: SO^C 11.3 CAC OAC TINH KY THUAT CUA M A Y : Td may bien ap 450.000 kVA-500 kV gdm may bien ap pha Moi may dupe nghien eUu day du tfnh nang hien dai va cac chi tieu ky thuat tien tien dUa tren eo sd tieu chuan lEC; May lam viec hoan toan tU ddng va cd he thdng bao ve nhd he thdng thiet bj cung cap tin hieu; bao ve dupe bd tri tren than may Cac tfn hieu dupe ndi vao eae tu dieu khien va eac may ngat va cac thiet bj bao ve va lUdng dat tram May dupe thiet ke dieu chinh dUdi tai phfa 500 kV, cd dieu khien tai cho va tU xa Viee dieu chinh ddng thdi eac bd dieu chinh cua tUng pha thdng qua he thdng dieu khien tuddng "XENXIN" He thdng lam mat dupe thiet ke tU ddng dieu khien ddng hoac ngat cae quat mat, may bdm dau lam mat phu 32 Ttr dpng hoa / 4, 2011 thude vao che dp cua phu tai, cung nhU tfn hieu tU ddng bao cua he thdng ddng hd nhiet dp dau, nhiet dp cac bdi day dupe bd trf tren nap may May cd thiet bj bao dau va tuddng bao tfn hieu mUe dau blnh dau phu giam xudng qua mUe cho phep Khi dd nd se cung cap tfn hieu bao ddng; sau mdt thdi gian nhat djnh, se cap tin hieu eho may ngat lam viee, tach toan bd may bien ap khdi ludi dien Ben hdng may cdn bd tri van an toan de bao ve thiing may an toan cd sU eo tang ap ben Tren dUdng dng dan len binh dau phu cd bd tri van tang ap de phdng hien tupng tang ap dot ngdt may va bd trf ro le hoi bao ve He thdng tin hieu tu ddng cua Ro le hoi dupe cap cho he thdng may ngat sudt qua trinh lam viec Neu qua trinh van hanh may bien ap, may ed hien tupng khdng binh thudng se sinh khf, sinh ddng dau chay ngUpe role hoi se tU ddng phat tfn hieu cho may ngat May ngat lap tUe lam viee tach may bien ap khdi he thdng lUdi dien Ngoai ra, may bien ap edn lap thiet bi nhiet dp eae bdi day, nhiet dp dau Idp tren ben may de theo ddi che dp lam viec eua may Bd phan nhiet cung tU ddng cung cap tfn hieu eho he thdng quat cung nhu he thdng bao ve may mdi chan sU 500,220 va 35 kV, sU trung tfnh ed bo trf tU 3-4 bien ddng de ddng dien cac bdi day cung nhu bao ve may qua tai, hoac cd sU ed tren lUdi dien Cae may bien ddng dupe ndi vao eae thiet bj bao ve de theo ddi che dp lam viec cung nhU bao ve may qua trinh van hanh Hai ben hdng may bd trf gian tan nhiet (he thdng lam mat) Tren moi gian lam mat ed bd trf bom dau, quat mat va ddng hd lUu lUdng dau Viec ddng ngat eae bom thUc hien d tij dieu khien tU dpng ben hdng may sU tang giam eua phu tai III CAC GIAI PHAP TRONG TINH TOAN THIET KE May bien ap tU ngau pha 450 MVA-500± 8x1,25% /225/35kVbaogdm may bien ap tu ngau pha 150.000 kVA 500/± 8x1,25%/225/35 kV Mac du da giam ve cdng suat cdn /3, tach may lam may, nhUng may bien ap tU ngau pha van rat Idn ve cdng suat, to ve ki'eh thUde, lam khd khan van chuyen va lap rap, thi edng Nha san xuat phai dau rat nhieu thiet bj eho phu hpp, vi vay se tdn kem rat nhieu, tfnh kha thi thap Mudn de tai thUe thi, chung tdi phai tan dung nhUng thiet bj edng nghe hien cd, dau tu nhUng thUcan thiet de nang cao chat lUcfng san pham, phu hgp vdi trinh dp cdng nghe che tao May bien ap 500 kV Viee lUa chpn phuong an tdi Uu de nghien eUu thiet ke che tao May bien ap 500 kV la mdt van