chuong 3

Ch 3Chng 3

H THNG NI T

Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 1

Chng 3: H THNG NI TMC TIU

Sau khi hc xong chng 3

Phn tch c u, nhc

g gsinh vin c kh nng:

im, tnh nng v phm ving dng ca cc h thng

i h ngun ni t chun.

C kh nng tnh ton,thit k, thi cng h thngni t tha cc tiu chun


hin hnh.

Chng 3: H THNG NI T

NI DUNG3.1 Cc h thng ni t chun3 2 in tr sut ca t3.2 in tr sut ca t3.3 Loi ni t3.4 Cc kiu ni t3.5 in tr ni t3.6 Phn tch h thng ni t hin i


3.1. CC H THNG NI T CHUN

H thng in phn phi c phn loi da vocch b tr h thng ni t.cch b tr h thng ni t. IT, TT, TN C, TN S, TN CS Ch ci th I ch tnh cht ca trung tnh ngun: Ch ci th I ch tnh cht ca trung tnh ngun:

T: Trung tnh ngun trc tip ni t.I : Cc phn t mang in cch ly vi tI : Cc phn t mang in cch ly vi t.

Ch ci th II ch hnh thc bo v: T: Ni t trc tip

N: Ni trc tip bng dy dn bo v vi im i t (th l d t t h)


ni t ca ngun(thng l dy trung tnh)

3.1. CC H THNG NI T CHUN

Trong mng TN dng thm 1 hoc 2 ch ci h h h b t d t t h d nh ngha cch b tr dy trung tnh v dybo v:

C D t t h N d b PEC : Dy trung tnh N v dy bo v PEchung nhau thnh 1 dy PEN.

S D t t h N d PE t h bitS : Dy trung tnh N v dy PE tch bitnhau.

CS: Dy N v PE kt hp trong 1 viCS: Dy N v PE kt hp trong 1 viphn ca h thng.


3.1. CC H THNG NI T CHUN1. H thng IT:

V thit b V thit bc ni tring.g Tit din dyPE nh hndy N. Bnh thnggtrn dy PEkhng c st

Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 6H thng ITp.

3.1. CC H THNG NI T CHUN1. H thng IT: Gim ngng qu p khi xut hin s c chmg g q p t cun cao sang cun h MBA ngun.

Khi h cch in dng s c th nht thng Khi h cch in, dng s c th nht thngthp v khng nguy him.

S c th 2 xy ra trn pha khc to dng ngn S c th 2 xy ra trn pha khc to dng ngnmch v gy nguy him.

C d thit b h h khi 2Cn s dng thit b vn hnh khi c s c 2pha hay lp t thit b kim sot cch in.


3.1. CC H THNG NI T CHUN2 H th TT S n gin. S dng 2 h thng ni t ring nn cn lu

2. H thng TT:

S dng 2 h thng ni t ring nn cn lu bo v qu p. Tit din dy PE c th nh hn dy N v xc Tit din dy PE c th nh hn dy N v xcnh theo dng sc. Bnh thng, dyPE khng c st p. Khi s c, xungin p trn dy PEth

Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 8H thng TTthp.

3.1. CC H THNG NI T CHUN3. H thng TN:

a. H thng TN-S D U ti l t b Dng s c v U tip xc ln nn cn trang bthit b t ng bo v ngt ngun khi c s c. D PE t h bit d N kh i t l l i Dy PE tch bit dy N, khng ni t lp li.

Bnhth thng,khng cdng indng inv st ptrn dy

Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 9H thng TN-S

yPE.

3.1. CC H THNG NI T CHUN3. H thng TN:

b. H thng TN-C Ni t lp lim bo dy PE ni t mi TH. Dng s c v H thng TN-C

U tip xc ln nn cn trang b thit b t ng bov ngt ngun khi c s c. Bnh thng, v thit b, t v dy N c cng U. Khi s c st p ngun, nhiu ln.

Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 10 Khi ti khng i xng, trong dy PE c in.

3.1. CC H THNG NI T CHUN3 H h TN3. H thng TN:

c. H thng TN-C-S H thng n kt hp gia TN C(tr c) TN S H thng ny kt hp gia TN-C(trc) v TN-S(sau). im phn dy PE t dy PEN thng lim u ca liim u ca li.

Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 11H thng TN-C-S

3.1. CC H THNG NI T CHUNPhm vi ng dng cc h thng ni t

TT :mng in hn ch kim tra hay c th m g yrng.

IT : yu cu lin tc cung cp in IT : yu cu lin tc cung cp in. TN : mng in kim tra thng xuyn hay khngm rngm rng.

- TN-S: bt buc cho mch s dng dy ng c 10 2 h h 16 216mm2.

3.1. CC H THNG NI T CHUNPhm vi ng dng cc h thng ni t

Trong thc t, vic chn loi h thng ni t cng , gc vo cc yu cu sau:

9 An ton chng in git (TN-C TN-S)9 An ton chng in git (TN C, TN S)9 An ton chng ho hon(TN-S)9 Bo v chng qu p (IT)9 Bo v chng nhiu in t ( TT, TN-S)Bo v chng nhiu in t ( TT, TN S)9 Lin tc cung cp in (IT)


3.1. CC H THNG NI T CHUNPh i d h th i tPhm vi ng dng cc h thng ni t

Loi mng in Khuyn dng

C th s/dng

Khng s/dngdng s/dng s/dng

Mng in rt ln vi R30Mng truyn hnh,

TN TT TN-C,IT

TN TT ITtruyn thanhMng in vi dng r ln (>500mA)

TN

TN

TT IT

IT,TT

Mng ngoi tri vi ng dy trn khng

My pht in d phng TT

TT TN

TN

IT

IT


My pht in d phng TT TNIT

3.1. CC H THNG NI T CHUNLoi ti Khuyn

dngC th s/dng

Khng s/dng

Ti nhy cm vi dng s c ln (ng c)

Ti i h i

TNTTIT

Ti vi mc cch in thp (l in, my hn)Thit b 1 pha s dng TN C IT

TN TT IT

TT TN SThit b 1 pha s dng in p (L N)

Ti vi mc gy nguy him ( t b

TN-C,IT

TT ITTN

TT,TN-S

cao (cn trc, bng chuyn)

My cng c

TT ITTN

TN S TN C IT TT


My cng c TN-S TN-C,IT TT

3.1. CC H THNG NI T CHUNC l i kh Kh C th KhCc loi khc Khuyn

dngC th s/dng

Khng s/dng

Mng cp in t MBA IT khng IT cTTMng cp in t MBA ni sao-saoCng trnh d chyM i i BA

IT khng c dy N

IT c dy N

TT

IT TN-S,TT TN-CMng in vi trm BA khch hng

Mng in vi my bin tn

TT

TT TN ITMng in vi my bin tn

Mng in vi vic lin mch ni t khng m

TT

TT TN-S

TN,IT

TN-C,ITboThit b in tMng iu khin t/b cm

TN-S TT TN-C


Mng iu khin t/b, cm bin PLC v t/b chp hnh IT TN-S,TT

3.1. CC H THNG NI T CHUN4. Quy nh v dy bo v PE v PEN

Dy PE ni cc vt dn t nhin v v kim loi Dy PE ni cc vt dn t nhin v v kim loikhng mang in ca cc thit b to li ng p. Dy PE thng bc cch in mu vng sc Dy PE thng bc cch in mu vng scxanh lc. Trn dy PE khng cha thit b ng ct. Dy PEN c chc nng ca dy trung tnh v dy Dy PEN c chc nng ca dy trung tnh v dybo v c tit din khng nh hn dy trung tnh. Phng php chn tit din dy PE v dy PEN: Phng php chn tit din dy PE v dy PEN:9 PP n gin ho9 PP t hit


9 PP ng tr nhit

3.1. CC H THNG NI T CHUN4. Quy nh v dy bo v PE v PEN

Bi tp v d: Xc nh tit din ti thiu cap dy PE trong mng h p s dng cp n li bngng, c v bc cch in PVC. Bit dng ngn

h h t I 25kA thi i t hmch chm t I=25kA, thi gian ct ngn mchca CB tC = 30ms ? Gii

Phng php ng tr nhit

Ch S 35 2


Chn SPE = 35 mm2

3.2. IN TR SUT CA T L in tr ca khi lp phng t mi cnh 1cm c n v m

Bin thin trong phm vi rng v ph thuc vo: cu to, m t, to, dnh cc ht t, mui.

