thiet ke mba 400kv ngam dau

7/31/2019 Thiet Ke Mba 400kv Ngam Dau

1/87

n tt nghip Thit kmy bin p 400kVA ngm du

SV: Nguyn Tun Long - Lp: TB -T 1

LI NI U

My in l mt loi hin t gm c mch t v mch in lin

quan vi nhau. Mch t gm cc b phn dn t v khe h khng kh.

Mch in gm hai hoc nhiu dy qun c th chuyn ng tng i vi

nhau cng b phn mang chng.

My bin p l mt h thng bin i cm ng in t dng bin

i dng in xoay chiu tin p ny thnh dng in xoay chiu c

in p khc. Cc dy qun v mch t ca n ng yn v qu trnh bin

i t trng sinh ra sc in ng cm ng trong dy qun thc hin

bng phng php in.

Mt khc, my bin p n cn c vai trong quan trng trong nn kinh

t quc dn nh trong cng nghip, nn nghip, giao thng vn ti, cc h

iu khin.

y trong n thit k my bin p ngm du ny ca em c

lm theo trnh t sau:

Khi nim chung v thit k my bin p

Tnh ton sb v chn cc kch thc ch yu

Tnh ton dy qun my bin p

Tnh ton ngn mch

Tnh ton kt cu mch t

Tnh ton nhit

Phn chuyn : So snh cng ngh mi v hiu qu ca n

Trong qu trnh thit k mn hc v thi gian c hn v kin thc

cn hn ch. Nn vic tnh ton khng khi thiu st. Mong cc thy, c


2/87



cho nhn xt n ny c hon thin hn. Em xin cm n thy

Nguyn c S tn tnh gip , to iu kin cho em hon thnh tt

n ny v hoc em c hc hi nhiu vn v my bin p trong thi

gian khai thc.Xin chn thnh cm n

H Ni, ngy thng nm 2004

Ngi thit k


3/87



CHNG I: KHI NIM CHUNG V THIT K MY

BIN P

I.1. I CNG

My bin p in lc l mt b phn rt quan trng trong h thng

in. truyn ti in nng t cc trm pht in n cc h tiu th cn

phi c ng dy ti in. Nu khong cch gia ni sn xut v h tiu

th ln th mt vn rt ln t ra v cn c gii quyt l: Vic truyn

ti in nng i xa lm sao cho kinh t.

Nh ta bit, cng mt cng sut truyn ti trn ng dy nu

in p c tng cao th dng in chy trn ng dy s gim xung,

nh vy c th lm tit din dy nhi do trng lng v chi ph dy s

gim xung. V th mun truyn ti cng sut ln i xa t tn hao v tit

kim c kim loi mu trn ng dy ngi ta phi dng in p cao

ng 35, 110, 220 v 500KV. Trn thc t cc my pht in khng c

kh nng pht ra nhng in p cao nh vy thng ch 3 n 21KV l

cng, do cn phi c thit b tng p u ng dy ln. Mt khc

cc h tiu th thng yu cu in p thp t 0,4 n 6KV do ti y

phi c thit b gim in p xung. Nhng thit b dng tng p u

ra ca my pht tc l u ng dy dn in v gim in p ti h

My phtin

Tng p Gim p


4/87



tiu th tc l cui ng dy dn c gi l my bin p. Thc ra trong

h thng in lc mun truyn ti v phn phi cng sut t nh my in

n tn cc h tiu th mt cch hp l thng phi qua 4 5 tng tng

gim in p nh vy. Do tng cng sut ca my bin p trong hthng in lc thng gp 4 5 ln cng sut ca trm pht in. Nhng

my bin p (MBA) dng trong h thng in lc gi l my bin p in

lc hay my bin p cng sut. T ta thy r my bin p ch lm nhim

v truyn ti hoc phn phi nng lng ch khng phi l bin ho nng

lng.

Ngoi my bin p in lc cn c nhiu loi my bin p dng

trong cc ngnh chuyn mn nh my bin p chuyn dng cho cc l in

luyn kim, my bin p hn in, my bin p dng trong thit b chnh

lu, my bin p dng cho o lng, th nghim

Khuynh hng pht trin ca my bin p hin nay l thit k ch

to nhng my bin p c dung lng tht ln, in p tht cao, dng

nguyn liu mi gim trng lng v kch thc my. V vt liu hin

nay dng loi thp cn lnh khng nhng c t tnh tt m tn hao stla t do nng cao c hiu sut ca my bin p. Khuynh hng dng

dy nhm thay dy ng va tit kim c dy ng va gim c trng

lng my cng ang pht trin.

nc ta ngnh ch to my bin p ra i ngay t ngy ho

bnh lp li. n nay chng ta sn xut c mt khi lng my bin

p kh ln v nhiu chng loi khc nhau phc v cho nhiu ngnh sn

xut trong nc v xut khu.

I.2. NH NGHA V NGUYN L LM VIC.

Ta xt my bin p mt pha hai dy qun. Dy qun 1 c W1 vng

dy, dy qun 2 c W2 vng dy c qun trn li thp 3. Khi t mt


5/87

i

th

s

i

ch

th

1

n tt nghi

n p Ut x

p s sinh

in n

n i2u ra

Ti v

iu

Gi s

ng do n

Do

2 s l:

p

ay chiu

a t thn

g e1 v e2

.

i dng i

c truyn t

in p

inh ra c

theo nh

o dy q

mc v

. Dy qu

n l U2.

dy qun

xoay chi

g l mt h

lut cm

T

n 1 tron

ng vi c

hai s c

h vy

1 sang d

u t vo

m hnh s

ng in t

it kmy

s c

hai dy q

sc in

ng ln

y qun 2.

l mt h

in. =

, sc i

in p 400

dng in

n 1 v 2,

ng s s

ca dn

m s hn

sint.

ng tro

VA ngm

i1, trong l

cm ng

inh ra d

in xo

h sin th

g dy qu

u

i

ra

g

y

n


6/87



( )

1 1 1

1 m

1

d d .sin te W . W .

dt dt

W . . .cos t 1

2E .sin 2

= =

=

=

( )

m2 2 2

2 m

2

d .sin tde W . W .

dt dt

W . . .cos t 2

2E .sin

2

= =

=

=

Trong :

1 mi

EE

2

= = 4,44. F. W1. m. (3)

2 m2

EE

2

= =4,44. F. W2. m. (4)

L gi tr hiu dng ca cc sc in ng dy qun 1 v 2. Cc biuthc (1) v (2) ta thy sc in ng trong dy qun chm pha so vi t

thng sin ra n mt gc2

. Da vo biu thc (3) v (4) ngi ta nh

ngha t s bin i c my bin p nh sau:

1 1

2 2

E WK

E W=

Nu khng kin p ri trn dy qun th c th coi E1 = U1; E2 =

U2 sauy ra:

1 1

2 2

E UK

E U=


7/87



nh ngha: T nguyn l lm vic cbn trn ta c nh ngha my

bin p nh sau: my bin p l mt thit bin tng yn, lm vic da

trn nguyn l cm ng in t bin i mt h thng dng in xoay

chiu din p ny thnh mt h thng dng in xoay chiu in pkhc vi tn s khng thay i. My bin p c hai y qun gi l my

bin p hai dy qun. Dy ni vi ngun thu nng lng gi l dy qun

scp, my bin p 3 dy qun 6 dy scp v th cp cn dy qun th

3 vi in p trung bnh. My bin p bin i h thng xoay chiu 1 pha

gi l my bin p mt phat, 3 pha gi l 3 pha, ngm trong u gi l my

bin p du

I.3. CC I LNG NH MC

Cc i lng nh mc ca my bin p quy nh iu kin k thut

ca my. Cc i lng ny do nh ch to quy nh v thng ghi trn

nhn my bin p.

1. Dung lng hay cng sut nh mc Sm.

L cng sut ton phn hay biu kin a ra dy qun th cp ca

my bin p. n v KVA hay VA

2. in p scp nh mc: U1m

L in p dy qun scp tnh bng V hay KV. Nu dy qun s

cp c cc u phn nhnh th ngi ta ghi cin p nh mc ca u

phn nhnh.

3. in p dy thcp nh mc: U3m

L in p dy ca dy qun th cp my bin p khng ti v in

p t vo dy qun scp l nh mc. n v l: KV, V


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4. Dng in dy nh mc scp: I1m v th cp I2m

L nhng dng in dy ca dy qun s cp v th cp ng vi

cng sut v in p nh mc. n v: A, KA

C th tnh nh sau:

m m1m 2m

1m 2m

S SI ; I ;

U U= =

i vi my bin p ba pha:

m m1m 2m

1m 2m

S SI ; I ;

3.U 3.U= =

5. Tn snh mc: Hz

Thng my bin p in lc c tn s cng nghip f = 50Hz

Ngoi ra trn nhm my cn ghi nhng s liu khc nh: s pha, s

v tu dy qun, in p ngn mch Un% ch lm vic ngn hn

hay di hn phng php lm lnh.

Sau cng hiu rng khi nim nh mc cn bao gm c tnh trng

lm vic nh mc ca my bin p na m c th khng ghi trn nhn my

nh: nh mc, chnh lch nh mc, nhit nh mc ca mi

trng xung quanh.

1.4. SDNG VT LIU TRONG CH TO

Vic tm kim mt loi vt liu mi l nhm mc ch ci thin cc

c tnh c my bin p nh gim tn thao nng lng, kch thc, trng

lng, tng tin cy ca n. Khuynh hng chung thng thay vt liu

qu him bng nhng vt liu r tin v d tm kim hn nh dng dy

nhm thay dy ng trong my bin p cng sut nh v trung bnh l mt

v d.

Vt liu dng trong my bin p thng l:


9/87



Vt liu tc dng: dng dn in nh dy qun, dn t nh li

thp

Vt liu cch in: dng cch in gia cc cun dy hay gia

cc cun y vi cc b phn khc bng cc vt liu nh catong,cht cch in, s, du bin p

Vt liu kt cu: dng gi bo v my bin p nh bulong, v

my

Vic thay i vt liu dng i khi lm thay i qu trnh cng ngh

quan trng hay nhng kt cu cbn ca my bin p. Cho nn iu

lin quan cht chn tin b ca qu trnh cng ngh.

+ Vt liu quan trng trc tin trong ngnh ch to my bin p l

tn Silic hay cn gi l thp k thut in

+ Vt liu tc dng th hai l kim loi dy qun. Trong nhiu nm

ng vn l kim loi duy nht dng ch to dy qun m khng c thay i

g. V nh ta bit ng c in trsut rt nh, dn in tt, d gia cng

(hn, qun) bo m bn cin tt. Gn y ngi ta c dng nhmthay thng lm dy qun. Nhm c u im l nh, sn hn, r hn,

nhng tt nhin c nhc im l in trsut ln hn do dn in km

hn, bn ccng km hn v li rt khn trong vic hn ni. Khi dng

nhm thay ng m bo c cng sut tng ng th th tch nhm

tng ln, gi thnh cc cng vic v ch to dy qun, chi ph v vt liu

cch in, sn tm. Tng ln. Nhng khon tng th c b li bi

gi thnh nhm r hn. Nn ni chung gi thnh ton b my bin p bngnhm v dy ng thc t khng khc nhau l bao nhiu.

+ Vt liu cch in phn ln cc my bin p dng dy qun c

cch in bng giy cp, thuc cch in cp A c nhit gii hn cho

php +1500C. Vi chiu dy cch in c hai pha 0,45 0,5mm. Vic


10/87



dng dy dn c cch in cao hn E, B, F khng c ngha lm v nhit

cho php ca dy qun my bin p c quy nh khng chcp cch

in ca vt liu cch in m cn nhit cho php ca du ngm dy

qun na. Mt loi cch in hay dng bc dy na l men cch in(emay). Song ngi ta cng ch dng n cch in cp B m t khi dng

dy cch in cao hn na. V mt l do na l nhit cho php cng cao

th mt dng in chn cng ln th tn hao ngn mch tng ln lm cho

hiu sut ca my gim xung ng k. cch in cc b phn mang

in vi b phn khng mang in ca my ngi ta dng vt liu cch

in. Khi my lm vic do tc ng c nhit , chn ng v cc tc ng

l ho khc cch in s b lo ho ngha l mt dn cc tnh bn vin vc. Thc nghim cho bit khi nhit tng qu nhit lm vic cho php

8 100C th tui th ca vt liu cch in khong 15 20 nm. V vy khi

s dng my in trnh my qu ti lm nhit tng cao trong mt

thi gian di.