de phUe tap Phuong an Uu viet phai giai quyet hang loat nhUng van de ve ket cau nhU: phu hop vdi nhUng dieu kien nha xUdng, van chuyen tren dudng di, tinh kinh te, tfnh cdng nghe va cung nhu tfnh thUc thi eua de tai De giai quyet nhUng van de tren, chung tdi nghien eUu ket eau mach tU dac biet, cae bdi day cung bd trf trudng tap trung; ap dung ket eau vanh dien dung kieu may Dd la may bien ap pha, tru nhUng chi ed tru lap rap bdi My, de tao he thdng dien dung hop ly nhat van de bao ve ehdng set Thiet ke bdi day da tao dUde he thdng dien day lech Day cung la ket cau rat phu hpp vdi trinh dp edng dung dpe true va ngang true hpp ly chju dUOc sdng set vdi nghe eua EEMC hien tai Ket eau hoan toan mdi, tUtrUdc den chUa ed dinh xung 1550 kV Ket cau bdi day cdn tao dUOe ddng dau chuyen ddng cUdng bUc lam tang them kha nang ddi lUu nhiet nhu sach vd ly thuyet rupt may bien ap Mat khac, ket cau bdi day da tinh den May bien ap tu ngau pha 500 kV cd ket cau dac biet, cho van de lam triet tieu lUc dien ddng hUdng true len gdng tU nen viec tfnh toan khdng gidng hoan toan nhu may bien ap tU ngan mach GiUa cae bdi day bd tri cac dng Idng tao cac ngau 110, 220 kV thdng thudng De dam bao viec tinh toan thiet ke eiia may bien ap cdng, chung tdi phai giai quyet vach ngan, cung vdi he thdng vanh chan gdc de phan chia nhUng van de mdi: Nhu viec tfnh toan ket cau may bd trf mach eUdng dp dien trUdng, lam giam cUdng dp dien trUdng may Phan dau 220 kV eua cudn 220 kVed dien trUdng manh tU lech, eac bdi day bd trf tren tru lech cung da cd cac bien phap tao cac dng chan cat dien trUdng De nghien eUu van de nay, chung tdi phai thiet ke va che nhUng doan nhd khdng gay nguy hai cho may tao may bien ap tu ngau pha "Md hlnh thu nhd" cd cac thdng sd tuong tUnhU thdng sdcua may bien ap 500 kVdang nghien Khi thiet ke da ap dung mdt sd bien phap lam giam tdn hao cUu: 1500 kVA-50/22.5/3.5 kV Phan dieu chinh bd trf tren cudn khdng tai va tdn hao ngan mach may Ket qua dd dugc day 50 kV± 8x1,25% thUe te Po = 57 kW va Pk = 293,5 kW, dp dn 68 db da dat tieu chuan may cd chat lUpng eao Sau hoan viee che tao may md hlnh, chung tdi da tien hanh thi nghiem rat nhieu lan, d nhieu gdc dp khac Khdi luong may 218 tan, thiet ke may bien ap phai tinh de tim dUpc quan he giUa mach tU vdi eac bdi day, giUa den viec thao rdi cac cum phu kien van chuyen, cung nhU cac bdi day bd tri leeh tren tru lien quan vdi cac thdng sd eua cd qui trinh lap dat may Viec bd tri hpp ly cae dau day ra, eac vj tri cua bd dieu chinh De tai da nghien cUu thiet ke vdi cae ty le cdng suat cua dudi tai se dan den kieh thUde vd may nhd gpn Ngoai giai cudn day 35 kV lap tren tru chinh, va cudn 35 kV lap tren tru quyet cac van de ddng deu tU trudng dau 500 kV mdt each phu Sau moi lan thay ddi ty le cdng suat lai tien hanh thU ed hieu qua nghiem nhieu lan d nhieu gdc dp khac Cac sd lieu Thiet ke phan vd may bien ap tren eo sd kha thi edng nghe 6{jgc la CO sd de tim eae qui luat quan he giUa cac thdng sd eua nha may, qua nghien cUu ket cau cac loai vd may cua eac cua may bien ap thuc nUdc da quyet djnh chpn ket cau vd kieu bae, gan dUng, day Viee