Xc nh theo biu thc:4aR 9 a: khong cch i ( ) = 4aR

(a2 + b2)2a 1+ _

(4a2 + 4b2)2a

gia cc cc (m)

9 b: chiu su cc (a + b ) (4a + 4b )chn trong t (m)

9 R: in tr t th hin trn my o in tr


y theo phng php c.

3.2. IN TR SUT CA T TH a > 20b : = 2aR thay i theo ma nn tt = .Km9 tt : in tr sut tnh ton9 Km : h s thay i (h s ma)m

Hnh thc su t b Km Ghi chH s thay i in tr sut ca t theo ma Km

ni t

phn ni t(m)m

Thanh t 0,5 1,41,8 o vo nm ngang 0,81 1,251,45 ma khCc ng

0,8 1,21,4 o vo


thng ng ma ma

3.2. IN TR SUT CA T Tnh ton s b c th dng tr s gn ng ca cho 1 s loi t c trnh by bng di:

T i t t tLoi t Gi tr in tr

sut gii hn(m)Gi tr in tr sut

khi thit k(m)

Tr s in tr sut ca t

sut gii hn(m) khi thit k(m)Nc bin 0,15 0,25 0,2

t en 5 100 8t en 5 100 8

t st m 2 12 10

N h 10 500 20Nc sng,ao h 10 500 20

t pha st 20 200 30


t rung 20 100 40

3.2. IN TR SUT CA TLoi t Gi tr in tr

sut gii hn(m)Gi tr in tr sut

khi thit k(m)

B tng 40 1000 100

t kh 20 1000 100t kh 20 1000 100

t pha ct 300 500 400

Than 1000 5000 2000

t nh 1000 50000 3000

Ct 1000 10000 3000

l 10000 0000 20000


t ln 10000 50000 20000

3.3. LOI NI T1. Ni t t nhin ng dn nc hay v bc kim loi (khng

phi ng nhin liu) l trang thit b ni t. Ch c coi l ni t b sung2. Ni t nhn to m bo R t nm trong gii hn cho php,

n nh lu di Ni t bng cch cc thp, thanh dp hnh

h ht di 2 3 t 0 5 0 8ch nht di 23m ng xung t 0,50,8m. Tit din cc ni t 48mm2 vi U1000V v

100 2 i U > 1000V


100mm2 vi U > 1000V.

3.3. LOI NI Tc im trang thit b ni t kiu c v kiu mi

Thit b kiu c Thit b kiu mi

- ng KL =3550mm, d=35mm l = 23m

- Cc ng li thp =1316mm d = 1 4; 2 4; 3md=35mm, l = 23m =1316mm, d = 1,4; 2,4; 3m

- Thanh thp dp d4mm S48mm2

- Cc m li thp =1316mm, d= 1; 1,5; 3md4mm, S48mm , ; , ;

- Cp ng trn S25mm2 - Bng ng 50mm0,5mm- Cp ng trn S25mm2Cp ng trn S25mm2- Li ng trn- Bn ng trn


i t thit b i t ki ki i

3.3. LOI NI Tc im trang thit b ni t kiu c v kiu miThit b kiu c Thit b kiu mi

- Lin kt gia cc v cp

+ Kp kim loi

-Lin kt gia cc v cp

+ c xit cpp o+ Hn in+ Hn gi

c t cp+ Hn ho nhit

- Ci to t+ Than + Mui

- Ci to t+ Ho cht gim in tr t

- Bng ng ni t- Bng ng ni t

- Hp btng kim tra

- Hp kim tra ni t bng


ni t nha tng hp

3.4. CC KIU NI TNi t tp trung Ni t mch vng

Bng ng ni t

Cc ni t Cp ng lin kt cc cc Khong cch ccbng 2 ln chiu di Hng cc ni t cch

1 1ni tg

cc loi tr hiu ngmn che.

mp tng 11,5m.

S dng khi phm vi S dng ni t m,in tr sut thp, xa t h( i )

g p cng trnh hp ( th)hoc trang thit b cU 1000V I h t l


cng trnh(ngoi ) U>1000V, I chm t ln.

