thiet ke mang 110kv

LI M U--------Ngy nay, nn kinh t nc ta ang pht trin mnh m, i sng nhn dn cng nng cao nhanh chng. Nhu cu in nng trong cc lnh vc cng nghip, nng nghip, dch v v sinh hot tng trng khng ngng. c im chnh ca h thng li in truyn ti v phn phi l cung cp in trc tip cho ngi tiu dng . v th mng in c thit k phi m bo cht lng in nng ,p ng nhu cu s dng in nng ca nhn dn v cc cng ty x nghip . Mng in 110kV v trm bin p 110/22kV l b phn quan trng ca h thng in truyn ti v phn phi . nu b s c s nh hng ti tin cy cung cp in ca ton h thng. Thit k mng in m bo cc yu cu k thut v ph hp v vn kinh t, ta cn tnh ton la chn phng n ti u nht . Mc d ,ti c gng nhng do thi gian v kin thc c hn nn lun vn tt nghip kh trnh khi nhng sai st .Rt mong n nhn c nhng ng gp qu bu t thy c v cc bn . Ti xin chn thnh cm n!

Tp.H Ch Minh ,thng 01 nm 2010 Sinh Vin :Nguyn Thanh Tuyn

LI CM N ** **Lun vn tt nghip ny l kt qu ca qu trnh hc tp v cng l s kt tinh ca nhng kin thc qu bu m ti tch lu c trong sut thi gian hc tp ti i Hc Tn c Thng. hon thnh c lun vn tt nghip ny ,ti nhn c rt nhiu s gip ca nhiu ngi.Ti xin chn thnh bit n v gi li cm n n: Ton th qu thy c Khoa in in T -Trng i Hc Tn c Thng. tn tnh dy d, truyn t kin thc v gip ti trong sut thi gian hc tp ti trng cng nh thi gian thc hin lun vn . Ti xin chn thnh cm n Thy : Tin S H Vn Hin Ging vin i Hc Bch Khoa Tp.H Ch Minh ngi trc tip hng dn v lun tn tnh gip ti trong sut qu trnh thc hin lun vn. Cm n gia nh bn b lun lun bn cnh v ng vin ti . Mc d ,ti c gng nhng do thi gian v kin thc c hn nn lun vn tt nghip kh trnh khi nhng sai st .Rt mong n nhn c nhng ng gp qu bu t thy c v cc bn . Ti xin chn thnh cm n!

Tp.H Ch Minh ,thng 01 nm 2010 Sinh Vin :Nguyn Thanh Tuyn

NHN XT CA GING VIN HNG DN............................................................................................................................................................................................................................. ............................................................................................................................................................................................................................. ............................................................................................................................................................................................................................. ............................................................................................................................................................................................................................. 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NHN XT CA GING VIN PHN BIN............................................................................................................................................................................................................................. ............................................................................................................................................................................................................................. ............................................................................................................................................................................................................................. ............................................................................................................................................................................................................................. 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BI THIT KT MNG IN 110 kVI.V tr ngun v ph ti 4

3 N

1

2 6 5 10 km/khong chia II. S liu ph ti Ph ti Pmax (MW) Pmin (%Pmax) Tmax cos Udm(kV) p cho php Yu cung in III. S liu ngun : cung cp cho ph ti cu LT cp LT LT LT LT LT 1 14 2 16 3 18 4 15 5 17 6 14

40% 40% 40% 40% 40% 40% 5000 5000 5000 5000 5000 5000 0.8 22 0.75 22 0.8 22 0.75 22 0.8 0.75

lch in +5% +5% +5% +5% +5% +5%

IV.Cc yu cu : 1- Phn tch ngun v ph ti 2- D kin cc phng n v mt k thut 3- So snh phng n v kinh t 4- S ni dy mng in v my bin p 5- B kinh t trong mng in 6- Tnh ton chnh xc cn bng cng sut khng 7- Tnh ton in p lc ph ti cc i, cc tiu, s c 8- iu chnh in p 9- Cc ch tiu kinh t k thut . V. Bn v 1. Cc phng n khu vc, bng s liu so snh phng n 2. Cc ch tiu kinh t k thut 3- S nguyn l

BI THIT K TRM BIN P1- ng dy ni t h thng n trm bin p 2- S ng dy cao p t thanh ci cao p ca trm i n cc trm khc: 1 ng . 3. Ph ti ca trm : Pha h p : - Cng sut : 14 MW, cos = 0.8 - S ng dy : 6 - th ph ti : Gi 1 2 30 14 60 3 30 15 60 4 30 16 70 5 40 17 80 6 50 18 80 7 60 19 100 8 60 20 100 9 60 21 60 10 60 22 40 11 70 23 40 12 70 24 30 %Pmax 30 Gi 13

