Nha May Nhiet Dien1

8/3/2019 Nha May Nhiet Dien1

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n thit k nh my in

V Th HngHT1 K52 - 1 -

LI M U

hn hai th k, in nng tr thnh dng nng lng thit yu nht, ph

bin nht trong i sng x hi cng nh hot ng lao ng sn xut ca con ngi.Xut pht t tm quan trng , ti mi quc gia trn th gii, cng nghip in lun

l ngnh cng nghip c bn, mi nhn ca nn kinh t quc gia.

i vi nc ta, cng nghip in lun c ng v Nh nc xc nh l

ngnh cng nghip mang tnh nn tng nht, c nhim v quan trng l phc v v

thc y qu trnh cng nghip ho, hin i ho t nc. Vic xy dng cc nh

my in c quan tm ng mc, vi hng lot cc cng trnh th k: NMT Sn

La,NMT Ho Bnh, NMT Yaly, NMN Ph Li 1,2, Ninh Bnh...

Trong chin lc pht trin cng nghip in ca nc ta, xut pht t iukin t nhin ca t nc, thu in chim mt v tr ht sc quan trng, bn cnh

pht trin hp l cc nh my nhit in. Vic pht trin cc nh my nhit in l

khng th thiu, bi l chng b sung cho thu in trong ma kh, cng nh phc v

cc nhu cu thc t cc b khc ca tng a phng, n v.

L ngnh cng nghip thuc s hu Nh nc, cng nghip in c nhng thay i

to ln cng vi qu trnh chuyn i c ch. Bc sang nn kinh t th trng, in

nng l sn phm hng ho, sn xut in c coi nh sn xut hng ho.

Vi s thay i nhn thc nh vy, vic xy dng cc nh my in khng cnmang tnh bao cp, m cng phi m bo hiu qu kinh t, ti thiu l thu hi vn

u t, trnh lng ph hoc u t khng hiu qu.

Vi nhim v thit k tt nghip c giao gm hai ni dung chnh :

1- Thit k phn in nh my nhit in.2- Thit k trm bin p 10/0,4kV.

Qua thi gian lm thit k tt nghip, vi khi lng kin thc c hc tp v

c s gip ca cc thy c trong khoa, c bit l s ch dn trc tip v tn tnh

ca c gip em hon thnh bn thit k ny.

Tuy nhin do thi gian v kh nng c hn, nn bn n ny khng trnh khi

nhng thiu st. V vy em rt mong c s ng gp kin ca cc thy c.

Em xin chn thnh cm n !

Sinh vin


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CHNG I

TNH TON PH TI V CN BNG CNG SUT

I.1/ Chn my pht in:

Theo nhim v thit k, nh my nhit in bao gm 4 t my

50MW. Do bit s lng v cng sut ca tng t my nn vic chn

my pht in ch cn lu chn cc my pht in cng loi n gin

trong vic vn hnh, in p cng cao cng tt gim dng nh mcca my pht v dng in ngn mch cp in p ny.Ta chn my

pht ng b c cc thng s nh sau:

Loi mypht

Sm

MVA

Pm Um CosmIm

x"d x'd xdMW kV kA

TB-55-2 68,750 55 11,5 0,8 3,462 0,123 0,182 1,452

I.2/ Tnh ton ph ti v cn bng cng sut cp in p my pht:

Theo bi: Pmax = 12 MW ; cos = 0,85.

p dng cc cng thc:

Trong :Pmax : cng sut tc dng ca ph ti ch cc i (MW)

P(t)% : cng sut tc dng ca ph ti ti thi im t cho

di dng phn trm.

P(t) : cng sut tc dng ca ph ti ti thi im t (MW)

Tnh c cng sut ca ph ti cc khong thi gian khc nhau

trong ngy:


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Thi gian 0-8 8-10 10-18 18-21 21-24

P(t)% 70 70 90 100 90

P(t) 8,4 8,4 10,8 12 10,8

S(t) 9,882 9,882 12,076 14,118 12,706

Da theo kt qu tnh ton trong bng, ta v c th ph ti ca

cp in p my pht:

Hnh 1.1. th ph ti cp in p my pht

I.3/Tnh ton ph ti v cn bng cng sut cp in p trung:

Theo bi ta c: Pmax= 90 MW; cos = 0,85

p dng cc cng thc trn, ta c bng s liu sau:

Thi gian 0-8 8-10 10-18 18-21 21-24

P(t)% 70 70 90 100 80

P(t) 63 63 81 90 72

S(t) 74,118 74,118 95,294 105,882 84,706

0 2 4 6 8 10 12 14 16 18 20 22 24

2

4

6

8

10

12

14

15

9,882

12,706

14,118

12,706

h

MVA


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Da theo kt qu tnh ton trong bng, ta v c thph ti ca

cp in p trung 110kV:

Hnh 1.2 th ph ti cp in p trung

I.4/Tnh ton cng sut pht ca c nh my in:

Theo bi th y l nh my nhit in gm 4 t my, mi tmy 55MW. Pmax = 220MW, cos = 0,8.

p dng cc cng thc trn, ta c bng s liu sau:

Thi gian 0-8 8-10 10-18 18-21 21-24

P(t)% 70 90 90 100 80

P(t) 154 198 198 220 176

S(t) 192,5 247,5 247,5 275 220

0 2 4 6 8 10 12 14 16 18 20 22 24 h

MVA

20

40

60

80

100

74,118

95,294

105,882

84,706


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Hnh 1.3 th cng sut pht ca ton nh my

I.5/Tnh ton cng sut t dng ca nh my:

Nh my thit k c cng sut t dng cc i bng 8% tng cng

sut nh mc. l ngun cung cp khc nhau phc v cho qu trnh tng ho cc t my pht in.

Cng sut t dng gm 2 thnh phn:

Thnh phn khng ph thuc vo cng sut pht ca nhmy (chim khong 40% tng cng sut t dng).

Thnh phn ph thuc vo cng sut pht ca nh my(chim khong 60% tng cng sut t dng ca nhmy).

Ta s dng cng thc sau tnh cng sut t dng ca nh my

theo thi gian:

Std(t)= NM%

.S100

.(0,4 + 0,6.

NM(t)

NM

S

S)

Trong :

0 1 4 6 8 10 12 14 16 18 20 22 24

100

200

300

h

MVA

192,5

247,5

275

220


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Std(t): ph ti t dng ti thi im t.

%: lng in phn trm t dng.

SNM: cng sut ca nh my.

SNM(t): cng sut ca nh my theo thi gian.