xay dUng md hinh nghien cUu de tlm qui luat quan han kfn nhu kieu may eua Phap Ket cau khac phuc triet de van de chay dau day may he cua eac ket eau vdi thdng sd cua loai may bien ap tU ngau mdt pha dac biet da giup eho chung tdi cd them sd lieu tham khao TU dd da cd nhUng hieu chinh hop ly tfnh IV CAC GIAI PHAP CONG NGHE: toan Vl vay eae sd lieu sau thi nghiem dugc eua may 500 kV - Oe thiet ke dupe thUc thi, ngUdi thiet ke cae chi tiet hoac phij hop vdi sd lieu da dUOc tfnh toan cac ket cau, phai tim hieu ky eac tinh nang thiet bj hien cd cua - Van de ve phan bd dien trUdng: cac CO sd nUde de khai thac, ddng thdi phai tlm cac giai Giai quyet van de phan bd dien trudng may bien ap phap cdng nghe tren eo sd trinh dp cdng nghe hien cd eua ed tu ngau truyen tai 500 kVvdi dien ap thU xung set 1550 kV la cdng ty, de san pham lam dam bao chat lUpng eao ca mdt van de het sUe phue tap Bat cU mdt co sd san xuat may - Oe che tao va lap rap an toan may bien ap nay, EEMC da bien ap nao tren the gidi cung phai het sUe than trpng bd gan tram ty ddng de eai tao nha xUdng, he thdng Ipe va van de Dien trUdng phan bd d dau vao 500 kV, tap trung say khdng khf, dau tu thiet bj edng nghe phu hpp vdi cdng d cae gdc bdi day 220 kV, bdi day dieu chinh cua cudn day 500 nghe che tao may 500 kV kV cac bdi day 35 kV la nhUng vung nguy hiem cua may Vi vay, - Cdng nghe da giai quyet dUpc mach tU ghep nUa vdi ddi viec thiet ke bd tri cac vanh chan phai tren co sd nghien cUu vdi loai may bien ap cdng suat 150.000 kVA ed dUdng kfnh Idn tfnh toan kha nang dU phdng dp ben xung set eua eac vung hon m, bao gdm eac ranh dau ngang, dpc; la ket cau tien tien trpng yeu may Oe giam cudng dp tae ddng cua dien nhat tren the gidi hien Day cung la phuong phap edng trudng d nhUng vung nay, phai bd tri eac vanh chan gde Cae nghe mdi dau tien dUOc nghien cUu va thUc thi tai Viet Nam vanh chan gdc phai giai quyet rat nhieu yeu cau ve ky thuat, Viec nghien cUu che tao ga de lap rap mach tU cd khdi yeu eau dp chinh xac cao, yeu eau ve ddi luu dau tan nhiet lupng gan 70 tan vdi 62.600 loai la tdn day 0,23 mm cd kieh may, yeu cau ve tinh dn djnh co hpc cd lUc dien ddng thudc khae ma qua trinh dUng len khdng bj bien tae ddng, yeu cau ve tfnh kinh te va cudi ciJng la dam bao tinh dang Cdng nghe quan day true dUng de giai quyet cac bdi day kha thi 500 kV cd khdi lUdng hon 11 tan, da giup eho van de nang cao Ngoai cae van de tren, de tai da ap dung mdt sd ket cau tdi chat luong san pham Cac thiet bj sU dung lap rap ga Uu cua eae nUde phat trien nhU:DUe, Nga, My, Nhat Dd la viee ghep, Cac ket cau cdng nghe giai quyet cae van de ton hao ap dung mdt sd bien phap tang cUdng each dien d vung tU khdng tai va cd tai nhu sU dung toan bd dai thuy tinh, cdng dac biet Automation Today / 4, 2011 33 nghe dai mach tUda lam giam tdn hao dang ke eho may - Cdng nghe che tao bdi day da giai quyet dupe mdt each chfnh xac kieh thudc cua bdi day, dam bao dien trd mot chieu, cung nhu dam bao dp chinh xac cae ket cau bao ve dien ap xung set bdi he thdng chdng set thiet ke tren cac bdi day Ngoai viec thi cdng chinh xae ket eau bdi day da tang them