Vt liu kt cu dng ch t cc b phn v chi tit truyn ng hoc

kt cu my theo dng cn thit m bo cho my lm vic bnh thng.

Ngi ta thng dng gang thp cc loi, hp kim v cc vt liu bng cht

do.

1.5. CC KT CU CHNH CA MY BIN P.

My bin p thng dng cc phn chnh sau:

- Li st (hay cn gi l mch t) v cc kt cu ca n, dy qun, h

thng lm lnh v v my.

1. Li st v kt cu ca n

Li thp lm vt liu dn t cho t thng trong my bin p. ng

thi lm khung qun dy. Li st gm cc l thp Silic ghp li c p

bng x p v bu lng to thnh khung my bin p. Trn cn bt cc


11/87



gi u dy dn ra ni vi cc sc xuyn hoc cc ty np my

cc my bin p du ton b li st c qun dy v cc dy dn ra c

ngm trong thng ng du my bin p gi l rut my. Cc my bin p

cnh, rut my gn vi np my c th nhc ra khi thng du xc ra,lp rp, sa cha. Vi my bin p cng sut 1000KVA trln v rut my

rt nng nn c bt cnh vi y thng v lc lp rp sa cha th

phi nng v thng ln khi y v rut my. Li st gm hai phn: tr T

v gng G. Tr l phn li c lng dy qun, gng l phn li khng c dy

qun dng khp mch t gia cc tr.

2. Dy qun.

Dy qun my bin p l b phn dng thu nng lng vo v

truyn ti nng lng i. Trong my bin p hai dy qun c cun HA ni

vi li in p thp v cun CA ni vi li in cao hn. my bin p

c 3 dy qun ngoi hai dy qun CA v HA cn c dy qun th 3 vi

in p trung bnh gi la TA. My bin p bin i h thng xoay chiu

mt pha gi l my bin p mt pha. My bin p bin i h thng dng

in xoay chiu 3 pha gi l my bin p 3 pha. My bin p ngm trongdu gi l my bin p du. My bin p khng ngm trong du gi l my

bin p kh.

3. H thng lm lnh v v my.

Khi my bin p lm vic, li st v dy qun u c tn hao nng

lng lm cho my bin p nng ln. Mun my bin p lm vic c lu

di phi tm bin php gim nhit ca my bin p xung tc l qu

trnh lm ngui my bin p. C th lm ngui bng khng kh t nhin

hoc bng du my bin p. My bin p dng khng kh lm ngui gi

l my bin p kh, my bin p dng du lm ngui gi l my bin p

du. Hu ht my bin p lm ngui bng du bao quanh li thp v dy


12/87



qun s nng ln v truyn nhit ra ngoi vch thng nhhin tng i

lu. Nhit lng t vch thng li truyn ra khng kh xung quanh bng

phng php i lu v bc x. Nhvy m hiu ng lm lnh c tng

ln cho php tng ti in ti vi thp v dy qun, tng c cng sutmy bin p. My bin p c cng sut t (10 16).103 KVA thng phi

tng cng lm ngui bng si lu cng bc bng qut gi. m

bo du trong my lun lun y trong qu trnh lm vic trn my bin p

c 1 thng du ph hnh tr thng t nm ngang vi bnh u chnh bng

ng dn du. Tu theo nhit ca my bin p m du gin n t do

trong bnh du ph, khng nh hng n lng du my bin p. V vy

bnh du ph cn c gi l bnh du gin n.

Trn np thng cn cc s bt cc u dy dn ra ni vi cc dy

qun trong my bin p vi li in thit bi ni chnh p, thit b

o nhit bin p, mc treo mt khc du my bin p ngoi tc dng

lm lnh con ngi l mt cht cch in tt, nhng nhc im l du

my bin p ng thi cng l vt liu d chy nn sinh ra ho hon. V

vy trong nhiu trng hp phi c thit b v bin php chng chy thch

hp.

1.6. MC CH YU CU V NHIM V.

m bo v tnh ton hp l tn t thi gian vic thit k my

bin p s ln lt tin hnh theo th t.

1. Xc nh cc i lng cbn.

Tnh dng in pha, in p pha ca dy qun Xc nh in p th ca cc dy qun

Xc nh cc thnh phn ca c ngn mch


13/87



2. Tnh ton cc kch thc ch yu.

Chn s v kt cu li st

Chn loi v m hiu tn silic cch in ca chng. Chn cng

t cm li st

Chn kt cu v xc nh cc khong cch in cht c cun dy

Tnh ton s b my bin p chn quan h ca kch thc ch

yu theo tr s i0, P0, On, Pn cho.

Xc nh ng knh tr, chiu cao dy qun. Tnh ton sb li

st

3. Tnh ton dy qun CA v HA

Chn dy qun CA v HA

Tnh cun dy HA

Tnh cun dy CA

4. Tnh ton ngn mch.

Xc nh tn hao ngn mch

Tnh ton in p ngn mch

Tnh lc cbn ca dy qun khi my bin p b ngn mch

5. Tnh ton cui cng v h thng mch tv tham s khng ti ca

my bin p.

Xc nh kch thc c th ca li st

Xc nh tn hao khng ti

Xc nh dng in khng ti v hiu sut


14/87



6. Tnh ton nhit v h thng lm ngui my bin p.

Qu trnh truyn nhit trong my bin p

Khi nim h thng lm ngui my bin p

Tiu chun v nhit chnh

Tnh ton nhit my bin p

Tnh ton gn ng trng lng v th tch b gin du

7. Tnh ton v la chn mt s ch tiu kt cu.

Phn ny c trnh by cch tnh v chn mt s chi tit kt cu quan

trng nh bulong p gng v mt sai p trc, gng, vch np y thng,bnh du gin n, b phn tn nhit.

CHNG II: TNH TON CC KCH THC CH YU.

II.1. XC NH CC I LNG CBN

1. Dung lng mt pha

' mf

S 400S

m 3= = = 133,333 [KVA]

2. Dung lng trn mi tr

' mt

S 400S

t 3= = = 133,333 [KVA]

3. Dng in dy nh mc.

+ i vi pha cao p.

3m

2m 3

2

S 400.10I

3.U 3.22.20= = =10, 5 [A]

+ i vi pha h p.


15/87



3

m1m 3

1

S 400.10I

3.U 3.0,4.20= = 57,35 [A]

4. Dng in pha nh mc.

V dy qun ni /Y0-11 nn

22f

I 10,5I

3 3= = = 6,062 (A)

1f 1I I= = 577,35 (A)

5. in p pha nh mc.

+ i vi pha CA: U2f= U2 = 22.000 (V)

+ i vi pha HA:3

11f

U 0,4.10U

3 3= = = 230,9 (V)

6. in p thnghim ca cc dy qun

Theo bng (2) ta tra c: Ut2 = 55 [KV]

Ut1 = 5 [KV]

II.2. CHN CC S LIU XUT PHT V TNH CC KCH THC CH

YU.

7. Chiu rng quy i ca rnh ttn gia dy qun CA v HA

Vi Ut2 = 55[KV] theo bng 19 TKMBA thy Phan T Th ta tra:

a12 = 18 (mm): khong cch gia cun CA v HA

12 = 5 (mm): ng cch in gia cun CA v HA

d2 = 30 (mm): chiu di u tha

a22 = 18 (mm): khong gia cun CA v CA

22 =3(mm): tr v dy qun HA

lo2 = 45 (mm): khong cch gia dy qun CA n gng.


16/87



8. Cc hng s tnh ton a, b c th ly gn ng

Theo bng 13, 14 ca thy Phan T Th ta tra c:

a = 1,38

b = 0,34

9. H sKf = 0,93 (theo bng 15):l h s tnh n tn hao ph trong dy

qun.

10. H s ari vi mt dy cng sut v din rng:

Ni chung thay i rt t.

1 2r 12 a aa a

3+= +

Trong :

241 2a a K. S'.103

+ =

Vi K = 0,52 (theo bng 12)

Vy:

21 2 4a a

0,52. 133,333.103

+ = =0,0177 (m)

ar= 0,018 + 0,0177 = 0,0357 (m)

11. H s quy i ttrng tn ly: Kr = 0,95

12. Cc thnh phn in p ngn mch.

nnr

P 5500U % 1,37%10.S" 10.400

= = =

2 2 2 2

nx n nrU % U % U % 40 1,375 3,756%= = =

13. Ta chn tn cn lnh m hiu 3405 c chiu dy 0,30 mm


17/87



Theo bng 11 Phan T Th ta c:

Bt = 1,62T

H s gang: Kg = 1,015 (theo bng 6 Phan T Th)

p tr bng nm vi dy qun, p gng bng x p, khng dng

bulong xuyn qua tr v gng. S dng li thp c 4 ni ghp nghing 4

gc ca li, cn 2 ni ghp gia dng ni ghp thng l tn. Lm nh vy

gim bt tn hao do tnh dn t khng ng hng.

Phng php ghp hin i nht hin nay l ghp cho gc cho tn

thao trong mch t nh nh. Kt cu mch t kiu khng gian nh trn rt

tin cho sn xut hng lot v cng tc sa cha v rt d ckh ho, t

ng hoa v d tho d, lp rp.

Theo bng 4 Phan T Th ta chn s bc thang trong tr l 6, s bc

thang ca gng ly bng 5 bc.H s chm kch Kc = 0,931 (theo bng 4 Phan T Th): khng c

tm st p tr

H sin dy Kd = 0,92 (theo bng 10 Phan T Th): khng ph

hai lt sn cch in

5

21 1

43

Lp 1 Lp 2

3 4

1 2 1

5


18/87



Vy h s li dng: Kld = Kc. Kd = 0,913. 0,92 = 0,839

T cm trong gng:

( )

t

gg

B 1,62B 1496 T

K 1, 015= = =

T cm khe hkhng kh mi ni thng

BK= Bt = 1,62 (T)

Mi ni nghing:

( )' tKB 1,62

B 1,145 T 2 2

= = =

Sut tn hao ca thp trong tr v gng

Theo bng 45 Phan T Th:

Pt = 1,194 (W/kg)

Pg = 1,150 (W/kg)

Theo bng 50 Phan T Th: Sut t ho trong tr v gng

qt = 1,645 (VA/kg)

qg = 1,526 (VA/kg)

Sut t ho khe hkhng kh.

- Mi ni thng: PK= 20480 (VA/m2)

- Mi ni nghing: PK= 2800 (VA/m2)

14. ng knh tr ca my.d = A. x

Trong : A l hng s

x = 4


19/87



r r 442 2

nx t ld

S'.K .a 133,333.0,95.0,0357A 0,507. 0,507.

f.U .B .K 50.3,756.1,62 .0,839= =

A = 0,163

a. Trng lng st (GFe): GFe = GT+ Gg

- Trng lng tr: 21T 2A

G A xx

= +

+ A1 = 5,663.104. Kld. A

3. a = 5,663.104. 0,839. 0,1633. 1,38

A1 = 283,95 (Kg)

+ A2 = 3,605.104. Kld. A

3. Lo2 = 3,605.104. 0,839. 0,1632. 0,45

A1 = 36,16 (Kg)

Vy: 2T283,95

G 36,16xx

= +

- Trng lng ca gng: Gg = B1x3 + B2x

2

+ B1 = 2,4. 104. Kld. Kg. A

3 (a + b + e)

Trong e = 0,405: l h s quy i mt na tit din hnh bc thangv hnh ch nht.

B1 = 2,4. 104. 0,839. 1,015. 0,1633. (1,38 + 0,34 + 0,405)

B1 = 188,08 (Kg)

+ B2 = 2,4. 104. Kld. Kg. A

3 (a11 +a22)

B1 = 2,4. 104. 0,839. 1,015. 0,1633. (0,018 + 0,018) = 19,54 (Kg)

Vy: Gg = 188,08x3 + 19,54 x2

2 2

Fe

283,95G 188,08x 55,7x

x= + +

b. Trng lng dy qun: 1dq 2C

Gx

=


20/87


21/87



2

0 0

2 2

0 0

283,95P 1,13.1,194 36,16x 0,5.10,64G

x

1,13.1,150 188,08x 19,54x 0,5.10,64G 6G

= + +

+ + +

P0 = 244,40x2 + 74,17x2 + 6,28G0.

383,11

x

Mt khc

4 3 3

0 ldG 0,486.10 .K .A .x= : Trng lng mt gc ca li

4 3 3 3

0G 0,486.10 .0,839.1,015.0,163 .x 17,92x= =

Vy P0 = 356,93x3

+ 74,17x2

+383,11

x

- Cng sut t ho c th tnh sb (theo 5-31) Phan T Th vi cc

h s tra bng 50, 53.