Kt qu tnh ton cho trong bng:

Thi gian 0-8 8-10 10-18 18-21 21-24

S(t) 15,785 18,095 18,095 19,25 16,94

Hnh 1.3 . th ph ti t dng ca nh my

I.6/Tnh cng sut pht v h thng:

Nh my in lin lc vi h thng thng qua ng dy 220kV

nhm mc chvn hnh h thng in c kinh t v hiu qu, tng

cng d tr cng sut trong h thng. Da vo cng sut pht ca nh

my v yu cu ca ph ti ti cc thi im khc nhau ta c th xc nh

c cng sut pht v h thng theo cng thc sau:

SVHT(t)= SNM(t)[ST(t) + Smf(t) +Std(t)]

Trong :

0 2 4 6 8 10 12 14 16 18 20 22 24

7

14

21

MVA

15,785

18,095

19,25

16,94


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SVHT(t) - Cng sut pht v h thng ti thi im t

SNM(t) -Cng sut pht ca nh my ti thi im t

ST(t) - Ph ti cp in p trung ti thi im t

SUF(t) - Ph ti cp in p my pht ti thi im t

STD(t) - Ph ti t dng ti thi im t

Kt qu tnh ton c cho theo bng :

Thi gian 0-8 8-10 10-18 18-21 21-24

SNM 192,5 247,5 247,5 275 220

SUF 9,882 9,882 12,706 14,118 12,076

SUT 74,118 74,118 95,294 105,882 84,706

STD 15,785 18,095 18,095 19,25 16,94

SVHT 92,715 145,405 121,405 135,75 105,648

thcng sut pht v h thng theo kt qu tnh trong bng:


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Hnh 1.4. th cng sut pht v h thng

Nhn xt chung:

Ph ti ca nh my phn b khng u trn c ba cp in p v

gi tr cng sut cc i c tr s l:

SUFmax = 14,118 MVA

SUTmax = 105,882 MVA

SVHTmax = 145,405 MVA

T th ph ti tng hp ta thy ph ti trung p chim phn lncng sut do nh my pht ra do vic m bo cung cp in cho ph

ti ny l quan trng.

Tng cng sut ca h thng in cha k nh my thit k l:

SHT = 4000 MVA vi d tr quay l 6 % tng ng vi cng sut d

tr l SdtHT =6%.4000 = 240 MVA ln hn cng sut ca mt t my

pht v ln hn cng sut v h thng cc i l 145,405 MVA.

0 2 4 6 8 10 12 14 16 18 20 22 24

170

255

h

MVA

15,785 18,095 19,25 16,9425,667 27,977

30,801 33,368 29,646

99,785 102,95

126,095

139,25

114,352

192,5

247,5

275

220

Std

S+td

Sdp

S+td

S+dp

ST

Snm


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Nh vy c th thy nh my c vai tr quan trng trong vic cung

cp in cho ph ti ph ti trung p v ph ti a phng. Tuy nhin

vi nhim v ca mnh, nh my cng c nhng ng gp mt phn cng

sut ln trong thi im cc i ca ph ti h thng, SVHTmax = 145,505

MVA trong khong thi gian 8h 10h hng ngy.


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CHNG II

CHN S NI IN CA NH MY

II.1/ Chn s ni in ca nh my:

Chn s ni in ca nh my l mt khu rt quan trng. Cc

phng n a ra phi m bo tin cy cung cp in cho cc ph ti,

c tnh kh thi, hiu qu kinh t cao.

Ph ti cp in p my pht :SUFmax = 14,118 MVA, cng sut ny c ly t 2 pha h

p ca my bin p lin lc. ta khng cn s dng thanh gp my pht.

Cng sut cp in p trung:STmax = 105,882 MVA

STmin = 74,118 MVA

do c th ghp mt hoc hai b my pht - my bin p

bn trung p.

Cp in p cao (v h thng) v cp in p trung u ctrung tnh trc tip ni t, h s c li:

Vy ta dng 2 my bin p t ngu lm lin lc gia cc cp in p.

D tr quay ca h thng l 240 MVA ln hn tng cngsut nh mc ca 2 t my nn v l thuyt c th ghp 2 t

my pht vi 1my bin p.

Da trn cc c im trn, ta a ra cc phng n ni in chnh

cho nh my thit k:


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II.1.1/ Phng n 1:

Trong phng n ny dng 2 b my pht my bin p hai cun

dy cp in cho thanh gp in p trung 110kV, 2 my pht cn li c

ni vi thanh gp in p cao. Dng 2 my bin p t ngu lin lc

gia cc cp in p v pht in ln h thng. in a phng c

trch t pha h ca my bin p lin lc. in t dng c trch t u

cc mi my pht.

u im: n gin trong vn hnh, s lng cc thit b cao p t

nn gi thnh u t thp.

PA1

220110

HTD

SUT

TN1TN2 B1

B2

MF1 MF2 MF3 MF4


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II.1.2/ Phng n 2:

Phng n ny dng 1 b my pht my bin p hai cun dy cp

in cho ph ti cp in p 110kV, 3 my pht cn li c ni vi

thanh gp in p cao. Dng 2 my bin p t ngu lin lc gia cpin p trung v h thng.

u im: m bo cung cp in lin tc cho cc ph ti.

Nhc im: s lng cc thit b cao p nhiu hn phng n 1

nn chi ph u t cao hn.

PA2

220110

HTD

SUT

TN1 TN2

B1 B2

MF1 MF2 MF3 MF4


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II.1.3/ Phng n 3:

Trongphng n ny th 2 my pht pha cp in p trung c

ni vi 1 my bin p 2 cun dy.u im: S dng t my bin p v kh c in hn so vi phng

n trn.

Nhc im: Khi hng my bin p hai dy cun th 2 my pht

khng th cung cp cho ph ti in p trung. Khi h thng s b thiu

ht 1 lng cng sut kh ln phi huy ng d tr nng ca h thng

ng thi khng m bo cung cp in cho ph ti cp in p trung.

Kt lun:

Qua cc nhn xt u im v nhc im ca tng phng n, ta

nhn thy phng n 1 v 2 l hai phng n kh thi, c tin cy cung

cp in cao. V vy ta chn 2 phng n ny tnh ton c th, la

chn phng n ti u.

PA3

220110

HTD

SUT

TN1

TN2

B1

MF1 MF2 MF3 MF4


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II.2/ Chn my bin p:

tit kim chi ph u t, cc my bin p hai dy qun trongb

my phtmy bin p khng cn dng my bin p iu p di ti v

khi cn iu chnh in p ch cn iu chnh dng kch t ca my pht

l .

Cc my bin p t ngu dng lm lin lc l loi cn c iu p

di ti v ph ti ca chng thay i mnh. Trong ch vn hnh khc

nhau ph ti thay i nhiu nn nu ch iu chnh dng kch t ca my

pht th vn khng m bo c cht lng in p.

