Cac Phan Tu Co Ban Cua HTD

8/6/2019 Cac Phan Tu Co Ban Cua HTD

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TS. L MINH PHNG [CHNG II: CC PHN TCBN CA H THNG IN]

BI GING MN CUNG CP IN Page 1

CC THIT B CBNCc thit b cbn ca nh my in v trm in

1. My pht in ng b. (k hiu trong bn v)2. Thanh dn3. My bin p lc v MBA t ngu4. My ct cao p5. Dao cch ly, dao tip a.6. My ct di ti, cu ch, chng st van, khng in,7. My bin dng8. My bin in p9. ng dy trn khng10.Cp v dy dn.


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I. MY PHT IN NG B1. Chc nng: Sn xut ra in nng v l thit b cbn ca nh my in. Dng ca my in

quyt nh cu trc v c im vn hnh ca ton nh my.2. Phn loi:- My pht tc nhanh 1000-1500- 3000vng/pht: ng dng trong cc nh my nhit in v

nh my in nguyn t.- My pht tc thp hn 1000 vng/pht thng ng dng cho nh my thy in.- Cng sut my pht thng nh hn 800MW. Tuy nhin hin nay ang thit k my pht c

cng sut ln hn.3. c im vn hnh:- in p nh mc ca my pht thng cao hn 5% so vi in p li, b cho phn tn hao

in p.- H s cng sut my pht ph thuc vo c tnh ca ti. Khi h s cng sut tng vi dng in

khng i th cng sut tc dng tng c th lm qu ti my pht. Khi gim h s cng sut s khngs dng ht cng sut ca tuabin. V vy phi lun gi cho in p my pht gi trnh mc vkhng i.

- H thng kch t ca my pht ng b cp ngun DC cho cun kch t. Trong thc t rt hays dng my pht mt chiu, hoc b bin i cng sut AC-DC.

- H thng lm mt my pht thng s dng khng kh, ngoi ra c th s dng nc, du.- Trong trng hp s c cho php khong thi gian qu ti ng vi dng qu ti:

Iqt/Im 1,1 1,15 1,2 1,25 1,3 1,4 1,5 2,0T(pht) 60 15 6 5 4 3 2 1


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II. SCCH IN1. Chc nng: c nhim vdy dn v cch in cho ng dy trn khng cho cc thit bphn phi ca nh my in v trm bin p.2. Phn loi: theo kt cu ta chia s cao p ra lm hai loi:sng v s treo- Sng c dng cho cc ng dy trn khng h p v cao p nh hn 35 kV. Sngc cnh trn ct in hay trn x ca ct in bng cc tr x bng kim loi

Skiu thanh Skiu thanh Skiu ng ngoi tri

- S treo c dng ph bin cho ng dy trn khng in p t 35 kV tr ln. S treo cni li vi nhau thnh tng chui. S lng a s trong mt chui s ph thuc vo cp in p cang dy.

Streo

Streo

3. Cu to:Nguyn liu ch to s cch in l cao lanh (t st trng), thy tinh hoc vt liucomposit.

4. Thng sS Streo K hiu

Dng in nh mc IdmDng in bn nhit Inh

in p nh mc in p nh mc Umin p phng in t in p phng in t Updu

in p phng in kh in p phng in kh UpdkLc ph hy nh nht Lc ph hy nh nht Fmin (N)Khi lng Khi lng m


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5. Chn v kim tra cch in:- Sc chn v kim tra theo tc dng ph hy ca dng in ngn mch xung kch ixk(kA). Ti trng xu nht i vi s l ti trng gy nn m men un ln nht, v s chu un kmhn chu lc ko v v nn.

luoim UU

min6.0 FFF cptt = 2710.76.1

1xktt iF

=ak

vh

xki

hk

'=

Trong :Fcp- lc cho php tc dng ln u s (N)Ftt- lc tnh ton tc ng ln u s.k- h s hiu chnh, h s ny c th tnh trc tip hoc s dng bng sau.a -Khong cch gia cc pha (m)

- (A) dng in ngn mch xung kch.