( )ir ig' '' ' ''io0 if if t T 0 if if g g 0 0

''

if K K K

K .KKQ K .K .q G . G K .K .q G . G N 2 G

2 2

K q n T

= + +

+

Trong :

( ) ( )

( ) ( )

' '' 2

if t K

'' ' 2

if g K

K 1,20 q 1,645 VA / Kg P 20480 VA / m

K 1,06 q 1,526 VA / Kg P 2800 VA / m

= = =

= = =

Kio = 42,45: l h s gia tng dng in do cng sut t ho tng ln

(theo bng 53 Phan T Th)

nK: S khe hkhng kh trong li thp

Kig = Kn.' ''

io t ioK K K+ + : H s chung lm tng cng sut t ho

gng

Kn = 4: h s biu th s lng gc ni c dng ni nghing


22/87



Kt = 2: h s biu th s lng gc ni c dng ni thng

2

ioK 4,3=

''

ioK 11,0= (theo bng 52a Phan T Th)

Kig = 4,43 + 2.11 = 39,2

Kir = 1,18 (theo bng 52b Phan T Th): l h s kn nh hng

do chiu rng l tn gc mch t.

Q0 = 1,2. 1,06. 1,645.(GT + 0,5. 42,45 G0)

+ 1,2. 1,06. 1,526 (Gg 6Gg + 0,5. 1,18. 39,2G0)

+ 1,06. 2800. 4. TK+ 1,06. 20480. 2TK

Q0 = 2,092 GT + 44,40G0 + 1,94Gg + 44,89G0 11,6G0

+ 11872TK+ 43417 K

K

Mt khc tit din tr tnh sb theo 2-28 Phan T Th

Tt = 0,785. Kld. A3. X2 = 0,785. 0,839. 0,1632. X2 = 0,0174x2

Din tch khe hmi ni thng'' 2

K tT T 0,0174x= =

Din tch khe hmi ni nghing

' 2 2

K tT 2T 2.0, 0174x 0.0246x= = =

Thay vo sau khi bin i ta c.

Q0 = 1757,26x3 + 1161,062 + 594,02x

- Gi thnh vt liu tc dng:

td Fe dqC C C= +

Trong :


23/87



2 2Fe Fe283,95

C G 188,08x 55,7xx

= = + +

dq dd 2 2

298,56 588,64C 1,86.G 1,86.1,06.

x x= = =

Vy: 2 2td 2 2283,95 588,68

C 188,08x 55,7xx x

= + + +

16. Thnh phn phn khng ca dng in khng ti

( )

2 2

0ox

594,021757,26x 1161,06x

Q xi %10S 10.400

+ += =

iox = 0,44.x3 + 0,29 x2 + 0,15x

17. Mt dng in trong dy qun.

( )6 2f n12Cu dq

2

K .P 0,93.55002,67x.10 A / m

298,56K .G2,4.10 .

x

= = =

Trong :

KCu = 2,4. 10-12

Pn = 5500 (W)

dq 2

298,56G

x=

1,2 1,8 1,87 1,88 1,89 2,4 3,0 3,6

4

x = 1,048 1,16 1,167 1,17 1,172 1,245 1,32 1,38

2 4x 2= 1,096 1,344 1,161 1,368 1,374 1,55 1,734 1,90

3 4x 3= 1,148 1,56 1,588 1,60 1,61 1,93 2,29 2,62


24/87



1,2 1,8 1,87 1,88 1,89 2,4 3,0 3,6

2

T

283,95G 36,16x

x= +

310,57 293,36 292,52 292,15 291,95 284,12 277,81 274,46

Gg = 188,08x2 + 19,54x2 237,32 319,66 325,26 327,65 329,64 393,27 464,58 529,88

3 2

FeG 188,08x +55,7x

283,95+

x

=

547,89 613,02 617,78 619,8 621,59 677,39 742,39 804,34

3 2

0P 356,93x 74,14x

383,11

x

= +

+

856,60 986,75 996,02 999,99 1003,4

3

111,54 1226,2

0

135,68

Tt = 0,0174x2

0,0190 0,0233 0,0236 0,0238 0,0239 0,0269 0,030 0,033

3 2

0Q 1757,26x 1161,x

594,02

x

= +

+

3856,6

6

4813,8

6

4879,7

3

4907,6

4

4931,3

1

5668,2

7

6487,4

0

7240,4

7

( )0oxQ

i %10S

= 0,964% 1,203% 1,2199

%

1,227% 1,233% 1,417% 1,621% 1,801%

= 2,67x. 106 (A/m2) 2,79.106

3,096106

3,115106

3,124106

3,129106

3,324106

3,524106

3,684106

dq 2

298,56G

x=

272,4 222,14 219,36 218,29 217,29 192,61 172,17 157,13

d=A.x = 0,163.x 0,1708 0,1890 0,1902 0,1907 0,191 0,2029 0,2151 0,2249

d12 = a. d = 1,38.d 0,2357 0,2608 0,2624 0,2631 0,2635 0,2800 0,2968 0,3103

C = d12 + a12 + a22 0,3297 0,3608 0,363 0,3639 0,3644 0,384 0,4058 0,4223

3 2

td

2

C 188,08x 55,7x

283,95 588,64x x

= +

+ +

1084,9

7

1050,9

9

1050,2

8

1050,0

9

1050 1057,1

5

1081,8

5

1114,1

5


25/87



100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

01,2 1,4 1,6 1,8 2,0 2,2 2,4 2,6 2,8 3,0 3,2 3,4 3,6

856,6

986,75

1111,54

1236,2

1353,68

1,87

1,88

1,89

P0

1

1,203

1,621

1,417

1,801

2

10%

iox

Po(W)


26/87



Po(W)

500

100

200

300

400

500

600

700

800

677,39

613,02

743,39

804,34

1,2 1,8 2,4 3,0 3,61,87

1,

8

8

1,

8

9

547,89

Gdq

GFe


27/87



18. Chn h s hnh dng

Tr s thng bin thin trong 1 phm vi rt rng t 1,2 n 3,6.

Bng phng php tnh ton sb gn ng my bin p, ta tm sao cho

Ctd t gi tr nh nht, nhng phi tho mn iu kin:

i0 1,5% (theo b)

P0 1000 W(theo b)

4,5.106 (A/m2)

r 25 MN/m2

Da vo bng tnh ton ta tm c.

= 1,88 x = 1,17; x2 = 1,368; x3 = 1,60

Khi :

P0 = 999,99 (W) 1000 (W)

i0 =1,227% (tho mn)

= 3,124.106 (A/m2) < 4,5.106 (A/m2)

CTd = 1050,09

19. ng sut ko

3 6 2 3nr Cu n f r

PM .x 0,244.10 .K .K .K x

aA

= =

Trong :

Kt = 0,93 Pn = 5500

Kr= 0,95 a = 1,38

A = 0,163


28/87



nr

nx

U

U

n

n

100K 1,41 1 e

U

= +

M: Un = 4% (theo b)

Unx = 3,75%

Unr= 1,375%

Do :.1,375

3,756n

100K 1,41 1 e 46,41

4,0

= + =

Vy r= 0,244 . 10-6. (46,41)2 . 0,93 . 0,95 .

5500.1,6

1,38.0,163

= 18,16 (MN/m2)

20. ng knh tr st

d = A. x = 0,163. 1,17 = 0,19071 (m)

Theo tiu chun quc t quy nh th ng knh tr st ca my s l:

dm = 0,20 (m)

21. Tnh tr s ti u

4 4

* md 0,20 2,25A 0,163

= = =

Vy x = 1,224; x2 = 1,498; x3 = 1,83

- Trng lng dy qun

( )1dq 2C 298,56

G 199,3 Kg

1,498x

= = =

- Trng lng ca li

GFe =2 2 283,95188,08x 55,7x

x+ + = 559,59 (Kg)

- Dng in khng ti


29/87



i0 = 0,44x3 + 0,29x2 + 0,15/x = 1,361%

22. ng knh trung bnh ca rnh gia

d12 = a. dm = 1,38. 0,2 = 0,276 (m)

23. Tit din hu hiu ca tr st

Tt = Kd. Tb

Trong : Kd = 0,92

Tb = 288,4 (cm2) = 0,02884 (m2) theo 42b

Vy: Tt = 0,92. 0,02884 = 0,0265 (m)

24. Chiu cao sb ca dy qun

( )122d 3,14.0,276

l 0,385 m2,25

= = =


30/87



CHNG III: TNH TON DY QUN MY BIN P

III.1. CC YU CU CHUNG

C th chia lm hai loi

1.Yu cu vn hnh: Gm in cv nhit

a. Yu cu vin

Khi vn hnh thng dy qun my bin p c in p lm vic bnh

thng v qu in p do ng ngt mch trong li in hay st nh gy

nn nh hng ch yu do cch in chnh ca my bin p, tc l cch

in dy qun vi nhau v gia dy qun vi v. Cn qu in p do st

nh thng ln ng dy thng nh hng n cch in dc ca my

bin p. Tc l gia cc vng dy ri dy hay gia cc bnh dy ca tng

dy qun.

b. Yu cu vchc

Dy qun khng b bin dng hoc h hng di tc dng ca lc c

hc do dng in ngn mch gy nn.

c. Yu cu vnhit

Khi vn hnh bnh thng cng nh trong trng hp ngn mch,

trong thi gian nht nh dy qun khng c c nhit cao qu v lc

cht cch in s b nng mt tnh n hi, ho dn v mt tnh cch

in. V vy khi thit k phi m bo sao cho tui th ca cht cch in

l 15 n 20 nm.

2. Yu cu v ch to.

Lm sao cho kt cu n gin tn t vt liu v nhn cng, thi gian

ch to ngn gi thnh h nhng m bo v mt vn hnh


31/87



* Nh vy yu cu i vi thit k l:

+ Phi c quan im ton din: Kt hp mt cch hp l gia hai yu

cu v ch to v vn hnh sn phm c cht lng tt m gi thnh h.

+ Phi ch yu n kt cu v ch to dy qun sao cho thch hp

vi trnh k thut ca xng sn xut.

+ Phi nm vng nhng l lun c lin quan n dy qun CA, vt

liu cch in

* Qu tnh thit k ca ds c th tin hnh theo 3 bc

+ Chn kiu v kt cu dy qun.

+ Tnh ton sp xp v b tr dy qun

+ Tnh ton tnh nng ca my bin p

3. Cc kiu dy qun my bin p.

Theo cch qun dy ta c th chia dy qun my bin p ra lm cc

kiu chnh sau y:

Dy qun hnh ng dy dn ch nht;

Dy qun hnh ng dy dn trn;

Dy qun hnh xon;

Dy qun hnh c lin tc

Ngi ta cn c th phn bit ra loi dy qun mt mch (n) hay hai

mch (kp), c hon v hay khng hon v,

a. Dy qun hnh ngdy dn chnht

Loi dy ny qun dng dy tit din ch nht qun thnh hnh tr.

Nu dng in ln qu th ghp nhiu si sngng. Lc tt nht l dng

cc si cng kch thc ghp k nhau theo hng trc, khng nn ghp k


32/87



theo hng knh cho t thng tn trong cc si dy ging nhau v nh

vy tn hao v dng in xoy trong chng s ging nhau v v mt ckh

ghp hng trc cng tt hn. Mt khc dng mt cdy sphc tp

cho vic t hng. Nu phi dgn dy c tit din khc nhau th phi cmt b k nhau bng nhau ghp (hnh 3-19). Ni chung dy qun np

(theo cnh ln) si dy (hnh3-20a), khng nn qun gn dng (theo cnh

nh) si dy (hnh 3-20b) v s kh qun hn m cng lm cho cc si dy

d b nghing i (hnh 3-20c); tn hao ph do dng in xoy tng ln, tn

nhit li km. C th dng cch qun dng khi t l cc cnh ca si dy

trong phm vi t l sau: 1,3 < a/b < 3,0.