%Pmax 60

4. Nhim v : - Gii thiu trm thit k - Xy dng th ph ti cc cp in p . - Chn cp in p ti in t h thng v trm . - Cc phng n s trm Chn s lng v cng sut my bin p . - Chn phng n trm . - S nguyn l . - Tnh ton ngn mch chn thit b v kh c . - Chn thit b o lng . - Chn dy cho cc ng dy cao p , trung p , l ra h p, cc dy dn trong trm . - S mt bng, mt ct . - Ni t trm Chng st nh trc tip vo trm . - ...................................................................................................................... - ......................................................................................................................

Lun vn tt nghip

Thit k mng in110kV v trm bin p110/22kV

CHNG 1

CN BNG CNG SUT TRONG H THNG IN1.1 NI DUNG Cn bng cng sut trong h thng in nhm xt kh nng cung cp ca cc ngun ph ti thng qua mng in Ti mi thi im lun phi m bo cn bng gia lng in nng sn xut v tiu th. Mi mc cn bng cng sut tc dng P v cng sut phn khng Q xc nh mt gi tr tn s v in p Qu trnh bin i cng sut v cc ch tiu cht lng in nng khi cn bng cng sut b ph hoi , xy ra rt phc tp , v gia chng c quan h tng h n gin bi ton, ta coi s thay i cng sut tc dng P nh hng ch yu n tn s , cn s cn bng cng sut phn khng Q nh hng ch yu n in p.C th l khi ngun pht khng cng sut P cho ph ti th tn s b gim i ,v ngc li .khi thiu cng sut Q in p b gim thp v ngc li Trong mng in ,tn tht cng sut phn khng ln hn cng sut tc dng, nn khi cc my pht in c la chn theo s cn bng cng sut tc dng, trong mng thiu ht cng sut khng. iu ny dn n xu cc tnh trng lm vic ca cc h dng in, thm ch lm ngng s truyn ng ca cc my cng c trong x nghip gy thit hi rt ln. ng thi lm h in p ca mng v lm xu tnh trng lm vic ca mng. Cho nn vic b cng sut khng l v cng cn thit [ mc ch ca b s b trong phn ny l cn bng cng sut khng v s liu chn dy dn v cng sut my bin p cho chng sau ] S d b cng sut khng m khng b cng sut tc dng P l v khi b Q, gi thnh kinh t r hn, ch cn dng b t in pht ra cng sut phn khng. Trong khi thay i cng sut tc dng P th phi thay i my pht, ngun pht dn n chi ph tng ln nn khng c hiu qu v kinh t.

GVHD:TS.H Vn Hin SVTH: Nguyn Thanh Tuyn

10

Lun vn tt nghip


1.2 Cn bng cng sut tc dng : Cn bng cng sut tc dng l cn bng cng sut cn thit gi tn s trong h thng v c biu din bng biu thc sau:

PFvi:

= m p pt +

p md + p td + p dt

p f : tng cng sut tc dng pht ra do cc my pht in . p pt : tng ph ti tc dng cc i . p td : tng cng sut t dng ca cc nh my in . p dt : tng cng sut d tr p md : tng tn tht cng sut tc dng trn ng dy v trm bin p.m Tng ph ti : h s ng thi ( gi thit chn 0.8 )

p pt : ppt1 + ppt2 +ppt3 +ppt4 + ppt5 + ppt6 p pt =14+16+18+15+17+14=94(MW)

Tn tht cng sut tc dng trn ng dy v my bin p :

p md : 10%*m* p pt p md : 0.1*0.8*94 = 7.52 (MW )Trong thit k mn hc gi thit ngun in cung cp hon ton cho nhu cu cng sut tc dng v ch cn bng t thanh ci cao p ca trm bin p ca nh my in .Nn tnh cn bng cng sut tc dng theo biu thc sau :

PF PF

= m p pt +

p md

= 0.8*94+7.52 = 82.72 (MW )

1.3 Cn bng cng sut phn khng


11

Lun vn tt nghip


Cn bng cng sut phn khng nhm gi in p bnh thng trong h thng in v c biu din bng biu thc :