- S treo c chn v kim tra theo tc dng lc ng in v tc dng nhit ca dng in ngnmch

max,lvm II

IInh


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max

I

,lvI - dng lm vic ln nht

- dng ngn mch duy tr


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III. THANH DN1. Chc nng: c nhim v chuyn dng in t ngun n thit b phn phi. Qua dng c

chuyn qua h thng thanh ci v chuyn vo li in.2. Phn loi: Trong mng in phn phi in p ln hn 1000V thng s dng thanh gp lm

bng ng, nhm, thp dng trn hay hnh ch nht.

3. Thng s cbn- Kch thc thanh dn ( mmmm )- Dng in cho php ca thanh dn cptdI (A).

4. La chn:a. La chn thanh dn theo dng in lu di cho php:

321

max,

kkk

II

lvcptd

Trong :

k1 - h s hiu chnh khi thanh dn t nm ngang: 95.01 =kk2 h s hiu chnh xt ti trng hp nhiu thanh ghpk3 h s hiu chnh theo nhit mi trng


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b. Kim tra thanh dn theo iu kin tc dng ca dng in ngn mch: m bo bn ckhc dng in ngn mch i qua, ng sut tnh ton ca thanh dn khng c ln hn ng sutcho php ca n:

ttcp Lc cho php un cong thanh dn:

l

WF

cpcp

10=

Lc tnh ton do tc ng hc ca dng in ngn mch:22 10.76.1 = xktt i

lF

a

l

ttcp

Trong : W- m men cn, cm3

- chiu di khong cch gia hai s, cm

a- Khong cch gia cc pha, cmFF


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- i vi thanh dn n:W10

lFtttt =

- i vi thanh dn ghphbW ..210 2

lflF Rtttt

2

+=

W10

lFtt - l thnh phn tng h gia cc pha

hb ..2 2lf R

2

- l thnh phn tng h gia cc thanh trong mt pha

22

10. =i

f xkR b

- lc tc dng ring gia cc thanh trong mt pha kg/cm

l - khong cch gia cc ming m

- h sc xc nh tng cong


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c. Kim tra bn nhit ca thanh dn: m bo bn nhit ca thanh dn cn sao chodng in ngn mch qua chng khng lm tng nhit vt qu gii hn cho php.

nmqdnh tIs = .

4..R

f

hbl

Trong :

nhs - tit din bn nhit, (mm2)

- h s nhit.

nmqdt - thi gian ngn mch quy i (s)

I - dng in ngn mch duy tr (kA)


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IV. MYBIN P LC1. Chc nng: l thit bin chnh ca trm bin p, c nhim v chuyn i in p t cp in

p t 6,3-10,5 kV ln 110-750 kV cho chuyn ti, hay chuyn t cp in p cao xung cp inp 6-10kV v 0,4 kV cho cc h tiu th.

2. Phn loia. Theo iu kin lm vic: MBA thng thng v MBA c bitb. Theo dng lm mt: MBA du (M), MBA kh (C), MBA cht liu cc in khng chy

(). MBA du dng cho ni c kh nng chy n thp. Ni c kh nng chy n cao sdng hai loi cui

c. Theo s pha: MBA 1 pha, 3 phad. Theo kh nng iu khin in p: MBA c v khng c kh nng iu khin in p

di ti.e. Theo s cun dy: hai cun dy, ba cun dy.f. Theo chc nng: MBA tng, hin p.

3. Cu to v thng s k thut- Thng s cbn ca MBA:

Cng sut nh mc Sm (kVA) in p nh mc ca cc cun dy chnh Umcao, Um_ha (kV) S kt ni ca cc cun dy (Y, ), Dng in nh mc cun cao p Im(A) Dng in ngn khng ti Io (A) hoc %Im in p ngn mch Unm (%). Tn hao cng sut khng ti Po(kW) Tn hao cng sut ngn mch Pnm (kW). cos2 h s cng sut mch th cp H s mang ti =S/Sm.

- Thang cng sut nh mc chun ca MBA v my bin p t ngu.