Nu qun mt lp ta c kiu dy qun hnh ng mt lp hay cn gi

l ng n (hnh 3-12a). Nu qun hai lp ta c kiu hnh ng kp (hnh 3-

12b). Ku hnh ng kp th hai lp ni tip vi nhau (qun lp trong t trn

Hnh 3-20: Cc phng php qundy

a) qun np si; b) qun gn dng sidy; c) qun gn dng nhng khng

t yu cu

Hnh 3-21: Dy qun hnh ng, a) ngn 6 vng; b) ng kp 12 vng

a

1

2

3

4

5

6

6

4

5

3

1

2

6

4

5

3

5

6

4

1

2

2

3

1

7

9

8

1 0

1 2

1 1

7

10

8

9

11

12

a) b) c) a) b)

a'


33/87



xung sau lp ngoi qun ngc t di ln nhhinh 3-21b). Nh

vy u dylp trong v ui lp ngoi c in p bng in p pha ca

dy qun.

Nu Um di 100V th cch in gia hai lp rt n gin, hocdng mt rnh du rng 4 8 mm hoc dng mt ng giy cch in l .

Nu in p t 3 n 6kV th phi lm rnh du c ba cch in gia dy

2mm. Nu U > 6000V th cch in s kh khn hn do khng dng

kiu dy qun ny cho cc my bin p cng sut t 25 n 630 kVA.

c rnh du thng dng que nn cch in bng g. Khng nn

lm nhiu que nm qu v du s kh lu thng, cng khng nn t qu v

ng dy d b bin dng thnh hnh a gic. Khong cch gia cc que nmthng vo khong 150 120mm

Kiu dy qun hnh ng n c nhc im l hai u khng c g

gi cht nn d b tung ra do thng ch dng trong cc my bin p

nh, cng sut mi tr t 3 n 10kVA. Dy qun hnh ng kp n nh v

ckh hn v ni chung ch to cng n gin nn c dng ph bin

trong cc my bin p cng sut t 630 kVA trxung in p di 6kV.

Trong my bin p th dy qun hnh ng n v kp ch yu lm

cun HA.

Gn y ngi ta nghin cu v s dng c kt qu loi dy qun

nhiu ng nhiu lp dy ch nht cho c cun dy CA. Kt cu ca loi

dy qun ny ch khc vi dy qun hnh ng n gin trn l ch n

gm nhiu lp v cc si dy qun ny cng khng dng kiu qun dng

cc si dy qun. Chiu qun dy cc lp cng khc nhau, thng cc lp

l qun theo mt chiu, cc lp chn qun theo chiu khc. Gia cc lp c

lt vi lp giy cp lm cch in lp v phng phng in gia cc lp,

cch in lp phi cao hn dy qun 30-50mm. Mi lp pha trn v di

vn phi c nhng vnh m ph bng cacton cch in buc cht vo cc


34/87



vng trn v di ca dy qun (hnh 3-22). Vic lt cch in nh vy l

rt cn thit v loi dy qun ny in p gi vng u ca bt k mt lp

no vi vng cui cng ca lp tip theo cng chnh l in p gia hai lp

c th t n 5000 n 6000V, nu in p lm vic ca dy qun l35kV.

Hnh 3-22: Dy qun ng nhiu lp dy ch nht

1. Cch in bng giy cp; 2. Vnh m ph bng cacton cch in;

3. Nn dc to rnh lm lnh

tng b mt lm lnh lp dy qun, thng ton b dy qun

c lm mt vi rnh dc trc gia cc lp. Chiu rng rnh thng vo

khong 1/100 chiu cao ca dy qun.

Dy qun hnh ng nhiu lp tit din dy ch nht thng c lmdy qun cao p CA cho cc my bin p dung lwongj t 630 n 40000

80000 kVA, in p 10 v 35 kV. Kiu dy qun ny ngy cng c s

dng rng ri v bn chc ca n khi ngn mch kh bo m do kt

cu dy qun gn cht. Mt khc n cn cu im na l lp y ca s

1 2 3


35/87



mch t tt hn cc dy qun khc. Rnh du lm lnh dc trc cng c

hiu qu truyn nhit tt hn cc loi dy qun c rnh du hng knh.

bn vin khi c qu in p cng tt hn cc loi dy qun kiu bnh

dy. Tuy nhin nhiu loi dy qun ny c nhc im cbn l b mtlm lnh b gim i nhiu so vi loi dy qun bnh dy.

Mt bin th mi ca dy qun hnh ng na l dy qun bng cc

tm nhm hay ng mng khng bc cch in hay c dng trong cc

my bin p n 1000kVA, in p HA di 1kV. Hnh 3-23 l mt v t

v dy qun hnh ng nhiu lp qun t cc tm nhm. Mi lp l mt

vng, chiu rng ca tm nhm bng chiu cao ca dy qun. Cch in

gia cc vng dy thng l mt hai lp giy tin, giy in thoi hay

giy cp cao hn tm dy qun 16 n 24 mm. Dy qun kiu ny c u

im l d qun nhng km chu lc c lc ngn mch. Mun c bn

c cao phi dng nhm

tm hay nhm c

cng cao nh A6,

hay A5. Tuy nhin, v

tm nhm hay ng

khng bc cch in

nn kiu dy qun ny

li c u im l tn

nhit tt hn so vi loi

dy qun kiu dy dn.

Lp y ca s mch tcng tt hn nhng

cng ngh qun dy s

3

2

1

Hnh 3-23: Dy qun hnh ng nhiu lp

lm bng cc tm nhm. 1- Tm nhm

mng; 2- Cch in lp bng giy; 3- m

u dy qun bng ba cch in


36/87



phc tp hn khi in p cng cao, v v l nhm hay ng mng nn kp

gia cc dy dn ra cng kh khn hn. Do kiu dy qun bng kim loi

tm ny thng dng cho cun CA vi in p khng qu 10kV.


37/87



b. Dy qun hnh xon

Dy qun gm mt hyn si dy ch nht chp li qun theo chiu

trc nhng ren c. Cc si dy chp thng xp theo hng knh v

nht thit phi c tit din v kch thc cc si nh nhau.Nu chp cc si thnh mt mch qun t trn xung di ta c kiu

dy qun hnh xon mch n (hnh 3-24a). Khi dng in ln qu phi

chp thnh hai mch qun, ta c kiu dy qun hnh xon mch kp

(hnh 3-24b)

Kiu dy qun ny c s vng t, tit din ln nn dng lm dy

qun HA. u im ca n l chu c lc chc tt, tn nhit tt. Nhng

nhc im l chiu di cc si dy ghp khng bng nhau nn in trkhcnhau, t thng tn khng u (cng xa tr st t thng tn cng nh)

nn in khng cng khcnhau. Mt khc dng in phn b khng u

lm tng tn hao ph. V vy cc si dy chp qun quanh tr cn c

hon v.

i vi dy qun hnh xon mch n theo chiu di dy qun ngi

ta thng hon v tp trung ba ch (hnh 3-25) gm:

- Hai hon v phn b tkhong v 2/3 chiu cao cun dy

- Mt hon v ton bgia on dy

Ti ch hon v cc si ghp chp phi i ch cho nhau (si ngoi

vo trong, si trong ra ngoi) v th cn phi c mt khong cc si

dy trnh nhau. Nh vy chiu cao dy qun tng thm mt rnh du v

mt bnh dy (hnh 3-26). Ni chung hon vc d dng v dy qun

chc chn th s si ghp chp khng nn qa 4.


38/87



Hnh 3-24: Dy qun hnh xon a) mch n (6 vng dy); b) Mch kp (4

vng dy).

i vi dy qun hnh xon mch kp ngi ta khng dng kiu

hon v tp trung ti 3 ch nh vy m hon v phn bu, ngha l c

bao nhiu si dy chp th c by nhiu ln hon v v phn b v tr hon

v trn ton chiu cao dy qun (hnh 3-27). V nhc hai mch chy song

song nhau nn ch hon v khng cn phi trnh nhau m c thi ln

v tr cc si dy d dng, do vic hon v khng nh hng ti chiu

cao dy qun (hnh 3-28)Dy qun hnh xon thch dng cho cc cun HA in p t 0,230

n 35kV vi cc my bin p c cng sut t 160 n 1000kVA.

c. Dy qun hnh ng nhiu lp

a)

b)

Tit dinmt vng


39/87



Dy dn dng l dy trn qun thnh hnh tr nhiu lp (ln hn 2),

ng tm. V s vng dy trong mt lp nhiu nn in p gia cc lp cao

do cch in ca dy dn khng m bo, do vy phi thm cch in

gia cc lp. Thng dng vi lp giy cp cch in l (i vi inp 10kV, dng 3 lp dy 3 x 0,12mm; i vi in p 6kV dng hai lp

dy 2 x 0,16 mm). phng phng in b mt, chiu cao cch in

gia cc lp phi cao hn chu cao ca dy qun t 20 n 50 mm (c hai

pha) v c qun thm nhng gbng ba cch in. Nu s lp nhiu

qu th vic tn nhit s kh khn do cn phi c rnh du dc gia.

khi lm dy qun HA trong, rnh du c thgia dy qun, cn khi lm

dy qun CA ngoi, rnh u thng b tr vo qung 1/3 n 1/5 chiudy cun dy tnh t trong ra ngoi.

Hnh 3-30: Cch in phn du ca dy qun hnh ng nhiu lp.

Dy qun c th dng mt si hay hai si chp li, nhng t khi dng

ti 4 si. Khi dng nhiu si cng khng cn hon v v tr ca n phn b

tng i u n.

Vic rt u dy phn p cng d dng m khng cn ct hn u dy.

Cch in lp

Mnc

h

n

bngv

i

Qu

n

b

ng

Tm

ltc

c

hin

bng

giyc

p

Vnh m bngba cch in


40/87



Kiu dy qun ny c in dung hn trc ln, do h s

q

d

C

C = (trong C l tng in dung dc v Cq l tng in dung

ngang ca dy qun) nh nn chng st tt. Mt khc kt cu n gin, qu

trnh ch to cng d. Nhc im l chu lc co gii km v tn nhit cphn kh khn.

Dy qun ny ch yu c p dng cho cc my bin p c S di

630kVA v thng lm cun cao p vi in p 6,10 hay 35kV.

Hnh 3-30: Cch in phn du ca dy qun hnh ng nhiu lp

Ngoi ra cn c mt kiu

gn ging kiu ng nhiu lp dy

trn na gi l dy qun hnh ng

nhiu lp phn on, y cng

lm bng dy trn. Vic phn

on thnh nhiu bnh dy nh

vy (thng l tng i mt) s

gim c in p gia cc lp

cnh nhau trong tng bnh dy,

nh c th ci thin vn cch in gia cc lp. Mt khc

vic lm ngui cun dy cng d

dng hn. Nhc im ca dy

17

18

1920 13

14

15

16

1211

10

9

56

7

8

43

2

1

24 25 32 33 40

2623 31 3934

2722 30 3835

2821 29 3736

a)

b)nh 3-33 : Bnh dy kp c cchin lp bng caton (a) v bnh dy

n c cch in bng giy cp (b)

a) b) c) d) )


41/87

qu

d.

bch

d

b

ch

nh

ng

qu

n tt nghi

n ny l

y qun

y

h theo iu cao s

ngang (

h nn

p li q

Dy q

c im

oi thn

n c b

p

ic qun

kiu xoy

ngi ta

ng xoyi dy. Gi

nh 3-34)

c gi l d

n nhn

Hn

un lin t

l qu tr

l, th b

nh ny t

y phc t

c lin t

ng dy ti

c phna tt c c

. Sut cu

y bnh li

khng n

3-34: D

c c u

h qun p

nh tip t

c ht p

T

p hn, do

c

t din ch

. Nh vc bnh d

n dy kh

n tc. C

n qu 44.

y qun xo

im l ch

c tp, v

eo phi

hi qun

it kmy

gi th

nht qu

chiu cahay vi

ng c m

th dng

y c lin

u c l

khi mt

un t n

m t tro

in p 400

nh cao h

n lin tc

o bnh dbnh dy

i hn no

mt si h

tc

c c hc

nh qun

oi vo t

ng ra ngo

VA ngm

n.

thnh nhi

y va bt c r

ni c

y nhiu s

tt. Nh

t trong

ong. Mu

i nh b

u

u

gh

c

i

g

ra

n

h


42/87



trc , sau khi y bnh phi gi ly u cui v u u ca n

ri dng tay np li cho nhng vng trong ra ngoi v vng ngoi vo

trong. Nh vy ta c mt i bnh khc (xem gio trnh cng ngh ch

to my bin p ca b mn thit bin).Yu cu i vi dy qun ny l:

- Cc u ra ca dy qun pha ngoi cng bnh dy, cch in

phin phc. Nh vy s bnh dy phi l s chn.

- Khi chp nhiu si phi hon v gia cc si dy. nhng vic hon

vy c th tin hnh gia hai bnh cnh nhau v khng lm thay i

chiu cao ca dy qun (hnh 3-35).

