n mn hc Thit k cung cp in TRNG I HC PHNG NG KHOA H THNG
IN----***---
N MN HC CUNG CP INThit k cp in cho xng sa cha c khH NI 2010LI NI
U1 n mn hc Thit k cung cp in t nc ta ang trong cng cuc cng nhip ho
, hin i ho . Nhu cu in nng trong cc lnh vc cng nghip , nng nghip ,
dch v v sinh hot tng trng khng ngng i cng vi qu trnh pht trin kinh
t . Do i hi rt nhiu cng trnh cung cp in . c bit rt cn cc cng trnh c
cht lng cao , m bo cung cp in lin tc , phc v tt cc nghnh trong nn
kinh t quc dn.Trong c lnh vc cng nghip l 1 trong cc ngnh kinh t
trng im ca t nc, c Nh nc v Chnh ph u tin pht trin v c vai tr quan
trng trong k hoch a nc ta tr thnh nc cng nghip vo nm 2020. Thit k
cung cp in cho nghnh ny v th l 1 cng vic kh khn, i hi s cn thn cao.
Ph ti ca ngnh phn ln l ph ti h loi 1, i hi tin cy cung cp in cao.
Di s hng dn ca thy ThS. Nguyn c Minh,em c nhn ti Thit k cung cp in
chophn xng sa cha c kh. n bao gm 1 s phn chnh nh chn my v v tr t
trm bin p, chn dy v cc phn t bo v, hch ton cng trnh . y l mt n c
tnh thc tin rt cao, chc chn s gip ch cho em rt nhiu trong cng tc
sau ny.Trong qu trnh thc hin n, em nhn c s ch bo rt tn tnh ca thy
ThS.Nguyn c Minh cng cc thy c trong khoa H Thng in. Em xin chn thnh
cm n . H ni, thng 6 nm 2010 Sinh vin thc hin
CHNG I 2 n mn hc Thit k cung cp in XC NH PH TI TNH TON CA PHN
XNGI.1) Xc nh ph ti tnh ton ca cc nhm ph ti.Cng sut chiu sng
chung:
) ( 20 ) 50 . 20 .( 20 . .0 csckW b a P Phung V dng bng n si t
nn h s cos=0,9.I.1.1) Ph ti chiu sngTnh ton ph ti in l cng vic bt
buc v u tin trong mi cng trnh cung cp in. Vic ny s cung cp cc s liu
phc v cho vic thit k li in v sau ca ngi k s. Ph ti tnh ton c gi tr
tng ng vi ph ti thc t v mt hiu ng nhit, do vic chn dy dn hay cc
thit b bo v cho n s c m bo.C nhiu phng php tnh ton ph ti in nh phng
php h s nhu cu, hsthamgiacci. ivivicthitkcungcpinchophn xng sa cha
c kh, v c cc thng tin chnh xc v mt bng b tr thit b, bit oc cng sut
v qu trnh cng ngh ca tng thit b nn ta s dng
phngphphsnhucutnghpnhmphtinglc. Nidung chnh ca phong php nh sau: -
Thc hin phn nhm cc thit b c trong xng, mi nhm khong t 7 9 thit b,
mi nhm s c cung cp in t 1 t ng lc ring, ly in t 1 t phn phi chung.
Cc thit b trong nhm nn chn c v tr gn nhau trn mt bng phn xng. Cc
thit b trong nhm nn c cng ch lm vic , s lng thit b trong 1 nhm khng
nn qu 9 v gy phc tp trong vn hnh , gim tin cy cung cp in . - Xc nh
h s s dng tng hp ca nhm thit b theo biu thc sau :sdk=isdi iPk . P(
2.1 )- Xc nh s lng thit b hiu dng ca mi nhm nhd( l 1 s qui i gm c
nhd thit b gi nh c cng sut nh mc v ch lm vic nh nhau v tiu th cng
sut ng bng cng sut tiu th ca nhm thit b thc t ) . Cc nhm y u trn 4
thit b nn ta xc nh t s kminmaxPP, sau so snh k vi kb l h s ng vi
sdk ca nhm . Nu k > kb , ly nhq = n , l s lng thit b thc t ca
nhm . Ngc lic th tnh nhd theo cng thc sau :nhq =( )2i2iPP( 2.2 )3 n
mn hc Thit k cung cp in - H s nhu cu ca nhm s c xc nh theo biu thc
sau :knc = sdk + 1sdhqkn ( 2.3 ) - Cui cng ph ti tnh ton ca c nhm l
:Ptt = knc. iP ( 2.4 )Ta c th chia phn xng ra lm 4 nhm: Nhm 1 c 8
thit b gm:- 2 ba hi rn c P = 2.15 (kW)- 1 my hn %dm=25% c P = 2,2
(kW)- 1 l chy bng in c P = 19 (kW)- 1 l in ha cng linh kin c P = 19
(kW)- 1 thit b ti cao tn c P = 19 (kW)- 2 my p ma st c P = 2.10
(kW) Nhm 2c 7 thit b gm:- 1 my hn%dm=25% c P = 2,2 (kW)- 2 l in cng
ha nhin liu c P = 2.19 (kW)- 1 thit b ti bnh rng c P = 20 (kW)- 1
thit b ti cao tn c P = 19 (kW)- 1 my p ma st c P = 10 (kW)- 1 my nn
kh c P = 22,8 (kW) Nhm 3 c 9 thit bgm:- 1 my hn%dm = 25% c P = 2,2
(kW)- 2 l chy bng in c P = 2.19 (kW)- 1 l in ha cng linh kin c P =
19 (kW)- 2 thit b ti bnh rng P = 2.20 (kW)4 n mn hc Thit k cung cp
in - 1 thit b ti cao tn c P = 19 (kW)- 1 my p ma st c P = 10 (kW)-
1 my nn kh c P = 22,8 (kW) Nhm 4 c 9 thit b gm:- 2 ba hi rn c P =
2.15 (kW)- 2 l in ha cng linh kin c P = 2.19(kW)- 1 thit b ti cao
tn c P = 19 (kW)- 2 my p ma st c P = 10 (kW)- 2 my nn kh c P =
2.22,8 (kW)I.1.2) Ph ti ng lc:Trc khi tnh ton cn qui cc ph ti lm
vic ch ngn hn lp li v ch lm vic lm vic di hn , theo cng thc :P = Pt
. , kW .Trong :- Pt : l cng sut ca ph ti, tc l cng sut nh mc ca ph
ti , kW- P : cng sut qui v ch lm vic di hn ca thit b .- : h s tip
in ca thit b , kWNh vy , ph ti tnh ton ca my hn dm%=25%l :22, 2. 0,
25 P =1,1 (kW)Cn c vo s b tr thit b trong nh xng , v da theo cc
nguyn tc phn nhm trn , c th chia cc thit b thnh 4 nhm . Kt qu tng