- Cu to


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My bin p du


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4. Mt sc im khi vn hnh MBA- b tn hao in p i vi MBA tng p pha cao p thng c in p cao hn in p li10%, i vi MBA h p pha h p c in p cao hn 5-10% in p nh mc li.- Ti cc trm bin in p thng s dng MBA 3 pha hoc nhm cc my bin p mt pha.- Trong h thng in v trong nh my ngi ta thng s dng MBA ba pha, v MBA mt phamc tin hn nhiu v cn nhiu kim loi mu hn (c th l Cu 20%) vi cng mt cng sut, Vth MBA mt pha ch s dng trong nhng trng hp khng th lp t MBA ba pha- Thi gian lm vic chun ca MBA l 25 nm c cho php qu ti. C 3% non ti cho php 1%qu ti trn cng n v thi gian. 1% non ti ma h cho php 1% qu ti ma ng. y l qu ti

bnh thng (qu ti thng xuyn), tuy nhin qu ti thng xuyn cho php ca MBA du l30%, MBA kh l 20%.- Trong trng hp s c, khi ngt mt trong hai MBA, MBA th hai cho php qu ti 40%khng qu 6 gitrong vng 5 ngy m.


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- My bin p t ngu c 2 cun dy ni t chung Yo v cun th ba u tam gic, cun ny lic hai cun dy c tnh in t. Do c cun ni tam gic m sc in ng ca hi bc 3 b trittiu v gim in tr th t khng mng trung tnh ni t. iu ny rt quan trng trong vicnng cao nhy ca rle bo v cu ch trong li in.- ng dng MBA t ngu trong h thng cung cp in: lin lc gia li in cao p. Khi tas dng hai cun dy u Yo u vi nhau. Cn cun th 3 c ni vi my pht, MBA t dng

v my b ng b, trm b tnh hoc h.5. La chn MBA:a. Dng MBA: vic la chn dng MBA da trn iu kin lp t, lm mt, mi trng. MBA35kV trln thng lm mt bng du v c lp t ngoi tri. MBA in p 6,3-22kV thngl dng kh v c th lp t trong nh v cung cp in cho nh hnh chnh.b. La chn s lng MBA:- i vi h tiu th loi 1 v mt phn loi 2, s lng MBA cn c la chn t nht 2, m bo tin cy cung cp in. Tuy nhin v mt kinh t trm hai MBA hp l hn mt my vnhiu hn hai my.- i vi h tiu th loi 3 v mt phn loi 2 c th dng phng n mt MBA v ngun d trt trm bin p bn cnh.

c. La chn cng sut MBA:- Theo iu kin qu ti thng xuyn: MBA c nhng lc vn hnh non ti, th cng c thvn hnh qu ti trong mt khong thi gian no m khng b h hng. Tc im ca th

ph ti, c c trng bi h sin kn ta c th xc nh c kh nng qu ti ca MBA. Trnh ttnh ton:

1.Theo th ph ti ta chn cng sut MBA sao cho maxS_minS MBAmS

2.ng tr th ph ti thnh th hai bc bng cch xc nh h s vn hnh qu ti K2v h s vn hnh non ti K1.

a. Xc nh h s ti tng giv h s ph ti cc i

MBAm_

ii

S

SK = ;

MBAm_

iS

S

SK maxmax =

Trong - cng sut ti ca MBA.

b. Xc nh h s vn hnh qu ti K2 v thi gian qu ti T2 bng cch ng tr vngc cng sut ti ln hn cng sut nh mc ca MBA (h s Ki>1)

Nu th ph ti ch c mt vng qu ti lin tc v c hai hay nhiu bc nh hnh 1


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i

iit

T

TKK

=

2

2

Nu th ph ti c nhiu vng qu ti khng lin tc nh hnh 2 th ch ly vng no

c tng ii TK2 ln nht tnh nh trn, cc vng cn li s xt khi xc nh K1

v = iTT2 Nu max th 22 tK2 9.0 KKt K =

Nu max th max2 9.0 KKt < 2 9.0 KK = v 2

2

2TKT ii=

max )9.0( K

Nu th ph ti ch c mt vng qu ti lin tc v ch c mt bc th max2 KK = v

= iT2 T

Sm_MBA

T246

Smax

Smin

S(kVA)

c. Xc nh K1: ch cn ng tr th ph ti trong khong thi gian 10 gi trcvng tnh K2 (k c phn qu ti khng c xt khi tn K2).

10

2

11

==jj

t

TKKK

Nu vng trc K2 khng th ly 10 gisau K2. Nu tng vng u nh hn 10 gith gp phn sau ra phn trc K2.