Dy qun xoy c lin tc ch yu dng lm cun CA v thngdng trong mt di cng sut rng cacs my bin p t 160 n

100000kVA, in p t 2 n 500kV v hn na. N cng c th dng lm

cun HA cho nhng my bin p c dng in t 10, 15 n 300A.

Ngoi nhng kiu dy qun cnh thng dng trn cn mt s kiu

dy qun khc nh dy qun khng cng hng, dy qun xen k dng

trong nhng my bin p chng st, my bin p hn in

Nh bit (chng 1) hin nay ngoi dy qun lm bng dy ng,

mt s nc cng nghip pht trin trn th gii cn dng dy nhm. Nh

vy s tit kim c ng mt kim loi chin lc rt quan trng, mt

khc nhm nh, r hn nn gim c trng lng my v mt phn gi

thnh vt liu dy qun. Tuy vy dng nhm vn cn c mt s kh khn

v k thut lm gim tnh nng ca my cn phi tip tc khc phc. Do

n cha c dng nhiu trong cc my bin p loi ln.

III.2. TNH TON DY QUN H P

1. Sc in ng ca mt vng dy l:

Uv = 4,44.f.Bt.Tt = 4,44 . 50 . 1,62 . 0,0265 = 9,53 (V).

2. S vng dy mt pha ca dy qun.


43/87



W1 = f1

V

U 230,9

U 9,53= = 25 (vng).

Vy in p thc t trn mi dy:

UV = f1

1

U 230,9

W 25= = 9,236 (V)

3. Cng tcm thc trong tr st.

Bt = V

t

U 9,2361,569T

4,44.f.T 4,44.50.0,0256= =

4. Mt dng in p trung bnh.

tb = 0,746 . Kf.4n V

12

P .U.10

S.d

tb = 0,746 . 0,93 .5500.9,236

400.0,276. 104 = 3,19 . 106 (A/m2).

5. Tit din sb vng dy ca dy qun h p.

T1 =

1f

tb

I

Trong : I1f= 577,35: l dng in pha nh mc.

Vy: T1 = 6577,35

3,19.10= 180,98 . 10-6 (m2).

6. i vi kt cu dy qun h p c in p nh hn 10kV ta dng mt

tm ng mng khng bc cch in, c chiu cao 38,5 (cm) qun 25 vng.

Ta kp tm ng mng

cng giy cch in, qun lin

tc 25 vng thnh hnh ng. Dy

qun kiu ny c u im l d

qun, chu c lc clc ngn


44/87



mch tt, lp y ca s mch

t cng tt hn.

7. Chiu dy ca di ng.

= 1T '

l

Trong : T1 = 180,98 (mm2).

l = 38,5 (cm) = 38,5 . 10 (mm)

Vy: =180,98

38,5.10= 0,47 (mm)

8. Chiu dy mt vng dy ca di ng.

h1 = + 0,3 = 0,47 + 0,3 = 0,77 (mm)

y ta coi chiu dy cch in l 0,3 (mm)

9. Chiu dy ca dy qun h p.

a1 = w1. H = 25 . 0,77 = 19,25 (mm)

10. ng knh trong ca dy qun h p.D1 = dm + 2 U01

Trong : dm = 20 (cm)

a01 = 0,5 (cm)

Vy: D1 = 20 + 2.0,5 = 21 (cm)

11. ng knh ngoi dy qun HA

'' '

1 1 1D D 2a= + = 21 + 2. 1,925 = 24,85 (cm)

12. Trng lng dy qun HA


45/87



' ''

' 51 1Cu1 1 1

D DG 28t. .W .T .10

2

+=

( )5Cu121 24,85

G 28.3. .25.180,98.10 87,13 Kg

2

+= =

13. B mt lm lnh dy qun h p

M1 = 3..( )' '' 41 1D D .l.10+

( ) ( )41M 3 .38,5.10 1,66 cm= 21 + 24,85 =

III.3. TNH TON DY QUN CAO P

1. Chn siu chnh in pVi kiu ny on dy iu chnh gia dy qun vi u

ni thun nh hnh v

Chn my bin p c 4 cp iu chnh:

+5%, +2,5%, -2,5%, -5%

2. S vng dy ca cun cao p vi in p nh mc

f 22mm 1

f1

U 22000W W 25. 2381

U 230,9= = = vng

3. S vng dy ca mt cp iu chnh in p.

Wcd = 0,025.W2m = 0,025.2381= 60 vng

4. S vng dy tng ng cc u phn p

Cp 23100V:

W2 = W2m + 2W2c = 2381 + 2.60 = 2501 vng

Cp 22500V:

W2 = W2m + W2c = 2381 + 60 = 2441 vng

A6

A4

A2

A

A5

A3

A7

A


46/87



Cp 22000V:

W2 = W2m = 2381 vng

Cp 20900V:

W2 = W2m - 2W2c = 2381 2.60 = 2261 vng

5. Sb chn mt dng in

( )' 22 tb 13,19 A/mm = = = M

6. Tit din sb vng dy

' 2f

2 '2

I

T =

Trong :

I2f= 6,062: dng in pha nh mc

Vy: ( )' 226,062

T 1,900 mm3,19

= =

7. Theo bng 38 vi S = 400KVA, If2 = 6,062 (A); T2 = 1,900(mm2)

U2 = 22KV. Ta chn kt cu dy qun hnh ng nhiu lp dy dn

trn

Theo bng 21: ta chn kch thc dy dn ghi nh sau

1,501 1,77

1,60

8. Tit din ton phn ca mi vng dy

T2 = nv2. Td2 = 1. 1,77 = 1,77 (mm2)

9. Mt dng in thc

( )22f22

I 6,0623,43 A/mm

T 1,77 = = =

10. S vng dy trong mt lp


47/87



3 3

2l1 '

v2 2

l .10 0,385.10W 1 240

1.1,60n d= = = (vng)

11. S lp dy qun

2l2

l2

W 2501n 10m466

W 240= = = 11 lp

12. in p lm vic gia hai lp k nhau

Ul2 = 2. Wl2. Uv = 2. 240. 9,236 = 4433,28 (V) ta cho chn loi cch

in giy cp X, chiu di cch in 7x0,12 (mm). u tha cch in l 22

(mm)

Vy: l2 = 7. 0,12 = -,84 (mm)

14. B tr dy qun cun cao p qun ln ng cch in v c rnh du

gia hai t lp.

15. Chiu di dy qun cao p

( ) ( ) ( )' ' 32 2 l2 22a d n m n m 2 a 10 m = + + + +

Trong : n + m = nl2 = 11 lp

00

.............0

0

00

.............0

0

00

.............0

0

00

.............0

0

00

.............0

0

00

.............0

0

00

.............0

0

00

.............0

0

00

.............0

0

00

.............0

0

00

.............0

0

4 Lp 7 Lp

240v

ng


48/87



D22 = 5 (mm) khong cch gia 2 t lp

Vy a2 = (1,6. 11 + 0,84. 9 + 5) = 0,0301 (m)

16. ng knh trong dy qun CA

D2 = D1 + 2 a12 = 0,2845 + 2. 0,018 = 0,2845(m)

17. ng knh ngoi dy qun CA

D22 = D2 + 2 a2 = 0,2845 + 2. 0,0301 = 0,3447(m)

18. Trng lng ng dy qun CA

' ''

2 2a12 2m 2

D DG 28.t. W .T

2

+=

( )3a120,28445 0,3447

G 28.3. 2881.1,77.10 111,5 Kg2

+= =

19. B mt lm lnh ca dy qun.

M2 = 1,56. K. (( )' ''2 2 2D D l+ (m2)

Vi K = 0,88

Vy M2 = 1,5. 3. 0,88. 3,14. (0,28445 + 0,3447). 0,495

M2 = 3,02 (m2)


49/87



CHNG IV: TNH TON CC THAM S NGN MCH

IV.1. TN HAO NGN MCH

1. Tn hao trong dy qun h p.

Nh ta bit PCu t l vi bnh phng ca mt dng in v vy

khi m bo cho PCu bng hng s nu tng th GCu phi gim. Nhng

khng t vn tng nhiu gim trng lng ng. V vy trng

lng ng khng gim c bao nhiu m tn hao ng s tng ln nhiu

ln (c th qu mc quy nh). ng thi dy qun s pht nng nhiu v

phi dng nhiu du lm ngui dy qun.

PCu1 = 2,4.2

1 . GCu1 = 2,4. (3,19)2. 87,13 = 2127,94 (W)

2. Tn hao ng ca dy qun cao p

- Tn hao ph trong dy qun cao p

8 2 4 2

f 2k 1 0,044.10 . .d .n= +

Trong :

3

2r

2

d m 1,50.240.10k .0, 95

l 0,385

= = = 0,888

Vy: Kf2 = 1 + 0,044.8 2 4 2 1210 .0,888 .1,5 .11 .10 = 1m0022

Vy: Tn hao ng ca dy qun cao p l

( )22Cu2 2 a12 f 2P 2,4. .G .K 2,4. 3,43 .111,5.1,0022= =

PCu2 = 3155,21 (W)

3. Tn hao trong dy dn ra

Pr= 2,4. 2. Gr


50/87



:Mt dng in trong dy dn ra, chnh l mt dng in ca

dy qun c dy dn ra.

- Khi dy qun cao p ni ta c

lr2 = 14. l = 14. 0,385 = 5,39 (m)

- Khi dy qun h p ni Y ta c

lr1 = 7,5. l = 7,5. 0,385 = 2,887 (m)

* Vy trng lng ca dy dn ra chnh l:

- Dy qun cao p

Gr2 = lr2 Tr2. Cu2 = 5,39. 1,77. 8900.10-6

= 0,085 (Kg)

Pr2 = 2,4. 22 r 2.G = 2,4. (3,19)2. 4,634 = 113,17 (W)

4. Tn hao trong vch thng du v cc chi tit kt cu khc

Pt = 10. K. S (W)

Trong : K = 0,015 (theo 40a Phan T Th)

S = 400KVA

Vy Pt = 10. 400. 0,015 = 60 (W)

5. Tng tn hao ng ca dy qun cao p v h p

PCu = PCu1 + PCu2 + Pr1 + Pr2 (W)

PCu = 1217,94 + 3155,21 + 113,17 + 2,4 = 5398,72 (W)

6. Tng tn hao ngn mch ca my bin p

Pn = PCu + Pt = 5398,72 + 60 = 5458,72 (W)

7. Sai s nh hn so vi tiu chun.

n ntt

n

P P 5500 5458, 72.100 .100

P 5500

= = 0,75%


51/87


52/87



d 1 2 =2

M: d12 =' ''

1 2D D 0, 21 0,3447

2 2

+ += =0,277 (m)

Vy:

3,14.0,277

0,385 = = 2,21

ar: chiu rng qui i ca rnh du

1 2r 12

a a 0,0192 0,0301a a 0,015

3 30,0314(m)

+ += + = +

=

Ly Kr= 0,93; Uv = 9,3 (V)

Vy:

3

nx

7,9.50.133,3.2,21.0,0314.0,93U 10

9,3

= = 3,928%

3. in p ngn mch ton phn l

2 2 2 2

n nr nxU U U 1,364 3,928= + = + = 4,158%

4. in p ngn mch sai s ln hn so vi tiu chun.

n ntt

n

U U 4,0 4,158.100 .100

U 4

= = 3,59%

IV.3. TNH LC CBN CA DY QUN.

Khi my bin p b s c ngn mch th dng in ngn mch s rt

ln. Nhng vn nhit i vi my bin p ko quan trng lm, v nu b

tr thit b bo v tt, my ngt tng s ct phn s c ra khi li in,

do vn cn li ch yu l lc chc gy nn tc dng nguy hm i


53/87



vi dy qun my bin p. Bi vy m bo cho my bin p lm vic

an ton, khi thit k phi xt n nhng lc co hc tc dng ln dy qun

khi ngn mch xem bn ca dy qun my bin p c hay khng. Do

vy Phi xc nh tr s cc i c dng in ngn mch

Xc nh lc chc gia cc dy qun

Tnh ng sut c ca m cch in gia cc dy qun v bn

thn dy qun.