II.2.1/ Phng n 1:

II.2.1.1/ Chn my bin p:

a./ Chn my bin p 2 dy cun:

Cng sut my bin p b B1 v B2c chn theo iu kin:

SB1 = SB2 SmF = 68,750 MVA

PA1

220110

HTD

SUT

TN1

TN2 B1

B2

MF1 MF2 MF3 MF4


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Tra bng ph lc, ta chn my bin p c cc thng s chnh nh

sau :

Loi

Sm

(MVA)

Um (kV) Tn tht (kW)

UN % I0 %Cao H P0 PNTP 80 115 10,5 70 310 10,5 0,55

b./ Chn my bin p t ngu:

Cng sut ca cc my bin p t ngu ni b vi my pht in

c chn tho mn iu kin cun h p phi ti c ton b cng sut

ca my pht in.

Do cun h p c thit k vi cng sut tnh ton S Hm = SmTN

nn cng sut my bin p t ngu c chn tho mn iu kin:

STN1 =STN2 1 .SmFTrong l h s c li ca my bin p t ngu:

Vy chn my bin p t ngu tho mn iu kin:

STN1 = STN21

.SmF =

1

0,5.68,750 = 137,500 MVA

LoiSm

MVA

in p (kV)Tn tht (kW)

UN%

I0%

UC UT UHC-

T

C-

H

T-

H

C-

T

C-

H

T-

H

ATTH 160 230 121 10,5 85 380 - - 11 32 20 0,5Trng hp ny my bin p ch bit PN C-Tdo ta c th ly:

PN C-H =PN C-T = 0,5PN C-T = 0,5.380 = 190 kW

II.2.1.2/ Phn b cng sut cho cc my bin p:

a./ Phn b cng sut cho cc my bin p hai cun dy:


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Cc my bin p bc vn hnh bng phng vi cng sut:

b./Phn b cng sut cho cc my bin p t ngu:

Dng cng sut qua cc pha ca my bin p lin lc c xc

nh theo cng thc:

CT UT B1 B21

S (t)= S (t)-S -S2

CC VHT1

S (t)= S (t)2

CH CT CC1

S (t)= S (t)+S (t)2

Trong :

SCC(t), SCT(t), SCH(t) :cng sut ti qua pha cao, trung, h

ca my bin p t ngu ti thi im t.

SBi:cng sut ti qua my bin p b th i.Bng phn b dng cng sut cho cc my bin p t ngu theo

thi gian c cho theo bng di:

Thi gian 0-8 8-10 10-18 18-21 21-24

SCC(t) 46,358 72,703 60,703 67,875 52,824

SCT(t) -27,745 -27,167 -16,579 -10,997 -22,162

SCH(t) 18,613 45,536 44,124 56,878 30,662

II.2.1.3/ Kim tra qu ti ca my bin p:

a./Trong ch lm vic bnh thng:

i vi my bin p hai cun dy:

Cc my bin p ni b B1 v B2c chn vi cng sut ln hn

cng sut ca cc my pht in. Do cc my bin p ni b khng

cn kim tra qu ti trong mi ch vn hnh.


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Cc my bin p t ngu:

T kt qu tnh ton trn, ta nhn thy rng trong ch bnh

thng th my bin p t ngu lun lm vic trong ch ti cng sut

t cun h, trung ln cun cao.

Ta thy SCCmax = 72,703 MVA < SmTN = 160 MVA

Vy my bin p t ngu khng b qu ti trong ch lm vic

bnh thng.

b./Trong trng hp s c:

b.1./Khi ph ti cp in p trung l cc i:

Theo kt qu tnh ton phn trn : SUT max = 105,882 MVA ;

SVHT = 135,75 MVA ; SUF = 14,118 MVA ; Std = 19,25 MVA.

S c hng mt b my pht my bin p bn trung p:

iu kin kim tra qu ti s c my bin p t ngu l:

sc

qt dm TN bo UTmaxS +S S2K

trong :sc

q tK =1,4 :h s qu ti cho php.

sc

qt dm TN boS +S2K = 2.1,4.0.5.160 +63,938 = 287,938 > SUT max = 105,882

MF4MF3MF2MF1

B2

B1TN2

TN1

SUT

HTD

110220

PA1


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Vy iu kin trn c tha mn.

Phn b cng sut qua cc pha ca my bin p t ngu:

CT UTmax bo

1S = S -S

2=1

2

.(105,88263,938) =20,972 MVA

CH F dm UF td

1 1S =S - S - S

2 4= 68,750 -

1

2.14,18 -

4

119,25 =56,879 MVA

CC CH CTS =S -S = 56,87920,972 = 35,907 MVA

Trong ch ny i vi my bin p t ngu, cng sut truyn t

pha h ln pha trung v cao.

SCH = 56,879 < TNdmS = 80 MVA

Cun h khng qu ti nn my bin p t ngu khng qu ti.

Cng sut thiu:So vi trng thi lm vic bnh thng, vo cng thi im th

cng sut pht v h thng b thiu mt lng :

Sthiu = SVHT2.SCC = 135,752.35,907= 63,936SUTmax= 105,882


Phn b cng sut qua cc pha ca my bin p t ngu: CT UT max boS = S -2S =105,882-2.63,938 = -21,994 MVA

CH F dm UF td

1S =S -S - S

4=68,750-14,118-

1

4.19,25=49,82 MVA

CC CH CTS =S -S =49,882-(-21,994) = 71,814 MVA


pha h v trung ln pha cao.

SCC = 71,814 SUT max = 74,118


Phn b cng sut qua cc pha ca my bin p t ngu: CT UTmax bo

1S = S -S

2=1

2.(74,118-64.804) = 4,657 MVA

CH F dm UF td

1 1S =S - S - S

2 4= 68,750 -

1

2

9,882 -1

4

15,785 = 59,863 MVA

CC CH CTS =S -S = 59,8634,657 = 55,206 MVA


pha h ln pha trung v cao.

SCH = 59,863 1000A nn khng cn

kim tra iu kin n nh nhit.

2./ Kim tra iu kin n nh ng:

iu kin kim tra n nh ng l ng sut vt liu phi nh hn

ng sut cho php tt < cp. Vi ng: cp = 1400 kG/cm2

.Lc in ng c tnh theo cng thc:

Ftt = 1,76.10-8

. 2xk.l

Ia

Trong :

l: khong cch 1 nhp (80 200 cm). Ta chn l = 150 cm.

a: khong cch cc pha (20 100 cm). Ta chn a = 80 cm.

ta c:

h

y

y

y

b

c


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Momen un:

ng sut tnh ton:

Kim tra c cn t thm ming m trung gian hay khng:

Lc tc dng ln mt n v di (cm) ca mtnhp thanh dn:

m bo n nh ng phi c:

cptt 1 2 = + 2 cpCu 1 -

2

2 1cpCu 1

y-y

F L -

12W

Ta c L=150cm < 200,503 cm nn khng cn t thm ming m

m thanh dn chn vn m bo n nh ng khi ngn mch.