Q F =vi :

m Q pt +

Q B + Q L - Q c + Q td + Q dt

Q F : tng cng sut pht ra ca my pht inm Q pt : tng ph ti phn khng ca mng in c xt n h s ng thi m Q pt = m [(ppt1* tg pt1 )+........+( ppt6* tg pt6 )] m Q pt =0.8*[(14*0.75)+(16*0.8819)+(18*0.75)+(15*0.8819)+(17*0.75)+(14*0.8819)] = 76.437*0.8 =61.149 (Mvar)

Q B : tng tn tht cng sut phn khng trong my bin p c th c lng Q B(MVAr) = 12%

S pt

= 12%

P

2

pt

+ Q 2 pt = 0.12 94 2 + 76.437 2 =14.538

Q L: tng tn tht cng sut khng trn cc on ng dy ca mng in. Vimng in 110KV trong tnh ton s b c th coi tn tht cng sut phn khng trn cm khng ng dy bng cng sut phn khng do in dung ng dy cao p sinh ra .

Q td : tng cng sut t dng ca cc nh my in trong h thng Q td = p td* tg tdQdt : cng sut phn khng d tr ca h thng Qdt = (5- 10%) Q pt Do trong thit k, ch cn bng t thanh ci cao p ca nh my in nn c th b qua Qtd v Qdt Tng cng sut khng pht ln thanh ci cao p ca my bin p tng :


12

Lun vn tt nghip


Q F = m Q pt + Q B =61.149 +14.538=75.687 (MVAr)Trong phn tnh ton ny khng b s b cng sut phn khng H s cng sut ngun : tg F=QF 75.687 = =0.915 PF 82.72

cos F =0.738.

Da vo s liu ban u ta lp c s liu ph ti sau: Bng 1.1Ph ti 1 2 3 4 5 6 P (MW) 14 16 18 15 17 14 Q (MVar) 10.5 14.111 13.5 13.229 12.75 12.347 cos 0.8 0.75 0.8 0.75 0.8 0.75 S (MVA) 17.5 21.33 22.5 20 21 18.667


13

Lun vn tt nghip


CHNG 2

D KIN CC PHNG N V MT K THUTa ra cc phng n v mt ni dy ca mng in mt cch c th v ng k thut . so snh v la chn phng n ti u nht 2.1 LACHN IN P TI IN4 Khu vc 2 3 N Khu vc 3 6 5 10 km/khong chia 1 Khu vc 1 2

Cp in p ti in ph thuc vo cng sut v khong cch truyn ti . Ngoi ra cn ph thuc rt nhiu yu t khc ngoi P v L , do cng thc di y ch l s b gn ng . Da vo cng thc STILL tm in p ti in U(kV) U = 4.34 l + 0.016 * P Trong : P : cng sut truyn ti (kW) l : khong cch truyn ti (km) Tnh cho cc ph ti ta c :


14

Lun vn tt nghip


Bng in p: Bng 2.1 Ph ti N-1 N-2 N-3 N-4 N-5 N-6 l (km) 31.113 39.661 49.193 56.089 49.1936 93.98 Upt (kV) 69.3196 74.6254 79.6947 74.6794 77.7809 77.3908

T s liu trn ta chn cp in p : 110(kV) ; Um = 110(kV) 2.2 CHN S NI DY CA MNG IN S ni dy ca mng in ph thuc vo nhiu yu t : sn lng ph ti , v tr ph ti, mc lin tc cung cp in, cng tc vch tin, s pht trin ca mng in Da vo s v tr ngun v ph ti gm ngun (N) v 6 ph ti. Ta chia s theo 3 khu vc sau: Khu vc 1gm ph ti 1&2 yu cu cung cp in lin tc Khu vc 2 gm ph ti 3&4 yu cu cung cp in lin tc Khu vc 3 gm ph ti 5&6 yu cu cung cp in lin tc 1. Khu vc 2: cho trc 2 ng dy kp hnh tia 2. Khu vc 3:cho trc ng dy kp lien thong 3. Khu vc 1:phi chn phng n Phng n 1:ng dy kp hnh tia 1 N 2


15

Lun vn tt nghip


Phng n 2:ung dy kp lin thng 1 N 2

Phng n 3: mch vng kn 1 N 2

in p 110 kV, Tmax = 5000 gi. Tra bng ta c dng kinh t Jkt = 1.1A/ mm2 i vi mng truyn ti cao p, chn dy theo mt dng kinh t. C rt nhiu phng php chn dy dn chng hn nh : Chn theo iu kin tn tht in p cho php, ng thi tha mn iu kin tn tht cng sut thp nht Chn theo iu kin pht nng cho php Chn theo iu kin kinh t Mt kinh t s ampe ln ht chy trong 1 n v tit din kinh t ca dy dn. Dy dn c chn theo Jkt th mng in vn hnh kinh t nht, tc tha mn kinh t nht, tha mn chi ph tnh ton hng nm thp nht. Jkt =b(avh + atc ) Im ax = 3 Fkt

