tcxdvn 319 2004 noi dat thiet bi

8/12/2019 TCXDVN 319 2004 Noi Dat Thiet Bi

1/80

B Xy dng--------

cng ho x hi ch ngha Vit Namc lp - T do - Hnh phc

S: 20/2004/Q-BXD ----------H ni, ngy 20 thng 8 nm 2004

Quyt nh ca b tr|ng B Xy dng

V vic ban hnh TCXDVN319 : 2004 "Lp t h thng ni t thit b chocc cng trnh cng nghip - Yu cu chung "

b tr|ng B Xy dng

- Cn c Ngh nh s 36 / 2003 / N-CP ngy 4 / 4 / 2003 ca Chnh phquy nh chc nng, nhim v, quyn hn v c cu t chc ca B Xy dng.

- Cn c Bin bn s 64 / BB- HKHCN ngy 24 thng 5 nm 2004 caHi ng Khoa hc k thut chuyn ngnh nghim thu ti xy dng tiuchun "Lp t h thng ni t thit b cho cng trnh cng nghip ".

- Xt ngh ca V tr|ng V Khoa hc Cng ngh

quyt nh

iu 1: Ban hnh km theo quyt nh ny 01 Tiu chun xy dng VitNam :

TCXDVN 319 : 2004 "Lp t h thng ni t thit b cho cc cng trnhcng nghip - Yu cu chung ".

iu 2: Quyt nh ny c hiu lc sau 15 ngy k t ngy ng cngbo.

iu 3: Cc ng: Chnh vn phng B, V tr|ng V Khoa hc Cngngh, Tng gim c Tng Cng ty lp my Vit Nam v Th tr|ng cc n vc lin quan chu trch nhim thi hnh Quyt nh ny ./.

Ni nhn:- Nh| iu 3- VP Chnh Ph- Cng bo- B T| php- V Php ch- L|u VP&V KHCN

B tr|ng b xy dng

Nguyn Hng Qun


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TCXDVN 319 : 2004

Lp t h thng ni t thit b

cho cc cng trnh cng nghip-

yu cu chungInstallation of Equipment Earthing System

for Industrial Projects-

General requirements


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Mc lc

Trang

Li ni u 4

1-Phm vi p dng 5

2-Ti liu vin dn 6

3-Nhng qui nh chung 7

4-Lp t in cc t 14

5-Lp t dy ni t chnh 18

6-Lp t dy bo v ca h thng ni t thit b cng nghip 21

7-Lp t dy ni ng th 31

8-Lp t h thng ni t thit b in cao p v trm bin p h p 34

9-Lp t cc hnh thi ni t cho h thng iu khin v gim st

s dng my tnh 52

10-Kim tra h thng ni t thit b 57

Ph lc A: Thut ng v nh ngha 60

Ph lc B: Phn loi ni lp t h thng ni t theo mc nguy him 67


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li ni u

TCXDVN....................: 2004 do Tng cng ty Lp my Vit nam bin son, V

Khoa hc Cng ngh trnh duyt, B Xy dng ban hnh theo quyt nh s

.........................../Q-BXD, ngy...........................


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Lp t h thng ni t thit b cho cc cng trnh cng

nghip Yu cu chungInstallation of Equipment Earthing System for Industrial Projects-General

Requirements

1-Phm vi p dng:

1.1-Tiu chun ny qui nh cc yu cu chung v la chn v lp t h thng

ni t ca cc thit b in lm vic vi in p xoay chiu ln hn 42V v in

p mt chiu ln hn 110V trong hng ro mt cng trnh sn xut cng nghip.

H thng ni t thit b qui nh theo tiu chun ny thuc c hai hnh thi ni

t, ni t bo v v ni t chc nng, trong ni t bo v l ch yu.

1.2- Tiu chun ny khng p dng cho vic lp t h thng ni t ca nh

my in, |ng dy ti in trn khng, trm bin p trung gian thuc cc d

n pht, dn v phn phi in nng v mt s cng trnh c cng ngh c bit

nh| cc cng trnh ngm, bn cng, sn bay, ch bin du m, hm l, v.v...

1.3-Khi lp t h thng ni t thit b, ngoi vic p dng tiu chun ny cn

phi tho mn cc yu cu qui nh trong cc h s k thut c lin quan.


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2-Ti liu vin dn:

Tiu chun ca U ban k thut in quc t v thit b in h p IEC 439-1

1992

Tiu chun ca U ban k thut in quc t v lp t in IEC 364-4

1993

Tiu chun ca U ban k thut in quc t v lp t in IEC 364-5

1994

Qui phm ca Hi k s| in Anh v lp t dy in IEE

1981

Tiu chun c v lp t in AS 3000

1991


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3-Nhng quy nh chung

3.1-Cc b phn c tnh dn in khng mang in trn ton cng trnh |c lit

k d|i y phi |c bo v chng mi nguy him do chm in gin tip bng

bin php ni t thit b kt hp vi t ng ct ngun cung cp bng thit bbo v:

- b phn c tnh dn in h ca thit b in nh| my bin p, myin v kh c in, v.v...

- b phn c tnh dn in h ca thit b v ph kin chiu sng;- b phn truyn ng c tnh dn in ca my in v kh c in;- khung kim loi ca t, bng in v bn iu khin;- v kim loi ca cc my in di ng v cm tay;- v kim loi v cc lp bc kim loi ca cp;


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- ph|ng tin bao che v ph kin kim loi phc v lp t dy v cp innh|ng khng trc tip mang dng in nh| ng lun dy, khay, thang,

mng cp; hp ni kim loi, dy thp treo cp in, ct kim loi, v.v...

- v kim loi, tip im ni t ca cm v ca cm c dy ni di.3.2-Khng cn ni t bo v cho cc thit b c cc hnh thi bo v sau:

- thit b c cch in kp hoc cp cch in t|ng |ng;- thit b |c cp in thng qua mt bin p cch ly dng ring cho n c

cun dy pha tiu th in cch ly v in vi ngun in;

- thit b lm vic vi in p cc thp.3.3-Ni no khng th lp t dy v cp in xa hn cc kt cu kim loi phc

v mc ch khc th cc kt cu cng phi ni t. Cc kt cu kim loi phi

ni t gm:

a) ng kim loi i ni, thng, b, chu, vi, ng thi n|c bn, ng gp

n|c m|a v cc hng mc t|ng t;

b) khung s|n ca cc cn cu, thang my, bng ti, thit b bc d, gt,nh ng v cc hng mc t|ng t khc trn c lp thit b in.

c) |ng ray v kt cu thp khc tip cn |c.

Mch ni t ca cc kt cu kim loi ngoi tri phi c tng tr nh i vi

dng cao tn to bi phng in kh quyn.

3.4-Phi ni t cun th| cp ca cc my bin p o l|ng.

3.5-Trn quan im ni t, mt tp hp bao gm mt ngun cp in h p nh|

my pht in hoc my bin p, ton b dy v cp in cng cc thit b s

dng in nng ca ngun cp in phi |c coi l mt h thng in c

mt trong cc kiu ni t TN, TT v IT. Trong cc h thng ny, b phn cp


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in nh| my pht in, my bin p |c coi l ngun in nng tch ri khi

cc thit b cn li ca h thng v phn cn li |c coi l mng in.

3.6-Mi ngun cp in hoc mi mng in phi c mt thanh ci hoc u cc

ni t chnh c th ni vo :

- in cc t hoc ph|ng tin ni t ni vi im ni t ca ngun;- dy ni t bo v mch;- dy ni ng th chnh;- dy ni t chc nng (nu c yu cu);- trc ni t;- dy ni t chnh

nh| minh ho trn hnh 1.


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3.7-Phi b tr thanh ci hoc u cc ni t chnh ch d tip cn c th

tho ri cc mi ni khi cn o in tr ni t ca h thng ni t. Mi ni

thanh ci hoc u cc ni t chnh phi vng chc v c v m bo duy tr

|c tnh lin tc v in v ch c th tho ri bng dng c.


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3.8-Tr tr|ng hp c bit, mi h thng in h p gm ngun cp in l

my pht in h p hoc cun h p ca my bin p v mng in ca n trong

cng trnh cng nghip phi ni t kiu TN.

3.9-Trong h thng TN, nn s dng thit b bo v qu dng nh| my ct hoc

cu ch t ng ct ngun khi c s c chm t v phi tun th cc qui nh

sau:

- trong h thng TN, chiu di ca cp xut pht t sau my ct hoc cuch khng |c v|t qu chiu di ti a tnh ton trn c s hn ch tng

tr ca mch vng chm t nhm m bo cho thit b bo v c lin

quan tc ng tin cy;

- trong s TN-S, dy trung tnh ch |c ni t ti trm bin p. Ccin cc t b sung v tr khc, nu cn, ch |c ni vo dy PE;

- trong s TN-C, khi dy trung tnh cn ni t lp li gim in pchm, phi b tr cc in cc t b sung cch khong dc theo dy PEN

trong in cc t b sung cui phi t ti phn x|ng cnh t cp

in chnh. Khng |c ct h mch dy PEN bng thit b ct bo v v

phi ni dy PEN xut pht t thanh ci PEN ca t phn phi vi v kimloi ca thit b dng in tr|c khi ni dy PEN vi cc trung tnh ca

thit b .