V.2/ Chn s :

Ta chn loi s sau:


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Ta chn s t trong nh theoiukin: Um mng Um sTra ti liu chn s loi O-10-375OB-Y3 c thng s:

in p nh mc: Um = 10 kV

Lc ph hoi nh nht khi un tnh: Fph = 375 kG

Chiu cao ca s: H = 18 cm

Kim tra iu kin n nh ng:

iu kin l bn s phi mbo: 'tt tt phH'

F =F 0,6FH

Trong :

cpF =0,6375=225kG

Ftt: lc in ng tc dng ln thanh dn khi ngn mch 3 pha,

Ftt = F1 = 162,53 kG

h 12,5H'=H+ =18+ =24,25

2 2cm

Vy s chn m bo iu kin n ng.

V.3/ Chn thanh dn mm:

Trong nh my in, s dng dy dn mm ni in t my

bin p ln thanh gp cao, trung p cng nh lm thanh gp. Do cc


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thanh gp cng nh khong cch t cc my bin p ln cc h thng

thanh gp u kh ngn nn dy dn mm c chn theo dng in lm

vic cho php qua n trong tnh trng lm vic cng bc. Cc dy dn,

thanh gp cng cp in p thng c chn cng loi.

Icp cb

hc

I

k

V.3.1/ Chn dy dn, thanh gp cho mch 220kV:

1./ Chn tit din thanh gp:

Theo kt qu tnh ton trong phn trn, ta xc nh c dng lm

vic cng bc ca mch 220kV l 220cb

I = 0,312 kA.

Do :

Tra ti liu, ta chn dy nhm li thp ACO-240 c Icp = 610A,

ng knh dy d = 22,4 mm. i vi cp in p 220kV, khong cch

gia cc pha ta chn l a = 5m = 500 cm.

2./ Kim tra iu kin n nh nhit khi ngn mch:

Tit din nh nht m bo n nh nhit ca cp in p 220kV:

Fmin =NB F

C

Trong :F: tit din dy c chn, mm2.

C: hng s ph thuc vo nhit dy dn, vi dy dn AC

c C = 88 (2

A s

mm).

BN: xung lng nhit khi ngn mch (A2.s)

BN = BNCK + BNKCK


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BNCK: xung lng nhit ca thnh phn chu k ca dng

ngn mch.

BNKCK: xung lng nhit ca thnh phn khng chu k ca

dng ngn mch.

Xc nh xung lng nhit ca thnh phn chu k:

xc nh xung lng nhit ca thnh phn chu k

ca dng ngn mch, s dng phng php gii tch th. Ta coi gn

ng:

BNCK =2tbi

I .t

vi2 2

2 i-1 itbi

I +II =

2v i i-1t=t -t

Tra bng vi X*tt xc nh c gi tr hiu dng ca dng ngn

mch thnh phn chu k ti cc thi im ti im N1 nh trong bng:

Thi gian t, s 0 0,1 0,2 0,5 1,0X*ttNMm 0,311

I"NM (t) 3,25 2,7 2,43 2,28 2,1

INM(t) 2,244 1,864 1,677 1,574 1,45

IHT(t), kA 3,369

IN1(t), kA 5,613 5,233 5,046 4,943 4,819

T bng kt qu trn ta tnhc:

Xung lng nhit ca thnh phn chu k:


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= 24,986.10

6

A

2

.sXc nh xung lng nhit ca thnh phn khng chu k:

Xung lng nhit ca thnh phn khng chu k c xc nh theo

cng thc sau:

BNKCK =2

aN1I (0).T

Vi Ta l hngs thi gian tng ng ca li, vi li

in c U1000V th Ta = 0,05s. BNKCK = (5,613.10

3)

2. 0,05 = 1,575.10

6A

2.s

Vy xung lng nhit ca dng ngn mch ti N1 l:

BN = BNCK + BNKCK = (24,986 + 1,575).106

= 26,561.106

A2.s

Do :

Vy dy dn pha 220kV m bo iu kin n nh nhit.

3./ Kim tra iu kin pht sinh vng quang:

iu kin pht sinh vng quan ph thuc vo s sp xp hnh hc

ca cc pha trong khng gian. Xt hai trng hp:

Nu3 pha t trn nh ca mt tam gic u:

iu kin kim tra: vq luoiaU =84mrlg >U =220 kVr

Trong :

m: h s xt ti x x b mt ca dy dn, chn m = 0,9

r: bn knh dy dn, d 22,4r= = =11,2 mm=1,12 cm2 2

a: khong cch gia cc trc dy dn, a = 500 cm


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500U =840,91,12lg =224,36>220vq 1,12

Nu 3 pha t cch iu nhau trong mt mt phng nm ngang:

iu kin kim tra: vq luoiaU =84mrlg >U =220 kVr

=0,96224,36=220,53>220kV

Vy dy dn chn m bo iu kin vng quang.

V.3.2/ Chn dy dn, thanh gp cho mch 110kV:

1./ Chn tit din thanh gp:

Theo kt qu tnh ton trong phn trn, ta xc nh c dng lm

vic cng bc ca mch 110kV l 110cbI = 0,556 kA.

Do :

Tra ti liu, ta chn dy nhm li thp AC-300/29 c Icp = 690 A,

ng knh dy d = 24 mm. i vi cp in p 220kV, khong cchgia cc pha ta chn l a = 3m = 300 cm.

2./ Kim tra iu kin n nh nhit khi ngn mch:

Tit din nh nht m bo n nh nhit ca cp in p 220kV:

Fmin =NB F

C

Trong :

F: tit din dy c chn, mm2.

C: hng s ph thuc vo nhit dy dn, vi dy dn AC

c C = 88 (2

A s

mm).

BN: xung lng nhit khi ngn mch (A2.s)

BN = BNCK + BNKCK


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BNCK: xung lng nhit ca thnh phn chu k ca dng

ngn mch.

BNKCK: xung lng nhit ca thnh phn khng chu k ca

dng ngn mch.