Mt dng kinh t khng ph thuc vo in p mng in Jkt t l nghch vi in tr sut nu dy dn c b th Jkt ln


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Lun vn tt nghip


Jkt t l nghch vi in tr sut nu cng ln th Jkt c gi tr cng nh Quy tc Kelvin: khi dy dn c tit din ti u, phn gi c ph thuc tit din dy dn bng chi ph hin thi ha do tn tht cng sut v tn tht in nng trong thi gian sng ca ng dy iu kin tha hip ti uv cp = f f

Tc l Ly o hm

vt = f

v cp = =0 f f

vt theo Vt=V+Cp=A+BU+CLf+3 I2maxLR / f , ta c iu f

kin ti u quy tc Kelvin K. Fcp = 3 I2maxLR / fcp Lc ny chn dy dn th s tha mn chi ph tnh ton hng nm thp nht 2.2.1 Phng n 1 khu vc 1 2.2.1.1 chn dy phng n 1 khu vc 1: 1N I1 1

N 2N I2 2

S1=14+j10.5

S2=16+j14.111

a) Dng in cc i trn mi l ca tng on dy I1 max= I2 max=14 2 + 10.5 2 3 110 2 16 2 + 14.1112 3 110 2 10 =45.9256 (A)3 3

10 =55.984 (A)

Vi Tmax = 5000 (gi \ nm)v mt dng kinh t Jkt = 1.1 (A/mm2) b) Tit din kinh t tnh ton :


17

Lun vn tt nghip


F1kt = F2kt =

45.9256 = 41.75 (mm2) chn dy dn AC 95 1 .1 55.984 = 50.89 (mm2) chn dy dn AC 95 1 .1

Chn tit din tiu chun vi nhit mi trng xung quyanh thc t l 400c v h s hiu chnh K=0.81 c) Kim tra iu kin pht nng lc s c Khi t 1 dy trn ng dy l kp, dy cn li phi ti ton b dng in ph ti cn gi l dng in cng bc (Icb).Khi : Bng dng cho php : tra ph lc 2.6& 2.7 on N- 1 N- 2 Loi dy AC - 95 AC - 95 Dng cho php (Icp) 0.81 335=271.35 0.81 335=271.35

Dng cng bc khi t mt l I1cb=2 45.9256= 91.912 (A) < k Icp1 = 271.35 (A) I2cb=2 55.984= 111.968 (A) Is c d) Chn ct: Chn tr mt mch m hiu -110-3 (trang 149 sch hng dn thit k mng H Vn Hin ) cc kch thc :h3=4m ,a1=2.1 m ,b1=4.2 m, b2=2.1 mDab = 4.5117 (m ) Dbc = 6.3 Dca = 5.8

(m ) (m )

Dm = 3 Dab Dbc Dca = 5.48567 (m )

Dy dn AC-185: ng knh :d=19 (mm) S si :35 si Tra bng 2.5 sch thit k mng in (H Vn Hin) Ta c : k=0.768 Bn knh t thn : ds=r k=7.296 (mm) in tr :r0=0.17 (/km) Cm khng:


33

Lun vn tt nghip


x0 = 2 104 2 f lnDung dn:

Dm = 0.4161 ( ) km ds

b0 =

2 f = 2.7434106 ( 1 ) .km Dm 6 1810 ln ra h3 c b a1 b1 b

Dy dn AC-150 ng knh :d=17 (mm) S si :35 si Tra bng 2.5 sch thit k mng in (H Vn Hin) Ta c : k=0.768 Bn knh t thn : ds=r k=6.528 (mm) in tr :r0=0.21 (/km) Cm khng:

x0 = 2 104 2 f ln

Dm = 0.4231 ( ) km ds


34

Lun vn tt nghip


Dung dn:

b0 =

2 f = 2.696106 ( 1 ) .km Dm 6 1810 ln rb0 10-6 (l/km) 2.7434 2.7434 2.696 Y= b0.l (l/)10-6 85.355 108.806 122.274