3.10-Ch cho php p dng kiu ni t TT cho mng in h p c cng sut

nh nu vic thc hin ni t kiu TN gp kh khn nh| khi cp in xut pht

t sau my ct hoc cu ch n ph ti qu di, khng m bo cho thit b bo

v c lin quan tc ng tin cy hoc i hi tn km khng hp l.

Phi la chn cc in tr ni t ca ngun in v mng in trn c s m

bo nhy ca bo v chm t v nn s dng thit b dng in d| lm thit

b ct bo v.

3.11-H thng h p ni t kiu IT ch p dng khi c nhng yu cu c bit

v an ton cp in. in tr ni t ca mng in trong h thng IT phi ph


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hp vi thit b kim tra cch in i vi t ca mng in , nhm pht hin

nhanh im chm t th nht v phi m bo cho thit b bo v t ng ct

nhanh ngun in ra khi mng in khi im chm t th hai xut hin m

im chm t th nht ch|a |c loi tr.

Phi t bo v chng qu in p tn s cng nghip cho mng in. Nu

ngun in l my bin p c in p pha s cp ln hn 1000V th phi t bo

v chc thng cch in cho cun h p ca my bin p.

3.12-Khi trm bin p cp in h p cho mt cng trnh cng nghip trc tip

ni vi l|i cao p bn ngoi cng trnh, nu vic thc hin mt h thng ni t

chung cho thit b in cao p v thit b in h p ca trm gp kh khn v

i hi tn km khng hp l th nn p dng hai h thng ni t ring bit:mt cho thit b in cao p v mt cho thit b in h p.

3.13-Khi cng trnh cng nghip c trm bin p trung gian hoc trm ct u

vo phn phi in nng c in p dy nm trong khong t 3kV n 24kV

cho cc trm bin p h p ca cc phn x|ng hoc khu vn phng th mi trm

bin p nh| th phi c mt h thng ni t chung cho cc thit b in cao v

h p v phi p dng s TN pha h p.

3.14-Trong cng trnh cng nghip, im trung tnh ca my pht, v my pht,

v cc thit b in v cc kt cu kim loi ca trm pht in d phng u phi

ni vi in cc t thng qua mt u cc hoc thanh ci ni t chnh v phi

ni u cc hoc thanh ci ni t chnh ny vi thanh ci bo v trong t cp

in cho ph ti s c bng dy bo v i cng vi cp cp ngun t my pht,

ng thi ni thanh ci bo v trong t cp in cho ph ti s c vi thanh ci

t trong t ng ct in tng ca trm bin p th|ng trc c lin quan. Numy pht d phng gn ngun th|ng trc, im trung tnh ca n |c php

ni vi in cc t ca ngun ny v khng cn c in cc t khu vc my

pht.

3.15-Vic la chn cc in tr ni t ca ngun v mng in trong mt h

thng in h p tr|c ht phi da trn c s tnh ton dng ngn mch chm


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t ln nht trong h thng in h p kt hp vi mt s gii php v cu

hnh ni t v ni ng th nhm tho mn cc yu cu v in p chm trong

iu 3.16.

3.16- ln v thi gian duy tr ca in p chm trong h thng in h p

khng |c v|t qu cc gi tr cho trong bng 1 vi iu kin in p chm cho

php l 42V i vi dng xoay chiu tn s cng nghip v l 110V i vi dng

mt chiu.

Bng 1 - Thi gian duy tr ln nht cho php ca in p chm trong h

thng in h p ph thuc ln ca n vi iu kin in p chm cho

php l 42V i vi dng xoay chiu tn s cng nghip v l 110V i vi

dng mt chiu.

Thi gian duy tr ln nht cho php ca in p

chm

s

Tr s hiu dng ca in

p chm

V

i vi dng xoay chiu

tn s cng nghip

i vi dng mt chiu

42

50

65

75

90

110

150

5,00

4,00

3,00

0,60

0,45

0,34

0,27

0,17

5,00

5,00

5,00

5,00

5,00

5,00

1,00

0,40


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220

280

350

500

0,12

0,08

0,04

0,30

0,20

0,10

3.17-Khi la chn v lp t h thng ni t ca mt trm bin p lm vic vi

in p cao pha s cp, ngoi vic p ng cc yu cu ca iu 3.15, cn phi

tun th cc qui nh trong phn 8 ca bn tiu chun ny.

3.18-Phi la chn v lp t h thng ni t ca mng in sao cho:

a) gi tr in tr t thanh ci hoc u cc ni t chnh ca mng inn im ni t ca ngun in i vi cc h thng TN, hoc n

in cc t ca mng in i vi cc h thng TT v IT, phi ph

hp vi cc yu cu bo v v chc nng ca mng in v phi c

trin vng gi |c hiu qu lu di;

b) dng ngn mch chm t v dng in c th r ra t phi |c dni m khng gy nguy him g, c bit l do cc hiu ng cng thngv nhit, c nhit v c in;

c) trang b ni t phi bn chc hoc c thm ph|ng tin bo v chc c th thch nghi vi cc iu kin nh h|ng t bn ngoi.

3.19-Khi lp t h thng ni t, phi ht sc thn trng nhm trnh nguy c

to ra hin t|ng in phn lm hng cc b phn kim loi khc.

3.20-Nu mt khu vc sn xut no , mt s mng in khc nhau phi s

dng cc h thng ni t ring r th bt c dy bo v no chy qua gia hai

mng in khc nhau nh| vy cng phi sc mang dng in ngn mch

chm t ln nht c kh nng chy qua n hoc ch |c php ni t trong

phm vi mng in c lin quan vi n v phi |c cch in i vi h thng

ni t ca cc mng in khc. Trong tr|ng hp th hai, nu dy bo v l


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thnh phn ca mt si cp th dy bo v ch |c ni t trong phm vi

mng in c cha thit b ct bo v c lin quan vi n.

3.21-C th chia h thng ni t ca mt mng in thnh nhiu h thng ni

t con v trong tr|ng hp ny, mi h thng ni t con nh| th cng phi

|c lp t ph hp vi cc yu cu ca bn tiu chun ny.

3.22-H thng ni t c th s dng kt hp hoc ring r cho hai mc ch bo

v v chc nng tu thuc cc yu cu ca mng in. Ni no h thng ni t

s dng kt hp cho c hai mc ch bo v v chc nng, th phi |u tin

cho cc yu cu v ni t bo v.

4-Lp t in cc t:

4.1-Mi ni in c hiu qu vi ton khi t ca h thng ni t bo v thit

b in cng nghip phi thc hin bng cch s dng in cc t.

4.2-Cc loi in cc t |c tha nhn v kch th|c ti thiu ca chng |c

lit k d|i y:

a) in cc thanh hoc ng kim loi dng cc nhn:- in cc thanh kim loi trn dng cc nhn phi c |ng knh qui

nh bi thit k, nh|ng trong mi tr|ng hp khng |c nh hn

16mm nu l in cc thp v khng |c nh hn 12mm nu l


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in cc kim loi khng phi thp hoc l in cc c lp kim loi

bc ngoi khng phi st hoc thp; khng |c dng thanh thp

gai hoc thanh ct thp lm in cc t dng cc nhn;

- in cc thanh thp gc phi c chiu dy khng nh hn 4mm;in cc thanh thp gc phi |c m km nng hoc |c bo v

chng n mn bng ph|ng php khc;

- in cc ng kim loi dng cc nhn phi c |ng knh trong tithiu 19mm v chiu dy ng ti thiu 2,45mm; in cc ng thp

phi |c m km nng hoc |c bo v chng n mn bng

ph|ng php khc v phi l loi ng rn chc.

b) in cc thanh dt hoc dy kim loi trn nm ngng:- in cc thanh dt hoc dy kim loi trn phi c kch th|c qui

nh bi thit k nh|ng trong mi tr|ng hp khng |c nh hn

25mm x 1,5mm nu l thanh ng dt v khng |c nh hn

35mm2nu l dy ng trn;

- in cc thanh thp dt nm ngang phi c kch th|c khng nhhn 40m x 4m; cn in cc thanh thp trn nm ngang phi c

|ng knh khng nh hn 16mm; in cc thanh thp dt hoc

trn nm ngang phi |c m km nng hoc |c bo v chng n

mn bng ph|ng php khc; khng |c dng thanh thp gai hoc

thanh ct thp lm in cc t nm ngang.