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Nu tng c hai vng trc v sau nh hn 10, c ngha l thi gian qu ti142 T gith phi nng cng sut MBA.

3.Tng cong kh nng mang ti ca MBA ta xc nh h s qu ti cho php ca MBA),( 21 T KfK =qtcp

Nu 2K : MBA c chn ph hp vi th choK qtcp

K


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V. MY CT1. Chc nng: Dng ng ngt li in trn 1000V khi c ti v dng in ngn mch. Myct cao th c thng ngt ch bnh thng v ch s c khi dng in tng ln. My ctcao p l thit bng ngt tin cy nhng gi thnh cao, nn ch s dng nhng ni quan trng.2. Cu to v vn hnh:- Khi ngt mch in c dng gia hai tip im s xut hin h quang. ngt mch in khi cdng ln phi c b phn dp h quang: thng s dng kh trnn SF6, khng kh nn, du

hay chn khng.- iu khin ng ngt my ct c th bng tay, t xa hoc tng. Thit bng ngt my ct

c gi l b truyn ng, thit b ny c gn lin vi cc tip im.- Phn loi b truyn ng: b truyn ng l xo, b truyn ng kh nn, b truyn ng thy

kh3. Phn loi my ct:

My ct trong nh My ct ngoi tri My ct tng My ct vn hnh bng tay. My ct kh SF6 dng nhiu cho in p 6-22 kV My ct du dng nhiu cho in p 35 kV v cao hn My ct chn khng dng nhiu cho in p 6-22 kV My ct in t dng nhiu cho in p 6-22 kV My ct khng kh: cho in p 35 kV c kh nn dng cho110-500kV

4. Thngsnh mc ca my ct:Thng s K hiu V din p nh mc (kV)

mU 110

Dng in nh mc (A) mI 2000Dng in gii hn

Tr hiu dng (kA) Bin (kA) cpxk,i

31.580

Dng in n nh nhit 1s 2s 3s

nhI ---

31.5---

Cng sut ct nh mc (MVA)mcat_S 6000

Dng in ct nh mc (kA)mcat_I 31.5

Thi gian ng (s) dongt 0.25

Thi gian ct hon ton (s) catt 0.08

Lng tiu hao khng kh (m3) 11Khi lng (kg) 7500

5. La chon may cat cao ap.Chon may cat theo dang at thiet b: trong nha hay ngoai triLa chon may cat theo loai:

- MC dau : t dau , nhieu dau.

- MC khong kh- MC chan khong- MC kh SF6 hoac cac loai may cat ien khac phu hp vi ieu kien cho phep


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La chon may cat co c cau t ong lai hay khong t ong lai: neu may cat co at them c

cau t ong ong lai th kha nang cat cua no giam xuong bang cach them he so 1


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VI. DAO CCH LY1. Chc nng: l thit bin dng to ra khong h cch in t nhn thy trong mch ingia b phn mang dng in v b phn ct in vi mc ch m bo an ton cho nhn vin sacha trong thi gian sa cha hay thay i s.2. Vn hnh: Theo quy trnh vn hnh an ton trong thi gian sa cha, my ct phi c tipt c hai pha v dao cch ly c nhim v ny.- Dao cch ly khng c thit b dp h quang v th n ch c thng vi dng rt nh: dngkhng ti MBA (10kV n 750kVA; 20KV n 6300kVA; 35kV n 20000kVA v 110kV-40000kVA), dng trung tnh ni t MBA v cun dp h quang, dng c bng (khi in p lchnhau khng qu 2%), dng ngn mch vi t (khng qu 5A in p 35kV v 10A in p 10kV)hay dng khng ln tch t trong cp hay dy trn khng.- Khi ngt dng ti c th xy ra ngn mch cc pha ca dao cch ly v vy trnh ngt inkhi c ti nhm bng dao cch ly phi c thit b chn.3. Phn loi dao cch ly:

Dao cch ly trong nh Dao cch ly ngoi tri Dao cch ly mt cc Dao cch ly ba cc

4. Thng s dao cch ly iu kin la chon va kiem tra dao cach lyai lng chon va kiem tra Cong thcDong ien nh mcien ap nh mcDong ien cat nh mc