Bng tng kt phng n 3 khu vc 1:ng dy N-1 N-2 1-2 S l n n n M dy AC-185 AC-185 AC-150 Chiu Di (km) 31.113 39.661 45.354 r0 (/km) 0.17 0.17 0.21 x0 (/km) 0.4161 0.4161 0.4231 R= r0. l () 5.289 6.742 9.524 X= x0. l() 12.946 16.503 19.189

2.2.3.2Tnh ton tn tht s b phng n 3 khu c 1:S1

-jQC 1 Z1 N Z2 -jQC 2

-jQC1-2 Z1-2

-jQC1-2 S2

Trong tnh ton ny , ta b qua in dung ca ng dy, ta c s vi ph ti nh sau:S1 S1-2 SN-1 ZN-1 Z1-2 ZN-2 S2 SN-2


35

Lun vn tt nghip


Tng tr tng :

= (5.289 + j12.946) + (9.5244 + j19.189) + (6.742 + j16.5033) = 21.5559 + j 48.6387 ()Tng tr Z N-1-2

Z = Z N 1 + Z12 + Z N 2

= (5.289 + j12.946) + (9.5244 + j19.189) = 14.8135 + j32.1355 ()Tng tr ZN-2-1:

Z N 12 = Z N 1 + Z12

= (6.7424 + j16.5033) + (9.5244 + j19.189) = 16.267 + j35.6925 ()Cng sut trn on N-1: 2

Z N 21 = Z N 2 + Z12

S

N 1

=

S

1 Z N 2 1 + S Z

Z N 2

= 15 . 7383

j12 . 4181

(MVA )

S N 1 = 15 . 7383 + j12 .4181 (MVA )Cng sut trn on N-2: 2

S

N 2

=

S

1 Z

N 1

+ S Z

Z

N 1 2

= 14 . 2617S N 2

j 12 . 1925

(MVA )(MVA )

= 14 . 2617 + j 12 . 1925

Kim tra kt qu ta c :

S 1 + S 2 = S N 1 + S N 2 = 30 + j 24 . 6107 (MVA )Cng sut trn on 1-2 :S 1 2 = S N 1 S 1 = (15.7383 + j12.4181) (14 + j10.5) = 1.7383 + j1.9181 (MVA)


36

Lun vn tt nghip


Nt 2 l im phn cng sut :ZN-1 N S1 Z1-2 S1-2 2 2 SN-2 ZN-2 N

Y j N 1 2

Y j N 1 2

Y j N 2 2

j

YN 2 2

Tn tht cng sut on N-2 : Cng sut cui tng tr on N-2:

S N 2 = S N 2 j

YN 2 = 14 . 262 + j11 . 532 2

(MVA )

Tn tht in p trn on N-2:U N 2 = PN 2 RN 2 + QN 2 X N 2 = 2.604 (kV ) U m PN 2 X N 2 QN 2 RN 2 = 1.433 (kV ) U m U N 2 100 % = 2.368 % < 20 % U m

U N 2 =

Phn trm st p :U N 2 % =

Tn tht cng sut tc dng trn on N-2PN 2 = P 2 N 2 + Q 2 N 2 RN 2 = 0.1874 ( MW ) U 2 m

Tn tht cng sut phn khng trn on N-2:QN 2 P 2 N 2 + Q 2 N 2 = X N 2 = 0.4588 ( MVAr) U 2 mYN 2 = 14.449 + j11.331 (MVA) 2

Cng sut u ngun pht on N-2S N 2 = S N 2 + (PN 2 + jQN 2 ) j


37

Lun vn tt nghip


Tn tht cng sut on 1-2 : Cng sut cui tng tr on 1-2:

S 1 2 = S 1 2 j

Y1 2 = 1 . 738 + j1 . 176 2

(MVA )

Tn tht in p trn on 1-2:U12 = P2 R12 + Q12 X 12 1 = 0.356 (kV ) U m P2 X 12 Q12 R12 1 = 0.201 (kV ) U m U12 100 % = 0.323% < 20 % U m

U12 =

Phn trm st p :U12 % =

Tn tht cng sut tc dng trn on 1-2P12 = P 212 + Q 212 R12 = 0.0035 ( MW ) U 2 m

Tn tht cng sut phn khng trn on 1-2:Q12 P 212 + Q 212 = X 12 = 0.0035 ( MVAr) U 2 mY12 = 1.742 + j 0.441 2

Cng sut u ngun pht on 1-2S 12 = S 1 2 + (P12 + jQ12 ) j

(MVA)