1. Dng in ngn mch xc lp

mn

n

II .100

U=

Ta coi ngun cung cp c cng sut v cng ln

Im l dng in nh mc ca p phn p ca dy qun (A)

Vy:

n

577,35.100I 4,158= = 13885,28(A)

2. Dng in ngn mch cc i tc thi

rr

nx

U

U

max ni 2 .I 1 e

= +

= 2.13885,28. 1 e.1,364

3,928

+

( )1,09maxi 2.13885, 28. 1 e= + 19637,1 (A)

3. Lc hng knh

Khi hai dy qun cng chiu cao v cc vng dy phn bu trn

ton chiu cao. T trng tn gm c hai thnh phn dc trc vi t cm B


54/87



v thnh phn ngang trc vi t cm B, ng vi mi t trng tn th s c

lc tc dng tng ng.

- T trng tn B tc dng vi dng in gy nn lc hng knh Fr,

c th tnh nh sau:

Fr= 0,628(imaxW)2. . Kr. 10

-6 (N)

Trong :

W = 25 S vng dy ca dy qun h p

Kr= 0,93 imax = 19637,1(A)

= 2,21

Vy:

Fr= 0,628 (19637,1. 25)2. 2,21. 0,93.10-6 = 310982,84(N)

4. ng sut do lc hng knh gy nn

lc Fk tc dng ln cun dy ngoi (cun cao p) nn ng sut cngtrong cun CA s l:

6

nrnr

2 2

F .10

T .W

=

l

B'

B


55/87



M: rnrF

F2

=

Trong : T2 = 1,77 (mm2)

W2 = 2501 vng

Vy:

( )

rn r

2 2

2

nr

F 310982,84

2 T W 2.3,14.1m77.2501

11,18 MN/ m

= =

=

ng sut nr = 11,18 (MN/m2) nh hn ng sut cho php i vi

dy qun ng l: nr 30 (MN/m2).

5. Lc hng trc ch c mt thnh phn.

T trng tn ngang trc tc dng vi dng in sinh ra lc hng trc:

Ft

' rt r

aF F .

2t=

Trong : ar= 0,0314 (m)

l = 0,385 (m)

Fr= 310982,84 (N)

'

t

0,0314F 310982,84.

2.0,385= = 12681,63 (N)

Do cun dy phn bu theo chiu di dy qun nn lc hng

trc Ft = 0

Ft l lc dc th hai sinh ra do s phn b khng u theo chiu cao

dy qun.


56/87



Do vy lc p cc i gia chiu cao dy qun cao p: Fn2 = Ft =

12681,63 (N).

Cn li lc y ln ngang gng: Fg = 0.

6. ng sut gia cc vng dy cao p

6n2

n ' ''

1 22

F 12681,63.10

0,21 0,3447D D3,14. .0,0301. a

22

= =++

= 0,484

MN/m2

Trong :

a2 = 0,0301 (m)

D1 = 21 (cm) = 0,21 (m)

D2 = 0,3447 (m)

Nh vy n = 0,484 NM/m2t tiu chun cho php[n] 18 n 20

MN/m2.

1

l=38,5

(m)

2

+

Ft F

t = 0 Fg = 0

Fn = Ft

Fg = 0

Ft F

t = 0 Fg = 0

Fn = Ft

Fg = 0

Dy qun 1 Dy qun 2


57/87



CHNG V: TNH TON CUI CNG V H THNG

MCH T

Sau khi xc nh kch thc v trng lng ca dy qun sao cho v

tnh nng Un,Pnt yu cu ta s tin hnh tnh ton cui cng v mch t

xc nh cc kch thc c th ca bc thang ca tr st. Sau tnh

dng khng ti, tn hao khng ti v hiu sut ca my bin p.

V.1. XC NH CC KCH THC C TH CA LI ST.

Ta chn li thp 3 pha, 3 tr phng, cc l thp ghp xen k bng tn

cn lnh c 4 u ni nghing 4 gc. p tr dng bng vi thu tinh

khng c tm st p tr. Gng p bng x p gng. Tit din tr c 7 bc,

gng c 5 bc.

Kch thc cc tp l thp nh hnh v

Theo bng 41b ta c kch thc ca cc tp l thp nh sau:

Thttp Tr (mm) Gng trong na tit din tr - mm

1 190x22 190x22

2 175x26 175x26

3 155x15 155x15

4 135x11 135x11

5 120x6 120x18

6 105x5 -

7 75x7 -


58/87



1. Tng chiu dy cc l thp ca tit din tr (hoc gng)

2(22 = 26 + 15 + 11 + 6 + 5 + 7) = 184 (mm) = 0,184 (m)

2. Ton b tit din bc thang ca tr

Theo 42b ta c: Ttb = 288,4 (cm2) = 0,02884 (m2)

3. Tit din bc thang ca gng (theo 42b)

Tbg = 296,2 (cm2) = 0,02962 (m2)

4. Th tch mt gc ca mch t(theo 42b)

V0 = 4811 (cm3) = 0,004811 (m3)

5. Tit din hu hiu (thun st) ca tr

Tt = Kd . Tbt = 0,92. 0,02884 = 0,02653 (m2)

6. Th tch thun st mt gc ca mch t

V0 = Kd. V0 = 0,92. 0,008411 = 0,004426 (m3)

7. Tit din hu hiu (thun st) ca gng

Tg = Kd. Tbg = 0,92. 0,02962 = 0,02725 (m2)

8. S l thp trong tng bc ca tr v gng

t d

3

t

b .Kn

.1 0

=

Trong :

t l chiu dy ca mi l tn silic (mm)

Kd = 0,92 l h sin y ca tp l thp

- Bc 1:

1 3

0,184.0,92n 7,69 8 l

22.10= =


59/87



- Bc 2:

2 3

0,184.0,92n 6,53 7 l

26.10= =

- Bc 3:

3 3

0,184.0,92n 11,33 12 l

15.10= =

- Bc 4:

4 3

0,184.0,92n 15,45 16 l

11.10= =

- Bc 5:

5 3

0,184.0,92n 28,33 29 l

6.10= =

- Bc 6:

6 3

0,184.0,92n 34 l

5.10= =

- Bc 7:

7 30,184.0,92n 25 l7.10=

9. Chiu cao tr

lt = l + l0 + l

0

Trong : l0, l

0 l khong cch t dy qun n gng trn v gng

di. V khng c vnh st p dy qun ln: l0 = l

0.

Vy: lt = l + 2l0 = 0,385 + 2. 0,045 = 0,475 (m)

10. Khong cch gia hai tm tr

C = D2 + a22 = 0,3447 + 0,018 = 0,3627 (m)

11. Trng lng st mt gc theo (5 10)


60/87



G0 = Kd. V0. = 0,004426. 7650 = 33,86 (kg)

12. Trng lng st gng theo (5 14)

Gg = Gg + g

g

Trong :

+ Gg = 2 (t - 1) C.Tg. = 2. (3 1). 0,3627. 0,02725. 7650

= 302,43 (kg)

+ Gg = 2 G0 = 2. 33,86 = 67,72 (Kg)

Vy Gg = 302,43 + 67,72 = 370,15 (Kg)

13. Trng lng st tr (theo 5 15)

Gt = Gt + G

t

Trong :

Gt = t

( ) ( )

3 3

t 1g 0T .a .Y.10 G 3 0,02653.190.7650.10 33,86 =

Gt = 14,1 (Kg)

Vy Gt = 289,21 + 14,1 = 303,31 (Kg)

14. Trng lng st ton b ca tr v gng

GFe = Gt + Gg = 303,31 + 370l15 = 673,46 (Kg)

V.2. TNH TN HAO KHNG TI

Khi cp in p xoay chiu nh mc c tn snh mc vo cun

dy scp v cun dy khc hmch gi l ch khng ti.


61/87



Tn hao khng ti ca my bin p gm c: tn hao trong l thp

silic, tn hao ng trong dy qun do dng khng ti sinh ra, tn hao do

dng in r trong cc cht cch in. Tn hao ng lc khng ti dy

qun rt nh nn c th b qua.Ta xem tn hao khng ti gm hai thnh phn.

+ Tn hao trong tr st

+ Tn hao trong mch t

1. Tr s tcm trong tr

Li thp lm bng tn cn lnh m hu 3405, dy 0,30 mm do tr

s t cm trong tr st v trong gng l:

( )vtt

U 9,3B 1,579 T 4,44.f.T 44,4.50.0,02653

= = =

( )vgg

U 9,3B 1,537 T

4,44.f.T 44,4.50.0,02725= = =

Tr s t cm trong mi ni nghing.

tn

BB 1,116

2= = T

Tit din khe hkhng kh mi ni thng bng tit din tr hoc

gng

Tit din khe hkhng kh mi ni nghing bng

Tn = ( )2t2.T 2.0,02653 0,03752 m= =

2. Theo bng 45 vi tn 3405, dy 0,30 mm ta tra c cc sut tn hao

tng ng

Vi: Bt = 1,579 T; Pt = 1,093 W/kg; PK= 948 W/m2

Bg = 1,537 T; Pg = 1,021 W/kg; PK= 892 W/m2

Bn = 1,116 T; Pkn = 430 W/ m2


62/87



3. Theo 5-22, mc 5.2 i vi mch tphng ni nghing 4 gc, tr

gia ni thng, li st khng t l, tn c sau khi ct, c khbavia

ta tm c.

KPC = 1,05: h s kn tn hao do ct dp l tn thnh tm

KPg = 1,00: h s kn tn thao do gp mp hoc kh bavia

KPe = 1,02: h s tn hao do p trai

KPt = 1,02: h s tn hao do tho lp gng trn

KP0 = 9,6: h s gia tng tn hao cng sut gc ni

KPf= 1,13: h s tn hao ph

4. Tn hao khng ti

( )

( )

'

0 pg pt pe p0 t t g g d 0

t g ' ''

0 n p0 T p0 K K K

P K .K .K .K P G P G K .G

P PG K K K .K P n T

2

= + +

+ + +

Trong : G0 = 33,86 (kg)- Trng lng st 1 gc mch t

Kp0 = ' ''n p0 t p0K .K K .K 4.1,36 2.2,08 9,6+ = + =

Vy:

( )

0

1,093.303,31 1 1,021 302,43 4.33,86

1,093 1,021P 1,00.1,02.1,02.1,05.1,00. .33,86.9,6 4.0,03752.430

2

1.0,0265.984 2.0,0275.892

+ +

+ = + + + +

P0 = 1074,35 (W)

Vy sai s ln hn so vi tiu chun l;

1074,35 1000.100 7,43%

1000

=


63/87



Theo tiu chun ngi ta quy nh tn hao khng ti tnh ton khng

c vt qu +7,5% tr s tn hao tiu chun. Vy P0 =1074,35 (W) l

ph hp.

5. Sut tho

Theo bng 50 ta tm c sut t ho

- Vi Bt = 1,579 T th qt = 1,416 (VA/kg); qt.t = 17400 (VA/m2)

Bg = 1,537 T th qg = 1,292 (VA/kg); qk.g = 15240 (VA/m2)

Bkn = 1,116 T th qkn = 2500 (VA/m2)

6. i vi kt cu li thp v cng ngh ch to mch tc l tn sau

khi ct dp ta c cc h s sau:

Kig = 1,0; Kit = 1,02; Kic = 1,18; Kie = 1,04; Kib = 1,0; Kir= 1,18;

Kio = 42,45.

Vy:

( ) t g'ib ic t t g g d 0 ir ig 00 ig ie it

K K K

q qK .K q .G q G K G K K G

2Q K K K

q n T

+ +

=

+

Trong : Kig = Kn.Ki0 + Kt. K

i0 = 4.4,3 + 2. 11 = 39,2

( )0

1,416 1,2921,0.1,18 1,416.303,31 1,292 302,43 4.33,86 .1,18.39,2.33,86

Q .1,0.1,04.1,022

4.2500.0,03752 1,0.17400.0,0265 2.15240.0,02752

+ + + = + +

Q0 = 5526,48 (VA)

7. Thnh phn phn khng ca dng in khng ti

oox

Q 5526,48i

10.S 10.400= = = 1,382 %

8. Thnh phn tc dng ca dng in khng ti

0or

P 1074,35i

10.S 10.400= = = 0,268%


64/87



9. Dng in khng ti ton phn

2 2 2 2

o or oxi i i 0,268 1,382= + = + =1,408%

10. Sai s ca i0

so vi tiu chun

1,408 1,5.100

1,5

= -6,13%

V i0 nm trong gii hn cho php [i0%] = 15%

11. Tm s dng khng ti ca dy qun CA tng ng

( )0r0r mi 0,268

i I . 6,062. 0,0162 A

100 100

= = =

( )0x0x mi 1,382

i I . 6,062. 0,084 A100 100

= = =

( )00 mi 1,408

i I . 6,062. 0,0853 A100 100

= = =

12. Hiu sut ca my bin p.

Hiu sut ca my bin p lc ti nh mc s l:

0 n

m 0 n

P P% 1 100

P P P

+ = + +

Trong : Pm l cng sut tc dng ca my bin p (VA)

3

1074,35 5458,72% 1 .100 98,39%

400.10 1074,35 5458,72

+ = = + +


65/87



CHNG VI: TNH TON NHIT CA MY BIN P

Tnh ton nhit l tnh ton v nhit trng thi xc lp ngha l khi

my bin p lm vic ti nh mc, trng thi xc lp ny ton b nhit

lng do dy qun v li st pht ra xung u khuch tn ra xung quanh.