Thanh dt hoc dy kim loi trn dng lm in cc nm ngang phi c

chiu di ti thiu 3m. Tit din ca in cc t nm ngang cho cc thitb in c in p ln hn 1000V phi |c chn theo bn nhit xut

pht t nhit pht nng cho php l 400oC.

c) in cc tm kim loi:


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in cc tm kim loi phi l tm ng cng c chiu dy khng nh hn

1.5mm. Nn hn ch dng loi in cc ny v l do n mn, c bit l

cc ch ni.

d) in cc kim loi t chn mng cng trnh:in cc ny phi |c hn ni vi kt cu thp ca mng t nht hai

im cch xa nhau. Cc khu ni vi dy ni t chnh phi v tr d tip

cn kim tra v sau v vic thi cng cc mi ni phi |c gim st

cht ch tr|c khi b tng mng.

4.3-Cc b phn kim loi sau y c th dng lm in cc t t nhin:

- cc ng dn n|c khng thuc dch v cp n|c cng cng v cc ngdn bng kim loi khc t d|i t ca cng trnh tr cc |ng ng

dn cc cht lng d chy, kh v hp cht chy, n.

- thanh ging gia c v kt cu thp ca b tng d|i t ca nh vcng trnh xy dng, nh|ng phi thn trng khng lm hng ct

thp ca b tng chu ng lc tr|c.

- v bc ch hoc v bc kim loi khc khng phi nhm ca cp thomn cc iu kin ca iu 4.4;

- cc kt cu kim loi khc chn d|i t c mi tip xc hiu qu vbn vng vi ton khi t ph hp vi cc iu kin ca bn tiu

chun ny.

4.4-V bc ch v v bc bng kim loi khc khng phi nhm ca cc cp in

khng s h| hng v n mn thi qu c th dng lm in cc t min l c stho thun bng vn bn ca n v s hu cp v phi c s dn xp thch hp

n v s dng mng in cnh gic vi bt c thay i no trong h thng

cp c th lm hng vai tr in cc t ca cc cp ny.


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4.5-Vt liu s dng v cu to ca in cc t phi m bo cho n chng

|c ph hng do n mn.

4.6-Khi chn in cc t phi tnh n kh nng tng in tr ca in cc t

do n mn qua thi gian s dng.

4.7-Tt c cc loi in cc t phi c b mt sch khng ph sn, men hoc

cc vt liu khc c dn in km.

4.8-in cc t lp t ngoi to nh phi v tr t phi d|i m|a nng v xa

hn cc kt cu kim loi chn d|i t phc v mc ch khc. in cc t lp

t ngoi to nh phi t cch mng khng t hn 1m.

4.9-Phi duy tr c ly khng nh hn 0,5m gia in cc t v kt cu kim loichn d|i t ca cc h thng khc nhm hn ch kh nng xut hin tc dng

in phn c hi cho in cc hoc cho h thng khc.

4.10-in cc t thanh hoc ng kim loi dng cc nhn phi |c ng su

xung t ti su qui nh bi thit k. t phi lin th v chn cht ln ton

b chiu di ca in cc t. Khi chn v tr ng in cc t, phi chn ni

sn c m cao nht nu iu kin thc t cho php.

su lp t in cc t thanh hoc ng kim loi dng cc nhn do thit k

qui nh nh|ng nn trong khong t 0,5m n 1,2m tnh t nh cc n mt

t lin th. Cn chn su lp t in cc ln khi in tr sut ca t gim

theo su.

4.11-in cc t thanh dt hoc dy kim loi trn phi |c chn cht trong

m|ng t nm ngang. t lp li phi l t ng nht, khng |c cha

rm v ph liu xy dng v phi |c m cht.

su lp t in cc t thanh dt hoc dy kim loi trn do thit k qui nh

nh|ng nn trong khong t 0,5m n 1,2m tnh t nh trn ca in cc n

mt t lin th. Cn chn su lp t in cc ln khi in tr sut ca t

gim theo su.


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4.12-Chiu di ca in c|c t dng cc nhn do thit k qui nh nh|ng nn

trong khong t 2,5m n 3m. Cho php hn ni nhm tng chiu di ca in

cc trong tr|ng

hp in cc t cn c chiu di ln hn 3m, min l khng lm suy gim tnh

lin tc v in v v c ca in cc.

4.13-Tr khi c qui nh khc i, in cc t dng cc nhn ng thng ng

hoc nghing thuc h thng ni t ca mt phn x|ng phi ng cch nhau

khng qu 20m v ni vi nhau bng cc on in cc t nm ngang hnh

thnh mt mch vng in cc bao quanh phn x|ng .

4.14-Khi ng in cc t dng cc nhn xung t, phi s dng chp u cc

chuyn dng khng lm hng u trn ca in cc. Tr|ng hp t qu

cng, cho php s dng khoan mi c |ng knh mi khoan nh hn |ng

knh ca in cc sao cho khi ng in cc xung l khoan, cc lp t phi

chn cht ln ton b chiu di ca n.

4.15-Dy ni gia cc u cc dng thanh hoc ng kim loi dng lm in cc

phi c tit din khng nh hn tit din ca dy ni t chnh. Phi t dy ni

ny su do thit k qui nh nh|ng trong mi tr|ng hp khng |c nhhn 0,5m tnh t mt trn ca dy n mt t lin th.


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5-Lp t dy ni t chnh:

5.1-Khi lp t h thng ni t, phi c gng dy ni t chnh chy thng tthanh ci hoc u cc ni t chnh n in cc t hoc ph|ng tin khc to

|c mi ni in c hiu qu vi ton khi t. Khng |c u vo on dy

ni t chnh i t thanh ci hoc u cc ni t chnh n in cc t bt k

dy bo v no ca cc thit b in nm dc theo hnh trnh ca n.

5.2-Tr khi c qui nh khc i, dy ni t chnh dng trong h thng ni t

ca thit bi in cng nghip phi l dy mt li bc cch in PVC c kt cu

li ng ti lm ngui chm, nhiu si bn xon, cch in c mang k hiu

mu xanh v vng kt hp.

5.3-Khng |c dng dy nhm hoc nhm bc ng lm dy ni t chnh

chn trong t hoc trc tip ni vi in cc.

5.4-Khng |c dng ph|ng tin bao che dy v cp in, dy thp treo cp

in, v kim loi v lp bc thp ca cp lm dy ni t chnh.

5.5-Dy ni t chnh khng |c i chung vi dy dn ca mt t ng ct in

nhnh hoc ca mt ph ti nhnh trong mt ng lun dy hoc ng bao che.

5.6-Phi chn tit din ca dy ni t chnh ph hp vi qui nh ca iu 6.2

hoc 6.3 v nu chn trong t hoc trc tip ni vi in cc, tit din ca dy


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ni t chnh chn theo iu 6.2 hoc 6.3 cn phi tho mn iu kin b sung l

khng |c nh hn gi tr qui nh trong bng 2.

Bng 2 Bng qui nh tit din ti thiu ca dy ni t chnh chn trong

t

c bo v chng phhng c hc

khng c bo v chngph hng c hc

c bo v chng n mn theo qui nh ca iu6.2

16mm2 ng

16mm2 thp

khng c bo v chngn mn

25mm2 ng

50mm2 thp

25mm2 ng

50mm2 thp

5.7-Khng cn chn tit din ca dy ni t chnh theo tit din ca dy pha

mang in ca mch cp in tng trong cc tr|ng hp sau:

a) Tr|ng hp trn tt c cc l cp in cho cc t ng ct in nhnhv cc ph ti nhnh, cch in kp |c duy tr sut t hng kp dy

pha ph ti ca thit b bo v trong t ng ct in tng n tn hpdy vo ca ph ti in. Trong tr|ng hp ny c th chn tit din

nh nht ca dy ni t chnh theo tit din ca dy pha mang in

ca l ra c cng sut ln nht cp in cho t ng ct in nhnh

hoc cho ph ti nhnh;

b) Tr|ng hp dy dn ca mch cp in tng c tit din ln hn yucu tho mn nhu cu ti a ca ph ti tng ca mng in do phi

hn ch in p ri trn n.Trong tr|ng hp ny c th chn tit din

nh nht ca dy ni t chnh theo tit din nh nht ca dy pha tho

mn nhu cu ti a ca ph ti tng.

Dy ni t chnh khng trc tip ni vi in cc t v khng chn d|i t c

tit din chn ph hp vi 5.7 a hoc 5.7 b cn phi tho mn yu cu b sung l


22/80

khng |c nh hn 4 mm2 nu l dy ng hoc khng nh hn 16mm2nu l

dy nhm.

Dy ni t chnh trc tip ni vi in cc hoc chn d|i t c tit din chn

ph hp vi 5.7 a hoc 5.7 b cn phi tho mn iu kin b sung l khng |c

nh hn gi tr qui nh trong bng 2 ca iu 5.6.

5.8-Dy ni t chnh khi i ni mt ngoi to nh phi |c bo v chng ph

hng c hc trong phm vi 1,8m tnh t mt t hon thin.

5.9-Mi ni dy ni t chnh vo in cc t phi thc hin trong ging kim

tra vi kp ni bng kim loi khng phi st hoc khu ni vng chc khc c b

mt tip xc bng kim loi khng phi st |c k s| ph trch gim st lp t

in ca ch u t| ph duyt. Phi d tr mt chiu cao ti thiu 150mm cho

nh in cc nh ln khi mt t trong ging kim tra ni dy ni t chnh

vo in cc t.

