KHOA HOC PHAN TICH HOAT DONG CUA HE THONG ROLE BAO VE MAY PHAT C N G S U A T NHO TRONG QUA TRINH KHCH DONG DEN TS Nguyin Xuan Tiing, TS Nguyin Due Huy, TS Nguyin Xuan Hoang Viet Vien Dien - Dai hoc Bdch khoa Hd Noi ThS Le Viet Hung, ThS Ngo Thi Thanh Nga, ThS Vu T u i n Anh, KS Hoang Minh Du Vien Thuy dien vd Ndng lugng tdi tao Tom tdt: Bdi bdo trinh bay ket qud phdn lich vi hogl dpng cua he thdng rale bao ve cho mdy phdt thay dien nho qud trinh khai dong den; luai dien van hanh a trgng thdi tdch ddo co lap Vdn de cdn quan tam he thdng van hanh co lap la cong sudt ngdn mgch gidm thdp vd dnh huong tdi nhgy cua cdc rale bdo ve Bdi bdo di sdu nghien cuu cdc dnh huong ddi vdi he thdng rale bdo ve cho may phdt vd de xuat cdc gidi phdp cdn thuc hien nhdm dam bdo su Idm viec tin cay cua he thong role, cung nhu dam bdo bdo ve tdt mdy phdt qud trinh khoi dgng den Ket qud nghien cicu duac dp dung de phdn tich he thdng role bdo ve cho mdy phdt cua nha mdy thuy dien nho Sudi Tdn vdi nhieu kich bdn khoi dong den khac Tu khoa: rale bdo ve, mdy phdt dien, cong sudt nho, van hanh tdch dao, khdt dgng den Summary: This paper introduces analysis results regarding the operation of protective relaying system of small generator during black start process; network is being in an islanding state During islanding operation, the short circuit capacity of source may reduce significantly and it may lead to reduction in sensitivity of protective relay systems The paper focuses on impact of islanding operation mode to the operation of relay protection system for small generator and proposes solutions in order to overcome those drawbacks The results of analysis are applied to investigate the relay protection system of small generators at Suoi Tan hydro power plant with various black starting scenarios Keywords: protective relaying systems, generator, small sized generator, islanding operation, black start I DAT VAN DE qua dieu kien khan cap Voi uu thi phan b6 rpng khip ciia mang ludi thiiy dien nho khu vuc nong th6n va mien niii, h£ thdng diSn bi sir c6 thiSn tai, t6 may thiiy di$n nho co kha nang tu khoi phuc khoi dpng lai nhanh va cung c i p ngu6n dien tra lai, dong vai tro chu dpng va phat huy hieu Viec van hanh mang luai dien doc lap phu thugc viec phat trien hS th6ng nguon tai dia phuong va cac vung lan c ^ Tham chi ngu6n luoi dien qu6c gia bi ngat, mang luai dien dia phuong dua vao thiiy dien nho va nang lugng tai tao van co the van hanh dpc lap, dam bao dai sing dan sinh va cac boat dpng quan trpng khac , -,,•,.-, Mot cac van de can chu y thiet lap kich ban khoi dpng den cac to may thuy dien Ngircri phan bi^n: TS Nguyen Minh Viet Ngay nh$n bai: 10/11/2014 Ngaythongqua phan bi?n: 06/2/2015 Ngay duy?t dang: 05/6/2015 TAP CHl KHOA HOC VA C O N G N G H £ T H O Y L O I S6 27 - 2015 27 KHOA HOC M I li'l li'l I ' l M la viec cin phai xem xet lai he th6ng role bao ve di dam bao dp tin cay ciia he th6ng Ly cin xem xet lai la cac chiic nang bao ve dugc su dung cho may phat va cac gia tri chinh dinh di dua tren dua tren gia thiit nha may van hanh kit n6i voi he th6ng dien quoc gia Trong chi dp nha may van hanh dpc lap khoi dpng den, chi cap dien cho mpt so phu Xm lan can (islanding operation), rat co the cac he thong bao ve se khong dam bao boat d6ng diing nhu da dugc thiit ki su thay d6i cua cong suat ngan mach, chieu dong cong suit va nhieu yeu