Tn tht cng sut on N-1 : Cng sut cui tng tr on N-1:

S N 1 = S N 1 j

Y N 1 = 15 . 742 + j10 . 423 2

(MVA )

Tn tht in p trn on N-1:U N 1 = PN 1 RN 1 + QN 1 X N 1 = 1.984 (kV ) U m PN 1 X N 1 QN 1 RN 1 = 1.352 (kV ) U m

U N 1 =


38

Lun vn tt nghip


Phn trm st p :U N 1 % = U N 1 100 % = 1.803 % < 20 % U m

Tn tht cng sut tc dng trn on N-1:PN 1 = P 2 N 1 + Q 2 N 1 RN 1 = 0.1558 ( MW ) U 2 m

Tn tht cng sut phn khng trn on N-1:P 2 N 1 + Q 2 N 1 QN 1 = X N 1 = 0.3814 ( MVAr) U 2 m

Cng sut u ngun pht on N-1:S N 1 = S N 1 + (PN 1 + jQN 1 ) jSTT 1 2 3 Tn ng dy N-1 N-2 1-2 Tng tn tht

YN 1 = 15.898 + j10.286 (MVA) 20.1558 0.1874 0.0035 0.3467

Tn tht P (MW)

Tng st p trn mch N-1-2:U

= 0 . 323 % + 1 . 803 % = 2 . 127 %

2.2.4 Tnh ton khu vc 2: 2.2.4.5 Chn dy khu vc 2: ng dy kp hnh tia N-3 v N-4:

4I3 N 3 S3=18+j13.5

3N I4 4

S4=15+j13.229

N


39

Lun vn tt nghip


Dng in cc i trn mi l ca tng on dy I3 max= I4 max= F3kt = F4kt =18 2 + 13.5 2 3 110 2 15 2 + 13.229 2 3 110 2 10 =59.6793 (A)3 3

10 =52.486 (A)

59.047 = 53.6793 (mm2) chn dy dn AC - 95 1 .1

52.486 = 47.715 (mm2) chn dy dn AC 95 1 .1

Kim tra iu kin pht nng lc s c on N- 3 N- 4 Loi dy AC - 95 AC - 95 Dng cho php (Icp) 0.81 335=271.35 0.81 335=271.35

Dng cng bc khi t mt l I3cb=2 59.68=119.36 (A) < k Icp1 = 271.35 (A) I4cb=2 52.47=104.94 (A) U HT = 23 (kV ) Dng in nh mc: I m.BI = 6000A > I cb.22 = 469.75A n nh lc in dng:2 k ldd I1 m = 169.7 (kA ) > I xk = 11.026(kA )

n nh nhit: (k nh I m )2 t nh = 108 (kA 2 .s )> B N = 29.079(kA 2 .s ) Chn ph ti dng c o ca BI mc vo pha A: Tn dng c o Ampe k Walt k Var k in nng k tc dng in nng k phn khng Tng Ph ti (VA) 1 5 5 2.5 2.5 16

Tng tr cc dng c o:Z dc = S BI 16 = = 0.64 ( ) 2 I tc BI 25

Chiu di t t BI n cc dng c o l 40 mrdd . BI = Z m.BI Z dc = 1.2 0.64 = 0.56 ( )0.0175 40 0.7 = = 1.25 mm 2 rdd . BI 0.56

Tit din dy ti thiu: Fdd .BI =

Chn dy dn c tit din 5 mm2


156

Lun vn tt nghip

Thit k mng in 110kV v trm bin p 110/22kV

14.8 Chn BU 22kV. Cp in p 22kV c tt c 6 pht tuyn ti ph ti. cc dng c o ng vi mt ng dy:

Tn ng h

Ph ti bin in p AB VA

Ph ti bin in p BC VA 2

Vn k Ot k VAr k Cos k in nng k tc dng in nng k phn khng TNG 2 2 5 8 12 29

2 2 5 8 12 31

Ph ti my bin in p AB: S AB = 6 29 = 174 VA Ph ti my bin in p BC: S BC = 6 31 = 186 VA Chn my bin in p mt pha 4MS34 22kV c cc thng s sau: in p s cp : U m sc =22000 3 100 3 (kV)

in p th cp: U m thc =

(V)

Cng sut nh mc ng vi cp chnh xc 0.5%: S m.BU = 400 (VA )S m.BU = 400 (VA ) > S PT = 174 + 186 = 360(VA)S AB 174 = = 1.74 ( A) 100 100

