n Cung Cp in GVHD: T.S Trn Thanh Ngc
n Cung Cp in GVHD: T.S Trn Thanh Ngc
THIT K H THNG CUNG CP IN ti: Thit k h thng cung cp in cho xng c
khS MT BNGMt bng x nghip 40m x 40m
K hiu trn mt bngTn phn xng
IB phn my
IIB phn sa cha
IIINh xng
IVKhu vn phng
Danh sch cc thit b trong cc phn xngSttTn myCng sut - kw
I. B phn my
A 1My ca kiu i3
A 2Khoan bn3.3
A 3My mi th2.7
A 4My xc6.7
A 5My phay rng4.5
A 6My tin ren18
A 7My khoan ng12
A 8My bo ngang10
II. B phn sa cha
B 1Cu trc32
B 2B tng nhit10
B 3B ngm nc nng15
B 4T sy20
B 5L in8
B 6Bn th nghim10
III. Nh xng
C 1My bm4.8
C 2My bm9.7
C 3CHIU SNG
IV. KHU VN PHNG
MY VI TNH20
MY IU HO 23
Yu cu1. Vch s cp in.2. La chn cc phn t trong s : t ng lc, phn
phi, tit din cp, h thng n cao p, 3. La chn cc thit b trong trm phn
phi : thit b bo v, cp xut, my bin p, o m, ..4. Xc nh tn tht cng
sut, in p, in nng.5. B cng sut phn khng cho x nghip, so snh tn tht
vi trc khi b .6. M phng trong Matlab, so snh cc vn v tn tht gia m
hnh trong Matlab v tnh ton thc t ( Phn thm vo ).iu kin Phn i dy
trong nh my s dng phng n i ngm.Cc thit b, dy dn s dng hin ang c trn
th trng,
MC LCLI NI U7Chng 1: Xc nh ph ti tnh ton ca cc phn xng 8Chng
2:Chn thit b cho phn xng25Chng 3:Tnh ton ngn mch53Chng 4: Tnh ton
tn tht v b nng cao h s cng sut71Ti liu tham kho78
NHN XT CA GING VIN HNG DN
NHN XT CA GING VIN PHN BIN
LI NI UTrong s nghip cng nghip ha hin i ha nc nh hin nay th ngnh
cng nghip in thc s tr thnh 1 ngnh cng nghip mi nhn, v vai tr ca n i
vi ngnh cng nghip khc ngy cng c khng nh. C th ni pht trin cng
nghip, y mnh cng cuc i mi t nc gn lin vi s pht trin ca ngnh cng
nghip in.Khi xy dng mt nh my mi, mt khu cng nghip mi hay mt khu dn
c mi th vic u tin phi tnh ton ti l xy dng mt h thng cung cp in phc
v cho nhu cu sn xut v sinh hot trong khu vc .Trong cng cuc cng
nghip ha hin i ha, hin i ha, ngnh cng nghip nc ta ngy cng khi sc,
cc nh my, x nghip khng ngng c xy dng. Gn lin vi cc cng trnh l h
thng cung cp in c thit k v xy dng. Xut pht t yu cu thc t , cung vi
nhng kin thc c hc ti trng H Cng Nghip Tp HCM, chng em nhn c ti thit
k mn hc: Thit k h thng cung cp in cho xng c kh. y l mt ti thit k rt
b ch v thit thc, gip chng em trau di, b sung nhng kin thc cn thiu
xt trong chuyn ngnh ca mnh, t c th hon thin mnh v i ln.Trong thi
gian lm bi tp di va qua, vi s n lc ca bn thn cng s ch dn nhit tnh
ca thy gio hng dn Trn Thanh Ngc, chng em hon thnh xong bi tp ca
mnh.Mt ln na chng em xin chn thnh gi n thy Trn Thanh Ngc cng cc thy
c b mn lng bit n su sc nht.