hp ph ti tng nhm s c trnh by chi tit di y .Ph ti nhm 1 c tng hp nh
sau :H s s dng tng hp ca nhm l :i sdisdP.k 2.15.0,16 1,1.0,3
19.0,16 19.0,16 19.0,16 2.10.0,16kP 2.15 1,1 19 19 19 2.10 + + + +
+ + + + + + =0,16 Thy sdk=0,16 ax2mP: th c 1n thit b5 n mn hc Thit
k cung cp in -Xc nh tng cng sut ca1n thit b :11ndmiiP P-Xc nh cc gi
tr tng i :1 1;n pn pn p -Xc nh hqn : Xc nh theo cng thc :2 20, 95(1
)1hqnp pn n + Xc nh theo cng thc .hqhqn n nT nhm 1 ta c: P >
ax2mP = 192= 9,5 c 1n = 7 11ndmiiP P=2.15 + 19 + 19 + 19 + 2.10 =
107 1 17 1070,875; 0, 998 108,1n pn pn p 2 2 2 20, 95 0, 95(1 ) 0,
99 (1 0, 99)0,875 1 0,875 1hqnp pn n + + =0,85.hqhqn n
n=8.0,85=6,8.Ly theo gi tr t nhin nnhqn=7knc = ksd +sdhq1 kn = 0,16
+ 1 0,167 = 0,48 Tng cng sut tc dng tnh ton ca nhm ng lc 1 l :Ptt1
= knc .Pni = 0,48.108,1 = 52,37 kWH s cng sut tc dng ca nhm l :Cos
ni iniP .cos 2.15.0,6 1,1.0,35 19.0,6 19.0,6 19.0,6 2 .10.0, 6P 107
+ + + + + =0,6Cng sut biu kin ca nhm l : Stt1 = 6 , 037 ,
52cos1tbttP= 87,66 (kVA)6 n mn hc Thit k cung cp in Cng sut phn
khngca nhm l :Qtt1 = Stt12 ) (cos 1 = 87,66. 21 (0,6) = 70,29
(kVAr) Nhm 1:Bng1 .1 . Bng tng hp ph ti nhm 1.Ph tiI Cng sut P k
Pi.kicosP2PcosSptQpt1 15,00 0,16 2,4 0,6 225 9 25,00 20,001 15,00
0,16 2,4 0,6 225 9 25,00 20,002 1,10 0,3 0,33 0,35 1,21 0,385 3,14
2,943 19,00 0,16 3,04 0,6 361 11,4 31,67 25,334 19,00 0,16 3,04 0,6
361 11,4 31,67 25,336 19,00 0,16 3,04 0,6 361 11,4 31,67 25,337
10,00 0,16 1,6 0,6 100 6 16,67 13,337 10,00 0,16 1,6 0,6 100 6
16,67 13,33 108,10 0,16 17,45 0,6 1734,21 64,585Ksd 0,16 Pmax
/Pmin17,27nhq7knc0,48Ptt, kW 52,37cos0,60Stt, kVA 87,66Qtt, kVAr
70,29Tnh ton tng t cho cc nhm cn li c bng tng kt ph ti ca cc nhm
theo phng php h s nhu cu nh sau:7 n mn hc Thit k cung cp in Nhm
2:Bng1 .2 . Bng tng hp ph ti nhm 2.Ph ti II Cng sut P k
Pi.kicosP2PcosSptQpt2 1,1 0,3 0,33 0,35 1,21 0,385 3,14 2,944 19
0,16 3,04 0,6 361 11,4 31,67 25,334 19 0,16 3,04 0,6 361 11,4 31,67
25,335 20 0,16 3,2 0,6 400 12 33,33 26,676 19 0,16 3,04 0,6 361
11,4 31,67 25,337 10 0,16 1,6 0,6 100 6 16,67 13,338 22,8 0,16
3,648 0,6 519,84 13,68 38,00 30,40 110,9 17,898 2104,1 66,265Ksd
0,16 Pmax /Pmin20,73nhq7,00knc0,48Ptt, kW 53,05cos0,60Stt, kVA
88,78Qtt, kVAr 71,198 n mn hc Thit k cung cp in Nhm 3:Bng1 .3Bng
tng hp ph ti nhm 3.Ph ti II Cng sut P k Pi.kicosP2PcosSptQpt2 1,1
0,3 0,33 0,35 1,21 0,385 3,14 2,943 19 0,16 3,04 0,6 361 11,4 31,67
25,333 19 0,16 3,04 0,6 361 11,4 31,67 25,334 19 0,16 3,04 0,6 361
11,4 31,67 25,335 20 0,16 3,2 0,6 400 12 33,33 26,675 20 0,16 3,2
0,6 400 12 33,33 26,676 19 0,16 3,04 0,6 361 11,4 31,67 25,337 10
0,16 1,6 0,6 100 6 16,67 13,338 22,8 0,16 3,648 0,6 519,84 13,68
38,00 30,40 149,9 18,89 2865,05 69,985Ksd 0,13 Pmax
/Pmin20,73nhq8,00knc0,44Ptt, kW 65,21cos0,47Stt, kVA 139,67Qtt,
kVAr 123,519 n mn hc Thit k cung cp in Nhm 4:Bng1 .4Bng tng hp ph
ti nhm 4.Ph ti IV Cng sut k Pi.kicosP2PcosSptQpt1 15,00 0,16 2,40
0,60 225,00 9,00 25,00 20,001 15,00 0,16 2,40 0,60 225,00 9,00
25,00 20,004 19,00 0,16 3,04 0,60 361,00 11,40 31,67 25,334 19,00
0,16 3,04 0,60 361,00 11,40 31,67 25,336 19,00 0,16 3,04 0,60
361,00 11,40 31,67 25,337 10,00 0,16 1,60 0,60 100,00 6,00 16,67
13,337 10,00 0,16 1,60 0,60 100,00 6,00 16,67 13,338 22,80 0,16
3,65 0,60 519,84 13,68 38,00 30,408 22,80 0,16 3,65 0,60 519,84
13,68 38,00 30,40 152,60 24,42 2772,68 91,56Ksd 0,16 Pmax
/Pmin2,28nhq8,00knc0,46Ptt, kW 69,74cos0,60Stt, kVA 116,23Qtt, kVAr
92,98Ph ti tng hp ca nhm ng lc c tng hp theo phng php h s nhu cu
(phng php tng hp p dng cho cc nhm ph ti c tnh cht tng ng).10 n mn
hc Thit k cung cp in H s s dng tng hp ca 4 nhm ng lc l :ksd ni
sdiniP .k 52,37.0,16 53, 05.0,16 65, 21.0,13 69, 74.0 ,16P 52,37
53, 05 65, 21 69, 74 + + + + + + = 0,15Ly hqn=4.knc = ksd +sdhq1 kn
= 0,15 + 1 0,154 = 0,58Trong :- nhq: s lng hiu qu ca nhm ng lc, ly
bng s nhm ng lc = 4 .Tng cng sut tc dng ca nhm ng lc l :Pl = knc.P
= 0,58.240,37 = 138,51 (kW)H s costrung bnh ca nhm l :cos tb = ni
iniP .cos 52,37.0, 6 53, 05.0, 6 65, 21.0, 47 69, 74.0 , 6P 240,37
+ + + 0,56Nn cng sut biu kin ca nhm ng lc l :Sl 138, 51cos 0,
56dldlP 245,75 (kVA)V cng sut phn khng ca cc ph ti ng lc l :Ql =
S1.2 21 cos 245, 75. 1 0, 56 = 202,99 (kVAr)Vy c bng tng hp ph ti
ng lc theo phng php h s nhu cu nh sau:Bng1 .5Bng tng hp ph ti ng