Xc nh xung lng nhit ca thnh phn chu k:

xc nh xung lng nhit ca thnh phn chu k ca dng

ngnmch, s dng phng php gii tch th. Ta coi gn ng:

BNCK =2tbi

I .t

vi2 2

2 i-1 itbi

I +II =2

vi i-1

t=t -t

Tra bng vi X*tt xc nh c gi tr hiu dng ca dng ngn

mch thnh phn chu k ti ccthi im ti im N1 nh trong bng:

Thi gian t, s 0 0,1 0,2 0,5 1,0

X*ttNMm 0,236

I"NM (t) 4,85 3,8 3,3 2,85 2,55

INM(t) 6,696 5,246 4,556 3,935 3,521

IHT(t), kA 4,555

IN1(t), kA 11,251 9,801 9,111 8,49 8,076

T bng kt qu trn ta tnh c:

Xung lng nhit ca thnh phn chu k:


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=77,675.10

6

A

2

.sXc nh xung lng nhit ca thnh phn khng chu k:

Xung lng nhit ca thnh phn khng chu k c xc nh theo

cng thc sau:

BNKCK =2

aN1I (0).T

Vi Ta l hng s thi gian tng ng ca li, vi li

in c U1000V th Ta = 0,05s. BNKCK = (11,251.10

3)2. 0,05 = 6,329.10

6A

2.s

Vy xung lng nhit ca dng ngn mch ti N2 l:

BN = BNCK + BNKCK = (77,675 + 6,329).106

= 84,004.106

A2.s

Do :

Vy dy dn pha 220kV m bo iu kin n nh nhit.

3./ Kim tra iu kin pht sinh vng quang:

iu kin pht sinh vng quan ph thuc vo s sp xp hnh hc

ca cc pha trong khng gian. Xt hai trng hp:

Nu 3 pha t trn nh ca mt tam gic u:

iu kin kim tra: Trong :m: h s xt ti x x b mt ca dy dn, chn m = 0,9

r: bn knh dy dn,

a: khong cch gia cc trc dy dn, a = 300 cm


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Nu 3 pha t cch iu nhau trong mt mt phng nm ngang:

iu kin kim tra: Vy dy dn chn m bo iu kin vng quang.

V.4/ Chn ng dy cp cho ph ti a phng:

Ph ti a phng c cp in bng cc ng cp trn ngm

trong t. Tit din cp cho ph ti a phng thng c tnh theomt dng kinh t Jkt.

Thi gian s dng cng sut cc i ca cp:

Tmax =

24

UFi ii=1

UFmax

S t

365S

Theo kt qu tnh ton trong chng trc, ta c bng tnh ton:

Thi gian 0-8 8-10 10-18 18-21 21-24

S(t), MVA 9,882 9,882 12,706 14,118 12,706

Tra bng, ng vi cp in lc li nhm v Tmax =

h ta

c Jkt = 1,2 A/mm2.

V.4.1/ Chn tit din cp:

1./ Cp kp:

Theo nhim v thit k, ph ti a phng c 2 ng cp n 4

MW. Dng in lm vic bnh thng:


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Tit din kinh t ca cp:

Tra ti liu chn cpnhm 3 li cch in XLPE in p 10kV do

ACATEL ch to c F = 150 mm2, Icp = 440 A.

V.4.2/ Kim tra cp theo iu kin pht nng:i vi cp n, khng c tnh trng lm vic cng bc nn ch

kim tra cp theo iu kin pht nng bnh thng:k1.k2.IcpIbt.

vi k1, k2h s hiu chnh theo mi trng t cp v s cp t

song song vi nhau.

k1 =cp 0

cp odm

-

-

cp: nhit lu di cho php ca thanh dn bng ng, cp =70

oC

0: nhit mi trng xung quanh, 0 = 35oC

0m: nhit tiu chun, 0 = 15oC

k1 =70 35

70 15

=0,798

k2 0,93.

i vi cp kp, phi kim tra pht nng khi lm vic cng bc:

kqt.k1.k2.IcpIbt vi kqt = 1,3

1./ Cp kp:

iu kin kim tra pht nng bnh thng:

k1.k2.IcpIbt 0,798.0,93.440 = 326,542 A > Ibt = 203,771 A

iu kin kim tra pht nng khi c s c:


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kqt.k1.k2.IcpIbt 1,3.0,798.0,93.440 =424,504A2.Ibt = 407,542ATha mn iu kin

V.4.3/ Kim tra n nh nhit ca cp khi ngn mch:

V.5/ Chn cc dng c o lng:

Trong nh my in, cc my bin in p, bin dng in c s

dng vi nhiu mc ch nh o lng, bo v, t ng ha, kim tra

iu kin chn my bin in p:

1. in p:UmBU Umg2. Cng sut nh mc th cp :S2mBU S2tt3. Cp chnh xc chn ph hp vi yu cu ca cc dng c

o.

iu kin chn my bin dng in:

1. in p: Um BI Umg2. Dng in: Im BI Ilvcb3. Ph ti : Z2mBI Z2 = r24. n nh ng: I1 ixk5. n nh nhit: (knh.I1m)2.tnh BN

V.5.1/ Chn my bin in pv my bin dng in cho cp 220kV:

1./ Chn my bin in p:

My bin in p c dng ly tn hiu in p phc v cho olng, kim tra, t ng ha.

Ta chn 3 my bin in p 1 pha kiu HK-220-58 u theo s

Y0/Y0/\, c cc thng s c bn nh sau:

Uscm ,kV Utcm ,V Utcph, V Cp chnh xc S2m,VA

220/ 100/ 100/ 1 600


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2./ Chn my bin dng in:

Cc my bin dng in c nhim v cung cp tn hiu cho cc

thit b bo v. Ta chn my bin dng in kiu -220-3T c cc

thng s sau:

in p kV Ism Itcm Cp chnh xc Ph ti nh mc Zm W Il

220 1200 5 0,5 2 108

Kim tra iu kin n nh nhit:

Do my bin dng in c dng s cp nh mc ln hn 1000A

nn ta khng cn kim tra n nh nhitKim tra n nh ng ca my bin dng:

My bin dng chn c

Il = 108kA > IxkN1 = 14,288 kA

nn my bin dngin chn m bo iu kin n nh ng.

V.5.2/ Chn my bin in p v my bin dng in cho cp 110kV:


Cc my bin in p c s dng ly tn hiu in p phc v

cho vic o lng, kim tra, t ng ha.

Ta chn 3 my bin A 1 pha kiu HK- 110-58 u theo s

Y0/Y0/\, c cc thng s chnh nh sau:

Uscm ,kV Utcm ,V Utcph, V Cp chnh xc S2m,VA

110/ 100/ 100/ 1 6002./ Chn my bin dng in:

Cc my bin dng in c nhim v cung cp tn hiu cho cc

thit b bo v. Ta chn my bin dng in kiu -110M c cc

thng s sau:

in p kV Ism Itcm Cp chnh xc Ph ti nh mc Zm W Il110 1000 5 0,5 0,8 108


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n thit k nh my in


Kim tra iu kin n nh nhit:

Do my bin dng in c dng s cp nh mc bng 1000A nn

ta khng cn kim tra n nh nhit.