CHNG IXC NH PH TI TNH TON PH TI CA TNG KHU V CA TON PHN XNG.I. T
VN Ph ti tnh ton l ph ti gi thit lu di khng i, tng ng vi ph ti thc
t (bin i ) v mt hiu qu pht nhit hoc mc hy hoi cch in. Ni cch khc,
ph ti tnh ton cng t nng thit b ln n nhit tng t nh ph ti thc t gy
ra, v vy chn cc thit b theo ph ti tnh ton s m bo an ton cho thit b
v mt pht nng . Ph ti tnh ton (PTTT),c s dng la chn v kim tra cc
thit b trong h thng cung cp in nh: my bin p, dy dn, cc thit b ng
ct, bo vPTTT cn c dng tnh ton tn tht cng sut, tn tht in nng, tn tht
in p, la chn dung lng b cng sut phn khngPTTT ph thuc vo nhiu yu t
nh:cng sut, s lng, ch lm vic ca cc thit b in, trnh v phng thc vn
hnh h thngNu PTTT xc nh c nh hn ph ti thc t th s lm gim tui th ca
thit b in, c kh nng dn n chy nNgc li, cc thit b c chn nu d tha cng
sut s lm ng vn u t, gia tng tn thtCng v vy, c nhiu cng trnh nghin
cu v phng php xc nh PTTT, song cho n nay vn cha c c phng php no tht
hon thin.Nhng phng php c kt qu tin cy th li qu phc tp, khi lng tnh
ton v cc thng tin ban u i hi qu ln v ngc li.C th a ra y mt s phng
php thng s dng nhiu hn c xc nh PTTT khi quy hoch v thit k h thng
cung cp in: II. CC PHNG PHP TNH TON PH TI1. Phng php xc nh ph ti
tnh ton (PTTT) theo cng sut t v h s nhu cu knc .
Trong : knc - h s nhu cu, tra trong s tay k thut. Pd - cng sut t
ca thit b hoc nhm thit b, trong tnh ton c th xem gn ng Pd =Pdm
(kW). Khi xc nh ph ti tnh ton theo h s nhu cu Knc trong cung cp in
th chnh xc khng cao l do s dng bng tra Knc cho trc. N khng ph thuc
vo ch vn hnh ca thit b trong nhm m Knc=Ksd.Kmax, c ngha l h s nhu
cu ph thuc vo nhng yu t k trn. Do khi ch vn hnh thay i trong nhm
thi Knc hiu qu s khng chnh xc.
2. Phng php xc nh PTTT theo hnh dng ca th ph ti v cng sut trung
bnh :
Trong : khd - h s hnh dng ca th ph ti, tra trong s tay k thut .
Ptb- cng sut trung bnh ca thit b hoc nhm thit b (kW).
3. Phng php xc nh PTTT theo cng sut trung bnh v lch ca th ph ti
khi gi tr trung bnh :
Trong : Ptb -cng sut trung bnh ca thit b hoc nhm thit b (kW) -
lch ca th ph ti khi gi tr trung bnh -h s tn x ca 4. Phng php xac nh
PTTT theo sut tiu hao in nng cho mt n v sn phm:
Trong : p0 -sut chi ph in nng cho mt n v sn phm (kWh/vsp). M-s
sn phm sn xut c trong mt nm. Tmax-thi gian s dng cng sut ln nht (h)
Phng php ny ch yu p dng cho tnh ton ph ti ca cc chung c, khch sn,
bnh vin,.c ph ti ca tng phn t l nh nhau v bit cng sut cho mt phn
t.5. Phng php xc nh PTTT theo sut trang b in trn n v din tch:
Trong : p0-sut trang b in trn mt n v din tch (W/m2 ). F -din tch
b tr thit b (m2 ). Gi tr p0 c th tra trong s tay. Gi tr p0 ca tng b
h tiu th do kinh nghim vn hnh thng k li m c.Phng php ny ch cho kt
qu gn ng, v vy n thng c dng trong giai on thit k s b. N cng c dng
tnh ton ph ti cc phn xng c mt my mc sn xut tng i u.
6. Phng php xc nh PTTT theo cng sut trung bnh v h s cc i .Khi
khng c cc s liu cn thit p dng cc phng php tng i n gin nu trn, hoc
khi cn nng cao chnh xc ca ph ti tnh ton th nn dng theo phng php tnh
theo h s cc i.