5.10-Mi ni ca dy ni t chnh vo thanh ci hoc u cc ni t chnh

phi thc hin bng kp dy vng chc kp dy ni t chnh gia cc b

mt kim loi v phi

m bo khng lm bung cc si bn ca cp. Khi dng kp ni cp xit cht

bng vt hoc bu lng th kp phi c khng t hn hai vt hoc bu lng.

5.11-Cnh mi im ni ca dy ni t chnh vi in cc t v cnh mi

im ni ca dy ny vi thanh ci hoc u cc ni t chnh, phi treo bin

cht do c ghi dng ch bn vng Mi ni in an ton, Khng |c tho vi

phng ch d c, chiu cao ch khng d|i 4,75mm, v tr d trng thy.


23/80

6-Lp t dy bo v ca h thng ni t thit b cng nghip:

6.1-Dy bo v khng phi l dy ni ng th phi c tit din:

- hoc tnh ton ph hp vi iu 6.2;- hoc, khi khng c iu kin tnh ton, c th chn theo bng 7 cho

trong iu 6.3.


24/80

Trong c hai tr|ng hp, phi i chiu kt qu thu |c vi qui nh ca iu

6.4.

6.2-Dy bo v khng phi l dy ni ng th phi c tit din khng nh hn

gi tr tnh theo cng thc sau y, ch p dng cho thi gian ct bo v khng

qu 5 giy:

S =k

tI2

mm2

trong :

S l tit din tnh bng mm2

I l gi tr (hiu dng nu l dng xoay chiu) ca dng in chm t khi s c

c tng tr khng ng k, c th chy qua thit b bo v c lin quan, tnh

bng A

t l thi gian tc ng ca thit b ct bo v, tnh bng giy

k l tha s ph thuc vt liu ca dy bo v, cch in v cc tham s khc,

nhit ban u v nhit cui ca n.

Gi tr ca k i vi dy bo v trong cc ng dng hoc dch v khc nhau cho

trong cc bng 3, 4, 5 v 6. Cc gi tr ca k da trn nhit ban u v nhit

cui ghi y bng.

Nu p dng cng thc trn m thu |c kch th|c phi tiu chun th kch th|c

ca dy bo v phi ly bng gi tr tiu chun ln hn gn nht.


25/80

Bng 3 - Gi tr k dng tnh dy bo v bc cch in khng lng trong

cp v khng buc thnh chm vi cp hoc dng tnh dy bo v trn

tip xc vi v bc cp

Cch in ca dy bo v hoc v bc cpVt liu dy dn

PVC cao su 85oC n nh nhit

90oC

ng

Nhm

Thp

143

95

52

166

110

60

176

116

64

Nhit ban u gi

thit

Nhit cui

30oC

160oC

30oC

220oC

30oC

250oC

Bng 4 - Gi tr k dng tnh dy bo v l mt li lng trong cp hocbuc thnh chm vi cp

Vt liu cch inVt liu dy dn


90oC

ng

Nhm

115

76

134

89

143

94

Nhit ban u gi

thit

70oC

160oC

85oC

220oC

90oC

250oC


26/80

Nhit cui

Bng 5 - Gi tr k tnh dy bo v l v bc kim loi hoc lp bc thp

ca cp

Cch in ca dy bo v hoc v bc cpVt liu dy dn


90oC

ng

Nhm

Thp

44

81

22

51

93

26

54

98

27

Nhit ban u gi

thit

Nhit cui

60oC

160oC

75oC

220oC

80oC

250oC

Bng 6 - Gi tr k dng tnh dy bo v khng bc cch in ni khng

c nguy c lm h| hng vt liu t gn do nhit ch nh trong bng

Cc iu kinVt liu dy dn

nhn thy v

trong din tch

hn ch *

cc iu kin

thng th|ng

c nguy c

chy

ng 228 159 138


27/80

Nhm

Thp

125

82

105

58

91

50

Nhit ban u gi

thit

Nhit cui:

dy dn ng

dy dn nhm

dy dn thp

30oC

500oC

300oC

500oC

30oC

200oC

200oC

200oC

30oC

150oC

150oC

150oC

Ghi ch:

* Nhit cho trong bng ch c gi tr khi n khng c hi cho cht l|ng mi

ni.

6.3-Khi khng c d liu tnh tit din dy bo v khng phi l dy ni

ng th theo cng thc cho trong iu 6.2, c th chn tit din ca dy bo v

khng phi l dy ni ng th theo bng 7 mc du ph|ng php ny nhiu khi

khng kinh t. Nu kch th|c thu |c ca dy bo v l phi tiu chun th chn

dy tiu chun c tit din ln hn gn nht.

Bng 7 - Tit din nh nht ca dy bo v tu thuc tit din ca dy pha

trong mch t|ng ng

Tit din ngang ca dy pha trong

mch t|ng ng (S)

mm2

Tit din ngang nh nht ca dy bo

v (Sp)

mm2

S 16 S


28/80

16 S 35

35 S 400

400 S 800

S 800

16

S/2

200

S/4

Ghi ch:

Cc gi tr qui nh trong bng 7 ch p dng cho dy bo v ch to bng kim

loi ging ca dy pha trong mch t|ng ng. Cn nu khng phi nh| th th

chn tit din ca dy bo v sao cho dn in ca n khng nh hn dn

in ca dy bo v chn theo bng 7 |c gi nh c cng vt liu ch to vidy pha.

6.4-Nu dy bo v l ring r, khng phi l thnh phn ca cp cp in, hoc

ca ph|ng tin bao che cp th trong mi tr|ng hp, n phi c tit din khng

nh hn:

- 2,5mm2 nu c bo v c hc, hoc- 4mm2nu khng c bo v c hc

v phi ph hp vi qui nh ca cc iu 6.7, 6.8, 6.9 ca bn tiu chun ny.

Vi dy bo v chn d|i t th p dng iu 5.6 ca bn tiu chun ny.

Ring tit din ca dy ni ng th phi ph hp vi phn 7 ca bn tiu chun

ny.

6.5-Tr|ng hp mt dy bo v |c dng chung cho nhiu mch nh| tr|ng

hp ca trc ni t th tit din ca dy bo v phi:

- |c tnh ton ph hp vi iu 6.2 vi gi tr km thun li nht cadng chm t v ca thi gian tc ng ca thit b bo v, chn trong

s cc mch c lin quan, hoc


29/80

- |c chn theo bng 7 cho trong iu 6.3 ng vi tit din ca dy phaln nht trong s cc mch c lin quan.

6.6-Cc vt dn k sau y |c php dng lm dy bo v:

- li dn trong mt cp nhiu li trong khi cc li kia dng lm dymang in ca mch c dy bo v ;

- dy trn hoc bc cch in t chung trong cng mt ph|ng tin baoche vi cc dy mang in ca mch c dy bo v ;

- dy trn hoc dy bc cch in ri t c nh;- ng lun dy hoc cc ph|ng tin bao che dy khc bng kim loi

tho mn cc yu cu ca iu 6.12;

- v kim loi, mn chn v lp bc thp ca mt s loi cp tho mncc yu cu ca iu 6.13;

- mt s b phn c tnh dn in ng ri.tho mn cc yu cu caiu 6.14.

6.7-Dy bo v c tit din nh hn 10mm2 phi l dy ng hoc nhm bcng nhiu si bn xon c s si bn khng |c t hn by.

6.8-Dy bo v li cng phi c tit din khng nh hn 10mm2v chiu dy

khng nh hn 1,5mm nu l dy ng dt hoc phi c tit din khng nh hn

16mm2v chiu dy khng nh hn 2mm nu l dy nhm dt.

6.9-Tr khi c qui nh khc i, tt c cc dy bo v i ni trong h thng ni

t ca thit bi in cng nghip phi l dy mt li bc cch in PVC c mangk hiu mu xanh v vng kt hp.

Cc loi dy bo v sau y khng cn phi bc cch in:

a) dy trn khng;


30/80

b) dy l|i dt;c) thanh dn cng;d) v bc cp c cch in khong;e) dy thp treo cp;f) ph|ng tin bao che dy in dng lm dy bo v;g) dy ng chn trc tip trong t hoc t trong ph|ng tin bao che

chn d|i t.vi iu kin tit din ca n khng nh hn 35mm2 .

6.10-Dy bo v lng trong v bc kim loi ca mt cp nhiu li cng vi cc

dy mang in ch |c dng ni t cho thit b in, k c tip im ni tca cm, |c cp in t mch i bn trong cp .

6.11-Dy bo v i cng vi cc dy mang in bn trong mt ng lun dy

hoc mng hp ch |c dng ni t cho thit b in, k c tip im ni

t ca cm, |c cp in t mch i bn trong ng lun dy hoc mng hp

. Tt c cc dy bo v t trong ng lun dy hoc mng hp bng kim loi

phi ni vi ng lun dy hoc mng hp .

