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E] KHOA HQC - CdNG N H | NGHICN cim UNH HITIUNG CUA HC TH6NG N6I D/^T utn QUA DlCN AP VA QUA UONG D I I N KHI Sif Cd CHAM ukl TRONG lirOl DICN PHAN P H | 22 KV pha dfty Vi pha m Nguyin Luang Mfnh, V6 NhUQutic rdng Cdng ty Oiin li/c miin Trung TOMTAT LUdl d l | n phdn phdi (LDPP) 22 kV khu vpc m l l n Trung h l | n dang vdn hdnh vdi d^ng cdu true pha - ddy, bdn kfnh cdp d i l n ddi hdng chye klldmlt {ed m^t sd dudng ddy ddi t r i n 50 km) Qua thuc t l vdn hdnh, dd xdy n h i l u trudng hpp cham ddt m^t pha (CDMP) gdy qud dl^n dp cdc pha khdng cham ddt vd qud ddng d l | n d pha bj ch^m ddt qud mPc chju dpng eiia t h i l t bl Oi h^n c h i dnh hUdng cua loai sped ndy din t h i l t bj, cdn quan tdm d i n h l | n tUpng qud d i | n dp vd qud ddng d l | n xdy sped cham ddt t r i n ludi vi|c tfnh chpn t h i l t bj d i | n Bdi bdo nghiln cCfu dnh hudng ciia h | thdng ndi ddt d i n mCfc dO qud dl$n dp vd qud ddng d l | n sp cd cham ddt LDPP 22 kV ddi vdi dang cdu trOc lUdl pha ddy vd pha ddy, d l cd Ofng dpng h l l u qud vdo thpc t l \ Dit vin dt: I lOkV LDPP 22 kV cd trung tfnh n6l ddt true tiep, cham ddt dupe xem Id dang su cd ngdn mach n i n phdi dUOc each ly vdi thdl gian ngdn nhdt Trong khodng thdl gtan d pha bj sp ed vd qud d i l n dp d pha khdng sp c6 MPc Lfltni) ($>\m\— tP su cd xudt h i l n cho d i n sp c6 dupe ed ldp, cde t h i l t bj t r i n ludi d i l n se chju tac ddng eiia qud ddng d i l n 22k\' Hinh So dd don g i i n LOPP 22kV H i s6 q u i dl«n i p x i y NMMP, tang cao d i l n dp vd ddng d i l n phu thudc vdo tinh chdt noi dat ciia lUdi d i l n (ndi dat hieu qud hay khdng h l l u ''•-I ] ^• r^^ .' , X, ' 1 qud), dUdc phdn dnh qua ty sd d i l n khdng t h P t p khdng X, ' , fx, ,) \ l^- ll X, L X, J (TTK) X^ vd dien khdng thPtpthudn (TTT) X,.ThUc t l , thiet ke LDPP 22 kV d Vilt Nam thi cde vdn d l ndy ehUa dUde quan tdm diing mpe, nhdt Id h i sd qud d i l n dp vd ed t h i se ddn den viec chpn Ipa cde t h i l t bj d i l n khdng phii hpp vdi dac tinh ciia ludi d i l n Quan h i giiifa tinh chlCt n6i dit cua h i thdng • Khi ngdn mach hai pha cham ddt N " d pha B va phaC: Ddng d i l n chay qua d i l m trung tfnh chfnh Id ddng ngdn mach pha cham ddt I " " K =INB +INC =— den dong dien vd dien dp c6 sU co cham ddt: Xet LOPP 22 kV nhU hinh 1, xdy sped cham ddt d cudi dudng day tai d i l m N, Ddng d i l n vd d i l n dp eiia ;— (3) 2X„+Xi He d qud d i l n dp cd ngdn mach pha cham ddt, 3X, cac pha xdy CDMP vd cham dat hai pha dUdc tfnh X, toan [4]: (4) '•' X, - Khi ngdn mach mdt pha (NMMP) N"' d pha A: Dong dien ngdn mach (DONM) ciia pha A chfnh Id X, Quan he glQa 1^' 'vil„"", ddng dien chay qua diem trung tfnh IN = IN, 3E 12 Wen Jk Bin song ' X + X, ^ X, IN" " X i + Xo ^ (5) KHOA HQC - CONG NGHf: \3 1^"' nguy h i l m hon ddng I,"", vd € * ' • ' * > C^'* nghia Id qud 1- L>f l" s'' j^ ^!