lc.Nhm ng lcNhm KsdKncPttcosStt QttPtt.ksdp.cos1 0,16 0,48 52,37
0,60 87,66 70,29 8,45 31,292 0,16 0,48 53,05 0,60 88,78 71,19 8,56
31,703 0,13 0,44 65,21 0,47 139,67 123,51 8,48 30,654 0,16 0,46
69,74 0,60 116,23 92,98 11,16 41,84 240,37 432,34 357,97461 36,65
135,48ksd0,15Knc0,58cos 0,56P138,5111 n mn hc Thit k cung cp in
S245,75 `Q202,99I.1.3) Ph ti tng hp.Ph ti tng hp ca cc nhm v c tnh
cht khc nhau nn c tng hp theo phng php s gia:Tng cng sut tc dng ca
phn xng c xc nh nh sau: .N dli i csP P k P +Trong :Pli: L ph ti ng
lc ca cc nhm.ki: h s c xc nh0,04( ) 0, 415iPik Pcs.lm: Tng cng sut
chiu sng ca phn xng. ( )0,04.20138, 51 ( ) 0, 41 .205151, 45N dl i
csP P k PkW + 1 + 1 ]H s cng sut tng hp ca ton phn xng:. os .
ososdl tb cs csNdl csP c P ccP P ++V bng n chiu sng c chn l bng n
si t nn coscs= 0,8.Thay s vo biu thc trn ta c: . os . osos151,
45.0, 56 20.0,80, 59151, 45 20sin 0,81dl tb cs csNdl csNP c P ccP P
+++ + Cng sut biu kin:( )151, 45256, 69os 0, 59NNPS kVAc T ta c cng
sut phn khng:( ) .sin 256, 69.0,81 207, 92 ArN NQ S kV 12 n mn hc
Thit k cung cp in ( ) 151, 45 207, 92 S j kVA +13 n mn hc Thit k
cung cp in CHNG IILA CHN PHNG N CP IN CHO PHN XNG.II.1)Trm bin p
phn xng .Trm bin p l mt phn t rt quan trng ca h thng in nc nhim v
tip nhn in nng t h thng, bin i t cp in pny sang cp in p khc v phn
phi cho mng in tng ng.Trong mi trm bin p ngoi my bin p cn c rt nhiu
thit b hpthnh h thng tip nhn v phn phi in nng. Cc thit b pha caop
gi l thit b phn phi cao p (my ct, dao cch ly, thanh ci) vcc thit b
pha h p gi l thit b phn phi h p (thanh ci h p,aptmat, cu dao, cu
chy).Trm tng p thng c t ti cc nh my in tng inp t 0,46,3kV ln cc cp
cao hn vi mc ch truyn ti in nngi xa hn; Trm bin p trung gian l trm
gim p, tip nhn in nngt li 3522kV cung cp cho cc li phn phi 622kV ;
Trmbin p tiu th hay trm bin p phn xng c nhim v tip nhnin nng t mng
phn phi 622kV(i khi c mng 35 v 110kV) vcung cp cho li in h p.Kt cu
ca trm bin p ph thuc vo loi trm, v tr, cngdngca chng. Cc trm bin p
trung gian thng c xy dngvi hai dng chnh:- Trm bin p ngoi tri c cc
thit b phn phi pha caop c t ngoi tri cc thit b phn phi pha th cp c
ttrong cc t in hoc t trong nh.- Trm bin p trong nh: ton b thit b ca
trm t phas cp n pha th cp c t trong nh vi cc t phn phi tngng.Tt c
cc trm bin p cn phi tho mn cc yu cu c bn sau:- S v kt cu phi n gin
n mc c th.- D thao tc vn hnh.14 n mn hc Thit k cung cp in - m bo
cung cp in lin tc v tin cy vi cht lngcao.- C kh nng m rng v pht
trin.- C cc thit b hin i c th p dng cc cng nghtin tin trong vn hnh
v iu khin mng in.- Gi thnh hp l v c hiu qu kinh t cao.Cc yu cu trn
c th mu thun vi nhau, v vy trong tnhton thit k cn phi tm li gii ti
u bng cch gii cc bi ton kinht k thut.II.1.1)Xc nh v tr t trm bin p
phn xng .V tr ca trm bin p c nh hng rt ln n cc ch tiu kinht k thut
ca mng in. Nu v tr ca trm bin p t qu xa ph tith c th dn n cht lng
in p b gim, lm tn tht in nng.Nu ph ti phn tn, th vic t cc trm bin p
gn chng c th dnn s lng trm bin p tng, chi ph cho ng dy cung cp ln
vnh vy hiu qu kinh t s gim.V tr trm bin p thng c t lin k, bn ngoi
hoc bntrong phn xng.V tr ca trm bin p cn phi tha mn cc yu cu c bn
sau :- An ton v lin tc cp in.- Gn trung tm ph ti, thun tin cho ngun
cung cp i ti.- Thao tc, vn hnh, qun l d dng.- Tit kim vn u t v chi
ph vn hnh nh. - Bo m cc iu kin khc nh cnh quan mi trng, c kh nng iu
chnh ci to thch hp, p ng c khi khn cp...- Tng tn tht cng sut trn cc
ng dy l nh nht. Cn c vo s b tr cc thit b trong phn xng thy rng cc
ph ti c b tr vi mt cao trong nh xng nn khng th b tr my bin p trong
nh . V vy nn t my pha ngoi nh xng ngay st tng nh minh ho di y. Khi
xy dng ngoi nh th cn ch n iu kin m quan.Hng in ti TBA
Hnh 2.1. S b tr my bin p .15 n mn hc Thit k cung cp in II.2) Chn
cng sut v s lng my bin p:Cng sut ca my bin p c chn cn c vo cng sut
ca ph ti v kh nng chu qu ti ca my bin p. S lng my c chn cn ph thuc
vo yu cu tin cy cung cp in, nu ph ti quan trng (loi 1) thng chn 2
my lm vic song song.- H s in kn th c th c xc nh theo biu thc :kdk
=tb MMS T 50000,571S 8760 8760 < 0,75 Trong :Stb : Cng sut trung
bnh, kVA .SM : Cng sut cc i, kVA .TM : thi gian tiu th cng sut cc
i, cho bi .Nh vy my bin p c th lm vic qu ti 40% trong khong thi
gian cho php khng qu 6 gi.Cn c vo cng sut ca ph ti tng hp xc nh c
mc trn nn ta chn cng sut v s lng my bin p 22/0,4 kV theo 3 phng n
sau :Phng n 1: Chn hai my bin p.