6.12-V bao che v khung kim loi ca trang b in do nh ch to t hp sn

hoc v bao che kim loi ca h thng mng hp dn thanh ci |c php dng

lm dy bo v nu chng ng thi tho mn ba yu cu sau y:

a) tnh lin tc v in v kt cu c hc ca chng phi m bo khnng bo v chng ph hng c hc, ho hc v in ho;

b) tit din ca chng t nht cng phi bng kt qu tnh ton ph hpvi iu 6.2;

c) cho php ni vo chng cc dy bo v khc ti cc im ni xc nhtr|c.


31/80

6.13-V bc kim loi v/hoc lp bc thp hoc lp bc kim loi khc ca cp,

c bit l v bc ca cp c cch in khong c th dng lm dy bo v nu

chng ng thi tho mn cc yu cu a v b ca iu 6.12.

6.14-Dy bo v hnh thnh t cc b phn c tnh dn in ng ri phi ng

thi tho mn bn yu cu sau y:

a) tnh lin tc v in v kt cu c hc ca chng phi m bo khnng bo v chng ph hng c hc, ho hc v in ho;

b) tit din ca chng t nht phi bng kt qu tnh ton ph hp vi iu6.2;

c) phi c cc bin php gia c cn thn chng li s tho d chng;d) chng vn |c ch to cho cng dng ny hoc, nu cn, c th lm

cho chng thch nghi vi cng dng ny.

6.15-Khng |c chn bt k thit b ng ct no vo trong mch ca dy bo

v nh|ng cho php c cc mi ni chc chn c th tho bng dng c phc

v mc ch th nghim.

6.16-Cc mi ni ca dy bo v phi v tr d tip cn kim tra v th

nghim tr khi mi ni ca dy bo v l thnh phn ca mt khu ni cp in

nm trong hp ni kn hoc nhn chm trong nha cch in.

6.17-ng lun dy hoc ng bao che bng kim loi, lp bc kim loi hoc v

thp ca cp hoc dy thp treo, cp, nm ngoi hoc c sn bn trong si

cp, ch |c php dng lm dy ni t bo v chnh mch in i trong ng

kim loi hoc i trong cp .

6.18-Phi thi cng tht tt cc khu ni trn ng lun dy v mng dy in,

lp bc kim loi v v thp ca cp m bo tnh lin tc v in ca dy bo

v v phi c

bin php bo v chng n mn v chng ph hng c hc cho cc khu ni .


32/80

6.19-ng kim loi v thnh phn ca cng trnh kt cu thp khi dng lm mt

b phn ca dy bo v phi c cc cu ni kim loi vi kim loi.

6.20-ng kim loi dn kh t hoc cht lng d chy khng |c dng lm dy

bo v. Yu cu ny khng ngn cn vic ni dy ng th vo cc ng .

6.21-Tuyn khay hoc thang cp phi m bo tnh lin tc v in v phi ni

vo l|i in cc t ca ngun cp in cho cc cp i trong n sau mi khong

cch khng qu 30m, nh|ng khng |c dng bn thn khay hoc thang cp lm

dy ni t. Vic la chn v lp t dy bo v ca cc mch in i trong khay

hoc thang cp phi tun theo qui nh ca iu 3.20.

6.22-

ng lun dy bng kim loi co dn hoc gp |c khng |c dng lmdy bo v.

6.23-Khng |c dng dy bo v xut pht t thanh ci hoc hng kp ni t

ca mt t in ny ni t cho thit b |c cp in t mt t in khc.

6.24-Cc b phn c tnh dn in h ca cc kh c in khng |c dng

lm thnh phn ca dy bo v cho mt thit b in khc.

6.25-Dy ni t bo v khng |c i ngang qua cc kt cu st t trnh

hin t|ng cm ng v hiu ng gn, c th lm tng tng tr mch vng chm

t c lin quan.

6.26-Trong trm bin p phn x|ng, cho php lp t mt mch vng trc ni

t trong nh trm cho ni vo mch vng ny cc nhnh r l cc dy ni t

bo v ca cc thit b in v kim loi bao che ca trm. Cc mch vng trc

ni t ny c th chy men theo t|ng, dc theo cc rnh cp hoc cc tuynkhay cp v phi ni vi l|i in cc bao quanh trm t nht hai im cch xa

nhau.

6.27-Trong mng in phn x|ng, cho php lp t cc trc ni t trong v

ngoi nh x|ng cho ni vo trc ny cc nhnh r l cc dy ni t bo v

ca khung, v t hoc bng in, ph kin kim loi phc v lp t dy in, ct


33/80

n |ng trong cng trnh, bnh b, ng cng ngh v cc kt cu kim loi ca

nh x|ng v bng ti. Cc trc ni t ny c th chy men theo t|ng, dc

theo cc rnh cp, hoc cc tuyn khay, thang cp v phi ni vo l|i ni t

thng nht ca ton cng trnh sau mi khong cch khng qu 50m.

6.28-Khng |c ni dy ni t bo v t thit b ny sang thit b khc tr|c

khi ni vi trc ni t hoc vi thanh ci ni t chnh ca phn x|ng.

6.29-Cc b phn c tnh dn in ng ri khng |c dng lm dy PEN.

6.30-Ph|ng tin kim loi bao che dy v cp in khng |c dng lm dy

PEN

6.31-Dy PEN phi |c bc cch in ph hp vi in p cao nht ca mngin c th lp t n trong mng in , nh|ng dy PEN khng bt buc

phi cch in khi n i bn trong cc t hp thit b ng ct v thit b iu

khin.

6.32-Nu dng thit b gim st v kim tra mch ni t th khng |c chn

cun dy ng tc vo mch ca dy bo v.

6.33-Dy bo v mch ca mch cp in cho ph ti mch vng cng phi chytheo mch vng v phi ni t c hai u ti ni mch in xut pht.

6.34-Khi dng thit b bo v chng in git tc ng theo in p s c, phi

l|u ch ni dy bo v vo b phn c tnh dn in h ca thit b in c

ngun cp s b ct bi thit b bo v khi c s c chm t.

6.35-Ni no mt kh c in |c cp in bng cp mm hoc dy in mm

ni vi phch v cm th:

a) dy ni t sn c trong cp hoc dy in mm phi ni vi chu ni tring bit ca phch cm;

b) ngoi ra nu cp hoc dy in mm c v bc kim loi th v bc phi phi ni tht tt v in v v c vi khung kim loi ca kh c in


34/80

v vi phn kim loi ni t ca phch v ca khu ni chuyn tip , nu

c, gia phch v cm.

6.36-Phi lm u ct cho u dy bo v ni vi b phn kim loi h ca

thit b in. Kch th|c ca u ct phi ph hp vi tit in ca dy bo v v

ph hp vi l bu lng dnh sn cho mc ch ni t. Khi lm u ct cho u

dy bo v thit b in, khng |c ng tip xc vi nhm.

6.37-Phi lm u ct ng cho u dy bo v ng ni vi cc bnh b hoc

ng cng ngh hoc cc kt cu kim loi cn ni t khc.

6.38-i vi cp c v kim loi v cc lp kim loi che chn bn trong, phi ni

cc lp kim loi che chn bn trong vi v kim loi ca cp, cn mi ni chnh

ca dy ni t bo v th phi thc hin trn v kim loi ca cp v nu cp

lun qua mt bin dng pha khng th dy ni t bo v phi lun qua bin

dng pha khng tr|c khi ni vi t.

6.39-Kh nng ti dng in ca kp hoc ph kin u ni ca dy bo v phi

bng hoc ln hn so vi cc thnh phn dn in |c ni vi nhau.

6.40-Khi cn thit, dy ni t bo v ca mi ct n |ng v ca mi ct ca

|ng dy ti in trong hng ro cng trnh c th ni vi trc ni t xuyn

qua mt mch vng san bng th c bn knh 1m bng thp dt m km 25 x 3

chn quanh mng ct su 0,45m tnh t mt t lin th.


35/80

7-Lp t dy ni ng th:

7.1-Phi la chn v lp t cc dy ni ng th theo ng cc yu cu ca bn

tiu chun ny nhm hn ch n mc thp nht nguy c xut hin chnh lch

in p gia cc b phn c tnh dn in h ca thit b in v cc b phn

c tnh dn in tip cn |c khng lin quan n thit b in.


36/80

7.2-|ng ng kim loi dn n|c chnh ca mt to nh c cha trang b dng

in phi |c ni t bng mt dy ni ng th chnh ni n vi thanh ci

hoc u cc ni t chnh ca mng in ca to nh v phi m bo tnh

lin tc v kim loi ca phn |ng ng ni trn mt t t bn trong to nh ra

ti im tip xc vi mt t.

7.3-i vi dch v cp n|c, im ni ca dy ni ng th chnh phi thc

hin cng gn im |ng ng bt u i vo cng trnh cng tt vi iu kin l

nu ti im |ng ng c mt on ng cch in chn vo th im ni

ng th phi thc hin phn kim loi cnh on ng cch in ny v pha h

tiu dng.