t6 khac Do can co cac tinh toan thay doi gia hi cai dat cho cac bao ve hoac b6 sung them cac chiic nang bao ve khac neu can Bai bao se di sau nghien ciiu he thong rale bao ve cho to may thuy dien nho cua nha may thiiy dien Suoi Tan (1) van hanh cr che dp tach dao qua trinh khai dpng den, de xuat cac chiic nang bao ve can cai dat them va gia tri chinh dinh tuong img Mo hinh nghien ciiu hoan toan co the ap dung cho cac he th6ng c6 kha nang van hanh tach dao tuang tu khac Ngoai co thi'tuy chpn d^t them bao vf phat hien cham dit cuon day roto va bao ve ch6ng thip kich tir 2.2 Bao ve chong cham dat 90% cupn day stato (64,59N) Bao ve chong cham dit 90% cuon day stato sir dung de phat hien cac hien tugng ch^im v6 ciia cu6n day stato Bao ve chong cham dit 90% cuon day stato loai don gian co the su dyng phuang phap dong dien/ dien ap thii t^ kh6ng (64, 59N) Bao ve thuong dugc cai dat vai gia tri khoi dpng lon hon gia tri dong/ap khong can bang xuat hien sai so cua BU, BI luong hoac miic mat d6i xiing cua dien ap van hanh Vi vay boat dgng tach dao hoac qua trinh khoi dgng den kh6ng cSn chinh lai chiic nang 2.3 Bao ve qua dong dien (51) Chiic nang bao ve qua dong (51) thuong duac trang bi nhu bao ve du phong cho cac miy phat dien c6ng suat co lon, co vira va la bao ve chinh cho cae may phat cong suat nho II CAC VAN BE PHAT SINH Vdl HE THONG ROLE BAO VE MAY PHAT Ngu6n cap cho kich tir thudng dugc liy tnrc CONG SUAT NHO KHI VAN HANH tiip tii diu cue may phat, voi may phat co n6i luoi thi ngu6n cip cho kich tir tuong d6i CHE DO TACH DAO Bao ve chong qua dien ap/thip ap on dinh ke ca che ngin mach gia Tuy nhien voi may phat boat dpng a chi it tach dao thi xay ngin mach gin co thi lam dien ap dau cue giam thip va lam giM cong suat cap cho he thdng kich tii H? qua ciia viec la dong dien ngin mach co thi tang len giai doan diu nhien sau dd sS giam manh va lam giam dg nhay cua bao ve Do bao ve qua dong thuong la lo^i co th6i gian tre nen hien tugng chic chin se anh huong toi su lam viec ciia bao ve Do vay chiic nang can xem xet l^i may phat van hanh tach dao Bao V? chong luing cong suit ngugc 23 Bao ve chong ch^m dat cuon day roto (64R) Bao V? tin s6 cao/thip Cuon kich tir ciia may phat sit dimg ^jgn mot chiiu (DC), do xay cham dit mot 2.1 Cac bao ve thuong flat cho may phat co c6ng suit nho ( Chiic nang bao ve theo tan sd: can dugc chinh dinh lai vdi thdi gian lam viSc dai hon de phii hgp vdi kha nang dap ling cua bp dieu t6c hien cd va dam bao phoi hgp vdi dac tinh van hanh cho phep cua tuabin 3.2 Su dung bao ve qua dong c6 khoa/ham dien ap thap 3.2.1 Bao ve qua dong ket hgp vdi khoa di^n apthip(51&27) Bao ve qua dong co khoa dien ap thip (51&27) (Hinh I) cho phep chinh dinh dong dien khoi dgng thap hon da cd role dien ap thap (27) lam nhiem vu xac dinh trang thai sv cd va qua tai, dong khdi dgng thip nen bdo ve cd dp nhay cao hon Chiic nang bao ve nen dugc phdi hgp cbfit che vdi chiic nang sa thai phu tai CAC GIAI PHAP KHAC PHUC DE XUAT 3.1 Co-sd cua de xuat Qua phan tich co the thay ring ddi vdi may phat nho may phat van hanh d chi dp tach dao thi cin xem xet chinh dinh lai hoac bd sung them chiic nang cho cac bao ve sau; Chiic nang bao ve qua dong: cd thi khdng du dp nhay vdi cac sir cd ngin mach gin Giai phap dugc de xuat la su dung chiic nang bao vp qua dong kit hgp vdi khoa hoac ham dien ap thap Ngoai kich hoat them chiic 30 