Kiem tra dao cach ly theo on nh lc ong

ienKiem tra dao cach ly theo on nh nhiet

cbCCdm,

UU

II

HTCCdm,

II

ttcbdmcat ,,

II

ttxkcpxk ,,

22

NNcpNcp tItI


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VII. DAO TIP A1. Chc nng: l thit b dng to ngn mch nhn to trong trng hp khi c h hng trongMBA m dng khng rle bo v tc ng.- Dao tip a s dng s khng c my ct pha cao p.- Dao tip a c lp t ngoi tri

- iu khin dao tip t bng b truyn ng nhcc rle dng cc i v cun ngt. Dao tipa ng tng nhl so khi truyn ng tc ng t rle. Dao tip a ngt bng tay.- Khi s dng ng thi c dao cch ly tng v dao tip t trm bin p 35-220 kV cho

php tit kim my ct cao p m khng lm gim tin cy.

- Gii thch s: bo v MBA tc ng do MBA b h, tc ng n rle dao tip a lm daotip a ng li, to dng ngn mch v thit b bo vng dy tc ng. ng dy b ngt khingun bng my ct pha trn. Trong thi gian khng c dng chy trong dy dao cch ly t dngngt mch.- Tip a - Thit b mt cc ni vo trung tnh MBA (c th ni t hoc khng). Nguyn tclm vic tng t nh dao ni t, nhng ch khc l n c ng ngt bng tay.


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VIII. MY CT PH TI1. Chc nng :- L thit bng ct n gin v r tin hn my ct in thng c s dng cho li 6-22kVv thng ni tip vi cu ch cao p.

- C cu to gn ging nh dao cch ly nhng c bung dp h quang n gin nn n ch c thct dng in ti, ch khng ct c dng in ngn mch. ct dng in ngn mch ta s dngthm cu ch.- ng ngt li vi dng lm vic bng my ct ti. Khi c s c ngn mch th cu ch tcng v tch phn t s c ra khi li.

ai lng chon va kiem tra Cong thcien ap nh mc may cat phu taiDong ien nh mc may cat phu tai khong t ongDong ien ngan mach xung kch cho phep cua maycat phu tai

Dong ien o ben nhiet sau thi gian neu may catphu tai ch cat dong ien lam viec , khong co cau ch

Kiem tra theo on nh nhiet

Cong suat cat nh mc cua cau ch

HT

ttxkcpxk ,,

MCdm,

II

UU

cbMCdm,

ii

MCcat

Ncpt ,

NtII

NNcpNcp tItI22

SS

NMCCCatdm __

= IUS HTNM 3


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IX. CU CH1. Cu ch:- L thit b bo v tng ngt mch khi c s c qu ti v ngn mch. Mch b ngt khi ch bchy ra, v th tt c cc thit bc bo v.- Dy chy cu ch lm bng ch, hp kim ch vi thic, km, nhm, ng, bc:

Hp kim ch thic c nhit nng chy thp, in trsut kh ln, nn n thng

c ch to vi tit din ln v thch hp vi in p di 500V. i vi in p cao (hn 1000V), dy chy thng lm bng ng, bc c in trsut nh v nhit nng chy cao, v nu dng ch lng hi kim loi ta ra ln.

- u im: Cu to n gin. Tc ng nhanh (Nh hn mt chu k) Gi thnh thp.

- Nhc im: Ch ngt khi dng kh ln so vi dng nh mc ca dy ch. Khi cu ch ngt c th gy qu p. C th b ngt 1 pha (khi pha khng u)

2. La chn v kim tra cu ch:ai lng chon va kiem tra Cong thcDong ien nh mcien ap nh mcDong ien cat nh mc

Cong suat cat nh mc cua cau ch

cbCCdm,

UU

II

HTCCdm,

)3(

, Ndmcat II

SS

NMCCCatdm __

= IUS HTNM 3


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X. CHNG ST VAN1. Chng st van: c nhim v bo v sng in t qu in p chy tng dy truyn ti n

Cu trc cbn bao gm 2 cc lm vic trn nguyn l t u nhau. Mt cc ni vo thit bcn cc th 2 ni t. Bnh thng hai cc trng thi cch ly vi nhau. Khi sng in t quin p t gi tr Unhthng lm cho hai cc dn in qua nhau, mt phn sng qua thit bc bo v, phn cn li c chuyn xung t.