^ (i-• r- NMMP + Khi — ^ > (h§ thdng ndi ddt khdng hiiu qud) thi •f H dl|n dp ngdn mach pha cham ddt nguy hilm hon —^ * ' -^ —Ce(l,l -.-iNliyiNd.ii - 'N'" ^ V ' " ' ^^' nhCmg d i l m ngdn mach cham ddt cd t^ sd < — ^ < 4,5 thi C^'''*> C ^ " n i n qud d i l n dp ngdn mach pha cham ddt nguy h i l m hon NMMR Cdn tai ' o0^i , nhOng d i l m ngdn mach cham ddt cd ty sd — ^ > 4,5 thi ^1 °'°o C j " > C^''"' vdy qud d i l n dp NMMP nguy h i l m hon ngdn mach pha cham ddt Hinh Quan h i giOa Ced), Ce(l ,1), IN(1,1 )/IN(l) theo X0/X1 Cdc yiu ti dnh hifdmg d i n tfnh chat ncfi d&t cua h i thdng: TO (2), (4) v i (5) c6 t h i b i l u dien quan h? giffa cic 3.7 Tifng trd'ccia (Tu'dhg ddy trin Jr/iong: Tdng trd eiia dudng day tren khong (DDK) phu thudc vdo nhieu y l u td nhu t i l t d i l n day, vat lieu, khodng each pha, cdu true ddy dan, loai lUdi dien, dp cao treo day, nhilt dp ddy ddn va d i l n trd suat ciia dat D l tinh tong trd cua DDK cd the dung phuong phdp gidi tfch [1] hoac bang cdch tra bdng he s6 C j " , C ^ ' " v i l„"'/l„"'" theo ty s6 X,/X, nhir hinh Cac dudng dac tinh C^", C [ ' " va IJ'VI,"" cCing giao tai diem co — ^ = L riing duOng dac tinh C ' , C ' ^'^ X giao tai diem e d — - = 4,5 TP hinh 2, nhan thdy: + Khi < (he thong noi dat ta hieu qua), tat nhPng d i l m ngdn mach cham dat cd t^ sd — - < thi ? ^ < nen ddng I J ' " nguy hiem hdn ddng IJ", va C ' T(l.l) > Cg nghia Id qua dien dp NMMP nguy hiem hon Phuong phdp dung bang tra nhu sau [5]: Tdng trd dudng day da cho bang dUoe tfnh theo cac yeu td nhat djnh nhu khodng each pha, nhilt dp day dan, d i l n trd suat eua dat Do dd, dp chinh xdc phu thudc vdo su sai lech gida yeu td thpc te so vdi cac dieu kiln tfnh toan d bdng tra Yeu td ed dnh hudng Idn d i n chinh xac la khodng each pha Tong trd TTT va TTN phu thudc vao khodng each pha va diioc hieu chinh theo khodng each trung binh hinh hpc D^ giPa cdc pha: ngan mach pha cham ddt Tai nhPng diem ngdn mach X I'" cham dat cd t j ' sd < - — ^ thi ^ > luc ddng "1 D,b=VdA-BdA-cdB [ml (6) ^N vdi d^g, d ^ ^ dg J.- ((hoing each thuc te giCra pha A - B, A - C va B • C 1000 , 1000 , I ^ D „ = V l O O O 1000 2000 = 1260 m m = 4,132 1200 , 1000 f ^ D,^=Vl200.1000 2200 ft = 1382 mm = 4,533 D,^ = VlOOO 1000.1400 ft =1119 mm = 3,669 ft Hinh Khodng cdch trung b'mh hinh hoc cua dudng day 22 kV Oien & Oai songl 13 El KHOA HQC • CdNG NGH|; Bingl Ting tri cdc thinh phdn HSIxOng da ODK22 ItV of II af II x" C-50(1/0) C-70 (2/0) C-95 (3/0) 0,377 0,299 0,237 0,444 0,435 0,418 C-120(4/0) 0,188 0,413 C-150(300) 0,134 0,400 A-50(l/0) A-70 (2/0) A-95 (3/0) 