1 2256, 69128, 35( )2 2ttdm dmSS S kVA Khi xy ra s c ct 1MBA:
80%. 80%.256, 69146, 681, 4 1, 4ttdmBSS (kVA) Vy ta s chn hai my
bin p cng sut 2 160 (kVA )Phng n 2 : Dng 2 mba c cng sut l 2
180Phng n 3: Chn mt my bin p 256, 69( )dmB ttS S kVA Ta chn my bin
p cng sut 315(kVA) Xt v k thut, cc phng n khng ngang nhau v tin
cycung cp in: i vi phng n 1 v phng n 2, khi c s c mttrong hai my
bin p th my bin p cn li phi gnh ton b ph tiloi I v II ca phn xng, i
vi phng n 3 s phi ngng cungcp in cho cc h tiu th khi c s c trong my
bin p. mbo s tng ng v k thut ca cc phng n cn phi xt n thnhphn thit
hi do mt in khi c s c xy ra trong my bin p. Trc16 n mn hc Thit k
cung cp in ht ta kim tra kh nng qu ti ca my bin p khi mt trong hai
myb s c.Ph ti trong thi gian s c 1 my bin p bao gm ph ti loi I v
loi II .Ssc = Stt . 1 2m+ = 256,69 . 0,85 = 218,187 ( kVA )H s qu
ti kqt scnS 218,1871,36S 160 < 1,4 Vy m bo yu cu cung cp in.Hm
chi ph tnh ton quy i ca my bin p: ( ). . Z a k V ACtc kh BA +
+Trong :
atc: L h s tiu chun s dng hiu qu vn u t my bin p Vi my bin p do
Vit Nam sn xut th10,1258atc kkh: L t l khu hao ca my bin p 6, 64%
0, 064 kkh VBA: L vn u t trm bin p C: L gi thnh tn tht in nng 1000
C (/kWh) A : L tn tht in nng trong trm bin p v tnh theo cng
thc:
( )2. . . .P Sk ttA n Pt kWhon SdmBA _ + , Trong :n: l s my bin
p trong trm bin p Po: L tn tht in p khi khng ti (kW)
Pk: L tn tht in p khi ngn mch (kW)t: L thi gian vn hnh trm bin p
trong 1 nm t = 8760h
SdmBA: L cng sut nh mc ca my bin p (kVA)
: L thi gian tn tht ln nht v tnh theo cng thc: ( )( )240,124 .10
.8760axT hm +17 n mn hc Thit k cung cp in Vi 5000axT hm th ( )(
)240,124 5000.10 .8760 3411 h + Phng n 1: dng 2 my bin p 2x160
kVATn tht in nng ca trm bin p phn xng trong phng n1 l: 2. . . .P Sk
ttA n Pton SdmBA _ + ,
( )22, 95 256, 692.0, 5.8760 .3411. 21639, 9362 160kWh _ + ,Tng
chi ph quy i ca trm bin p trong phng n1 l:( ). .1Z a k V ACtc kh BA
+ + ( )6 60,125 0, 064 .(24,18 0,18.160).10 21639, 936.1 000 31,
65.10 + + + ()Tnh tng t cho 2 phng n cn li ta c bng tng kt sau:Bng
2.1. So snh cc phng n chn my bin p.Nhn xt:Ta thy tng chi ph quy i
ca trm bin p trong phng n 3 l nh nht v c vn u t trm bin p ban u
trong phng n3 cng nh nht trong 3 phng n.Vy trm bin p phn xng s gm
1my bin p c cng sut nh mc l 1x315kVA.Phng n( ) S kVAtt( ) P kWo ( )
W P kk VBA(106 )( ) AkWh Z (106 )Phng n 1 2x160 0,5 2,95 105,96
21639,936 41,67Phng n 2 2x180 0,53 3,15 113,16 20210,95 41,59Phng n
3 1x315 0,72 4,85 80,88 17292,71 32,5818 n mn hc Thit k cung cp in
II.3) La chn s ni in ti u.a) Chn s b phng n. cung cp in c th c nhiu
phng n i dy, c th dng s hnh tia c tin cy cung cp in cao, c th dng s
ng trc, hoc hn hp. Vi phn xng nn p dng s hnh tia v cc thit b kh tp
trung. Cc phng n c nu chi tit di y. cung cp in cho cc ng c my cng
c, trong xng d nh t 1 t phn phi nhn in t trm bin p v v cp in cho 4
t ng lc t ri rc cc cnh tng phn xng, mi t ng lc cp in cho cc nhm ph
ti phn nhm trn. Cn c vo s mt bng tin hnh xem xt 2 phng n sau.Phng n
1: t t phn phi ti gc xng v ko ng cp n t ng lc.Phng n 2: t t phn phi
ti trung tm ph ti v t ko cp n tng t ng lc. b) Tnh ton chn phng n ti
u.Phng n 1:Trm bin pHng in voT ng lc 4T ng lc 2T ng lc 1T ng lc
3Hnh 2.2. S ni in phng n 1.19 n mn hc Thit k cung cp in Ta chn dy
dn t trm bin p phn xng ti t phn phi v t t phn phi ti cc t ng lc l
loi dy cp ng 4 li v PVC (cp PVC) t trong rnh chn di phn xng.Cc ng
cp ti cc t ng lc gn nhau th c th t chung trong 1 rnh tit kim v chi
ph. Trong chng ny ta ch mi chn s b tit din ng dy v kim tra iu kin
dng pht nng lu di cho php Icp v tn tht in p. Cc iu kin khc v dng
ngn mch, dng Icp khi c cc thit b bo v ng c v mng in th ta s xt cc
chng sau, sau khi ta tnh ton chn cc thit b bo v. Chn tit din ng dy
theo dng pht nng lu di cho php Icp theo cng thc sau: . .1 2.1 2k k