Kim tra n nh ng ca my bin dng:

My bin dng chn c

Il = 108kA > IxkN2 = 28,640 kA

nn my bin dng in chn m bo iu kin n nh ng.

V.5.3/ Chn my bin in p v my bin dng in cho cp in p

my pht:

Mch my pht in,cc bin in p v cc bin dng in cung

cp tn hiu cho cc phn t bo v,o lng.Theo quy nh bt buc

phi c cc phn t o lng sau:Ampe k, Vonk, Tn s k, Cosk,

Ot k tc dng, Ot k phn khng, Ot k tc dng t ghi, Cng t tc

dng, Cng t phn khng. Cc dng c o c mc nh sau:

A A A W WWh VARh

V f

2.HOM-10

G

a

bc

VA


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Bin in p t u cc my pht ly tn hiu in p phc v

bo v Rle,o lng.t bit c cng t o m in nng nn cp

chnh xc phi chn l 0,5.

iu kin chn my bin in p:

S2tt = Sdc SBUm

Vi:

Sdc = 2 2

dc dcP Q

V ph ti ca cc bin in p l cc dng c o lng nn dng

hai my bin in p mt pha ni dy kiu tam gic khng hon ton V/V

v c ni vo u cc my pht ly cc in p dy ab v bc. Cc

dng c o lng c ni vo BU c cho bng sau:

T.T

Ph ti ab Ph ti bc

Tn ng hK

hiu P(W) Q(Var) P(W) Q(Var)1 Vn k B2 7,2

2 Tn s k 344 6,5

3 Ot k tc dng 341 1,8 1,8

4 Ot k phn khng

342/11,8 1,8

5 Ot k t ghi 33 8,3 8,3

6 Cng t tc dng T 0,66 1,62 0,66 1,627 Cng t phn khng TP 0,66 1,62 0,66 1,62

Tng cng 20,40 3,24 19,72 3,24

Ph ti my bin in p ab:

Sab =2 2

20,4 3,24 = 20,66 VA;


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Cosab =ab

ab

P 20,40,98

S 20,66

Ph ti my bin in p bc:

Sbc =2 2

19,72 3,24 = 19,98 VA;

Cosbc =bc

bc

P 19,720,98

S 19,98

Ta chn my bin in p HOM-10 Do Lin X c sn xut c cc

thng s sau :

Usc ,kV Utc ,V Cp chnh xc S2m ,VA Smax ,VA10 100 0,5 75 640

Chn dy dn ni t bin in p n cc dng c o :

Gi s di dy dn t BU n cc dng c o l l = 60m ;

Dng in trong cc pha a,b,c l :

Ia =ab

ab

S 20,660,2066

U 100 A;

Ic =bc

bc

S 19,980,1998

U 100 A;

n gin trong tnh ton ta coi:

Ia = Ic = 0,2 A;

Cosab = Cosbc = 1;

Khi :

Ib = 3 .Ia = 0,34 A;

Tr s in p ging trn dy dn pha a v b l:

U = (Ia + Ib)F

lCu.

ly: Cu = 0,0175.mm2/m

V mch c cng t nn:

U % Ucp% = 0,5%


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Vy tit din cn chn l:

Fdd (Ia + Ib)%

.

cp

Cu

U

l

= (0,2 + 0,34)5,0

60.0175,0= 1,134 mm

2

m bo bn c, chn dy ng bc cch in c tit din

Fdd =1,5 mm2.

2./ Chn my bin dng in:

Cc bin dng in c t trn c ba pha v c ni theo s

Y. V cc cng t c cp chnh xc 0,5 nn cc bin dng in cng c

chn c cng cp chnh xc.

Ta chn bin dng in kiu -10 c cc thng s sau:in p, kV Ism, A Itcm, A Cp chnh xc Ph ti Zm ,

10 5000 5 0,5 1,2

Bng cc dng c o lng ni vo BI nh sau:

Tht

Tn dng c K hiuPh ti ,VA

A B C

1 Ampe k -302 1 1 12 Ot k tc dng -341 5 53 Ot k t ghi 33 10 104 Ot k phn khng -342/1 5 55 Cng t tc dng 670 2,5 2,56 Cng t phn khng T-672 2,5 5 2,5

Tng cng 26 6 26

Pha a v pha c ca my bin dng mang ti nhiu nht:

Smax = 26 VA;

Tng tr cc dng c o mc vo cc pha ny l:

Zdc =max2 2tdm

S 26

I 5 = 1,04 ;


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n thit k nh my in


tho mn cp chnh xc ca my bin dng in l 0,5 cn chn

dy dn n cc dng c o c tit din ph hp.gi s chiu di dy dn

t bin dng in n cc dng c o lng l l = 60m.

Zdc +Zdd Zm

Tng tr ca dy dn:

Zdd Rdd =.l

F

Chn dy dn bng ng c tit din tho mn:

FddCu

dm dc

l. 60.0,01756,56

Z Z 1,2 1,04

mm2

m bo bn c ta chn dy ng bc cch in c tit din

Fdd =10 mm2.

Kim tra n nh ng ca my bin dng in:

My bin dng in -10 c s cp l thanh dn thit b phn

phi nn n nh ca ng ca n quyt nh bi n nh ca thanh dn

mch my pht in.Do vy khng cn kim tra n nh ng ca bindng ny.

Kim tra n nh nhit ca my bin dng in

Do my bin dng in c dng s cp nh mc ln hn 1000A

nn khng cn kim tra n nh nhit.

Nh vy my bin dng in tho mn yu cu.

V.6/ Chn khng in ph ti cp in p my pht:

5.6.2.Chn khng in

Khng in u ng dy ph ti a phng c chn theo cc iu

kin sau:

- in p : UmK Um.mng=10kV

- Dng in : IdmK IcbK

Trong : IcbKl dng in cng bc qua khng, c tnh khi phti a phng l ln nht v s c mt khng.


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n thit k nh my in


Ta c :

Ta chn khng in n cun dy bng nhm: PbA-10-1000 c ImK =1000A

- in khng XK%:

tnh in khng XK% ta lp s thay th nh sau:

Cp kp C1 c tit din: SC1 = 150 mm2

Cp li ng nn: C = 141 As1/2/mm2*My ct trm cui ng dy ph ti a phng c: Ictm = 20 kA vthi gian ct ngn mch l t2 = 0,5s. Chn thi gian tr l t = 0,5sVy thi gian ct ngn mch ca my ct 1: t1 = t2+ t = 0,5 + 0,5 = 1 s- Dng n nh nhit ca cp 1:

Vi: C l h s ph thuc vt liu cp (CAl = 141).

T1thi gian ct ca my ct 1: t1 = 1s

Cp C2 c tit din: SC2min = 50 mm2

Cp li ng nn: C = 141 As1/2/mm2- Dng n nh nhit ca cp 2:

Vi: C l h s ph thuc vt liu cp (CCu = 141).