Trong : Pdm -cng sut nh mc ca thit b hoc nhm thit b(kW).. kmax
-h s cc i, tra trong s tay k thut theo quan h : k max= f (nhq, ksd)
ksd-h s s dng, tra trong s tay k thut . nhq -s thit b dng in hiu qu
.
H s Ksd trong s tay hoc tnh bng cng thc i vi 1 thit b hoc i vi 1
nhm thit b th: . H s cc i kmax ph thuc vo ksd v nhq.Khi s dng cng
thc ny trong mt s trng hp c th ta c th s dng cng thc gn ng sau:Khi
n 3 v nhq < 4 :
i vi cc thit b lm vic ch ngn hn lp li th:
Trng hp n > 3 v nhq < 4 ph ti tnh ton c xc nh theo cng
thc:
Trong kpt l h s ph ti tng my.Nu khng c s liu chnh xc, h s ph ti
c th ly gn ng nh sau:kpt = 0,9 i vi thit b lm vic ch di hn.kpt =
0,75 i vi thit b lm vic ch ngn hn lp li.Khi nhq > 300, Ksd <
0,5 th Kmax c tnh kho st trn th ng vi nhq = 300.
Khi nhq > 300, Ksd > 0,5 th .Khi thit b c th ph ti bng
phng thig ph ti tnh ton ly bng ph ti trung bnh:
7. Phng php tnh mt s ph ti c bitTnh ton i vi thit b 1 pha:Khi
trong mng va c thit b 3 pha (thit b cn bng) v cng va c thit b mt
pha (thit b khng cn bng) th phi phn b cc thit b ln ba pha sao cho
tr s khng cn bng l nh nht. Khi ph ti tnh ton c tnh nh sau:Nu tng
cng sut ca thit b khng cn bng nh hn 15% tng cng sut ca thit b ba
pha th cc thit b mt pha xem nh l ba pha c cng sut tng ng. Khi ph ti
tnh ton c tnh ton theo cng thc sau :
Nu tng cng sut ca thit b 1 pha ln hn 15% tng cng sut ca thit b 3
pha th cc thit b mt pha quy i v ba pha c tnh nh sau:Trng hp cc thit
b mt pha u in p pha:
Trong : P1pha(max) l ph ti 1 pha ln nht.Trng hp cc thit b mt pha
u in p dy:
Trng hp trong mng li in va c thit b mt pha ni vo in p dy v va c
thit b ni vo in p pha th ta phi quy i v cng mt s u dy.Khi cng sut
quy i c tnh nh sau:
Trong Pqd(max) c so snh t 3 pha nh sau:
Sau chn ra pha no c cng sut ln nht th lag Pqd(max).Trong p(ab)a
, p(ba)b, p(cb)c. :l cc h s quy i c tra bng di y. H s quy i ph ti 1
pha ni vo in p dy thnh ph ti 1 pha ni vo in p pha ca mng.H s quy iH
s cng sut ca ph ti cos
0,30,40,50,60,650,70,80,91
p(ab)a, p(bc)b, p(ca)c1.41.171.00.890.840.800.720.640.5
p(ab)b, p(bc)c, p(ca)a-0.4-0.1700.110.160.200.280.360.5
q(ab)a, q(bc)b, q(ca)c1.260.860.580.380.300.220.09-0.05-0.29
q(ab)b, q(bc)c, q(ca)a2.451.441.160.960.880.800.670.530.29
Trong cc phng php trn, 3 phng php :1,5&6 l da trn kinh nghim
thit k v vn hnh xc nh PTTT nn ch cho kt qu gn ng .Tuy nhin, chng kh
n gin v tin li.Cc phng php cn li xy dng trn c s l thuyt xc sut thng
k, c xt n nhiu yu t .Do , c kt qu chnh xc hn, nhng khi lng tnh ton
ln v phc tp. Ty theo yu cu tnh ton v nhng thng tin c th c c v ph
ti, ngi thit k c th la chn cc phng php thch hp xc nh PTTT. Trong bi
tp ny, vi phn xng sa cha c kh, ta bit v tr, cng sut t v ch lm vic
ca tng thit b trong phn xng. Nn khi tnh ton ph ti ng lc ca phn xng
c th s dng phng php xc nh PTTT theo cng sut trung bnh v h s cc i.