I Icp ttIttIcpk k Trong : Icp: l dng in cho php lu di ca dy dn (A)
k1: l h s hiu chnh tnh ti nhit mi trng sn xut v s dng. k1=1 k2: l h
s hiu chnh tnh ti s dy dn t trong cng 1 rnh. ng dy cp t trm bin p
phn xng ti t phn phi(TPP)T phn phi t cch trm bin p LTBA-TPP = 10
(m) .y l ng cp tng dn in t TBA ti TPP.- Dng in tnh ton chy trong dy
cp l: ( )256, 693903. 3.0, 38SttI AttUdm Dng in pht nng lu di cho
php tha mn:( )390433, 33. 1.0, 91 2IttI Acpk k Vy ta chn cp PVC-300
c Fm = 240mm2 v Icp= 462 A.Cc thng s v in tr: x0 = 0,06 (/km) v r0
= 0, 08 (/km)- Tn tht in p thc t l:20 n mn hc Thit k cung cp in (
). .151, 45.0, 08 207, 92.0, 06. .0, 01 0, 6470, 380, 647% .100%
.100% 0,17%380P r Q xtt o tt oU L VTBA TPP TBA TPPUdmUTBA TPPUTBA
TPPUdm ++ 26 32256, 69(0,125 0, 04)(63, 58 0, 83.240).0, 01.10 .0,
08.0, 01.3411.10 .10000, 38Z + + +=1,68.106()Dng in tnh ton chy
trong dy dn t TPP ti t ng lc: hom3.SnIttUdm Xt t ng lc 1. t t ng lc
1 cch TPP khong LTPP-dl1 = 30m.Theo s b tr s b ng dy t trm bin p ti
cc t ng lc trn th 2 ng dy cp ti cc t ng lc 1, 2c th t chung trong 1
rnh.Nn k2=0, 85 v k1=1.- Dng in tnh ton chy trong dy dn ti t ng lc
1 l: ( )87, 66hom1133,18513. 3.0, 38SnI AttUdm Dng in pht nng lu di
cho php tha mn: ( )133,1851156, 69. 1.0, 851 2IttI Acpk k Vy ta chn
cp PVC-35 c Fm=35mm2 v Icp=159A.Cc thng s v in tr: x0 = 0,06 (/km)
v r0 = 0,57 (/km).- Tn tht in p thc t:21 n mn hc Thit k cung cp in
( ). .52, 37.0, 57 70, 29.0, 06hom1 hom1. .0, 03 2, 691 10, 382,
691% .100% .100% 0, 71% 5%1380P r Q xn o n oU L VTPP dl TPP
dlUdmUTPP dlU UTPP dl cpUdm++ < - Tn tht in nng trn on ng dy:(
)2287, 663 hom1. . . .0, 57.0, 03.3411.10 3103, 9421 1 2 20, 38SnA
r L kWhTPP dl o TPP dlUdm - Chi ph cho tn tht in nng trn on ng dy:
6. 3103, 942.1000 3,1.101 1C A CTPP dl TPP dl ()- Vn u t cho on ng
dy cp ny l:
6 6. (63, 58 0,83.35).10 .0, 03 2, 78.101V v Ld o TPP dl + ()-
Chi ph quy i ca on dy cp ny l:( )( )6 6 6. 0,125 0, 04 .2, 78.10
3,1.10 3, 56.101 d 1Z a k V Ctc kh TPP dl + + + + ()
Tnh tng t cho cc t ng lc cn li ta c bng tng kt sau:Bng2.2Bng chn
dy dn ca phng n 1.ng dyL, mPnhom , kWQnhom, kVArSnhom ,kVAItt ,
ALoi dy cpIcp , Ar0 ,/kmx0 ,/kmU ,VTPP-dl1 30 52,37 70,29 87,66
133,185 PVC-35 159 0,57 0,06 2,69TPP-dl2 50 53,05 71,19 88,78
134,887 PVC-50 188 0,4 0,06 3,354TPP-dl3 10 65,21 123,51 139,67
212,21 PVC-95 279 0,21 0,06 3,666TPP-dl4 30 69,74 92,98 116,23
176,59 PVC-70 233 0,29 0,06 2,03722 n mn hc Thit k cung cp in
Bng2.3Bng chn dy dn ca phng n 1. Phng n 2:Trm bin pHng in voT ng lc
4T ng lc 2T ng lc 1T ng lc 3Hnh 2.3. S ni in phng n 2.t t phn phi
gia phn xng . Khi khong cch t trm bin p n t phn phi l 35 m . Cc
khong cch t t phn phi n cc t ng lc c xc nh theo s b tr i dy trn v
tinh ton tng t nh phng n 1, kt qu tnh ton c ghi trong bng sau:ng dy
A,kWh C, 106v0, 106/kmVd, 106 Z, 106TPP-dl1 3103,942 3,1 92,63 2,78
3,56TPP-dl2 3723,7 3,7 105,08 5,25 4,57TPP-dl3 967,698 0,967 142,43
1,42 1,19TPP-dl4 2776,325 2,776 121,68 3,65 3,3823 n mn hc Thit k
cung cp in Bng2.4Bng chn dy dn ca phng n 2.on dyCng sut(KV)Dng
L(m)( ) Uv ( ) A kWh dV610C(/kwh) Z()TBA-TPP256,69 390 35 2,265
4358 9,2 1000 5,87TPP-DL187,66132,6123 1,343 2333,7 2,13 1000
2,69TPP-DL288,78134,3632 1,14 2383,2 3,37 1000
2,94TPP-DL3139,67210,7923 0,75 2226,4 3,8 1000
2,85TPP-DL4116,23176,5932 1,36 2961,6 3,9 1000 3,61Tng chi ph qui i
ca phng n 1 l:( )6 611, 68 3, 56 4, 57 1,19 3, 38 .10 14, 38.10 Z +
+ + + (/nm)Tng chi ph qui i ca phng n 2 l:( )6 625, 87 2, 69 2, 94
2, 85 3, 61 .10 17, 96.10 Z + + + + (/nm)Nhn xt:Nh vy xt v mt k
thut th cc phng n tng ng nhau (tn tht in p u rt nh) cn v mt kinh t
r rng phng n 1 tri hn hn.Nh vy ta chn phng n 1 tnh tip. Tc t 1 t
phn phi gc xng ri ko in n tng t ng lc theo s hnh tia. Tnh ton chn