Dng th cp trn dy pha a: I a = Dng th cp trn dy pha c: I c =

S BC 186 = = 1.86 (A ) 100 100


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Lun vn tt nghip


Chn dng Ia=1.86 A Dng th cp trn dy pha b: I b = 3 I c = 3 1.86 = 3.22 (A ) Chiu di t BU ti t dng c o : 50m Tit din dy ti thiu ca mch BU: S min =( I a + I b ) 0.0188 50 = 9 .3 0 .5

Chn dy cung cp t BU n cc dng c o c tit din :10 mm2 14.9 Tnh ton my bin p t dng . Cng sut t dng : S td = 0.4(MVA ) Chn cp in p t dng 0.4 kV in khng tng ng n thanh ci h p : xtd , ha = x ht +xt

2

= 0.5795

in khng tng ng nhn t thanh ci 22kV qui v cp 0.4kVxtd ht = xtd ,ha 0.4 2 S cb = 0.5795 0.4 2 = 0.00093 ( ) 100

Chn my bin p t dng c cc thng s k thut nh sau: Sm(kVA) 400 Ucao(kV) 22 Uh(kV) 0.4 Un% 4 Pn(kW) 5.75 P0(kW) 0.84

in tr MBA t dng quy v cp 0.4kV:R BA = Pn 0.4 2 1000 5.75 0.4 2 1000 = = 0.00575 ( ) S2 400 2 BA

Tng tr MBA t dng quy v cp 0.4kV:Z BA = U n 0.4 2 10 4 0.4 2 10 = = 0.016 ( ) S BA 400


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Lun vn tt nghip


Tr khng MBA t dng quy v cp 0.4kV:X BA = Z 2 R 2 = 0.016 2 0.00575 2 = 0.0149 ( ) BA BA

Tng tr tng ng nhn t thanh ci 0.4kV:Z td0.4 = R 2 + (X BA + X td ht ) = 0.0057 2 + (0.0149 + 0.000927 ) = 0.01687 ( ) BA2 2

Dng nh mc ca MBA pha 0.4kV :I m 0.4 = S m BA

3 0 .4

=

400 3 0 .4

= 577.35 ( A)

Dng ngn mch ti thanh ci 0.4kV:I nm 0.4 = 0.4 3 Z td 0.4 = 13.69 (kA )

Chn aptomat cung cp cho ph ti t dng cp 0.4 kV: 600A


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CHNG 15

TNH TON NI T V CHNG ST TRM15.1 TNH TON NI T T NHIN. s mch 110kV: n110 = 2 .in tr t o c do = 120 (.m ) in tr ni t ct in : Rct = 10 ( ) in tr 1km dy chng st : r0110 = 3.7 km Chiu di khong vt: l kh v 110 = 200 (m ) H s ph thuc dy chng st : k110 = 1 in tr ni t ca h dcs-ct:R cs c 110 = 0.5 + R cot 110 R cot 110 R cs 110 + 0.25 = 10 10 0.5 + + 0.25 0.74 = 2.3753 ( )

(

)

in tr dy chng st: R cs100 = k 110 r0110 l khv110 0.001 = 0.74 ( )

in tr t nhin ca phn trm pha 110kV :R tn 110 = R cs c110 2.3753 = = 1.18767 ( ) n 110 2

15.2 TNH TON NI T NHN TO. 15.2.1 Ni t mch vng. Mch vng dng thanh st trn ng knh : d thanh = 0.02 (m ) . Chon su t=0.8 m B di trm :63m B rng trm:47m Chu vi trm: L=220 m H s hnh dng ca thanh :l1 63 = = 1.34 K hd th = 5.72 l 2 47

H s ma ca thanh vo ma kh : k m th = 1.6 in tr tnh ton: tt = k m th do = 1.6 120 = 192 (.m ) in tr mch vng : K L2 tt log hdth d thanh t = 2 L 5.72 220 2 192 ln 0.02 0.8 = 2 3.14 220 = 2.316 ( )

Rmv


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Lun vn tt nghip


15.2.2 Ni t b sung. Ni t b sung dng tia. S tia n tia = 2 ,mi tia di l tia = 9 m . mi tia ng s cc : nc = 2 Tia lm bng st trn ng knh : d tia = 0.02 m cc lm bng st di : l coc = 3 m ng knh cc: d coc = 0.03 m H s ma ca cc vo ma kh: k m c = 1.4 in tr sut tnh ton theo cc: tt = k m c do = 1.4 120 = 168 (.m ) in tr tn ca mt cc : 2 l coc tt log d coc Rc = l 4 t + coc 2 + 0.5 log l 4 t + coc 2 2 l coc + l coc l coc = 50.2386 ( )