Ni chung tnh ton nhit ca my bin p gm cc phn sau y:

Tnh chn nhit chnh qua tng phn

Chn kch thc thng du bo m to nhit tt ngha l lm sao

nhit dy qun li st du khng qu mc quy nh. Kim tra nhit chnh ca dy qun, li st v du i vi

khng kh.

1. Nhit chnh trong lng dy qun hay li st vi mt ngoi ca n

a.i vi dy qun h p

410 1

c1

q .10

=

Trong :

1 l chiu dy cch in 1 pha (m)

1 = 0,4mm = 0,0004 (m)

c1 l sut dn nhit ca lp cch in ca dy dn, tra bng

54: cd1 = 0,27 (W/m.0C)

q1 l mt dng nhit trn b mt dy qun.

q1 = 1350,38 W/m2

Vy: 01 101c1

q . 1350,38.0,00042 C

0,27

= =


66/87



Nhit chnh trung bnh

0

01tb 01

21,33 C

3 = =

b.i vi dy qun cao p khng c rnh du ngang

( )2

0

02 1 2

tb

PaC

8 = =

Trong a= 0,0301 (m): Chiu dy ca dy qun.

( )

2 28

1

d

P 1,68. .10d' d'

= + (W/m3

)

Vi: d = 1,5.10-3 (m)

d = 1,6.10-3 (m)

= 3,43.106 (A/m2)

1 = 0,84.10-3 (m): Chiu dy cch in

( ) ( )

( )( )

2 26 3

3

3 3

3,42.10 . 1,5.10P 1,68. 113912,12 W / m

1,6 0,84 .10 .1,6.10

= =

+

( )1tb

1 1

d';

d'

1 + = +

(W/m. 0C)

Vi 1 = 0,27 (W/m0C): Sut dn nhit ca cch in gia cc lp tra

theo bng 54 Phan T Th.

c

0,7.

=

: Sut dn nhit bnh qun qui c ca dy qun.

( ) 23

1,6 1,5 .10d' d0,0666

d 1,5.10

= = =


67/87



0,27

1,5010,7. 0,666

= =

( )

( )

3

0

tb3 3

1,501.0,27 1,6 0,84 .100,583 W / m C

1,501.0,84.10 0,27.1,6.10

+ = =

+

Vy:

2 20

02

tb

Pa 113912,19.0,030122,12 C

8 8.0,583 = = =

Trn thc t: i vi dy trn ngi ta thng khng quan tm ti

im nhit ln nht m quan tm ch yu ti nhit chnh trung bnh.

0

02tb 02

2 222,12 14,74 C

3 3 = = =

2. Nhit chnh gia mt ngoi dy qun i vi du 0d

a.i vi dy qun h p

0,6

0d1 1K.q =

Trong : K = 0,285

q1 : Mt dng nhit ca dy qun (W/m2)

q1 = 1350,38 (W/m2)

0,6: Ch s ly tha kinh nghim

Vy 0d1 = 0,285. 1350,380,6 = 21,530C

b.i vi dy qun cao p

0,6

0d2 2K.q = = 0,285. 1045,560,6 = 18,460C

3. Nhit chnh trung bnh ca dy qun vi du

0

0d1tb 0b1 0d1 1,33 21,53 22,86 C = + = + =


68/87


69/87



4l h tkq K.K=

Trong : K = 2,5 l h s kn nh hng ca chiu cao thng v

p sut kh quyn.

Kh = 1,4 l h s kn qh ca hnh dng ca thng (bng 56)

t.k= 22,80C

Vy qdl = 2,5.1,4. 4 22,8 = 7,64 (W/m20C)

- Mt b phn truyn ra theo phng php bc x

44bx tkq 2,8. 2,8. 22,8= = = 6,11 (W/m

0C)

7. Tiu chun v nhit chnh v yu cu nhit i ho i vi my

bin p.

nhng vng kh hu nhit i m, ly nhit trung bnh cc i

hng nm ca mi trng xung quanh l +400C vi m tng i l

905% (khi nhit xung quanh l +350C), khi nhit chnh ca cc

b phn ca my bin p so vi nhit ca mi trng xung quanh khng

c vt qu gi tr ghi di y.

Cc b phn trong my

bin p

Nhit chnh

cao nht (0C)Phng php o

Dy qun 65 in tr

B mt li st v cc chi tit

kt cu

70 Nhit k

Lp du mt trn cng 60 Nhit k

Ngoi ra bnh gin du phi cht ht m silicagen ht ht kh

m, tng tui th cho du, cho cch in. Nn thit k mt loi ng sc bit

ring cho vng nhit i v b phn chng st cn phi c tng cng.


70/87




71/87



CHNG VII: TNH TON NHIT CA THNG DU

VII.1. TNH TON NHIT CA THNG DU

Thng du ng thi l v my ca my bin p, trn c t cc

chi tit my rt quan trng nh s ra ca cc dy qun cao p v h p, ng

phng n, bnh gin du v vy thng du ngoi yu cu phi tn nhit

tt cn phi bo m cc tnh nng vin (nh bo m khong cch cho

php gia dy qun vi vch thng), c bn chc m bo, ch to li

n gin v c kh nng rt gn c kch thc bn ngoi.

1. Chn loi thng

Theo bng 57 ta chn loi thng vch kiu cnh sng

2. Chn cc kch thc ti thiu bn trong ca thng

i vi my bin p c cp in p dy qun cao p n 110KV, dy

dn ra cun cao p t gia gng v vch thng th A, B c tnh nh sau:

a. Chiu rng ti thiu ca thng.

B = D2 + 0,8 (m)

Trong : D2 = 0,3447 (m)

Vy: B = 0,3447 + 0,8 = 1,1447 (m)

b. Chiu di ti thiu ca thng

A 2C + D2 + 0,8 (m)

Trong : C = 0,3672 l khong cch hai tm tr

A = 2. 0,3627 + 0,3447 + 0,8 = 1,87 (m)

c. Chiu cao ca thng gm 2 phn

H = H + H2 (m)


72/87



+ H1 l khong cch ty thng n ht chiu cao li st

H1 = bt + hg + n.10-3

Trong : n = 2 (mm) l chiu dy tm lt di gng

lt = 0,475 (m): chiu cao tr

bg

g

g

Th

b= Tbg = 0,02962 (m

2)

bg = 2(0,022 + 0,026 + 0,015 + 0,011 + 0,018)

bg = 0,18 (m): Chiu rng ca gng

( )g 0,02962h 0,16 m0,184

= =

Vy: H1 = 0,475 + 2. 0,16 + 0,03 = 0,825 (m)

+ H2: khong cch ti thiu t gng n vch thng

H2 = 1,5. 300 = 450 mm = 0,45 (m)

Vy H = 0,825 + 0,45 = 1,275 (m)

3. Sb tnh din tch b mt bc x ca thng du

i vi thng c y ch nht

Mbx = Mcn. K = 2 (A + B). H. K (m2)

Trong : Mcn = 2 (A + B). H l din tch mt thng phng y ch

nht.

K = 1,4: h s kn nh hng ca hnh dng mt thng (bng 59)

Vy Mbx = 2.(1,87 + 1,1447). 1,275. 1,4 = 10,76 (m2)

4. Din tch b mt i lu ca thng du

Cn c vo tn hao, vo nhit chnh gia vch thng v mt

trng xung quanh ta xc nh c


73/87



( )' 2l bx1,25t.k

1,05 P M 1,25M ; m

2,5.=

P = Pn + P0 = 5458,72 + 1074,35 = 6533,07 (W)

t.k= 22,80C

Vy:

( )( )' 2l 1,25

1,05.6533,07M 1,12.10,76 43,01 m

2,5. 22,8= =

VII.2. THIT K THNG DU

Cn c vo b mt bc x v i lu ca thng va tnh sbtrn thit k thng du, thng du c chiu rng 1,147 (m), chiu di 1,87

(m), chiu cao 1,275 (m), hnh dng mt thng c b tn nhit kiu vch

sng. Kiu ny gn y c dng rt ph bin cho cc my cng sut t

100 n 630 KVA v loi thng ny ch to n gin, cnh sng c th un

trn u hay ghp hai mp bng k thut hn tip xc ln. C th dng bnh

gin du hoc khng. Khi khng c bnh gin du th du c th gin nt

do trong cnh sng nhn hi c cnh, thng hon ton kn.

Chn b tn nhit c vch dng cnh sng u trn.

b

c

a t


74/87



1. B mt bc x ca vch thng cnh sng

Mbx.s = [[2 (A + B) + (B + 2b.10-3]]. Hs

Trong ; b = 300mm l chiu su ln nht ca cnh sng

Hs = H 0,1 = 1,275 0,1 - = 1,175 (m): Chiu cao ca cnh

A = 1,8 (m); B = 1,1447(m)

Vy:

Mbx.s = [2. (2,87 1,1447) + 3,14 (1,1447 + 2. 300.10-3)Hs

Mbx.s = 6,928. 1,174 = 8,14 (m2)

2. B mt i lu ca thng cnh sng

Ml.s = m. ls. Ks. Hs

Trong : Ks l h s tnh n mc i lu kh khn ca khng

kh gia cc cnh sng

Ks =

2

1 190

b

a =

Chn C = 20 mm: Chiu rng ti thiu ca khe du ma

c= 2,5 a =

2,5C

A = 50 (mm) = 0,05 (m): chiu rng khe khng kh

0,3

60,05

= =

2

s

6K 1 0,81

190= =


75/87



+ t = (a + b + 2 ): chiu di 1 bc sng

Trong : = 1,0mm = 0,001 (m) (chiu dy tn)

t = 0,05 + 0,02 + 2. 0,001 = 0,072 (m)

+ Chiu di khai trin 1 cnh sng

( )sc c

l 2 b t c2 2

= + +

( )s0,02 0,02

l 2 0,3 0,072 0,02 3,14.2 2

= + +

ls = 0,6634 (m)+ S lng cnh sng

( )2 A B Bm

t

+ =

( )2 1,87 1,447 3,14.1,1447m 71

0,072

+= = ci

Vy Ml.s = 71. 0,6634. 0,81. 1,175 = 44,83 (m2)

3. B mt bc x ton phn ca thng cnh sng

Mbx = Mbx.s + Mt + 0,5Mn

Trong : Mt = 0,1t.m = 0,1. 0,072. 71 = 0,5112 (m2)

Mt l b mt phn vch trn ca thng khng c cnh sng

Mn l b mt np thng

( )nn n n nb

M b l b4

= + : B mt hnh hc ca np thng

Vi: bn = B + 2 bv = 1,1447 + 2. 0,1 = 1,35 (m)

ln = A + 2bv = 1,87 + 2. 0,1 = 2,08 (m)


76/87



bn: Chiu rng np thng

ln: Chiu di np thng

bv = 0,1 (m): Chiu rng vnh np thng

( )n3,14.1,35

M 1,35 2,07 1,354

= + = 2,032 (m2)

H s 0,5 kn s che khut b mt np thng do cc chi tit my

t trn np.

Vy Mbx = 8,14 + 0,5112 + 0,5. 2,032 = 9,67 (m2)

4. B mt i lu ton phn ca thng cnh sng

Ml = Ml.s + Mt + 0,5 Mn

Ml = 44,83 + 0,5112 + 0,5. 2,032 = 46,36 (m2

VII.3. TNH TON CUI CNG NHIT CHNH CA DY QUN V

DU CA MY BIN P.

Sau khi thit kc nhng kch thc c bn ca thng du,

tnh ton Mbx, Ml ca thng cn phi kim tra li nhit chnh thc t

ca dy qun v du i vi khng kh.