Cc phn xng cn li, do ch bit din tch v cng sut t ca n, nn xc nh ph
ti ng lc ca cc phn xng ny, ta p dng phng php tnh theo cng sut t v h
s nhu cu. Ph ti chiu sng ca cc phn xng c xc nh theo phng php sut
chiu sng trn mt n v din tch sn xut. III. TNH TON1. Tnh ton ph ti b
phn myDo y l phn xng sa cha c kh nn theo bng tra (sch thit k cp in
ca Ng Hng Quang- trang 269) ta c Ksd = 0.15 v cos = 0.6.Tng s thit
b nhm 1 l n = 8.Cng sut ln nht ca nhm thit b Pmax = 18Tng s thit b
c cng sut cng sut max l n1 = 3
Tra bng tra (sch thit k cp in ca Ng Hng Quang- trang 270) ta tm
c nhq*= 0.715Ta c nhq= nhq*n= 0.7158= 5,72 (ly nhq = 6)Tra bng tra
(sch thit k cp in ca Ng Hng Quang- trang 271) vi nhq= 6 v ksd= 0.15
ta c kmax= 2,64Ph ti tnh ton ca nhm b phn my:Ptt= kmax.ksd.Pdm =
2,640,1560,2 = 23,84 (kW)Qtt= Ptt.tan= 23,841,33=31,71 (kVar)
(KVA)
2. Tnh ton ph ti b phn sa chaDo y l phn xng sa cha c kh nn theo
bng tra tra (sch thit k cp in ca Ng Hng Quang- trang 269) ta c Ksd
= 0.15 v cos = 0.6.Tng s thit b nhm 1 l n = 6.Cng sut ln nht ca nhm
thit b Pmax = 32Tng s thit b c cng sut cng sut max l n1 = 2
Tra bng tra (sch thit k cp in ca Ng Hng Quang- trang 270) t n* v
P* ta tm c nhq*= 0.77Ta c nhq= nhq*n= 0.776= 4,62 (ly nhq = 5)Tra
bng vi nhq= 5 v ksd= 0.15 ta c kmax= 2,87Ph ti tnh ton ca nhm b phn
sa cha:Ptt= kmax.ksd.Pdm = 2,870,1595 = 40,9 (kW)Qtt= Ptt.tan=
40,91,33=54,4 (kVar)
(KVA)
3. Ph ti tnh ton ca khu nh xng Do y l phn xng sa cha c kh nn
theo bng tra ta c Ksd = 0.15 v cos = 0.6.Do y l nhm thit b ch c 2
my bm, n < 3 nn ta c:
4. Ph ti tnh ton ca khu vn phngThit b khu vn phng l cc thit b 1
pha. Do ta phi quy i chng v cng sut 3 pha.Ta c cng sut 3 pha tng ca
cc khu cn li l
Cng sut 1 pha khu vn phng :
Theo l thuyt quy i ta phi so snh cng sut 1 pha vi 15% cng sut 3
pha tng. ta c:
Ta thy:
Theo l thuyt trn ta c:
5. Ph ti chiu sng cho ton phn xngTrong phn xng cha sa c kh, h
thng chiu sng s dng n si t, tra bng (sch thit k cp in ca Ng Hng
Quang - trang 269) ta c p0=15 W/m2.Vy ph ti chiu sng ca ton phn xng
l:
Do dng n si t nn cos=1Suy ra: Qcs=06. Ph ti tnh ton cho ton phn
xng
7. Tnh ton dng nh mc cho tng thit bi vi phn xng sa cha c kh th h
s cos =0,6.T ta c th tnhc Im ca tng thit b thng qua cng sut ca chng
.