3.4. CC KIU NI TThi cng h thng ni t cn ch : Trc khi t xung t, cc (thanh) ni t bng st, thp phi nh sch g, trng km(nu cn),

khng sn hoc dng cc thp bc ng. d i t h h h 0 5 0 7 ng dy ni t chnh chn su 0,50,7m ngoi tri v t trong rnh hay ni theo tng trong nhtrong nh. Dy ni t chnh v trangthit b ni vi nhau thng quathit b ni vi nhau thng quabng ng ni t. Cm nitrc tip trang thit b vi dy


ni t chnh. Bng ng ni t

3.5. IN TR NI T1 X h i t i t HT i t i1. Xc nh in tr ni t _ a.HT ni t n gin

Loi in cc Mt ct ngang

Mt chiu

Cng thc Ghi chngang chiu

bngch

L dCc chn thng ng (1)

Lh

dCc chn di t mt khong h

(1)

d

L

d

LThanh nm ngang trn mt tThanh nm

(1)

hd

d

L

Thanh nm ngang chn di t mt khong h

(2)


Ghi ch: (1) d

3.5. IN TR NI T1 X h i t i t HT i t i


Mt chiu

Cng thc Ghi ch

1. Xc nh in tr ni t _ a.HT ni t n gin

g gbng

Hai cc nm ngang chn di t mt h d L/2 (2)chn di t mt khong hBa cc nm ngang

h d L/2

L/3

(2)

chn di t mt khong hBn cc nm ngang

hd

L/4

(2)

(2)Bn cc nm ngang chn di t mt khong h

hL/4

d


Ghi ch: (2) d

3.5. IN TR NI T1 Xc nh in tr ni t a HT ni t n gin


Mt chiu

Cng thc Ghi ch

1. Xc nh in tr ni t _ a.HT ni t n gin

ngang chiu bng

ch

Su cc nm ngang chn di h L/6 (2)ngang chn di t mt khong hTm cc nm

h

d

L/6 (2)

L/8ngang chn di t mt khong hBn KL trn ng

h (2)d

L/8

Bn KL

(3)Bn KL trn ng knh D chn di t mt khong h

h hnh vung cnh a th D=1,13a


Ghi ch: (2) d

3.5. IN TR NI T1 X h i t i t

Vng c in tr s t t cao din tch lp t

1. Xc nh in tr ni t a. H thng ni t n gin (1cc ni t) Vng c in tr sut t cao, din tch lp tni t b hn ch c th s dng h thng ni tvi chiu di cc t n 20m hoc hnvi chiu di cc t n 20m hoc hn. t c cu to 2 lp vi khc nhau th in trcc ni t thng ng l: 9 i t cc ni t thng ng l:RC=

2[ h + (L h) 1 ]

1 ln( 4Ld

)9 1, 2: in tr sut lp t trn v di (m)2[

1+ (L - h) 2

] v di (m)

9 h: b dy ca lp t trn (m)9 L: chiu di cc ni t (m)


lp t trn (m)9 d: ng knh cc ni t (m)

3.5. IN TR NI T1 X h i t i t

HT ni t gm n cc chn

1. Xc nh in tr ni t b. H thng ni t hn hp

9 r in tr mt HT ni t gm n cc chnthng ng: RC=rC/(n.C) HT ni t gm thanh(dy)

9 rC:in tr mtcc ni t9 n: s cc ni t HT ni t gm thanh(dy)

nm ngang ni cc cc chnthng ng: Rth= rt / th

9 n: s cc ni t9 rt: in tr thanhdythng ng: Rth rt / th

HT ni t gm cc cc vthanh (dy) kt hp:

dy9 c,th: h s sdng cc v thanh( y) p g9 RC, Rth: in trh thng cc v

RTH =

RC.RthR +R


thanh (dy) ni tRC +Rth

3.5. IN TR NI T2 Ph h d i t i t2. Phng php v dng c o in tr ni t

a. Phng php Ampere k v Volt k Khong cch gia cc t E cc d S cc

G U

Khong cch gia cc t E, cc d S v cc ph H l 20m. Dng MBA cch ly cung

i V

G

E ES S H

UMeasAII

cp ngun in p xoaychiu c th thay i gi trvo 2 u cc E v cc SES vo 2 u cc E v cc S.

in tr ni t cn o:R I URE RS RHRE = I.Umeas

PP ny dng o in

20m 20m

Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 33PP volt k Ampere k tr ni t c gi tr nh.