T2thi gian ct ca my ct 1: t2 = 0,5s

Ta c:

Nh vy:

Mt khc ta c:

XHT

XBA

MC XMC1

MC XMC2

N4

N5

N6


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n thit k nh my in


Vy:

Ta chn khng in n c cun dy bng nhm loi PbA-10-1000-6

c:

ImK= 1000 A; XK%= 6%; UdmK=10kV

Kimtra khng in chn :

in khng ca khng chn tnh trong h n v tng i c bn

l:

Khi ngn mch ti im N5 trn s ta c dng ngn mch l:

Do IN5 = 15,753 kA < InhC1= 21,150 kA nn khng in chn tho

mn yu cu k thut.

5.7. Chn chng st van

5.7.1. Chn chng st van cho thanh gp

Trn cc thanh gp 220kV v 110kV t cc chng st van vi nhim vquan trng l chng qu in p truyn t ng dy vo trm. Ccchng st van ny c chn theo in p nh mc ca trm: Um CSV >Um mng

- Trn thanh gp 220kV chn chng st van loi cacbua silic c Udm= 220kV t c 3 pha.

- Trn thanh gp 110kV chn chng st van loi 3EP1 c Udm =110kv t trn c 3 pha.

5.7.2. Chn chng st van cho my bin p*Chng st van cho my bin p t ngu:

Cc my bin p t ngu do c s lin h v in gia cao v trungp nn sng in p c th truyn t cao p sang trung p v ngc li. u ra cao p v trung p t cc chng st van:

+ Pha cao p chn chng st van loi cacbua silic SiC c Udm =

220 kV t c 3 pha.+ Pha trung p chn loi 3EP1 c Udm= 110kV t c 3 pha.


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*Chn chng st van cho my bin p 2 cun dy ni b:Trn thanh gp 110kV c t cc chng st van nhng i khi c nhngng st c bin ln truyn vo trm, cc chng st van y phngin.

in p d cn li truyn ti cun dy ca my bin p vn rt ln c thph hng cch in ca cun dy, c bit l phn cch in gn trungtnh nu trung tnh cch in. V vy ti trung tnh ca my bin p haicun dy cn b tr mt chng st van.Tuy nhin do in cm ca cun dy my bin p bin ng st khiti im trung tnh s gim mt phn, do chngst van t trungtnh c chn c in p nh mc gim mt cp.Ta chn chng st van loi 3EE1Vy ta c bng tng kt thng s cc loi chng st van:

Loi chngst van Cp inp kV in pln nhtca likV

in plm vicln nhtkV

Dnginphngnhmc kA

Vt liuv

SiC 220 245 216 50/63 S3EP1 110 170 186 40 S3EE1 35 36 42 1 S

CHNG 6

CHN S V THIT B T DNG

in t dng l mt phn in nng khng ln nhng li gi mt phn

quan trng trong qu trnh vn hnh nh my in, n m bo hot ng

ca nh my nh : chun b nhin liu, vn chuyn nhin liu, bm nctun hon, qut gi, thp sng, iu khin, tn hiu v lin lc ...

in t dng trong nh my nhit in c bn c th chia lm hai phn

:

- Mt phn cung cp cho cc my cng tc m bo s lm vic ca

l v tua bin cc t my.

- Phn kia cung cp cho cc my cng tc phcv chung khng lin

quan trc tip n l hi v tuabin nhng li cn thit cho s lm vic ca

nh my.


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n thit k nh my in


Ta chn s t dng theo nguyn tc kinh t v m bo cung cp

in lin tc, i vi nh my in thit k ta dng hai cp in p t

dng 6,3kV v 0,4kV.

6.1.Chn my bin p t dng cp 1

Cc my ny c nhim v nhn in t u cc my pht 11,5 kV cung

cp cho ph ti t dng cp in p 6,3 kV phn cn li cung cp tip cho

ph ti cp in p 0,4 kV.Cng sut nh mc ca my bin p t dng cp 1 c chn nh sau

:

Trong : l h s % t dng

n l s my pht trong nh my


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Ta chn my bin p loi TMH 4000 c cc thng s nh sau :

Loi my bin

p

UmC

(kV)

UmH

(kV)

SmB

(kVA)

P0

(kW)

PN

(kW)UN% I0%

TMH 6300 10 6,3 6300 7,65 46,5 6,5 0,8My bin p d tr :c chn ph hp vi mc ch ca chng : my

bin p d tr ch phc v thay th my bin p cng tc khi sa cha

.

Cng sut my bin p d tr c chn nh sau :

Ta chn my bin p d tr loi TMHC 10000c cc thng s nh

sau:

Loi my bin

p

UmC

(kV)

UmH

(kV)

SmB

(kVA)

P0

(kW)

PN

(kW)UN% I0%

TMHC 10000 10,5 6,3 1000 12,3 85 14 0,8

6.2.Chn my bin p t dng cp 2

Cc my bin p t dng cp 2 dng cung cp in cho ph ti cp

in p 0,4 kV v chiu sng. Cng sut ca cc loi ph ti ny thngnh nn cng sut my bin p thng c chn loi my c cng sut

t 630-1000 kVA. Loi ln hn thng khng c chp nhn v gi

thnh ln v dng ngn mch pha 0,4kV ln.

Cng sut ca my bin p t dng cp 2 c chn nh sau :

Vy ta chn loi my bin p ABB-500 c cc thng s sau :

Loi my

bin p

SmB

(kVA)

in p (kV) Tn tht (kW) UN%

cun

cao

cun

h

Po PN

ABB -500 500 6,3 0,4 1 7 4

6.3.Chn my ct pha cao p ca my bin p t dng cp 1

Chn tng t nh vi my ct ca cp in p 10,5 kV c la

chn trong chng 4 .Tc l loi my ct 8BK41.


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Cp

in p

(kV)

i lng tnh ton

Loi

my ct

i lng nh mc

Icb

(kA)

IN

(kA)

Ixk

(kA)

Um

(kV)

Im

(kA)

Ict m

(kA)

Im

(kA)

10,5 - 60,347 153,618 8BK41 12 12,5 80 225

6.4.Chn my ct pha h p ca my bin p t dng cp 1

chn my ct in trong trng hp ny ta tnh dng ngn mch ti

thanh gp phn on 6,3 kV (im N5). Ta c s thay th tnh ton

ngn mch nh sau:

My ct c chn theo iu kin sau:UmMC Ummng; ImMC Icb

I2

nh . tnh BN im ixk

IcmIN5

Trong chng ngn mch ta tnh c dng ngn mch chn kh c

in mch t dng l: IN5 = 53,342 kA.in khng ca h thng tnh n im ngn mch N5 l:

in khng ca my bin p t dng cp 1 l:

Vy dng ngn mch ti im N5 l:

Dng xung kch ti im ngn mch N5 l:

Ta chn my ct 8BM20 c cc thng s k thut nh sau:

XHT XB1

N4N5

6,3 kV


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n thit k nh my in

V Th HngHT1 K52 - 100 -

Loi my ct Um, kV Im, A Icm, kA im, kA

8BM20 7,2 1250 25 63

My ct chn c: Im = 1250A > 1000A

im = 63kA > ixk = 22,612 kADo vy khng cn kim tra n nh ng v n nh nhit.