1. Nhit chnh ca thng i vi khng kh.

( )0,8

0 n

t.K

bx l

2 p P

2,8M 2,5M

+ = +

Trong : K = 1,05 v tnh ton 1 my bin p

( )0,8

0

t. K

1,05 1044,35 5458,7222,85 C

2,8.9,67 2,5.46,36 + = = +


77/87



2. Nhit chnh ca du st vch thng so vi thng

( )0,6

0 n

d.t 1

l

K p PK .0,165

M

+ =

Trong :

K1 = 1: khi lm lnh bng du t nhin

K = 1,05

P0 = 100W, Pn = 5458,72 (W)

Ml = 7,11

( ) 0,6 0d.t

1,05 1074,35 5458,720,165 3,3 C

46,36.46,36

+ = =

3. Nhit chnh ca du so vi khng kh.

' 0

d.k d.t t .k 3,3 22,85 26,15 C = + = + =

4. Nhit chnh ca lp du trn so vi khng kh phi t tiu

chun.d.k= (dt + t.k) = 1,2. 26,15 = 31,38

0C

Vy d.k= 31,38 500C (tho mn)

5. Nhit chnh ca dy qun vi khng kh phi t tiu chun.

0.k= 0dtb + d.k 600C

+ i vi dy qun h p

01.k= 0d1tb + d.k = 22,86 + 26,15 = 49,01 600C

+ i vi dy qun cao p

02.k= 0d2tb + d.k = 32,2 + 26,15 = 58,35 600C


78/87



CHNG VIII: XC NH SB TRNG LNG

RUT MY, V MY, DU V BNH GIN DU

Rut my, v my, du v bnh gin du ca my bin p ch c th

tin hnh c sau khi hon thin thit ky cc chi tit ca my

bin p. Nhng vi nhng tnh ton trn cng c th xc nh sbc

trng lng ca my, rt cn thit cho vic tnh ton kinh t khi cn phi

nh gi cc phn ng thit k.

1. Trng lng rut my (phn tc dng) tc l ton b li st c cc dy

qun v dy dn ra (t np my) c th xc nh gn ng.

Gr= 1,2 (Gdq + G1) ; (Kg)

Trong : Gdq l trng lng ton b dy qun v dy dn ra

Gdq =GCu1 + GCu2 + Gr1 + Gr2

Gdq = 87,13 + 111,5 + 4,634 + 0,085 = 203,35 (kg)

G1: Trng lng ca li stG1 = GT + Gg = 303,3 + 370,15 = 673, 5(Kg)

Ta c h s trng lng my tng thm do cch in v kt cu khc

bng 1,2

Vy Gr= 1,2 (203,35 + 673,5) = 1052,3 (Kg)

2. Trng lng du

Gd = 1,05 [(vt vr) + Vcs]. du

Trong : vr l th tch rut my

( )2rrr

Gv ; m=


79/87



Vi rCu = 5500 Kg/m3: T trng trung bnh ca rut my

( )3r1052,3

v 0,19135 m5500

= = = 191,35(dm3).

Vt: th tch bn trong ca thng du phng

V l y hnh ch nht n

vt = A. B. H = 1,87. 1,1447. 1,274 = 2,73 (m3)

hay vt 2730 (dm3)

( )2

cs s

CV 71 C b c H

8

= +

( )2

cs

0,02v 71 0,02 0,3 0,02 1,175

8

= +

vvs = 0,48 (m3)

Vy trng lng ton b ca du

Gd 1,05[2,73 0,19135 + 0,48].0,9.103

Gd = 456,14 (Kg)

3. Bnh gin du.

Theo quy nh my c dung lng 100KVA trln u c bnh gin

du. Bnh gin du thng dng hp hn chiu dy 1 3mm v c t

nm ngay trn np thng.

i vi loi thng phng:

Chiu di bnh gin du: lgd = 1,1447 (m)

4. ng knh bnh gin du

Vg = (7 10%) th tch du trong thng

Vg = 0,7. Vd


80/87



M Vd = Vt - Vr= 2,73 0,19135 = 2,538 (m3)

Vy ng knh bnh gin du l:

( )g

gd

4.V 4.0,177

d 0,1969 m.l 3,14.1,1447= = =

5. Khi lng bnh gin du

Sxqgd = 2. . R. lgd = 2. .0,9845. 1,1447 = 0,7 (m2)

Chn thng gin du c b dy 1,5 (mm)

Vgd = Sxqgd. 0,0015 = 0,00105 (m3)

Vy trng lng bnh gin du

Gd = Vgd. Fe vi Fe = 7850 Kg/m3

Gd = 0,00105. 7850 = 8,243 (Kg)


81/87



PHN CHUYN : TM HIU CNG NGH MI CA

CNG TY LIN DOANH CH TO BIN TH ABB

Trong nhng nm gn y cng ty lin doanh ch to my bin p

ABB a vo Vit Nam mt s cng ngh mi p dng cho my bin

p phn phi v t c mt s hiu qung k. Sau y ti xin gii

thiu v phn tch mt su nhc im ca chng.

1. MCH T

Cng ty ABB c trang b my ct tn tng theo chng trnh

c kh nng ct cho gc cc l tn vi cc gc ct tu . Kt cu ghp cc

l tn thnh li cc gc c ghp mi ni nghin nn gim c tn hao

khng ti.

Xt trng hp my khng ti ta c:

- Theo cng thc (5-19) ca ti liu Thit k my bin p in lc

ta c:

Po = Kgp. Ktp. Kcp. Ktp [Pt. Gt + Pg (Gg Kd. Gg) +Pr Pg+

. Gg. (Kn .

Kpg)

+ Pk. k. Tk]

= Kgp. P0.

Vi Kgpc xc nh theo bng 43 Thit k my bin p in

lc th:

Vi mi ni thng: Kgp = 1,9.

Vi mi ni nghing: Kgp = 1,28.

Tng t nh vy vi cng sut t ho khng ti Q0 ta c:


82/87



Q0 = Kgi. Q0

p ng tin vic sn xut theo n t hng ca khch hng.

Tn nh my c nhp t mt s nc t bn pht trin nh Nht, Thu

in hoc M c chiu dy 0,27 thuc loi tn cn ngui bt ng hng.

Vic thit k tit din ca tr khng phi l hnh trn nh thng

thng cc nc khc vn lm m l hnh Ovan, rt t bc. u im ca

loi mch t kiu ny l n gin do t c l tn v khng phc tp khi

ghp thnh li, to c cc rnh du ln trong li. Nhc im ca loi

ny l h s lp y thp, vic tn dng khng gian trong my khng trit

nn chi ph dy ng s tng ln. Theo kiu ny rt c li trong cng

ngh sn xut my bin p phn phi theo hnh thc t hng v nng sut

cao, thi gian ch to ngn.

Vic ghp mch ty cng c im khc vi li ghp kinh in

trc y. Mch ty c ghp ng (trc y vn thng ghp

trng thi nm ngang) nn khng phi ghp trc gng trn v khng th

nhm ln v nu ghp ln l tn s khng vo c. Chnh v phng php

ghp ny m nng sut ghp s tng ln do bc thao tc ghp gng trnv tho ra ghp li khi lp cun dy. Ngoi vic tng nng sut ra kiu ghp

ny cng hn chc tn hao khng ti do s v, p g, tho ra lp vo

lm bin tnh v try xc sn cch in ca cc l tn silic.

Li c ghp trong mt g nn ghp n u cht n y nn

vic gim st khe h ca cc mi ni rt d dng. Cng vi vic ct tn

trn my tng c bavia thp, h s p cht cao y cng l mt yu

t lm cho dng khng ti gim rt nhiu so vi tiu chun Vit Nam hin

nay (bng 1/3 n mt na).

Cui cng l vic p mch t cng c nhng thay i so vi cng

ngh Vit Nam. Mch tc p gi nhmt lp nha mng qut ln trn


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b mt ngoi. Gia cc l tn by gicng c mt lp nha mng nn cc

l tn c lin kt cht m khng cn phi p gia bng ai hoc chn

bng g. Cng ngh ny c u im lm cho tn hao st gim v cc l tn

khng b bin tnh do p qu cht hoc do t l. Nhc im ca cngngh ny l khi cn sa cha mch t s gp phi kh khn do phi glp

nha ny.

2. DY QUN.

Si mi trong cng ngh ch to dy qun ccng ty ABB th

hin trong cc kha cnh sau:

- u t my qun tng c iu khin theo chng trnh. Vi vic

s dng my qun dy kiu ny nng sut qun dy tng, cht lng qun

n nh tuy nhin ch yu qun hai loi dy qun ch yu l dy qun hnh

tr nhiu lp dy dn trn v dy qun t bng ng tc ch qun cc my

bin p phn phi ckhng ln.

- S dng kiu dy qun t bng ng. Theo phng php ny cc

cun dy h p t vng, c tit din ln c th qun t cc bng ng tm

c chiu rng bng chiu cao cun day. Nh vy trong trng hp ny

chiu cao mt vng dy ng bng chiu cao dy qun. ng c s dng

y l ng cun M1 trn (cha cch in). Khi qun thng ngi ta

qun cng vi mt bng cch in c chiu rng ln hn mt t. Qun theo

phng php ny thc cht l qun theo kiu ng tm (vng sau chng ln

vng trc). Tm cch in ng vai tr l cch in vng dy.

- ly u vo v ra ca cun dy ngi ta hn vo u v cuibng ng cc thanh ng (thanh ci). Vic hn mt thanh ci ng c tit

din tp trung ln vo mt l ng mng c thc hin bng thit b hn

h quang trong kh bo v (CO2) m bo cho l ng khng b qu

nhit v chy.


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- Cch in dng trong trng hp ny l giy cp hoc giy in

thoi c chiu dy khc nhau c in ln mt lp nh cch in. Sau khi

qun xong em gia nhit lp nha ny chy ra v dnh vo tm ng lm

thnh mt khi ng nht, va m bo c tnh tt va m bo to nhittt.

u im ca kiu dy qun ny l n gin trong cng ngh ch to,

lc ngn mch phn bu nn bn in ng cao. Ngoi tr vic hn

thanh ci ng vo tm mng cn c thit b cng nght tin ra vic

qun cun dy ny c nng sut cao hn nhiu so vi kiu dy qun hnh

tr, dy dn ch nht hoc dy qun hnh xon. Vic in cc m nha ln

giy cch in khng kh.

Nhc im ca kiu dy qun ny l tn nhit kh nn d b nng

cc b nu s vng dy ca dy qun nhiu. Vic sa cha cng s kh

phc tp v phi lm sch lp nha v lp giy trn tm ng.

Phm vi ng dng ca loi dy qun ny tng i rng. Phm vi

ng dng ch yu b gii hn dy ca tm ng. Nu tm ng mng

qu khi hn vo thanh ci ng sn xut kh, d b chy, tn nhit s khkhn hn, thng thng chiu dy tm ng khng nh qu 0,1mm. Thng

thng kiu dy qun ny c th p dng cho cc my c in p 0,4KV,

cng sut t 20KVA n 300KVA.

3. V MY BIN P.

V my bin p phn phi c lm theo kiu c nhiu cnh tn

nhit mi kh, khng c bnh gin du v ng phng n. Cng ngh chto loi v ny n gin v rt d tng ho. Ngi ta sn xut cc tm

thp kiu mi kh c chiu rng v chiu di bt k, tu theo v ln hay

cao bao nhiu th ct v hn li cho . Nh vy cng ngh ch yu trong

ch to v thng ny l p to cnh tn nhit trn tn v cng ngh hn.


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V tn mng v m bo hn kn du nn y ngi ta p dng cng

ngh hn h quang trong kh bo v.

My bin p s dng loi v ny c c im l khng cn bnh gin

du (bnh du ph) v khi nng ln lng du nra c cha ht vo cccnh tn nhit lc ny cng nra do tng p sut. Khi my ngui lng du

gim, p sut trong thng cng gim v cnh tn nhit lc ny cng thu li

nh c. Nh vy du c np y v trong bnh khng c khng kh nn

hon ton loi tr cc hin tng ht m, oxy ho du nh vn thng xy

ra trong cc my bin p thng thng.

Vic np du vo my bin p cng ty ABB c thc hin bng

cc thit b np du chn khng,sau khi my bin p c sy kh cng

trong l sy chn khng.

Vi tt c nhng ci tin nu trn cng ty ABB thu nhng

k cc my bin p phn phi hin ang c sn xut ti nh my ca

cng ty.


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MC LC

Trang

Li ni u ....................................................................................................... 1

Chng I: Khi nim chung v thit k my bin p .................................. 3

I.1. i cng ................................................................................................ 3

I.2. nh ngh

thiet ke mba 400kv ngam dau

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