b. Phng php my o vi cc ph v cc dC2

S

HC2

P2

P1

E/C1 S/P2 H/C2C1L

ESP1

S dng my o vi cc phS dng my o vi cc ph v cc d

Cc phCc d


Cc phCc d


b. Phng php my o vi cc ph v cc dR >RX

RC

RbRC

RCRX

RX

C

Rb~RX

RC

Rb

Rbd

RC RbRb

d: ng cho ln nht ca b dy mt t chn HT ni t

Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 35Cch b tr khong cch gia im d v im ph

3.5. IN TR NI T2. Phng php v dng c o in tr ni t

c. Phng php dng my o khng s dng g p p g y g gcc ph v cc d

U

I

o in tr ca 1 cc trong h thng ni t

R1 R2 R3 Rn-1 Rn

R1,n =R=U/I ;1R1

+ 1R21Rn

+ + )-1(


1 2 n

3.5. IN TR NI T3 V d t h t 3. V d tnh ton

a. V d 1: Xc nh R ca h thng ni t nhh h d i Bit i t t t kh lhnh di. Bit in tr sut ca t vo ma kh l200 m ?

Hp kim t i t

Cp ni tCp ng trnS=50mm2

Mi hn tra ni tt nn

5m

Cc thp bc ngL 3 16

6m

Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 37H thng ni t 5 cc dyL=3m, =16mm


a. V d 1: in tr ni t 1cc:

p dng cng thc:rC = 53,6()

Vi s cc n=5, t s a/l = 6/3, tra bng in tr h thng 5 cc:RC = rC/(n.C) = 53,6/(5.0,81) = 13,2()

Cp ng trn tit din 50mm2 => ng knh d=8mm in tr ni t ca cp ng trn c tng chiu di Lt = 46=24m, chn su so vi mt t h=0,5m:

p dng cng thc:rt = 16,8() => Rth = rt / th = 16,8/0,86 = 19,5() in tr ni t ton h thng:

RTH =RC.Rth = 7,9()


RTH = RC +Rth 7,9()


b. V d 2: Thit k h thng ni t c in tri t R 10 Bit 200 ( )?ni t R


b. V d 2:in tr ni

t 1 cc: rC = 69,7()Tra bng => = 0 81Tra bng => C = 0,81 in tr ca h thng 5 cc: RC = 17,2()p dng cng thc:

in tr ni t ca cp ng trn c tng chiu in tr ni t ca cp ng trn c tng chiu di Lt = 46=24m, chn su so vi mt t h=0,8m:p dng cng thc:Rth = 22,3()p g g th , ( )

in tr ni t ton h thng: RTH =

RC.RthR +R

= 9,7()


ton h thng: TH RC +Rth


c. V d 3:2

6m7m

Thit k h thngni t cho px cchiu di 20m rng

2m

chiu di 20m, rng10m, =150m?

Cc thp bc ng Cp v cc chnCc thp bc ng L=3m, =16mm

Cp ng trn

Cp v cc chnsu di t 0,8m. in tr sut tnh ton:Cp ng trn

S = 35 mm2

Cp ng trn

tt = .Km = 150.1,4 = 210(m)

i t i t 1 52 2()Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 41

S = 50 mm2 in tr ni t 1 cc: rC = 52,2()


c. V d 3:Vi n = 12, a/l = 6/3 = 2,tra bng => C=0.68

in tr h thng 12 cc: RC = 6,4 () in tr ca cp ng trn d=8mm(S=50mm2) ct hi di L 24 2 14 2 76 h itng chiu di Lt = 242+142=76m, chn su so vimt t h=0,5m:

p dng cng thc:rt = 6,37()

T b t 0 38=> R = r / = 16 7()p dng cng thc:Tra bng tm c th =0,38=> Rth = rt / th = 16,7()

in tr ni t R =RC.Rth = 9 7()


in tr ni t ton h thng:

RTH = RC +Rth= 9,7()


d. V d 4:T h i i i hiTnh in tr ni t ca mt cc ni t c chiudi L=30m, ng knh d=0,1m, chn khu vc clp t trn vi 1 = 2000 m v chiu dy h=10mlp t trn vi 1 2000 m v chiu dy h 10m,lp t di vi 2 = 750 m ?

d thp dng cng thc:RC=

2[ h + (L h) 1 ]

1 ln( 4Ld

)2[ h

1+ (L - h) 12

] d

R 35 6 ()Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 43

=> RC = 35,6 ()