6.5.Chn ptmt

chn ptmt ta tnh dng ngn mch ti thanh gp phn on 0,4kV

(im N6). Ta c s thay th tnh ton ngn mch nh sau:

ptmt c chn theo iu kin sau:

- in p nh mc: - Dng in nh mc: - Dng in ct nh mc:

Trong : - Imaxl dng in ln nht pha 0,4kV

- IN6l dng ngn mch ti thanh gp phn on 0,4kV

in khng ca my bin p t dng cp 2:

Vy dng ngn mch ti im N6 l:

Ta chn ptmt C801Nc thng s k thutnh sau:

Loi ptmt Um, V Im, A Icm, kA

C801N 690 800 25

N4

XHT XB1

N5

XB2

N6

0,4kV


101/103

n thit k nh my in

V Th HngHT1 K52 - 101 -

TI LIU THAM KHO

1.

Phn in trong nh my in v trm bin p TS. o QuangThch

2. Thit k nh my in v trm bin p PGS. Nguyn Hu Khi3. Thit k phn in nh my in v trm bin p PGS.TS. Phm

Vn Ha

4.Ngn mch trong h thng in GS.TS. L Vn t5. Thit k cp in Ng Hng Quang, V Vn Tm6. Hng dn thit k tt nghip k thut in cao p Nguyn Minh

Chc


102/103

n thit k nh my in

V Th HngHT1 K52 - 102 -

Mc lc

CHNG I ............................................................................................................... - 2 -TNH TON PH TI V CN BNG CNG SUT ........................................ - 2 -

I.1/ Chn my pht in:....................................................................................... - 2 -I.2/ Tnh ton ph ti v cn bng cng sut cp in p my pht: .................... - 2 -I.3/Tnh ton ph ti v cn bng cng sut cp in p trung:............................ - 3 -I.4/Tnh ton cng sut pht ca c nh my in: ............................................... - 4 -I.5/Tnh ton cng sut t dng ca nh my: ...................................................... - 5 -I.6/Tnh cng sut pht v h thng:..................................................................... - 6 -

Nhn xt chung: .................................................................................................... - 8 -CHNG II............................................................................................................ - 10 -CHN S NI IN CA NH MY ........................................................ - 10 -

II.1/ Chn s ni in ca nh my: .............................................................. - 10 -II.1.1/ Phng n 1: ........................................................................................ - 11 -II.1.2/ Phng n 2: ........................................................................................ - 12 -II.1.3/ Phng n 3: ........................................................................................ - 13 -

Kt lun:.............................................................................................................. - 13 -II.2/ Chn my bin p: ...................................................................................... - 14 -

II.2.1/ Phng n 1: ........................................................................................ - 14 -II.2.2/ Phng n 2: ........................................................................................ - 27 -

CHNG III .......................................................................................................... - 40 -TNH TON NGN MCH ................................................................................. - 40 -

III.1/ Phng n 1: .............................................................................................. - 40 -III.1.1/ Chn im ngn mch: ....................................................................... - 40 -III.1.2/ Xc nh in khng cc phn t: ....................................................... - 41 -III.1.3/ Tnh ton ngn mch ti cc im: ..................................................... - 42 -

III.2/ Phng n 2: .............................................................................................. - 53 -III.2.1/ Chn im ngn mch: ....................................................................... - 53 -III.2.2/ Xc nh in khng cc phn t: ....................................................... - 54 -III.2.3/ Tnh ton ngn mch ti cc im: ..................................................... - 55 -

CHNG IV .......................................................................................................... - 66 -TNH TON KINH T - K THUT .................................................................. - 66 -CHN PHNG N TI U .............................................................................. - 66 -

IV.1/ Chn my ct: ............................................................................................ - 66 -IV.1.1/ Chn my ct cho phng n 1: ......................................................... - 66 -IV.1.2/ Chn my ct cho phng n 2: ......................................................... - 67 -

IV.2/ Chn dao cch ly: ...................................................................................... - 68 -IV.2.1/ Chn dao cch ly cho phng n 1: ................................................... - 68 -IV.2.2/ Chn dao cch ly cho phng n 2: ................................................... - 69 -

IV.3/ Chn s thit b phn phi:................................................................... - 70 -IV.4/ Tnh ton kinh t - k thut chn phng n ti u: ................................. - 70 -

IV.4.1/ Phng n 1: ....................................................................................... - 71 -IV.4.1/ Phng n 2: ....................................................................................... - 73 -

IV.4.3/ La chn phng n ti u: ................................................................... - 74 -CHNG V ........................................................................................................... - 75 -CHN KH C IN V DY DN .................................................................. - 75 -


103/103

n thit k nh my in

V.1/ Chn thanh dn cng u cc my pht: .................................................... - 75 -V.1.1/ Chn loi v tit din: .......................................................................... - 75 -V.1.2/ Kim tra iu kin n nh ng khi ngn mch: ................................ - 76 -

V.2/ Chn s : ................................................................................................. - 77 -V.3/ Chn thanh dn mm: ................................................................................. - 78 -

V.3.1/ Chn dy dn, thanh gp cho mch 220kV: ........................................ - 79 -V.3.2/ Chn dy dn, thanh gp cho mch 110kV: ........................................ - 82 -V.4/ Chn ng dy cp cho ph ti a phng: ............................................ - 85 -

V.4.1/ Chn tit din cp: ............................................................................... - 85 -V.4.2/ Kim tra cp theo iu kin pht nng: ............................................... - 86 -V.4.3/ Kim tra n nh nhit ca cp khi ngn mch:................................... - 87 -

V.5/ Chn cc dng c o lng: ....................................................................... - 87 -V.5.1/ Chn my bin in p v my bin dng in cho cp 220kV:......... - 87 -V.5.2/ Chn my bin in p v my bin dng in cho cp 110kV:......... - 88 -V.5.3/ Chn my bin in p v my bin dng in cho cp in p my pht: -89 -

V.6/ Chn khng in ph ti cp in p my pht: ......................................... - 93 -5.7.2. Chn chng st van cho my bin p.................................................... - 95 -

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