Da vo cng thc trn ta tnh c dng nh mc ca cc thit b theo bng
sau:STTTn myCng sutIm
B phn my
1My ca kiu i37,6
2My khoan bn3,38,36
3My mi th2,76,84
4My sc6,716,97
5My phay rng4,511,4
6My tin ren1845,58
7My khoan ng1230,39
8My bo ngang1025,32
B phn sa cha
9Cu trc3281,03
10B tng nhit1025,32
11B ngm nc nng1537,98
12T sy2050,64
13L in820,26
14Bn th nghim1025,32
Nh xng
15My bm4,812,15
16My bm9,724,56
Khu vn phng
17My vi tnh2091
18My iu ha 2313,6
IV. XC NH TM PH TI IN T T PHN PHI V T NG LC.
1. Tm ph ti in.
Tm ph ti in l im quy c no sao cho m men ph ti t gi tr cc
tiu.Trong :Pi: Cng sut ca ph ti th i.li: Khong cch ca ph ti th I n
tm ph ti.Ta tm ph ti M( x0, y0, z0) c xc nh nh sau:
Trong :Si: Cng sut ton phn ca ph ti th i.xi, yi, zi: Ta ca ph ti
th I tnh theo mt h trc ta ty chn.Trong thc t thng ta t quan tm n ta
z nn ta ch xc nh ta x v y ca tm ph ti.Tm ph ti l im tt nht t cc trm
bin p, t phn phi v t ng lc nhm gim vn u t v tn tht trn ng dy.2. Tnh
ton.Ta c bng s liu v ta v cng sut ca cc thit b:SttTn myCng sut
(kw)X(m)Y(m)
I. B phn my
A 1My ca kiu i3318
A 2Khoan bn3.3918
A 3My mi th2.7313.5
A 4My xc6.7913.5
A 5My phay rng4.539
A 6My tin ren1899
A 7My khoan ng1233.5
A 8My bo ngang1093.5
II. B phn sa cha
B 1Cu trc3216.530
B 2B tng nhit1022.530
B 3B ngm nc nng1528.530
B 4T sy2034.530
B 5L in81024
B 6Bn th nghim1031.524
III. Nh xng
C 1My bm4.8330
C 2My bm9.7930
C 3CHIU SNG
IV. KHU VN PHNG
MY VI TNH20
MY IU HO 23
Xc nh tm ph ti khu b phn my:
Sau khi xc nh trn tm ph ti c nh du X trn bn v ta chn t t ng lc
gn tm ph ti v ca ra vo nh hnh trn.Xc nh tm ph ti khu b phn sa
cha:
Sau khi xc nh trn tm ph ti c nh du X trn bn v ta chn t t ng lc
gn tm ph ti v ca ra vo nh hnh trn.Xc nh tm ph ti khu nh xng:
Sau khi xc nh trn tm ph ti c nh du X trn bn v ta chn t t ng lc
gn tm ph ti v ca ra vo nh hnh trn.
Xc nh tm ph ti ton phn xng t t phn phi:
Sau khi xc nh trn tm ph ti trn bn v ta chn t t phn phi v tr nh
hnh trn.
S i dy phn xng
CHNG II CHN THIT B CHO PHN XNGI. Chn my bin pTa c Stt ton phn
xng l 223,79 (KVA). Ta chn my bin p ca ABB c cc thng s k thut nh
sau:
Sm (MVA)UTC (kV)USC (kV)0 (W)N (W)UN %Trng lng (kg)
2500,422640410041130
Kt cu trm bin p ta chn kiu trm nn, mt s c im ca trm nn: Trm nn
thng c dng nhng ni c iu kin t ai nh vng nng thn, c quan, x nghip nh
v va. i vi loi trm nn. thit b cao p t trn ct, my bin p thng l t ba
my bin p mt pha hay mt my bin p ba pha t bt trn b ximng di t, t phn
phi h p t trong nh. Xung quanh trm c xy tng ro bo v. ng dy n c th l
cp ngm hay ng dy trn khng, phn o m c th thc hin pha trung p hay pha
h p.
II. Chn my bin dng BITa c Itt = 340 (A) nn ta chn BI c t s bin
dng l 400/5.