dy cp t t ng lc ti cc thit b trong nhm.Ta chn dy dn t cc t ng lc ti
cc thit b trong nhm ng lc l loi dy cp ng 4 li v PVC (cp PVC) chn
ngm di t, i theo ng b gc.Cc ng cp ti cc thit b gn nhau th c th t
chung trong 1 rnh tit kim v chi ph. Trong chng ny ta cng ch mi chn
s b tit din ng dy v kim tra iu kin dng pht nng lu di cho php Icp v
tn tht in p. Cc iu kin khc v dng ngn mch, dng Icpkhi c cc thit b bo
v ng c v mng in th ta s xt cc chng sau:24 n mn hc Thit k cung cp in
Xt nhm ng lc 1Nhm ng lc 1 gm 8 thit b c cc thng s nh sau:Bng2.5Thng
s ca nhm ng lc 1.- Xt thit b 1 l ba hi rn, khong cch ti thit b l
Ll1-1=15m+ Dng in tnh ton chy trong dy dn l:( )25137, 9843. 3.0,
38SdmI I Att dmUdm + Dng in pht nng lu di cho php tha mn: ( )37,
98444, 687. 1.0, 851 2IttI Acpk k Vy ta chn cp PVC-4 c Fdm=4mm2 v
Icp=47ACc thng s v in tr: x0=0, 09(/km) v r0=5(/km)STT Tn my( ) P
kWdm( ) Q kVArdm( ) S kVAdm( ) U kVdmos c 1 Ba hi rn 15 20 25 0,38
0,62 Ba hi rn 15 20 25 0,38 0,63 My hn 1,1 2,945 3,143 0,38 0,354 L
chy bng in 19 25,333 31,666 0,38 0,65 Thit b ha cng 19 25,333
31,666 0,38 0,66 Thit b ti cao tn 19 25,333 31,666 0,38 0,67 My p
ma st 10 13,333 16,667 0,38 0,68 My p ma st 10 13,333 16,667 0,38
0,625 n mn hc Thit k cung cp in +Tn tht in p thc t: ( ). .15.5
20.0, 0091 1. 0, 012 2, 4251 10, 382, 425% .100% .100% 0, 638%
5%380P r Q xdm o dm oU L VdlUdmUU U cpUdm++ < +Tn tht in nng trn
on ng dy:( )22253 1. . . .5.0, 015.3411.10 1107, 281 1 2 20, 38SdmA
r L kWho dlUdm + Chi ph cho tn tht in nng trn on ng dy: 6. 1107,
28.1000 1,1.10 C AC ()+ Vn u t cho on ng dy cp ny l:
6 6. 66, 9.10 .0, 015 1.101 1V v Ld o dl ()+ Chi ph quy i ca on
dy cp ny l: ( )( )6 6 6. 0,125 0, 04 .1.10 1,1.10 1, 27.10dZ a k V
Ctc kh + + + + (). 26 n mn hc Thit k cung cp in Tng t, ta tnh ton
chi ph qui i cho cc phng n cn li, ta c bng sau. Bng2.6Bng la chn
loi dy cp v cc thng s.STTng dy L, mPdm,kWQdm,kVArSdm, kVA Itt, A
Loi cp Icp, Ar0, /kmx0, /km1 dl1-1 15 15 20 25 37,984 PVC-4 47 5
0,092 dl1-2 35 15 20 25 37,984 PVC-4 47 5 0,093 dl1-3 18 1,1 2,945
3,143 4,775 PVC-2,5 35 8 0,094 dl1-4 22 19 25,333 31,666 48,112
PVC-10 78 2 0,085 dl1-5 20 19 25,333 31,666 48,112 PVC-10 78 2
0,086 dl1-6 15 19 25,333 31,666 48,112 PVC-10 78 2 0,087 dl1-7 12
10 13,333 16,667 25,323 PVC-2,5 35 8 0,098 dl1-8 36 10 13,333
16,667 25,323 PVC-2,5 35 8 0,09 Bng2.7Bng s liu v chi ph tn tht in
nng v chi ph u t cho ng dy.STTng dyU, V A, kWh C, 106 v0, 106 /km
Vd, 106 Z, 106 1 dl1-1 3,03 1107,38 1,11 66,9 1,003 1,2752 dl1-2
7,07 2583,64 2,584 66,9 2,342 2,973 dl1-3 0,429 33,602 0.336 65,655
1,18 0,534 dl1-4 2,317 2605,52 2,605 71,88 1,58 2,8665 dl1-5 2,107
947,46 0,947 71,88 1,44 1,1856 dl1-6 1,58 710,595 0,71 71,88 1,08
0,8887 dl1-7 2,564 629,942 0,629 65,655 0,788 0,768 dl1-7 7,639
1889,83 1,889 65,655 2,364 2,27927 n mn hc Thit k cung cp in Xt nhm
ng lc 2 Gm 7 thit b c cc thng s nh sau:B ng 2.8Thng s cc thit b nhm
ng lc 2.STT Tn my( ) P kWdm( ) Q kVArdm( ) S kVAdm( ) U kVdmos c 1
My hn 1,1 2,945 3,143 0,38 0,352 L in cng ha nhin liu 19 25,333
31,666 0,38 0,63 L in cng ha nhin liu 19 25,333 31,666 0,38 0,64
Thit b ti bnh rng 20 26,667 33,333 0,38 0,65 Thit b ti cao tn 19
25,333 31,666 0,38 0,66 My p ma st 10 13,333 16,666 0,38 0,67 My nn
kh 22,8 30,4 38 0,38 0,6
Bng 2.9Bng la chn loi dy cp v cc thng s.STTng dy L, m Pdm,kW
Qdm,kVArSdm, kVA Itt, A Loi cp Icp, A r0, /kmx0, /km1 dl2-1 30 1,1
2,945 3,143 4,775 PVC-1,5 27 13,35 0,12 dl2-2 15 19 25,333 31,666
48,115 PVC-10 35 2 0,083 dl2-3 40 19 25,333 31,666 48,115 PVC-10 78
2 0,084 dl2-4 15 20 26,667 31,666 48,115 PVC-10 78 2 0,085 dl2-5 28
19 25,333 33,333 50,644 PVC-10 78 2 0,0828 n mn hc Thit k cung cp
in 6 dl2-6 29 10 13,333 31,666 48,115 PVC-10 78 2 0,087 dl2-7 25
22,8 30,4 38 57,735 PVC-10 78 2 0,08Bng 2. 10Bng s liu v chi ph tn