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XI. KHNG IN1. Khng in: l thit b dng gim dng ngn mch v dng khi ng ng c. Khng inc cu trc l cun cm c li thp, c cun bi cc dy cun cch in v c gn vo tm btng hoc vt cch in.


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XII. MY BIN DNG IN1. My bin dng in (BI):- BI trong li di 1000V gim dng in n gi tr ph hp vi cun dy ca cc thit bo vthit b bo v.- BI trong li trn 1000V ngoi nhim v gim dng in cn phi cch ly mch cao p vimch iu khin m bo an ton cho thit b di 1000V.

- Dng in th cp ca my bin dng thng l 5A2. La chon BI theo cac tieu chuan sau:

a. Theo dong th cap : 1,5,10 Ab. Theo cap chnh xac:

0,2 % dung cho PTN0,5 % dung cho cong t ien1% dung cho ong ho ien5-10% - dung cho c cau truyen ong may cat

c. Theo ien ap nh mc.

HTBIdm,

cbBIdm,1

ttdm SS 22

ttS2

txddcptbdm

UU

d. Theo dong ien s cap nh mcII

e. Theo phu tai mach th cap

Trong :- Phu tai nh mc cua mach th cap BI ( W )dmS2

- Phu tai tnh toan mach th cap BI ( W )

Phu tai nh mc cua mach th cap c tnh nh sau

dmdmdm ZIS 222

rrrZ

2

= ++= ,2

dd

txr

Trong o- tong tr cho phep toan phan cua mach th capdmZ2

- tong tr cac thiet b noi vao mach th captbrr - ien tr cho phep cua day noicp,

- ien tr tiep xuc = 1,0txr

Vay tiet dien nho nhat cua day dan c tnh theo cong thc

ddcp,

ddttdd

rlF ,=

ddtt,l - chieu dai tnh toan cua day dan phu thuoc vao s o ket noi

- ien tr xuat cua day dan.

- Khi s o noi hnh sao hoan toan : lltt = ;khi s o hnh sao khong hoan toan : lltt 5,1= ;khi

s o dung mot may bien dong : lltt 2= ; trong o l- chieu dai day dan t may bien dong en

cac dung cu o , tiet dien tieu chuan cua day dan khong c be hn tiet dien tnh toan . Tietdien nho nhat cua day dan mach th cap may bien dong bang 25,2 mm oi vi day nhom ,bang

1,5mm

2

oi vi day ong


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3. Kiemtra may bien dong:a. Theo o ben ien ong cua may bien dong: o ben ien ong cua BI c ac trngbang ty so gia tr hieu dung dong ien xung kch nh mc dmxkI , va dong ien s cap

goi la he so o ben dk

BIdm,1

dk

dmxk

d I

I

k

,

= He so do nha che tao quy nh . V vay ieu kien kiem tra o ben ien ong cua may bien

dong nh sau :)3(2 iIk ,, ttxkBIdmd

NNnhBIdmnh ,

nhK

(6-48)

b. Theo on nh nhiettIBtIK 22)( =

Trong o - he so o ben nhiet

BIdm,

nht

nhI

IK =

- thi gian

ai lng kiem tra Cong thcDong ien s cap nh mc ABIdd ,,

VAS dd2

dk

2L

)(2 congtacthietbithietbi

I

ien ap nh mc U kVBIdd ,,Phu tai cuon th cap

He so o ben ien ong trong cua may biendong ,Lc cho phep tren au s may bien dong t phacuoi (o ben ien ong ngoai ),kG

He so o ben mot giay

thbddBIdd ,,

UU

II

thbddBIdd ,,

2 rrISSS ++=

22 ttdd

= 1,0rcongtac

BIdmI ,2ttxkd

ik ,

aFd 10.88,0

li ttxk2

,2

nhddBIdd

N

nhtI

tIk

,,

Ky hieu : -Dong ien ngan mach xung kch ,kA ; - Dong ien ngan mach duy tr ; ,kA;