H s ma ca tia vo ma kh: k m tia = 1.6 in tr sut tnh ton theo tia: tt = o k m tia = 120 1.6 = 192 (.m ) tt log l2 tia t d tia = 28.9607 ( )

in tr tn ca 1 tia: R tia =

2 l tia

H s s dng tia : tia = 0.92 H s s dng cc: coc = 0.91 in tr tn ca h thng tia v cc:R 1tia coc = R tia R c 28.96 50.238 = 14.707 ( ) = tia R c + coc n R tia 0.92 50.238 + 0.91 2 28.96

H s s dng ca tt hp cc tia: = 0.83 in tr tn ca t hp tia cc b sung:


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Lun vn tt nghip


R bs =

R 1tia coc 14.707 = = 8.859 ( ) n tia 2 0.83

S v tr ni t b sung: 7 v tr in tr tn ca ton b h thng ni t b sung:R bs tong = R bs 8.859 = = 1.266 ( ) 7 7

in tr tn ni t nhn to :Rnt = R m v R bs tong R m v + R bs tong = 2.316 1.266 = 0.8185 ( ) < 1( ) 2.316 + 1.266

in tr tn ca ton h thng ni t nhn to v t nhin:Rnd = R nt R tn 0.8185 1.18767 = = 0.4845 ( ) < 0.5 ( ) R nt + R tn 0.8185 + 1.18767

15.3 TNG TR XUNG CA H THNG NI T C NI T B SUNG 15.3.1 i vi ni t mch vng. H s ma ca thanh vo ma st : k 'm th = 1.25 H s ma ca thanh vo ma kh: k m th = 1.6 in tr quy i ni t mch vngvo ma ma :R' mv

= R mv

k 'm th k m th

= 2.316

1.25 = 1.81 ( ) 1.6

15.3.2 i vi ni t b sung. H s ma ca cc vo ma st : k m c = 1.15 H s ma ca cc vo ma st : k m c = 1.4 H s ma ca thanh vo ma st : k m th = 1.25 H s ma ca thanh vo ma kh: k m th = 1.6 in tr quy i ni t thanh vo ma ma :R th = R th k m th k m th = 28.9607 1.25 = 22.6255 ( ) 1.6

in tr quy i ni t cc vo ma ma :


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Lun vn tt nghip


R = R c c

k m c kmc

= 50.2386

1.15 = 41.267 ( ) 1.4

in tr quy i ca t hp tia cc vo ma ma :R th c = R R th 41.267 22.6255 c = = 11.797 ( ) th R + n c c R th 0.92 41.267 + 2 0.91 22.6255 c

in tr tn qui i ni t b sung vo ma ma:R bs = R th c n th = 11.797 = 7.106 ( ) 2 0.83

15.3.3 Tnh tng tr xung ca h thng ni t. in cm trn 1 met chiu di: 110 l L 0 = 0.2 ln 0.31 = 0.2 ln 0.31 = 1.79 (H/m ) 0.01 r

in dn trn 1met chiu di:G0 =

1 1 = = 0.0025 1 .m 2 R mv l 2 1.81 110

(

)

in cm tng ng ca 1mt :L = L 0 1.79 = = 0.895 (H/m ) 2 2

in dn tng ng ca 1 mt :G = G 0 2 = 0.0025 2 = 0.005 1

( .m ) ( .m )

in dn tng: G = G l = 0.005 110 = 0.55 1

in cm tng: L = L l = 0.895 110 = 98.45 H m

L G 98.45 0.55 = = 5.492 ( s ) 2 3.14 2 dc u song : s = 5 ( s )

Thi hng : T1 =

T s :

Rmv 1.81 = = 0.255 Rbs 7.106

Gii phng trnh siu vit bng phn mm Matlab:tgX + 0.255X = 0

kt qu nghim X l: X( 1)= X( 2)= X( 3)= X( 4)= 2.51179 5.78949 8.24938 11.29147


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Lun vn tt nghip


X( 5)= 14.37226 X( 6)= 17.47326 X( 7)= 20.58605 X( 8)= 23.70614 X( 9)= 26.83113 X(10)= 29.95953 ch dng nghim X nh hn : 3 T1 2 3 5.492 3.14 2 X max = = = 5.6 rad 5 s Ch c nghim X1

thiet ke mang 110kv

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