3.6. PHN TCH CC H THNGNI T HIN INI T HIN I

Ni t truyn thng tuy d lm nhng hiu qu khng cao v gp mt s hn ch sau:khng cao v gp mt s hn ch sau:9 in tr ni t khng gim theo s lng cc.9 Mui d ho tan trong nc R khng n9 Mui d ho tan trong nc R khng nnh i hi phi kim tra, bo tr nh k.9 Lin kt cc b phn ni t bng c xit tuyLin kt cc b phn ni t bng c xit tuyn gin nhng khng m bo bn v dn in.9 Khng gim gi tr tng tr h thng ni t doKhng gim gi tr tng tr h thng ni t dokhng gim c thnh phn dung khng.=> Cc nhc im trn c th khc phc nh


p ng dng cc thit b, vt liu, cng ngh mi.


1.Thit b, vt liu v cng ngh mi:a in cc ni t: R()a. in cc ni t:

Cc thp bc ng=13mm 16mm

R()

= 23mm=13mm, 16mm,23mm c dn intt, chng n mn

= 16mm

, gcao, bn trong kt niv lp t. L(m)

12,5%

ng knh ccchn theo bn c Quan h R=f(L,)

Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 45hc v chiu di thng khng qu 3m.


1.Thit b, vt liu v cng ngh mi:a in cc ni t:a. in cc ni t:

Vic s dng ccdi qu 3m c xem

L1

L

L2 > L1=> < di qu 3m c xem

xt trong cc trnghp sau:

L2

9 Lp t trn cin tr sut ln.9 Din tch trinkhai h thng ni Gradient in th theo L


t b hn ch. Gradient in th theo L


1.Thit b, vt liu v cng ngh mi:b Lin kt gia cc b phn ni t:b. Lin kt gia cc b phn ni t:

c xit Hn ho nhit CADWELD Hn ho nhit CADWELD- Tn dng hiu qu- Khng h v gim cht- Khng h v gim chtlng theo thi gian- Khng b n mnKhng b n mn- Chu c s c lp li- Thit b nh, khng i hi


Thit b nh, khng i hingun ngoi, khng t. Hn Cadweld


1.Thit b, vt liu v cng ngh mi:c Ho cht gim in tr t:c. Ho cht gim in tr t:

C/ty Erico Lighting Technologiescung cp cc loi ho cht gimcung cp cc loi ho cht gimR: EEC v GEM nhm lm choR10 nh yu cu. Gm ion kim loi c tnh dnin cao , ho cht gi m vho cht kt dnh in tr t gim 5090% khi ha cht c cho


vo cc vng c cao nh t st hoc ct.


1.Thit b, vt liu v cng ngh mi:c Ho cht gim in tr t:c. Ho cht gim in tr t: u im:

B kh b t (kh b d- Bn vng, khng cn bo tr (khng b n mn dophn ng vi mui hay ho cht)

Gi R i t h- Gi R gi tr n nh- Khng b phn hu hay mc ra- Thch hp cho vic lp t ni t kh hay bn- Khng ph thuc s hin din ca nc duy tr


tnh dn in


1.Thit b, vt liu v cng ngh mi:d Cc ho cht :d. Cc ho cht : Ni c in tr sut t qu cao v din tchcho vic thi cng lp t b hn ch c th s g p dng cc ho cht in tr ni t thp.



1.Thit b, vt liu v cng ngh mi:e My o in tr ni t hin i:e. My o in tr ni t hin i:

Hin th mn hnh LCD Tm o rng v chnh xc cao 2% Tm o rng v chnh xc cao 2% C th o R bng phng php 2 cc hoc 4 cc t h t i t i BI BU o tng phn t vi s tr gip ca BI v BU T ng ho qu trnh o

T nhn bit kt ni dy o v kt ni n vi t B tr in tr dy o KQ chnh xc vi R nh

Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 51 Chc nng lu d liu v in kt qu ra giy