- thi gian ngan mach quy oi ;s; - Dong ien nh mc s cap cua may bien dong

,kA; a- khoang cach gia cac truc pha ,cm; l- khoang cach t may bien dong en s gan nhat t phacuoi

ttxki , I

cmL ,2

qdt

BIddI

,


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XIII. MY BIN IN P1. My bin in p(BU)c gn trn thanh ci hay ng dy c nhim vo lng v tcdng trong iu khin bng cch a thng tin v dng v in p n cc thit biu khin, bov.- BU c kt ni vi cun dy in p thit bo lng, bo v v theo di. BU trong li trn1000V cch ly mch cao p vi mch iu khin m bo an ton cho thit b di 1000V

- in p th cp ca my bin in p l 100V hay 100 3- Cp chnh xc ca BI v BU l 0,5;1;3 .- Cun th cp ca BI v BU c tip t trnh qu in p trn thit bo lng bo v viu khin.2. La chon BU :

a. Theo cap ien ap nh mc s cap, cap chnh xac va to au day.b. Theo ien ap th cap nh mcc. Theo s o to au dayd. Theo cap chnh xac : dung cu co yeu cau cao nhat.e. Theo phu tai; tong phu tai thiet b noi vao BU nho hn cong suat inh mc cua BU

( ) ( )22 += QPS2 dcdc - Chon day dan t BU en cac thit b sao cho ton that ien ap khong ln hn 0,5% ien apnh mc th cap.

ai lng chon va kiem tra Cong thcien ap s cap nh mc U kVBUdd ,,

VAdd,2,%U

HTBUdm,

BU

Loai va s o to noi dayPhu tai pha S

Sai so

UU

Phu thuoc vao chc nang cua may bien ap

dmtt ,2,2 SS

cpUU

Ten dung cu Cong suat yeu cautoan phan cuadung cu o ,VA

Vonmet ien tAmpemet ien tOat met sat ien ongOat met va Varmets sat ien ongTan so ke kieu rung

Tan so ke sat ien ongTan so ke ien t

Tan so ke ien tPha ke ien ongPha ke van nangCong t ba pha loai bien apCong t ba phaCong t mot phaR le ien apR le ien apR le cong suatCuon cat ien ap cc tieu

2,650,51,52

12335151,51,51,20,15153330


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BI GI Page 43

XIV. DY DN V CP- ac iem cua cap la cach ien tot. Cap c at di at va trong ham rieng nentranh c va ap c kh va anh hng trc tiep cua kh hau nh nang ma, gio.

- Cap c at di at nen khong anh hng en my quan, ng giao thong.- Nhc iem chnh la gia thanh at va thi cong phc tap, khi co s co kho tm ra v trs co, gay ton kem trong sa cha va mat thi gian.

- Cap ngam co mot hay nhieu loi co vo boc bao ve (thng la vo ch hay vo nhom).Cac day dan c cach ien vi nhau va cach ien vi vo.

- Loi cap c lam bang day ong hay nhom nhieu si van xoan. Cap mot loi day danco tiet dien tron, trong cap nhieu loi day dan co tiet dien hnh quat (hay bau duc) e tandung khoang khong gian ben trong vo cap

Mot vai kieu tiet dien dung trong cap ngam

- Day dan rong gia c dung cho loai cap ay dau. Cach ien c dung la giaytam dau, cao su, vai tam verni, oi vi cap ngam cao ap cach ien chu yeu la giay tamdau.

-

ien ap cao va phai (en 30KV) cach ien c dung co ket cau ran chac (H.2.6),cach ien nay la mot bang giay quan that chat quanh loi. Sau khi quan giay, cap ctam chan khong bang dau cach ien co o nht cao. V cach ien ran co khuynh hngton tai (vang quang) nen cach ien loai nay khong dung cho ien ap cao.

Cap mot loi, cach ien bang giay, vo ch

NG MN CUNG CP IN


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BI GING MN CUNG C Page 44

- cap cao ap, hp chat tam co o nht cao c thay bang chat co o nht thap (capay dau) hoac thay bang kh tr thng la kh nit (cap au kh) c duy tr ap suatcao e lap kn cac khe h nham tang cng o cach ien.

- Cap mot loi co day dan at ong truc ben trong vo ch, vo chi bao boc ben ngoai lpcach ien. Neu cap mot loi thuoc loai ay dau hay ay kh (loai co ap suat thap) th dauhay kh c dan vao t bnh cha xuyen qua phan ruot rong cua day dan hay qua cacng ong at gia lp vo ch va giay cach ien.