7.4-Cc h thng ng khc lin quan vi cc hng phun n|c cu ho hoc dnkh t, n|c nng, cht lng chy, kh trnh khi tip xc vi b phn c

tnh dn in h ca cc ph|ng tin bao che dy in v cc thit b in

khc, u phi ni ng th vi cc thit b in .

Cc b phn kim loi thuc cc h thng khc cn ni ng th |c lit k sau

y:

- cc b phn kim loi tip cn |c ca cc tuyn ng, thng, b cngngh;

- kt cu thp tip cn |c;- khung s|n ca cn cu, ca thang my v ca thit b t|ng t.

7.5-i vi ng dch v cp kh t, im ni ng th phi nm cnh ng h

o v pha h tiu dng, gia u ni vi ng h v nhnh ng r u tin v

cch ng h khng qu 60cm.

7.6-Vt liu v chng loi ca dy ni ng th phi tho mn mi yu cu trong

phn 6 ca bn tiu chun ny i vi dy bo v ni chung. Dy ni ng th

vn hnh trong iu kin m thp phi l dy bc cch in mt li bng ng

ti lm ngui chm nhiu si bn xon, c s si bn khng t hn by.


37/80

7.7-Khng |c dng dy nhm hoc nhm bc ng lm dy ni ng th lp

t trong khu vc cc thng, b cha n|c, hoc ni vo cc b phn th|ng

xuyn tip xc vi n|c k c n|c xut hin do ng|ng t trong iu kin vn

hnh bnh th|ng, hoc ni vi cc |ng ng dn cc sn phm nhit cao

hn hoc thp hn nhit mt tr|ng.

7.8-Dy ni ng th chnh phi c tit din khng nh hn mt na tit din

ca dy bo v ln nht ca mng in v trong mi tr|ng hp khng |c nh

hn 6mm2nu l dy ng hoc khng |c nh hn 10mm2nu l dy nhm.

Tuy vy, tit din ca n khng cn phi ln hn 25mm2nu l dy ng hoc

phi c mt tit din tho mn dn in t|ng |ng nu l dy bng vt liu

khc.

7.9-Dy ni ng th b sung ni hai b phn c tnh dn in h ca thit b

in phi c tit din khng nh hn tit din ca dy bo v nh hn trong s

cc dy bo v ni vo cc b phn c tnh dn in h ny v trong mi

tr|ng hp khng nh hn 2,5mm2 nu c bo v c hc, hoc khng nh hn

4mm2nu khng c bo v c hc.

7.10-Dy ni ng th b sung ni mt b phn c tnh dn in h ca thit

b in vi mt b phn c tnh dn in ng ri phi c tit din khng nh

hn mt na tit din ca dy bo v ni vo b phn c tnh dn in h ca

thit b in v trong mi tr|ng hp khng nh hn 2,5mm2 nu c bo v c

hc, hoc khng nh hn 4mm2nu khng c bo v c hc.

7.11-Dy ni ng th b sung ni hai b phn c tnh dn in ng ri phi c

tit din khng nh hn 2,5mm2 nu c bo v c hc, hoc khng nh hn

4mm2

nu khng c bo v c hc, ngoi tr tr|ng hp mt trong hai b phnc tnh dn in ng ri ni trn ni vi mt b phn c tnh dn in h ca

thit b in v trong tr|ng hp ny dy ni ng th b sung ni hai b phn

c tnh dn in ng ri phi c tit din khng nh hn mt na tit din ca

dy bo v ni vo b phn c tnh dn in h


38/80

ca thit b in v trong mi tr|ng hp khng nh hn 2,5mm2 nu c bo v

c hc, hoc khng nh hn 4mm2nu khng c bo v c hc.

7.12-Cho php dng cc b phn c tnh dn in ng ri ph hp ca mt kt

cu th|ng trc v bn vng hoc cc vt dn b sung hoc kt hp c hai lm

dy ni ng th b sung.

7.13-Vic thi cng cc mi ni v lm u cui cho dy ni ng th phi tun

theo mi qui nh trong phn 6 ca bn tiu chun ny i vi dy bo v ni

chung.


39/80

8-Lp t h thng ni t thit b in cao p v trm bin p h p

8.1-Phn 8 qui nh thm nhng yu cu ni t nhm m bo an ton chong|i v thit b lm vic trong h thng in h p khi c ngn mch chm t

trong h thng in cao p pha s cp ca trm bin p cp in cho h thng

in h p ngoi nhng yu cu ni t qui nh trong cc phn khc ca bn

tiu chun ny.

8.2- ln v thi gian duy tr ln nht ca in p s c chm t ca h thng

in h p khi c ngn mch chm t pha cao p ca trm bin p cp in cho

h thng in h p khng |c v|t qu cc gi tr cho trong bng 8.

Bng 8 - Thi gian duy tr ln nht cho php ca in p s c chm t

ca h thng in h p ph thuc ln ca n khi c ngn mch chm

t pha cao p ca trm bin p cp in.

Tr s hiu dng ca in p li trn

trang b ni t

V

Thi gian duy tr ln nht cho php ca

in p li trn trang b ni t

s

75

90

5,00

1,00


40/80

120

150

220

350

420

500

600

670

0,60

0,50

0,40

0,34

0,27

0,15

0,08

0,04

8.3- ln v thi gian duy tr ca in p tn s cng nghip c hi cho cch

in ca thit b trong mng in h p khi c ngn mch chm t pha cao p

ca trm bin p cp in cho h thng in h p khng |c v|t qu cc

gi tr cho trong bng 9.

Bng 9 - Thi gian duy tr ln nht cho php ca in p tn s cng nghip

c hi chocch in ca thit b trong mng in h p ph thuc ln

ca n khi c ngn mch chm t pha cao p ca trm bin p cp in.

Gi tr ln nht cho php ca in p c

hi cho cch in thit b trong mng in

h p

V

Thi gian duy tr

s

1,5 Un

1,5 Un + 750

5

5

Ghi ch: Un l in p danh nh gia dy pha v t


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8.4-H thng ni t ca mt trm bin p cp in cho thit b in h p nn l

mt h thng ni t chung cho cc thit b in cao v h p v phi ni vo

cc i t|ng sau y:

a) tt c cc b phn kim loi tip cn |c dng ng hoc dydn cao p;

b) tt c cc b phn kim loi ni vi cc b phn kim loi k trong mca;

c) v kim loi bao che ca trm bin p v ca cc thit b in cao p;d) cc chng st van cao p;e) v v cc lp bc kim loi ca cp cao v h p;f) trung tnh h p ca my bin p;g) v thng my bin p;h) cc chng st van h p;i) thanh ci ni t ca t ng ct in tng ca mng h p;

j) dy ni ng th chnh ca h thng ng n|c chn ngm;k) kim loi h ca thanh ging v gn tng cng ca sn v t|ng.

Cc i t|ng cn ni t k trn phi ni vi thanh ci hoc u cc ni t

chnh ca trm bin p nh| minh ho trn hnh 2.


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8.5-Mi thanh ci hoc u cc ni t chnh ca h thng ni t ca trm binp phi c t nht hai dy ni vi in cc t. Nn ni hai dy ni t chnh cn

c y vo cc gc i din nm hai u mt |ng cho ca mch vng

in cc t bao quanh trm.

8.6-Cho php thc hin mt h thng ni t chung cho cc thit b in cao v

h p ca trm bin p nu in tr ni t ca n khng ln hn 1 . H thng

ni t chung ca trm bin p c in tr ni t khng ln hn 1 |c coi l tho mn cc qui nh trong cc iu 8.8 v 8.9 ca bn tiu chun ny.

8.7-Tr|ng hp khng th p ng yu cu ca mc 8.6 th trang b ni t ca

trm bin p phi ng thi tho mn cc qui nh trong cc iu 8.8 v 8.9 ca

bn tiu chun ny nhm m bo an ton cho ng|i v thit b lm vic trong


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h thng in h p khi c ngn mch chm t trong h thng in cao p ca

trm bin p cp ngun cho h thng in h p va ni.

8.8-H thng ni t ca trm bin p phi tun th cc qui nh 8.8.1; 8.8.2;

8.8.3 v 8.8.4 tu thuc tng cu hnh ni t pha h p.

8.8 1-Cc k hiu |c s dng trong cc mc tip theo:

Im l phn ca dng in ngn mch chm t trong h thng in cao p chy

qua in cc t ca cc b phn c tnh dn in h ca trm bin p.

R l in tr ca in cc t ca cc b phn c tnh dn in h ca trm

bin p.

Uo l in p pha tc in p gia dy pha vi dy trung tnh ca h thng in

h p.

U l in p dy tc in p gia dy pha vi dy pha ca h thng in h p.

Uf l in p s c chm t hay cn gi l in p li trn trang b ni t

trong h thng in h p.

U1 l in p c hi cho cch in ca thit b in h p ca trm bin p

U2 l in p c hi cho cch in ca thit b in h p ca mng in h p.