Hinh Bdo v? qua dong kit hgp khoa dien dp thdp (51 & 27) Chiic nang khdng yeu ciu phai cd rale chuyen dung, tiip diim diu cua phin tii TAP CH( K H O A H O C V A C O N G N G H E T H U Y LOI S 27 - 2015 KHOA HOC dien ap thap cd thi dugc ndi tiip vdi tiep diem diu cua chiie nang bao ve qua dong hien cd Phuong thiic phu hgp vdi may phat cua thuy dien Sudi Tan (1) role bao ve dugc sir dung tai day la loai bao ve qua dong don gian Tuy nhien can chii y de thay ddi phuong thiic dau ndi cua role giam sat mach cat (74) de tranh bao nham cac gia tri chinh dinh (theo khuyen cao ciia Siemens (2)): U^SSSSM^M biet ddi vdi cac may phat hoat dpng tach dao nhu trudng hgp td may cua nha may thuy dien Sudi Tan Do cd the xem xet kich boat chiic nang cac ly sau: Chiic nang bao ve qua dong thii tu nghich dugc trang bi san cac role qua dong Dong dien ngan mach vdi su cd khdng ddi xung cd the thap (tham chi nho ban dong tai lon nhat) va cac role qua dong pha thdng thudng khdng du dp nhay de phat hien • D o n g d i e n k h d i d g n g : l,4*IdinhmuccQaniayphat Trong ludi dien nho cd lap, kha nang xay hien tugng van hanh vdi tai khdng can bing la de xay ra, tai khdng can bang se gay anh 0,8*Ud,nhmLrc 3.2.2 Bao v | qua dong vdi ham dien ap thap (51V) hudng true tiep tdi may phat (gay phat ndng hon binh thudng, rung dgng qua trinh Bao ve qua dong cd ham theo dien ap thap van hanh) (51V) boat dpng dua theo nguyen ly: dong dien khdi dgng tu dpng thay ddi theo di$n ap Nhu vay chiic nang bao ve theo dong thii tu dau cue may phat Khi dien ap giam thap, nghich nen dat vdi dac tinh thdi gian phu dong dien khdi dpng se ty thap dam bao thupc (Hinh 3), neu mire dp mat can bang nho cho bao ve qua dong cd dii dp nhay Dac tinh ling vdi trang thai van hanh binh thudng hoac lam viec cua mdt role qua dong cd ham dien qua tai thi thdi gian cat keo dai, neu miic dp mat can bang lon ling vdi trudng hgp su cd I ap thdng dyng dugc trinh bay tren Hinh khdng ddi xiing thi ngugc lai thdi gian cat phai ngan J, MCfc d$ thay doi d6ng • Dien ap khdi dpng cua role dien ap thap: khffi dOng Dong khdi dpng: thudng dat lon hon miic dp khdng ddi xung cua dong dien qua trinh van hanh Dai cai dat cd the dao dpng tir (0,1-0,3)* Iditih mirc cua BI- Tuy nhien, vdi may phat van hanh tach dao thi miic dp khdng ddi xiing cd the Idn nen cd the chpn gia tri cai dsit la U,J Idjnh mCrc cila BI- Hmh Bdove qudiBngvdi hamdienqy th^ (5iy) Chiic nang bao ve cd uu diem la thich nghi tot vdi mpi trang thai van hanh ciia may phat, nhien cin role chuyen dung do khd cd kha nang ap dung ddi vdi may phat cua nha may thuy dien Suoi Tan 33 Su dung bao ve qu^ ddng thir tu nghich (46) Bao ve qua dong thii ty nghich cd hieu qua dac Hinh Bdo ve qud dong thu tu nghich vai dgc tinh thoi gian phu thugc TAP CHf KHOA HOC VA CONG NGHE THUY LOl S6 27 - 2015 31 KHOA ur.r ^>{>].VJ»d!l^ v i phin cai d|t chinh dinh: Ddng khdi ddng ciia chiic nang bao ve so lech theo kieu cdng tir thdng cd thi dat thip khdng bi anh hudng bdi sai sd cua cac BI Di nang cao nhay cua bao ve cd thi dat gia tri d miic 0,2*Idinh m*c BI Thdi gian lam viec cua bao ve dat khoang 50ms de tranh tac ddng nhim cac dao ddng qua dp 3.5 Chirc nang bao ve theo tan s6 Vdi cac may phat van hanh d che dp tach dao thi chiic nang bao ve chdng ludng cdng suit ngugc khdng cdn tac dung, do se khdng phat hien dugc hien tugng mat ngu6n nang lugng so cip Do bao