kha nang chju lUe co hpc - Cdng nghe che tao vd: Tren cd sd sU dung cae trang thiet bj ehu yeu che tao cac may 220 kV, vd may sau gia edng dam bao dUpe kich thUdc hinh hpc, ve dp kin, ve tinh co hpe van chuyen Vd dUpc tinh toan va che tao vdi kha nang chju dp chan khdng tuyet ddi 760 mmHg - Cdng doan say: EEMC da ap dung cdng nghe say hien dai: Say hoi dau Thdi gian say giam edn 1/5 so vdi trUde day Cae edng nghe dugc nghien cUu apdung tren cd sd cdng nghe eua eae nUdc phat trien phu hop eho may 500 kV Den nay, de tai da hoan va da thU nghiem nhUng hang muc cudi ciJng Td may bien ap tU ngau truyen tai pha, cap dien ap: 450.000 kVA-500/225/35 kV cd khdi lUpng gan 652 tan lan dau tien dupe nghien cUu thiet ke va che tao cdng d Viet Nam May cd ket cau gpn, dep ve hlnh thUc, tdt ve chat lupng, cac tinh nang ky thuat tUOng dUOng vdi cac may cung loai cua cac nude tien tien May bien ap hien dang sSn sang chd chuyen di lap dat de khai thac V KET LUAN: Thanh edng cua de tai Nghien eUu thiet ke che tao may bien ap sieu cao ap 500 kV la mdc son ma tap the Cdng ty CP Che tao Thiet bj dien Ddng Anh da danh dau them mdt bude trudng cua nganh Co khf Dien lUc Viet Nam noi rieng va cua nganh edng nghiep nang Viet Nam ndi chung Cd duoc edng nhd nhUng ddng gdp quan trpng cua Bd Khoa hpe va Cdng nghe, Bd Cdng Thuong, Tap doan Dien lUc Viet Nam, Tdng Cdng ty Truyen tai va cua Cdng ty Truyen tai dien I da tao mpi dieu kien ung hd ve tinh than, tai chinh, tai lieu cho EEMC hoan nhiem vu Chung tdi tin tUdng rang nhUng nam tdi cac May bien ap 110,220 kV, May bien ap 500 kV EEMC che tao se cung cap du nhu cau cua nganh Dien viec phat trien lUdi dien 500 kV cung nhU chdng qua tai eae tram 500 kV tren toan qude ma khdng can nhap ngoai, gdp phan vao sU nghiep Cdng nghiep hoa va hien dai hoa dat nUdc.Q GIAI PHAP THU T H A P DUf UtU • • ^OIIU KHIEN TRAM K H O N G NGirtfl TRlTC IRAN ANH THAI I TONG QUAN CUA HE THONG THONG TIN VAN HANH: 1.1 He thong dieu khien tram va cac trung tam quan ly van hanh De dap Ung nhu cau quan ly van hanh he thdng cao ap (110/220/500kV), cac cdng ty truyen tai dien va cdng ty dien lUc can dUpc trang bj mdt he thdng thu thap va xU ly thdng tin van hanh tU mUe thap nhat cua he thdng la cac tram bien ap cho den mUc quan ly cua cdng ty, xi nghiep tham chi den tan cac dien luc dupe phan cap dieu khien phdi hpp vdi ludi dien trung the eua minh 34 Tir dong hoa / 4, 2011 • • • • DC r I rj p Trp Hinh 1-1: Kien true tong the he thong thu thap va xCfly thong tin van hd ... ultra-highvoltage transformer 450.000kva-500 /225/ 3 5kV This article focuses on introducing the research on manufaturing design of ultro-high-voltoge transformer 450.000kVA-500 /225/ 3 5KV mode successfully for... cudn cao ap (HV): 500/ x1,25% kV (dieu chinh dien ap dudi tai) , Dien ap cudn trung ap (MV) :225/ kV( Cupn cao ap va trung ap dau tU ngau) Dien ap cudn ap (LV): 35 kV Cdng suat danh djnh (Cao/ Trung/Ha):... trj''dinh (kV) 1550 170 Trung 4p (MV): 225 kV 245 Trung tfnh cao dp (HV) va trung ap (MV) Ha Sp (LV): 3 5kV 38.5 630 (cam ihtf., 200 Hz) 460 (cam (mg, 200 Hz) 70 38,5 70 Caodp(HV): 500 kV 950 N/A