8.8.2-Cc h thng TN:

a) Ch |c ni dy trung tnh ca h thng in h p vo in cc tca cc b phn c tnh dn in h ca trm bin p (xem TN-a

trn hnh 3) khi c th ct in p s c chm t R x Im ra khi cc b

phn ny trong khong thi gian cho trong bng 8.

Ghi ch:

Nu cc b phn c tnh dn in h ca thit b in h p ca mng

in nm trong vng nh h|ng ca dy ni ng th chnh th in p

chm s c gi tr bng 0.

b) Nu khng tho mn |c iu kin ghi trong mc a ca iu 8.8.2 thdy trung tnh ca h thng in h p phi ni t xuyn qua mt in


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cc t c lp v in (xem TN-b trn hnh 3). Trong tr|ng hp ny,

phi p dng mc 8.9.1 ca bn tiu chun ny.

8.8.3-Cc h thng TT:

a) Ch |c ni dy trung tnh ca h thng in h p vo in cc t cacc b phn c tnh dn in h ca trm bin p (xem TT-a trn hnh

4) khi m bo |c mi t|ng quan gia in p t ln cch in ca

thit b (R x Im + Uo) v thi gian ct in p ra khi thit b cho

trong bng 9 dnh cho thit b ca mng in h p.

b) Nu khng tho mn |c iu kin ghi trong mc a ca iu 8.8.3 thdy trung tnh ca h thng in h p phi ni t xuyn qua mt in

cc t c lp v in (xem TT-b trn hnh 4). Trong tr|ng hp ny,


Ghi ch:

Nu cc b phn c tnh dn in h ca thit b in h p ca mng

in nm trong vng nh h|ng ca dy ni ng th chnh th in p

chm s c gi tr bng 0.

8.8.4-Cc h thng IT:

a) Ch |c ni cc b phn c tnh dn in h ca thit b in h pca mng in vo in cc t ca cc b phn c tnh dn in h

ca trm bin p (xem cc hnh 5, 10, 11) khi c th ct in p s c

chm t R x Im ra khi cc b phn ny trong khong thi gian cho

trong bng 8.

b) Nu khng tho mn |c iu kin ghi trong mc a ca iu 8.8.4 thcc b phn c tnh dn in h ca thit b in h p ca mng in

phi ni t xuyn qua mt in cc t c lp v in i vi in cc

t ca cc b phn c tnh dn in h ca trm bin p (xem cc

hnh t 6 n 9).


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c) Khi cc b phn c tnh dn in h ca thit b in h p ca mngin ni t xuyn qua mt in cc t c lp v in i vi in

cc t ca cc b phn c tnh dn in h ca trm bin p nh| qui

nh trong mc b ca iu 8.8.4 v khi m bo |c mi t|ng quan

gia in p t ln cch in ca thit b (R x Im+ U) v thi gian ctin p ra khi thit b cho trong bng 9 dnh cho thit b in h p ca

mng in th tng tr trung tnh ca h thng in h p, nu c, |c

php ni vo in cc t ca cc b phn c tnh dn in h ca

trm bin p (xem hnh 6).

d) Khi cc b phn c tnh dn in h ca thit b in h p ca mngin ni t xuyn qua mt in cc t c lp v in i vi in

cc t ca cc b phn c tnh dn in h ca trm bin p nh| qui

nh trong mc b ca iu 8.8.4 nh|ng khng m bo |c mi t|ng

quan gia gi tr in p v thi gian ct ni trong mc c ca iu 8.8.4

th tng tr trung tnh pha h p, nu c, phi ni t xuyn qua mt

in cc t c lp v in (xem cc hnh 7 v 9). Trong tr|ng hp ny


8.9- hn ch in p c hi cho cch in trong thit b in h p, phi tunth cc qui nh 8.9.1 v 8.9.2 tu thuc tng loi hnh ca h thng ni t pha

h p.

8.9.1-Cc h thng TN v TT

Trong cc h thng TN v TT nu dy trung tnh ni t xuyn qua mt in cc

t c

lp v in i vi in cc t ca cc b phn c tnh dn in h ca trm

bin p

(xem TN-b trong hnh 3 v TT-b trong hnh 4) th phi m bo ct kp thi in

p c hi cho cch in (R x Im+ Uo) ra khi thit b h p ca trm bin p

trong khong thi gian t|ng thch vi cp cch in ca thit b h p .


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Ghi ch:

Cp cch in ca thit b h p ca trm bin p c th cao hn gi tr cho trong

bng 9.

8.9.2-Cc h thng IT

Trong cc h thng IT nu cc b phn c tnh dn in h ca thit b h p

ca mng in v c tng tr trung tnh h p, nu c, u ni t qua cc in

cc t c lp v in i vi in cc t ca trm bin p (xem cc hnh 7, 8

v 9) th phi m bo ct kp thi in p c hi cho cch in (R x Im+ U) ra

khi thit b h p ca trm bin p trong khong thi gian t|ng thch vi cp

cch in ca thit b h p .

Ghi ch:

Cp cch in ca thit b h p ca trm bin p c th cao hn gi tr cho trong

bng 9.

8.10-Tt c cc b phn ca h thng ni t bao gm im ni t trung tnh h

p phi |c thit k v lp t sao cho chng khng b h| hi khi c dng chm

t chy qua. Tuy nhin khi s dng h thng ni t chung, kch th|c ca dyni t cho thng my bin p phi |c tnh ton trn c s dng chm t ln

nht c th xy ra.

8.11-Khi khng th tho mn cc iu kin ca mt h thng ni t chung cho

cc thit b in cao p v h p ca trm bin p cp in cho thit b in h p

th |c php s dng hai h thng ni t ring r, mi h thng nh| th c mt

thanh ci hoc u cc ni t chnh ni vi in cc t c lp v in i vi

in cc t ca h thng kia.

8.11.1-Cc phn t sau y phi |c ni vo thanh ci hoc u cc ni t

chnh ca thit b in cao p:


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a) tt c cc b phn kim loi h tip cn |c dng ng hoc dyin cao p k c cc b phn kim loi ni lin v c kh vi cc b phn

kim loi h ;

b) v kim loi bao che ca trm bin p v ca thit b in cao p;c) v thng my bin p;d) chng st van cao p;e) v v cc lp bc kim loi ca cp cao p;f) kim loi h ca thanh ging v gn tng cng ca sn v t|ng.

8.11.2-Cc phn t sau y phi |c ni vo thanh ci hoc u cui ni tchnh ca thit b in h p:

g) im trung tnh h p ca my bin p;h) chng st van h p, nu c;i) v v cc lp bc kim loi ca cp h p;j) b phn kim loi h ch lin quan n h thng in h p.

8.12-Phi duy tr c ly khng t hn 2m gia in cc t ca thit b cao p v

in cc t ca thit b h p. C ly gia dy dn chn ngm ni vi cc in

cc t ca thit b cao p v dy dn chn ngm ni vi cc in cc t ca

thit b h p cng phi p dng tiu chun ny.

8.13- ni t cho thit b in cao p trong mng c trung tnh ni t hiu

qu, phi lp t mt l|i ni t gm cc in cc t nm ngang theo chiudi v theo chiu rng ca din tch t thit b in cao p v |c ni vi nhau

thnh cc mt lui. Phi ni dy ni t ca cc thit b in cao p vo l|i ni

t ny.


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Phi t cc in cc theo chiu di gia cc dy thit b in, dc theo hnh

lang phc v hoc li i li. Cn cc in cc theo chiu rng phi t cc v

tr thun tin gia cc thit b in. Cc in cc nm ngang phi t theo chu vi

ca din tch t thit b hnh thnh mt mch vng kn.

Khong cch gia cc in cc nhn to nm ngang |c qui nh bi thit k

nh|ng trong mi tr|ng hp khng |c ln hn 30m. Kch th|c cc l|i tip

gip vi ch ni im trung tnh ca bin p lc v dao ngn mch vi l|i ni

t khng |c ln hn

6m x 6 m.

Cc in cc nm ngang phi t su khng nh hn 0,5m v cch mng

hay b t thit b khng t hn 0,8m.

Cc in cc nm ngang t dc theo chu vi ca din tch t thit b cao p

ngoi tri phi |c chn su khng nh hn 1,2m v cch hng ro khng

t hn 2m. Mch vng ni t ngoi cng ny nn c dng a gic c cc gc t.

8.14- ni t cc thit b in cao p trong mng c trung tnh cch ly, phi

lp t mt mch vng ni t chy dc theo chu vi ca din tch t cc thit b

v ni dy ni t ca cc thit b vi mch vng ni t ny. Mch vng ni t

c th gm nhng in cc nm ngang t su khng nh hn 0,5m v cch

mng hay b t thit b khng t hn 0,8m. Khi in tr ni t ln hn gi tr

qui nh, phi t thm cc in cc nm ngang gia cc dy thit b in dc

theo hnh lang phc v hay li i li. Cng c th s dng in cc t dng cc

nhn ng thng ng hoc nghing v ni cc nh cc li vi nhau thnh mt

mch vng ni t.