0,605 0,481 0,380 0,441 0,431 0,419 A-120(4/0) 0,302 0,410 A-150(300) 0,213 0,400 A-185(350) 0,183 0,393 AC-5Q(1/0) AC-70 (2/01 AC-95 (3/01 0,696 0,556 0,449 0,512 0,503 0,490 AC-120(4/0) 0,368 0,466 AC-150(300) 0,213 0,389 AC-185(350) 0,190 0,385 Diy pha ^ «r < X i Diy trung tfnh a/kml of x" < ^ Diy ddng 4,3 0,764 1,323 1,3 C-35(2) 3,0 1,7 4,4 3,0 0,685 1,315 1,1 C-35(2] 1,6 C-50(1/0) 0,542 4,5 1,0 1,203 2,9 1,3 C-35(2) 0,624 1,298 3,1 1,5 0,366 1,872 4,5 0,9 C-50(1/0) 0,494 1,198 2,9 1,2 C-35 (2) 0,575 1,256 3,0 1,4 4,6 0,8 C-70 (2/0) 0,311 1,859 0,399 1,152 2,9 1,0 C-50(l/0) 0,440 1,186 3,0 1,1 Diy nhOm 0.783 1,899 4,3 1,8 A-35 (2) 1,058 1,471 3,3 2,4 0,659 1,889 4,4 0,934 1,460 1,5 A-35 (2) 3,4 2,2 0,559 1,877 4,5 1,3 A-50(1/0) 0,783 1,299 3,1 1,9 A-35 (21 0,834 1,448 3,5 2,0 0,480 1,872 A-50(l/0) 4,6 0,705 1,291 1,2 3,1 1,7 0,755 1,440 A-35 (2) 3,5 1,8 0,391 1,858 0,575 1,220 46 1,0 A-70 (2/0) 3,1 1,4 A-50(1/0) 0,616 1,280 3,2 1,5 0,357 1,851 47 0,9 A-9S (3/0) 0,501 1,163 3,0 1,3 A-70 (2/0) 0,544 1,213 1,4 3,1 Diy nhom ioi t h i p 0,374 2,086 1,7 AC-35 (2) 4,1 1,131 1,573 2,2 3,1 0,734 2,077 1,5 AC-35 (2) 0,991 1,563 2,0 4,1 3,1 0,627 2,064 4,2 2,9 0,844 1,433 1,3 AC-50(l/0) 1,7 AC-35 (2) 3,2 0,885 1,551 1,8 0,546 2,039 4,4 3,0 1,2 AC-50(1/0) 0,762 1,409 1,6 3,3 1,7 AC-35 (2) 0,803 1,526 0,390 1,963 5,0 1,0 AC-70 (2/0) 3,3 0,572 1,271 1,5 3,4 1,6 AC-50(1/0) 0,608 1,332 0,368 1,959 1.0 AC-95 (3/0) 5,1 0,547 1,219 3,2 1,4 1,4 AC-70 (2/0) 0,549 1,266 3,3 hqc giUa c6cphaD^^= I25m; W/iiir d6 ddy ddn t = S0°O Khodng cdch pha •ddtd= 0,555 0,477 0,415 1,901 1,893 1,877 Tinh vdi: Khodng cdch trung binh hinh h22m;Di^ntrdsudtcuaddtp^^=lCKinm Ghi chu: So hieu ngodc Id ioqi ddy ddn tuang di/ang theo AWC, tinh theo Kcmil Sai so ve i(hoing cich pha giOa g i i tri cho trudc b i n g tra vdi thuc t i den 50% cd t h ^ d i n d i n sai so cua tdng trd d mufc (0,2 -^ 8,8)% [2] Oiiu i n h hudng den sai s6 DONM, nhung thudng Ithong Idn so vdi phUdng p h i p giii tich Ap dung phuong phap tra b i n g de tinh toan tong trd DDK LOPP 22 l chieu dai dudng day tren 20 km va X/X, > chilu dai dudng day tren 10 km - Doi vdi cau true pha ddy, day trung tinh se lam i 10 15 20 25 30 35 40 4S SO KKml Hinh 7.J^ sd XO/Xl theo chieu dai DDK pdat = 100 Om Tir hinh va hinh nhan thay: Khi t i l t d i l n day dan pha tang len thi vdi cdu true pha day, ty sd R/X, giam nhieu (R^/X, < L = 50 km) nhung t^ sd X/X, lai tang nhanh (X/X, > L s 10km), vay tinh hieu qud eiia c h i dp ndi dat giam theo chieu dai dudng day Cdn vdi cau true pha day, cd day trung tinh thi ty sd R^/X, tang rat ft (R/X, > L > 25 km ddi vdi day trung tinh AC-120) Dien Jk D&i songl 15 E] KHOA HQC - CdNG NGH^ v i t^ sd n i y cing g l i m t i l t di^n