ve theo tan so thip la cin thiit cac trudng hgp nay, bao ve theo tin sd thip se phat hien hien tugng tin sd giam qua thap mat nang Thdi gian lam viec cd the dat xap xi giay, lugng so cap vao tuabin Su can thiet ciia chiic nang bao ve tan sd cao da dugc dien khdng cin phdi hgp vdi cac bao ve khac » Khdng y§u ciu lip dat them role, chi can su giai d cac phan tren dung chirc nang bao ve qua ddng cd san, Gia tri chinh dinh cho chiic nang bao ve theo v^y khdng can dau tu them ve mat role tin sd vSn hanh tach dao khdng bi rang Tuy nhien su dyng phuong an bao ve bupc bdi dieu kien van hanh dn dinh nhu Cling c6 mpt sd van de can quan tam: kit ndi ludi, nen cd the dya theo cac nguong » cin cd BI vdi duong kinh loi tir du Idn de lam viec/thdi gian cho phep cua tuabin Dieu c6 the dan tdi tan sd nam d nguong cao/ day quan cd the long lan qua loi tir Khdng c6 kha nang lam bao ve du phong thip mdt thdi gian dai ban, vdi miic cho may bien ap dau cue Tuy nhien may bien thay ddi cho phep Idn hon so vdi hoat ap dau cue da dugc bao ve bang bao ve so lech dpng ndi ludi Tuy nhien nha may thuy va bao ve qua ddng du phong nen khdng can dien Sudi Tan cung cap chi cho cac phy tai dan sinh (khdng phai phy tai cdng nghiep) bao ve du phong tir phia may phat nen van de cung khong gay anh hudng nhieu tdi tai 3.4 Su diing bao ve so lech theo nguyen ly tdng tir thdng don gian Vdi cac may phat nho, tiit dien day quan cuon stato nho, cd thi xem xet phuang an dat bao ve so lech theo nguyen ly tdng tir thdng (Hinh 4) Phuang an kha phii hgp vdi nha may thuy dien Sudi Tan xem xet cac yeu td sau: • Bao ve so lech se cd nhay cao hon vdi cac sy cd so vdi bao ve qua dong thdng thudng Do chi sii dung mdt BI cho moi pha nen loai trir dupe dong can bing sinh sai sd ciia BI dan tdi bao ve cd dp nhay cao Phuong an cdn cd the bao ve dugc ca su cd cham dit niu dong cham dat du Idn Chiic nang bao ve theo tan sd cdn quyet dinh tdi dp Idn cua cac nhdm tai dugc ddng vao van hanh cd lap va qua trinh khdi phuc cap dien, do nen dugc kiem tra thdng qua md phdng Kit qua md phdng vdi cac budc ddng tai khiu: va trudng hgp tan sd xudng thif Hinh Bdo v^ so lech theo nguyen ly cdng tunhit, h6 thdng van cd kha nang hdi phuc ve thdng su dung bdo ve qud dong dinh mirc dugc thi hien Hinh 32 TAP CHl KHOA HOC VA C O N G N G H E T H O Y L O I 27 - 2015 I KHOA HOC ^EggasB^ Qua md phdng cd the thay rang dap ling tan sd cua he thdng la chap nhan dugc, miic dao dgng tan sd khdng thap ban 46Hz va miic tri chi khoang dudi giay So sanh ket qua vdi cac thdng sd van hanh cho phep cua tuabin thuy dien cd thi thay rang cai dat role tan sd theo thdng sd van hanh cho phep ciia tuabin hoan toan dam bao de may phat van hanh dn dinh qua trinh khdi phyc lai tai Hinh Ddp ung tdn so truong hgp cue doan nhdt Thdng sd md phdng cua may phat nha may thiiy dien Sudi Tan ling vdi kich ban ddng tai gay syt giam tan sd Idn nhat: So dd ket ludi Hinh Sa kit ludi trudng hgp gay sut gidm tdn so lan nhdt ddng tdi • Sd lugng may phat Chi cd 02 may phat van hanh, gdm td may G2 (lOOOkW) va G3 (500kW) (td may Gl cd thdng sd tuang tu vdi G2) Cac tham sd cua may phat, bg dieu tdc, kich tir dugc su dyng dya tren sd lieu thu thap va cac sd lieu dien hinh cua md hinh thiet bi Cu the nhu sau: kV, H - 2(s); Xd - 1.014; Xd' = 0.314; X j " = 0.28; Tdo' = 6.55; Tdo" = 0.039; X^ = 0.77; Xq' = 0.375; Tqo" = 0.071; R = 0.005176; cos