2. Phn mm ph tr:

Cc thng s ng vo: ,L v ca cc/thanh/dy ni t, s lng cc, b

rng, b di, ng knh hchnchn

Kt t h t R i Kt qu tnh ton: R nit, s lng ho cht Gemcn s dng

Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 52Phn mm GEM 3.1

cn s dng


2. Phn mm ph tr: Ch h GEM Chc nng phn mm GEM- Tnh R ni t ca mt v nhiu cc khi c/

khng ho cht gim in tr Gemkhng ho cht gim in tr Gem- Tnh R ni t ca thanh(dy) ni cc cc b tr

theo ng thng khi c/ khng Gemtheo ng thng khi c/ khng Gem- Tnh R ni t ca thanh(dy) ni cc cc b trtheo mch vng khi c/ khng Gemtheo mch vng khi c/ khng Gem- Hng dn lp t h thng ni t chn thngng v chn nm ngang


ng v chn nm ngang

Tit din dy PE v dy PEN Tit din dy pha

Sph(mm2)Cu Al

Tit din dy PE

Tit din dy PEN

Tit din dy ni t

Cu AlPP n gin

Gi tr K cho dy PE

K =Qc(B+20) In (1 +

f i )

QC : nhit dung trn mt n v th tch ca VL dy

K n20(

B + i)

QC : nhit dung trn mt n v th tch ca VL dy dn (J/oC.mm3)

B : gi tr nghch o ca in tr sut dy dn 0oC

20 : in tr sut dy dn 20oC (.mm) hit b d d (oC)i : nhit ban u ca dy dn (oC)f : nhit cui cng ca dy dn (oC)I : dng in nh mc ca dy dn (A)


In : dng in nh mc ca dy dn (A)

Gi tr K cho dy PEGi tr K(A s-0.5/mm2) V bc cch inGi tr K(A.s /mm ) V bc cch in

PVC XLPE, EPR

Nhit cui cng(0C) 160 250Nhit cui cng(0C) 160 250

Dy bc khng t chung vi cp

Nhit ban u 30oC

Nhit ban u 30oCcp u 30 C u 30 C

ng 143 176

Nhm 95 116Nhm 95 116

Thp 52 64

Dy dn trong cp nhiu li NB 30oC NB 30oCng 115 143


Nhm 76 94

o in tr v in tr sut ca t

E/C1 ES/P1 S/P2 H/C2E/C1 S/

Cc tCc trung gian

Cc d9 E : Cc t9 ES : Cc trung gian

Cc phgian g g

9 S : Cc d9 H C h


9 H : Cc ph

H s s dng C, th

S

T s a/l a: khong cch gia cc ccl : chiu di ccS cc chn thng

ng

l : chiu di cc1 2 3

C th C th C thC th C th C th34

0,780,74

0,800,77

0,860,83

0,920,87

0,910,88

0,950,92

I. Cc cc t thnh dy:

56

10

0,700,630 59

0,740,720 62

0,810,770 75

0,860,830 75

0,870,830 81

0,900,880 8210

1520

0,590,540,49

0,620,500,42

0,750,700,68

0,750,640,56

0,810,780,77

0,820,740,68


30 0,43 0,31 0,65 0,46 0,75 0,58

H s s dng C, th

S

T s a/la: khong cch gia cc ccl : chiu di cc

S cc chn thng ng

1 2 3C th C th C th

468

0,690,620 58

0,450,400 36

0,780,730 71

0,550,480 43

0,850,800 78

0,700,640 60

II. Cc cc t theo chu vi

8102030

0,580,550,470 43

0,360,340,270 24

0,710,690,640 60

0,430,400,320 30

0,780,760,710 68

0,600,560,470 41

mch vng:

305070

0,430,400,38

0,240,210,20

0,600,560,54

0,300,280,26

0,680,660,64

0,410,370,35


100 0,35 0,19 0,52 0,24 0,62 0,33

H s s dng C, th

T s a/l a: khong cch gia cc ccl : chiu di ccS cc chn thng

ng

l : chiu di cc1 2 3

C th C th C thC th C th C th34

0,780,74

0,800,77

0,860,83

0,920,87

0,910,88

0,950,92

I. Cc cc t thnh dy:

56

10

0,700,630 59

0,740,720 62

0,810,770 75

0,860,830 75

0,870,830 81

0,900,880 8210

1520

0,590,540,49

0,620,500,42

0,750,700,68

0,750,640,56

0,810,780,77

0,820,740,68

Trng H S phm K thut Tp.HCM _ Bi ging mn An ton in 6130 0,43 0,31 0,65 0,46 0,75 0,58

chuong 3

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