d i y trung tinh c i n g t i n g , cdn t j sd X/X, g l i m r i t n h l i u (X/X, < L > 50 km ddi vdi d i y trung t(nh AC-120) v i t;> sd n i y g l i m khdng d i n g k l t i n g t i l t d i f n d i y trung tinh 3.3 Mdi quan h^ glOla cic t) i thi cd dang cau true lUdi cung deu ed C " " > C^"', vay qud dien dp d cac pha lanh xdy ngan mach pha cham ddt nguy hiem hdn TAI U | U THAM K H A O [IJ Central Station Engineers of the Westinghouse Electric Corporation {1970), Electrical Transmission and Distribution + Doi vdi ludi pha day thi ddng d i l n cham ddt 1^^ > 60% l^j"' d i l m ngdn Reference Book, East Pittsburgh, mach each nguon 60% 1^"' Pennsylvania diem ngdn mach d cudi dUdng ddy each ngudn den 50 km Do vay, vdi cdu triic [2] Cooper Power Systems ludi pha day bdo v l ro le lam vile tin cay hon sp cd NMMR (1990), Electrical Distribution System Protection - Third edition, USA Ket luin: He thdng ndi dat la hieu qud hay khdng hieu qud s i dnh hudng den qud dien ap va qua dong dien cd sU cd cham ddt t r i n ludi diln Tfnh hieu qua cua e h l dp ndi dat khdng nhiJfng phu thude vdo vile ndi dat trung tinh tai nguon ma edn phu thudc vao tong trd eiia DDK, vao ty I I X^/X, tai diem ngdn mach ma mPc tang cao ciia dien ap va ddng dien se thay ddi Trong tinh toan DDNM va cde ti so RyX|, x y x , theo chilu ddi dudng day vdi cdc dang cau true ludi, day trung tfnh bd tri cung vdi cac ddy pha tren mat phdng nam ngang, eac day pha va day trung tfnh bd trf t r i n mat phang thdng dijfng, va thay ddi cao ciia DDK Ket qud tfnh toan cho thay, anh hudng eiia cdch bd tri day dan va dp cao ciia DDK 22 kV den cac ty so R/X,, X/X, la khdng dang ke, [3] ShawPowerTechnologies_ Inc (2004) PSS-ADEPT User Manual, New York [4] Richard RDeper(l 996), Ngiiin mach h^ thong diin, Nha xuat bein khoa hocva ky thuat, Ha Noi [5] Nguyen Luang Minh (2007), 8do cdo chuyin de: Nghien ciiu anh hudng cua day trung tinh ludi dien 22 kV d che lam viec KDX va ngdn mach pha, £>k Nang Dien Jk Doi s6hg\ \j ... 0 ,41 8 C-120 (4/ 0) 0,188 0 ,4 13 C-150 (30 0) 0, 1 34 0 ,40 0 A-50(l/0) A-70 (2/0) A-95 (3/ 0) 0,605 0 ,48 1 0 ,38 0 0 ,44 1 0, 43 1 0 ,41 9 A-120 (4/ 0) 0 ,30 2 0 ,41 0 A-150 (30 0) 0,2 13 0 ,40 0 A-185 (35 0) 0,1 83 0 ,39 3 AC-5Q(1/0)... AC -35 (2) 0,991 1,5 63 2,0 4, 1 3, 1 0,627 2,0 64 4,2 2,9 0, 844 1, 43 3 1 ,3 AC-50(l/0) 1,7 AC -35 (2) 3, 2 0,885 1,551 1,8 0, 546 2, 039 4, 4 3, 0 1,2 AC-50(1/0) 0,762 1 ,40 9 1,6 3, 3 1,7 AC -35 (2) 0,8 03 1,526... 3, 0 1 ,4 4,6 0,8 C-70 (2/0) 0 ,31 1 1,859 0 ,39 9 1,152 2,9 1,0 C-50(l/0) 0 ,44 0 1,186 3, 0 1,1 Diy nhOm 0.7 83 1,899 4 ,3 1,8 A -35 (2) 1,058 1 ,47 1 3, 3 2 ,4 0,659 1,889 4, 4 0, 9 34 1 ,46 0 1,5 A -35 (2) 3, 4 2,2
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