CTRNG: Li tn hnh xuyn bng tn silic cht lng cao loi c nh hng, thm
t cao, tn hao thp. Cun dy th cp bng dy may cht lng cao qun trn li
tn hnh xuyn. Li tn v cun dy c bao bc bng epoxy m bo cch in cao, chu
m tt. V ngoi nha hoc epoxy m bo cch in gia cun dy th cp vi cun dy s
cp (cp hoc thanh ci). Ca s rng, d lun cp hoc thanh ci. C th thay i
t s bin dng bng cch thay i s vng dy s cp. u dy c np che bng nha v
vt kp ch. thp c 2 l 8 d cho vic lp t my bin dng CT-0.6 vo bng in.
Dng trong nh. Ch cc tnh khi u dy.THNG S K THUT:KiuDng s cp(A)Dng th
cp(A)S vngdy s cpDung lng(VA)Cpchnh xcKch thc (mm)Trng lng(kg)
ng knhDiRngCaoLp t
400/540051100.550120501401001.50
III. Chn my bin in p BU kim tra cch in v cung cp tn hiu cho h
thng bo v r le , o lng t cc my bin in p trn thanh gp 22kV , .Thng
chn my bin in p 4MS34 do hng SIEMENS bng 28.pl trang 269 (sch H
Thng Cung Cp in tp 2 ca Thy Trn Quang Khnh) ch to vi cc thng s nh
sau :
in p s cp Udmsc = 22/ kV
in p th cp Udmtc=100/VCp chnh xc 0,5Cng sut nh mc Sdm=400 VA
IV. Chn FCOTiu chun: ANSI C37.41, C37.42, IEC 282-2in p nh mc:
24kVDng in nh mc: 100 ATn s nh mc: 50HzKh nng ct ngn mch: 12kAin p
chu ng xung (BIL):150kVChiu di dng r: 600mmVt liu cch in: polymerng
cu ch bng fiberglass chu lc cao v c bc chng tia cc tm.V. CHN TIT
DIN DY DN.L thuyt:- La chn dy dn : C 3 phng php la chn tit din dy
dn - Chn theo mt dng kinh t Jkt. - Chn theo tn tht in p cho php
Ucp. - Chn theo dng in pht nng cho php Icp.Chn theo mt dng kinh t
Jkt : Jkt(A/mm2) l s (A) ln nht trn 1mm2 tit din. tit din chn theo
phng php ny c li v mt kinh t.Chn theo tn tht in p cho php Ucp: php
ny ly chi tiu cht lng in lm iu kin tin quyt.Chn theo dng in pht nng
cho php Icp: phng php ny tn dng ht kh nng ti ca dy dn v cp.
Li inJktIcpUcp
> 22kVS dng Jkt,kim tra lai theo Icp hay Ucp
1-22kVSo snh kinh t gia Jkt v Ucp kim tra li theo Icp
Um ta chn UCB =400VTa c dng in tnh ton ca khu b phn sa cha Itt =
60,36(A).Ta chn CB c thng s k thut sau:Tn CBLoiS pha, dng nh mcDng
ctIz cho php ca dy dnDng ngn mch
NF63-SWTiu chun3P, 63 A7,5 kA113 A5,285 kA(trang 63)
6.2.2 Chn CB bo v t t phn phi n t ng lc ca khu b phn sa cha.Vi
Um ton phn xng l 380V vi iu kin UCB>Um ta chn UCB =400VTa c dng
in tnh ton ca khu b phn sa cha Itt = 103.57(A).Tn CBLoiDng nh mcDng
ctIz cho php ca dy dnDng ngn mch
NF125-CWKinh t3P, 125 A10 kA206 A7,378 kA(trang 62)