Cac loai cach ien dung trong che tao cap ien:

Cach ien bang giay tam dau

Cach ien polyetylene (PE)

Cach ien polyvynilclorit (PVC)

Cach ien cao su

Cach ien polyetylen khau mach (XLPE)

a) Cap co ai cach ien:

b) Cap co ai kim loai

P IN


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XV. NG DY TRN KHNG- ng day tren khong c dung rong rai hn nhieu so vi ng day cap do vonau t t, de thi cong va de phat hien s co, sa cha bao hanh.

- Tuy theo ien ap nh mc phan loai lam 3 cap: Cap 1: ng day co ien ap ln hn 35kV

Cap 2: ng day co ien ap nho hn 35kV

Cap 3: ng day co ien ap nho hn 1kV

- e xay dng cac ng day cao ap, hau nh dung u tien day dan bang nhom v lydo kinh te va de thc hien. Phan ln cac day dan lam bang nhom loi thep, almelec (hpkim cua nhom) va bang almelec loi thep, t khi dung cap bang nhom tinh chat.

- Day chong set hoac bang thep ma kem hoac la bang almelec loi thep. Cap gomnhieu si day thep co boc nhom ben ngoai (nhom keo tren thep) s dung tot cho day noiat, day nay cung thay cho loi thep ma cua day nhom loi thep, tuy nhien gia thanh conat.

- Tat ca day nhom c dung di dang cap nhieu si va xoan. Cap ong nhat cche tao bang nhieu si co cung ng knh. Chung gom mot si day trung tam giabao boc ben ngoai bang nhieu lp day quan van xoan. H2.1 trnh bay cap nhom 7 si.Ngoai ra co mot so cax loai cap nh sau:

Cap 1+6 si = 7 si ng knh ngoai 3d





Mot so cap van xoan

- Cac day cap phc hp nh cap nhom loi thep (AC, ACSR) hay almelec thep gomcac si co ng knh bang nhau, tiet dien co the en 250 mm

2

(H.2.3). Tiet dien ln hnthng dung cap co si nhom va si thep khong cung ng knh, cho phep thay oi ty


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so gia tiet dien phan nhom va si thep e am bao va sc ben c va tnh dan ien cuaday dan. Phan thep dung tang cng sc ben c kh, phan nhom dung e dan ien.

Mot so day nhom loi thep ACSR

Day cap rong- Mot so ng day tai ien sieu cao ap co yeu cau phai tang ng knh day dan egiam ton thng vang quang va cam khang cua ng day nen co the dung day rong,


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loai day nay t c s dung v lap at kho va sc ben c cung kem. Mot dang khac cuaday dan ng day sieu cao ap la moi pha cua day dan c phan lam nhieu day at cac nh cua mot a giac eu (tam giac, hnh vuong, luc giac) goi la day phan pha.

- Day dan bang ong t thay dung ng day cao ap do ong la kim loai mau quhiem at tien ch dung ng day ha ap va trung ap nhng dan dan cung co khuynhhng thay bang day nhom.


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XVI. CT IN.1. Phn loi ct in:

a. Theo mc ch s dng: Ct trung gian: dng gi dy dn cao cho trc v khng chu lc ko ca

dy dn v v dy chng st Ct no dng kp dy dn mt sim trn ng di ca ng dy trn khngv phi chu ton b lc ko ca dy dn v dy chng st gia cc ct no. Ct ny phicng v bn. Ct gc. Ct cui. Ct chuyn. Ct chuyn dng: cho nhng ng dng c bit

b. Theo vt liu: Ct g, ct tre: thng s dng cho nng thn v cp in p di 10kV. Loi nyc u im r tin nhng c nhc im l khng bn v d mc. Ct b tng ct st: thng s dng mng in trung p, c kh nng chu lc ttr tin tui th cao nhng c nhc im l nng v kh vn chuyn. C st: Thng dng lm ct vt sng, vt cu, vt ng st, lm ct gc,v c th s dng cho cp in p cao: 110kV-750kV. Loi ny c chiu cao kh ln,chu lc tt nhng gi thnh cao.

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