tht in nng v chi ph u t cho ng dy.STTng dy U, V A, kWh C, 106 v0,
106 /km Vd, 106 Z, 106 1 dl2-1 2,76 218,06 0,218 64,825 4,537
0,9662 dl2-2 4,74 2131,78 2,131 71,88 3,235 2,6653 dl2-3 6,85
3079,24 3,08 71,88 4,67 3,854 dl2-4 6,098 2605,52 2,605 71,88 3,95
3,265 dl2-5 5,48 2729,59 2,729 71,88 3,74 3,3466 dl2-6 3,105
2652,89 2,652 71,88 4,03 3,327 dl-7 5,81 3138,12 3,138 71,88 3,31
3,68 Xt nhm ng lc 3Gm 9 thit b c cc thng s nh sau:Bng 2.1 1Thng s
cc thit b nhm ng lc 3.STT Tn my ( ) P kWdm( ) Q kVArdm( ) S kVAdm(
) U kVdmos c 1 My hn 1,1 2,945 3,143 0,38 0,352 L chy bng in 19
25,333 31,666 0,38 0,63 l chy bng in 19 25,333 31,666 0,38 0,64 l
in cng ha nhin liu 19 25,333 31,666 0,38 0,65 Thit b ti bnh rng 20
26,667 33,333 0,38 0,66 Thit b ti bnh rng 20 26,667 33,333 0,38
0,629 n mn hc Thit k cung cp in 7 Thit b ti cao tn 19 25,333 31,666
0,38 0,68 My p ma st 10 13,333 16,667 0,38 0,69My nn kh 22,8 30,4
38 0,38 0,6B ng 2.1 2Bng la chn dy cp v cc thng s:STTng dyL,
mPdm,kWQdm,kVArSdm, kVAItt, ALoi cpIcp, Ar0, /kmx0, /km1 dl3-1 5
1,1 2,945 3,143 4,775 PVC-1,5 27 13,35 0,12 dl3-2 7 19 25,333
31,66648,115PVC-6 59 3,33 0,093 Dl3-3 9 19 25,333
31,66648,115PVC-10 78 2 0,084 Dl3-4 16 19 25,333 31,66648,115PVC-10
78 2 0,085 Dl3-5 8 20 26,667 33,33350,644PVC-6 59 3,33 0,096 Dl3-6
28 20 26,667 33,333 50,644 PVC-10 78 2 0,087 Dl3-7 12 19 25,333
31,666 48,115 PVC-10 78 2 0,088 Dl3-8 20 10 13,333 16,667 25,323
PVC-2,5 35 8 0,099 Dl3-9 22 22,8 30,4 38 57,735 PVC-16 101 1,25
0,07Bng 2.1 3Bng s liu v chi ph tn tht in nng v chi ph u t cho ng
dySTTng dy U, V A, kWh C, 106 v0, 106 /km Vd, 106 Z, 106 1 dl3-1
0,197 15,576 0,016 64,83 0,324 0,0692 dl3-2 1,207 522,132 0,522
68,56 0,48 0,63 dl3-3 0,948 426,357 0,426 71,88 0,647 0,5334 dl3-4
1,685 757,968 0,758 71,88 1,15 0,9485 dl3-5 1,453 699,194 0,699
68,56 0,548 0,78930 n mn hc Thit k cung cp in 6 dl3-6 3,105
1469,777 1,47 71,88 2,012 1,87 dl3-7 1,264 568,476 0,568 71,88
0,863 0,718 dl3-8 4,274 1049,9 1,05 65,655 1,313 1,2679 dl3-9 1,773
938,025 0,938 76,86 1,691 1,217 Xt nhm ng lc 4Gm 9 thit b c cc thng
s nh sau:Bng 2.1 4Thng s cc thit b nhm ng lc 4.STT Tn my( ) P kWdm(
) Q kVArdm( ) S kVAdm( ) U kVdmos c 1 Ba hi rn 15 20 25 0,38 0,62
Ba hi rn 15 20 25 0,38 0,63 L in ha cng linh kin 19 25,333 31,666
0,38 0,64 L in ha cng linh kin 19 25,333 31,666 0,38 0,65 Thit b ti
cao tn 19 25,333 31,666 0,38 0,66 My p ma st 10 13,333 16,666 0,38
0,67 My p ma st 10 13,333 16,666 0,38 0,68 My nn kh 22,8 30,4 38
0,38 0,69 My nn kh 22,8 30,4 38 0,38 0,6B ng 2.1 5Bng la chn dy cp
v cc thng s:STTng dy L, mPdm,kWQdm,kVAr Sdm, kVA Itt, ALoi cpIcp,
Ar0, /kmx0, /km1 Dl4-1 26 15 20 25 37,984 PVC-4 47 5 0,092 Dl4-2 22
15 20 25 37,984 PVC-6 59 3,33 0,0931 n mn hc Thit k cung cp in 3
Dl4-3 10 19 25,333 31,666 48,115 PVC-10 78 2 0,084 Dl4-4 12 19
25,333 31,666 48,115 PVC-10 78 2 0,085 Dl4-5 30 19 25,333 31,666
48,115 PVC-6 59 3,33 0,096 Dl4-6 35 10 13,333 16,666 25,321 PVC-2,5
35 8 0,097 Dl4-7 32 10 13,333 16,666 25,321 PVC-4 47 5 0,098 Dl4-8
39 22,8 30,4 38 57,735 PVC-10 78 2 0,089 Dl4-9 28 22,8 30,4 38
57,735 PVC-16 101 1,25 0,07Bng 2.1 6Bng s liu v chi ph tn tht in
nng v chi ph u t cho ng dy.STTng dy U, V A, kWh C, 106 v0, 106 /km
Vd, 106 Z, 106 1 dl4-1 6,06 2214,54 2,214 66,9 2,01 2,5462 dl4-2
6,535 2359,82 2,359 68,56 3,291 2,93 dl4-3 3,37 1515,936 1,515
71,88 2,3 1,8954 dl4-4 4,001 1800,174 1,8 71,88 2,73 2,255 dl4-5
8,63 3943,8 3,944 68,56 3,43 4,516 dl4-6 5,983 1837,11 1,837 65,655
2,298 2,227 dl4-7 7,48 1312,22 1,312 66,9 2,677 1,7548 dl4-8 4,93
2660,58 2,66 71,88 2,804 3,1239 dl4-9 3,627 1918,69 1,918 76,86
3,459 2,489
Kim tra iu kin hao tn in p ca mng in i vi cc loi dy cp la chn
theo tnh ton trn.+Tn tht in p ca mng in h p:+ Tn tht in p cc i t