6.2.3 Chn CB bo v t t phn phi n t ng lc ca khu nh xng.Vi Um ton
phn xng l 380V vi iu kin UCB>Um ta chn UCB =400VTa c dng in tnh
ton ca khu b phn my Itt = 36.77(A).Tn CBLoiDng nh mcDng ctIz cho
php ca dy dnDng ngn mch
NF63-SWTiu chun3P, 40 A7,5 kA66 A6,460 kA(trang 64)
6.2.4 Chn CB bo v t t phn phi n t ng lc ca khu vn phng.Vi Um ton
phn xng l 380V vi iu kin UCB>Um ta chn UCB =400VTa c dng in tnh
ton ca khu b phn my Itt = 151.7(A).Tn CBLoiDng nh mcDng ctIz cho
php ca dy dnDng ngn mch
NF250-CWKinh t3P, 175 A18 kA301 A7,647 kA(trang 65)
6.2.5 Chn CB bo v t t phn phi n t chiu sng.Vi Um ton phn xng l
380V vi iu kin UCB>Um ta chn UCB =400VTa c dng in tnh ton ca khu
b phn my Itt = 109(A).Tn CBLoiDng nh mcDng ctIz cho php ca dy dnDng
ngn mch
NF250-CWKinh t3P, 125 A18 kA206 A6,713 kA(trang 65)
6.3 Chn CB ca tng b phn :
Cng thc tnh dng nh mc ca cc thit b: Vi my ca kiu i ta c dng Im
nh sau :
Tng t vi cc thit b cc b phn khc ta c bng s liu chn CB nh sau :
STTTn myCng sut (kW)Im(A)Tn CBIm CB (A)Ict CB (kA)Iz(A) Ik i din
(kA)
B phn my
1My ca kiu i37,6NF63-CW3P 10531
2My khoan bn3,38,36NF63-CW3P 10531
3My mi th2,76,84NF63-CW3P 10531
4My sc6,716,97NF63-CW3P 20541
5My phay rng4,511,4NF63-CW3P 15531
6My tin ren1845,58NF63-CW3P 5051134,910(trang 67)
7My khoan ng1230,39NF63-CW3P 32566
8My bo ngang1025,32NF63-CW3P 30553
B phn sa cha
9Cu trc3281,03NF125-CW3P 10010174
10B tng nhit1025,32NF63-CW3P 30553
11B ngm nc nng1537,98NF63-CW3P 40587
12T sy2050,64NF63-CW3P 635113
13L in820,26NF63-CW3P 30541
14Bn th nghim1025,32NF63-CW3P 305533,18(trang 66)
Nh xng
15My bm 14,812,15NF63-CW3P 15531
16My bm 29,724,56NF63-CW3P 305413,253(trang 68)
Khu vn phng
17My vi tnh2091NF125-CW1P 10010144
18My iu ha 2313,6NF32-SW1P 16531
S nguyn l
CHNG IIITNH TON DNG NGN MCH.I. Khi nim v ngn mch 1.1 Khi nim Phn
tch ngn mch l mt phn quan trng trong gii tch h thng in. Bi ton ngn
mch gm vic xc nh in p ti cc nt v dng in chy trn cc nhnh ngn mch 3
pha i xng (balanced faults ) v ngn mch khng i xng ( unbalanced
faults ) .Ngn mch khng i xng gm ngn mch mt dy chm t , ngn mch hai
dy khng chm t , ngn mch hai dy chm t .Cc thong tin c c t bi ton ngn
mch s phc v cho cng vic chnh nh r le v chn la thit b bo v Bin ca
dng in ngn mch ph thuc vo tng tr ca khp kn qua im xy ra ngn mch v
in p ca mng in . Tng tr trong bi ton ngn mch bao gm c tng tr qu ca
my pht trong li ( bao gm thnh phn siu qu , qu v trng thi tnh ).
