thiet ke mba 400kv ngam dau
TRANSCRIPT
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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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 2
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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 3
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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 4
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
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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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 6
( )
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=
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 7
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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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 8
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:
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 9
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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 10
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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 11
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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 12
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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 13
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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 14
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.
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 15
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.
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 16
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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 17
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
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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
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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
=
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SV: Nguyn Tun Long - Lp: TB -T 21
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
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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 :
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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
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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
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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)
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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
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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
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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
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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
= = =
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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
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* 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
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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'
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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
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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
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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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 36
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.
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 37
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.
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 38
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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 39
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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 40
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) )
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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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 42
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.
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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
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SV: Nguyn Tun Long - Lp: TB -T 44
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
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SV: Nguyn Tun Long - Lp: TB -T 45
' ''
' 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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 46
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
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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
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SV: Nguyn Tun Long - Lp: TB -T 48
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)
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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
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SV: Nguyn Tun Long - Lp: TB -T 50
: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%
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SV: Nguyn Tun Long - Lp: TB -T 52
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
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SV: Nguyn Tun Long - Lp: TB -T 53
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
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n tt nghip Thit kmy bin p 400kVA ngm du
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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
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n tt nghip Thit kmy bin p 400kVA ngm du
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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.
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n tt nghip Thit kmy bin p 400kVA ngm du
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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
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 57
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 -
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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= =
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n tt nghip Thit kmy bin p 400kVA ngm du
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- 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)
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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.
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 61
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
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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
=
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n tt nghip Thit kmy bin p 400kVA ngm du
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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%
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n tt nghip Thit kmy bin p 400kVA ngm du
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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
+ = = + +
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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
= =
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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
= = =
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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 = + = + =
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 69
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.
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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)
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+ 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
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( )' 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
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n tt nghip Thit kmy bin p 400kVA ngm du
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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= =
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+ 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)
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SV: Nguyn Tun Long - Lp: TB -T 76
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 + = = +
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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
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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=
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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
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SV: Nguyn Tun Long - Lp: TB -T 80
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)
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n tt nghip Thit kmy bin p 400kVA ngm du
SV: Nguyn Tun Long - Lp: TB -T 81
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:
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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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SV: Nguyn Tun Long - Lp: TB -T 85
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