TBA phn xng ti t phn phi v ti t ng lc 1v ti cc thit b thuc nhm ng
lc 1l: ( ) 0, 647 2, 69 7, 639 10, 976ax1 1 1 7U U U U Vm TBA TPP
TPP dl Dl + + + + 32 n mn hc Thit k cung cp in + Tn tht in p cc i t
TBA phn xng ti t phn phi v ti t ng lc 2 v ti cc thit b thuc nhm ng
lc 2 l: ( ) 0, 647 3, 354 6, 85 10, 851ax2 2 2 3U U U U Vm TBA TPP
TPP dl Dl + + + + + Tn tht in p cc i t TBA phn xng ti t phn phi v
ti t ng lc 3 v ti cc thit b thuc nhm ng lc 3 l: ( ) 0, 647 3, 666
4, 274 8, 587ax3 3 3 8U U U U Vm TBA TPP TPP dl Dl + + + + + Tn tht
in p cc i t TBA phn xng ti t phn phi v ti t ng lc 4v ti cc thit b
thuc nhm ng lc 4l: ( ) 0, 647 2, 037 8, 63 3, 049ax4 4 4 5U U U U
Vm TBA TPP TPP dl Dl + + + + Vy tn tht in p cc i ca mng in h p l:(
)( ) ax ; ; ; 10, 976ax ax1 ax2 ax3 ax4 ax1U m U U U U U Vm m m m m
m 10, 976ax% .100% .100% 2, 89%ax380UmUmU Ta c: % 2,89% 5%axU Um cp
< nn mng in m bo an ton k thut.CHNG IIILA CHN CC PHN T TRONG H
THNG CUNG CP IN V KIM TRA IU KIN DY CP**************** III.1) S trm
bin p phn phi mng h p phn xng.33 n mn hc Thit k cung cp in a) Tnh
ton ngn mchNgn mch l s c nghim trng trong h thng in v thng xuyn xy
ra trong h thng cung cp in. Dng in khi xy ra ngn mch l rt ln s dn n
cc hu qu sau: + Dng in tng lm tng nhit cc thit b, cch in b ph hy gy
ra chm chp chy n.+ Xut hin lc in ng rt ln c kh nng ph hy cc kt cu
ca thit b v tip tc gy chm chp chy n. V th, vic tnh ton dng ngn mch
c ngha quan trng, cc kt qu tnh ton l c s cho vic chn cc thit b bo v
v kim tra n nh nhit ca dy dn Cc im cn tnh ngn mch l:N1: Ngn mch
ngay sau trm bin p N2: Ngn mch trn thanh ci t phn phiN3: Ngn mch t
ng lc N4: Ngn mch trc cc ng c Xt nhm ng lc 2 (xt ngn mch trc thit b
xa nht l l chy bng in cch t ng lc Ldl2=18mTa c s thay th tnh ton
dng ngn mch: ZBAZBA TPP 2ZTPP dl 1 8Zdl N1 N2 N3N434 n mn hc Thit k
cung cp in Hnh 3.1. S thay th tnh ton dng ngn mch.b) Tnh ton cc gi
tr in tr ca cc phn t trn:i vi mng in cung cp, tng tr ca cc thit b:
thanh ci, aptomat, cu ch, dao cch ly thng rt nh so vi trm bin p nn
c th b qua Cng sut ngn mch SN=240MVA. + in tr ca trm bin p: Trm bin
p c 1 my bin p 1x315kVA c: P0=0,72kW v PN=4, 85kWv UN% = 4%
( )22.4, 85.0, 43 3.10 7, 821.102 20, 315P UN dmRBASdm (
)22%.4.0, 4320, 317.10100. 100.0, 315U UN dmXBASdmBA ( )2 2 2 2 3
37,821 20, 317 .10 21, 77.10 Z R XBA BA BA + + + in tr ca dy cp
PVC-300 c r0=0, 07 (/km) v x0=0, 06 (/km) t trm bin p ti t phn
phi:( )3. 0, 07.0, 01 0, 7.10 R r LBA TPP o BA TPP ( )3. 0, 06.0,
01 0, 6.10 X x LBA TPP o BA TPP ( )2 2 2 2 3 30, 7 0, 6 .10 0,
922.10_Z R XBA TPP BA TPP BA TPP + + + in tr ca dy cp PVC-50 c
r0=0, 4 (/km) v x0=0, 06 (/km) t t phn phi ti t ng lc 2 l: ( )3. 0,
4.0, 05 20.102 2R r LTPP dl o TPP dl ( )3. 0, 06.0, 05 3.102 2X x
LTPP dl o TPP dl ( )2 2 2 2 3 320 3 .10 20, 22.102 2 2Z R XTPP dl
TPP dl TPP dl + + 35 n mn hc Thit k cung cp in + in tr ca dy cp
PVC-10 c: r0=2 (/km) v x0=0, 08 (/km) t t ng lc 2 ti ng c 8 trong
nhm 2 l:( )3. 2.0, 018 36.102 8 2 8R r Ldl o dl ( )3. 0, 08.0, 018
1, 44.102 8 2 8X x Ldl o dl ( )2 2 2 2 3 336 1, 44 .10 36, 029.102
8 2 8 2 8Z R Xdl dl dl + + Ngn mch h p vn c coi l ngn mch xa ngun,
coi trm bin p phn xng l ngun. Tnh im ngn mch N1:in tr ti im ngn mch
N1 l:ZN1=ZBA=21,77.10-3 ()Dng ngn mch 3 pha l: ( )1, 05.1, 05.0,
411,1391 33.3.21, 77.101UdmI kANZN Ta xt
320, 317.1012, 6 337, 821.101X XN BAR RN BA < nn kxk=1, 37Dng
ngn mch xung kch l:( ) 2. . 2.1, 37.11,139 21, 5821 1i k I kAxk xk
N Gi tr hiu dng dng xung kch l:( ) . 1, 09.11,139 12,1421 1I q I
kAxk xk N Tnh im ngn mch N2:in tr ti im ngn mch N2
l:ZN2=ZBA+ZBA-TPP= (21, 77+0, 922).10-3=22, 692.10-3 ()Dng ngn mch
3 pha l:
( )1, 05.1, 05.0, 410, 6862 33.3.22, 692.102UdmI kANZN 36 n mn
hc Thit k cung cp in Ta xt t s20, 317 0, 622, 455 37,821 0, 72X X
XN BA BA TPPR R RN BA BA TPP++