Chnh v vy trong nhng vn kh ca bi ton ngn mch l thnh lp ma trn tng
tr hay tng dn Trong cung cp in ngn mch mt pha chm t l ngn mch c xc
sut xy ra ln nht ( khong 65%) v ngn mch ba pha c xc sut thp nht (
khong 5%) .Tuy nhin , chng ta cn phn tch hai dng ny bi cc nh hng ca
n l ng k n tnh trng lm vic ca h thng in . Mc khc vic tnh ton ngn
mch mt pha tng i phc tp hn so vi ngn mch ba pha , nn trong thc t
thit k ngi ta hay dung kt qu ca bi ton ngn mch ba pha i xng .V tnh
ton ngn mch chng ta phi k n c my bin p v my pht trong li , ngha l
chng ta phi tnh ton vi nhiu cp in p khc nhau . iu ny s phc tp khi
tnh trong h n v c tn thng thng , do khi tnh ton ngn mch ngi ta thng
quy i v cng mt cp in p thng qua vic s dng h n v tng i ( h n v khng
tn) Nguyn nhn ngn mch : nguyn nhn chung v ch yu ca ngn mch l do cch
in b hng . L do cch in b hng c th l : gi ci khi lm vic lu ngy , chu
tc ng ca nhit Hu qu ca ngn mch Pht nng cc b rt nhanh , nhit cao ,
gy chy n Gy st p li in , nh hng n nng sut lm vic ca my mc v thit b
Gy ra mt n nh h thng in do cc my pht b mt cn bng cng sut , quay
theo nhng vn tc khc nhauMc ch tnh ton ngn mchLa chn thit b ph hp ,
chu c dng in trong thi gian tn ti ngn mch Tnh ton hiu chnh bo v
roleLa chn s thc hip lm gim dng ngn mch La chn thit b hn ch dng ngn
mch Nhng bi ton lin quan n tnh ton dng ngn mch La chn s mch cung cp
in , nh my inLa chn thit b in v dy dn Thit k chnh nh bo v r leTnh
ton qu in p trong h thng in Tnh ton ni t Nghin cu n nh h thng in1.2
Phn loi ngn mch Ngn mch gin tip : l ngn mch qua mt in tr trung gian
, gm in tr do h quang in v in tr ca cc phn t khc trn ng i ca dng in
t pha ny n pha khc hoc t pha n t in tr h quang in thay i theo thi
gian , thng rt phc tp v kh xc nh chnh xc .Theo thc nghim
Trong :I: l dng ngn mch (A)l: l chiu di h quang in (m)Ngn mch
trc tip l ngn mch qua mt in tr trung gian rt b , c th b qua ( cn c
gi l ngn mch kim loi )Ngn mch i xng l dng ngn mch vn duy tr c h
thng dng v p ba pha tnh trng i xng Ngn mch khng i xng l dng ngn mch
lm cho h thng dng v p ba pha mt i xng Khng i xng ngang : khi s c xy
ra ti mt im , m tng tr cc pha ti im nh nhau Khng i xng dc : khi s c
xy ra m tng tr cc pha ti mt im khng nh nhauS c phc tp l hin tng xut
hin nhiu dng ngn mch khng i xng ngang dc trong h thng in II. M hnh
thay th cc phn t trong tnh ton ngn mch 2.1 Ngn mch ti thanh ci h p
MBANgn mch ti thanh ci MBA dung chn CB h p bo v cho TBA . Trong mt
s trng hp , kt qu ngn mch ny dung tnh ton phi hip bo v gia CB h p v
cu ch trung th FCO bo v cho MBA Trong qu trnh tnh ton , ch xt tng
tr MBA , b qua cc thnh phn khc trong HTTng tr MBAZBADng ngn mch s
cp In1Dng in ngn mch th cp In2Ngn mch ti 1 im trn li h th 2.2 Cc gi
tr tng tr 2.2.1 Tng tr h thng quy i v th cp MBA Tng tr h thng c xc
nh da vo cng sut ngn mch 3 pha do ngnh in xc nh ZHT = XHT = ZHT,
RHT = 0,1.XHTVi U2 in p nh mc th cp Vi Sn cng sut ngn mch h thng
2.2.2 Tng tr my pht quy i v th cp MBA Tng tr my pht c xc nh da vo
gi tr in khng siu qu ca my pht XMF = Vi U2 in p nh mc th cp ca
MBAVi SMF cng sut nh mc my phtVi in khng siu qu c trong l lch my
2.2.3 Tng tr MBA quy v th cp RBA = ZBA = Vi cng sut tn hao ngn mch
Vi Un% in p ngn mch %U2,I2 in p , dng in nh mc th cp2.3 Tng tr dy
dn Gi tr ro ro =gi tr xo c cho theo nh ch toF