8.15-L|i ni t ca trm ng ct cao p ngoi tri phi tho mn cc yu cu

sau y:

a) tng tr mch vng chm t phi thp;b) tng tr i vi dng cao tn phng in kh quyn phi thp;


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c) in p chm v in p b|c khng v|t qu gi tr cho php;d) nhiu n i vi h thng iu khin v gim st s dng my tnh cng

nghip phi mc ti thiu;

e) in p truyn lan ra ngoi khi c chm t phi mc thp nht;f) cc tuyn ng v |ng ray i qua hng ro cng trnh thuc khu vc ny

phi c on chn cch ly v in.


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9-Lp t cc hnh thi ni t cho h thng iu khin v gim st

s dng my tnh:

9.1-Phi ni t cc thit b thuc cu hnh ca h thng iu khin v gim sts dng my tnh bo v chng in git cho nhn vin vn hnh v ng|i

bo tr v cn chng nhiu cho mch tn hiu.

H thng iu khin v gim st s dng my tnh c hai hnh thi ni t:

- ni t khung hay cn gi l ni t bo v;-

ni t tn hiu hay cn gi l ni t chng nhiu.

Bn trong cc bng v bn iu khin thuc h thng iu khin v gim st s

dng my tnh, hai hnh thi ni t ni trn phi tch bit i vi nhau.

9.2-Trong mi bng hoc bn iu khin phi c mt on thanh ci hoc u

cc ni t dnh ring cho hnh thi ni t khung v phi ni n vi mt trc

ni t bng mt dy bo v ring. Trc ni t ny phi xut pht t mt thanh

ci ni t chnh dnh ring cho cc thit b thuc h thng iu khin v gimst s dng my tnh.

9.3-H thng ni t ca cc thit b iu khin v gim st s dng my tnh tr

in cc t phi hnh thnh c lp, khng cho ni vo cc dy bo v thit

b thuc h thng khc.

Tu theo mc nguy him ca cc s c chm t t thun li nht trong h

thng cp in i vi cc thit b iu khin v gim st s dng my tnh vkh nng hn ch in p tng trn in cc t ca h thng cp in m

thanh ci ni t chnh ca cc thit b iu khin v gim st s dng my tnh

- hoc phi ni vi mt l|i in cc t c lp v in;


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tuyn cp in ni trn c mt bin p cch ly chn vo gia v dy t bin p

cch ly ni vi ph ti c cch in tht m bo v khng ni vi im ni t

ca ngun in c lin quan.

9.9-Khi lp t h thng ni t chng nhiu, mi |ng dn chng nhiu ca

cp tn hiu ch |c php ni t mt pha nh| h|ng dn trn hnh 13 v theo

cc qui nh sau:

a-V chng nhiu nm trong cch in ca cc cp tn hiu i t cc t MCC

n cc bng m un I/O ca h thng iu khin v gim st s dng my tnh

phi ni t chng nhiu mt pha, th|ng thc hin trong cc t ni dy cp ra

lin quan vi cc bng m un I/O ni trn. Dy ni v chng nhiu ca cp vi

hng kp ni t chng nhiu phi lng trong ghen cch in.

b- V chng nhiu nm trong cch in ca cc cp tn hiu i t cc cm bin,

cc b tc ng v cc tip im van in t n hp ni trong phn x|ng v v

chng nhiu ca cp tn hiu c lin quan i t hp ni trong phn x|ng n

cc bng m un I/O ca h thng iu khin v gim st s dng my tnh phi

|c ni vi nhau thng qua hng kp dy trung gian cch in vi t t trong

hp ni v v chng nhiu ca cp tn hiu i t hp ni ny n cc bng m

un I/O ca h thng iu khin v gim st s dng my tnh phi ni t

chng nhiu mt pha, th|ng thc hin trong cc t ni dy cp ra lin quan vi

cc bng m un I/O ni trn. Dy ni v chng nhiu ca cp vi hng kp ni

t trung gian v vi hng kp ni t chng nhiu u phi lng trong ghen

cch in.

9.10-Khi lp t cc dy ni t chng nhiu, phi trnh khng chng hnh

thnh mt mch vng kn l nguyn nhn gy ra nhiu cm ng in t.

9.11-u dy ni v chng nhiu ca cp tn hiu phi |c ni vi hng kp

ni t chng nhiu bng u ct c l bt vt hoc bng u ty p lun vo l

ca hng kp dy c c cu xit cht.


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10-Kim tra h thng ni t thit b:

10.1- Ton b h thng ni t thit b phi |c kim tra nghim thu, kim tra

nh k v kim tra t xut nhm chng minh bng thc nghim rng n khng

c khuyt tt v in v v c v rng n tho mn mi yu cu ca bn tiu

chun ny.

Cc ph|ng php kim tra phi m bo khng xy ra nguy him cho ng|i

hoc ti sn hoc h| hng thit b ngay c khi i t|ng kim tra c khuyt tt.

Phi chun b sn sng cho ng|i kim tra cc thng tin cn thit nh|:

- thit k v bn v hon cng ca mt bng lp t in cc, s sp xpcc loi dy bo v k c dy ni ng th c ghi r s l|ng, kch th|cv chng loi dy;

- thng tin cn thit nhn dng cc thit b thc hin chc nng bo v,cch ly ng ct v v tr lp t ca chng;

- thuyt minh bin php s dng phi hp cc c tnh ca thit b bo v,bin php ni t ca mng in v tng tr ca mch c lin quan, nhm

hn ch ln v thi gian duy tr ca in p chm khi xy ra s cchm t;

- chng ch vt liu v bin bn th nghim ca nh cp hng.10.2- Kim tra nghim thu |c thc hin sau khi lp t xong v tr|c khi |a

vo s dng.

Ni dung kim tra nghim thu gm:

10.2.1- Kim tra bng mt:

Tr|c ht phi kim tra cc b phn ca h thng ni t t ngm d|i t

tr|c khi lp t hoc trong kt cu tr|c khi y kn ri mi n cc b phn

t ni. Cc b|c kim tra bng mt gm:


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- kim tra thc t lp t so vi thit k;- kim tra vic s dng vt liu theo yu cu ca thit k;- kim tra tt c cc mi hn, mi ni;- kim tra bin php chng n mn;- kim tra bin php bo v mch dn chng ph hng c hc, c bit khi

i qua cc khe ln, khe co dn v vt ch|ng ngi khc;

- kim tra bin php chng in p chm v in p b|c nh|ng ni cnthit;

- kim tra vic lp t.10.2.2-Kim tra bng thit b o:

- thng mch v kim tra cht l|ng u ni ca dy ni t bo v thuccc mch cp in cho ph ti mch vng;

- thng mch v kim tra cht l|ng u ni ca tt c cc dy bo v k ccc dy ni ng th chnh v dy ni ng th b sung;

- o in tr ca in cc t;- o tng tr mch vng chm t;- kim tra tc ng ca thit b dng in d|.

10.3-Kim tra nh k phi thc hin theo thi gian qui nh sau:

a) i vi h thng ni t lp t ni t nguy him th thc hin hai nmmt ln;

b) i vi h thng ni t lp t ni nguy him th thc hin mt nmmt ln;


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c) i vi h thng ni t lp t ni c bit nguy him th thc hin suthng mt ln.

Ghi ch:

- phi o in tr ni t ca h thng c v ma kh ln ma m|a;- xem Ph lc 2: Phn loi ni lp t h thng ni t theo mc nguy

him.

10.4-Kim tra t xut phi thc hin:

- khi xy ra tai nn, s c hoc c nguy c xy ra tai nn;- sau khi sa cha h thng ni t hoc lp t li thit b in;- sau khi c lt, bo, ng t, ho hon nh h|ng xu n cht l|ng ca

h thng ni t thit b;

- khi xy dng mi hay hay sa cha cc cng trnh khc c kh nng lmh| hng cc b phn ca h thng ni t.

10.5-Ni dung kim tra nh k v kim tra t xut gm:

- kim tra ton b h thng ni t;- kim tra cc mi hn , mi ni;- kim tra tnh trng cc lp m hoc sn chng n mn;- kim tra cc mt tip xc v in;- kim tra phn ngm, ch no nghi ng th phi o ln;- kim tra tnh trng t;- o in tr ca in cc t;- o tng tr mch vng chm t;


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- kim tra tc ng ca thit b dng in d|.10.6-Sau khi tin hnh kim tra h thng ni t ph hp vi cc yu cu ca

bn tiu chun ny, n v kim tra phi lp cc bin bn kim tra cn thit

trao cho n v giao vic. Mi thiu st |c pht hin trong qu trnh kim tra

phi |c khc phc v hon thin tr|c khi cp chng ch.

ph lc A ca tcxdvn............

Thut ng v nh ngha

1-Thit b in (Electrical equipment): Sn phm in phc v cc mc ch

pht, bin i, truyn ti, phn phi v s dng in nng nh| cc my in,


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my bin p, kh c in, my o in, r le bo v, vt t| v ph kin lp t

dy in, dng in.

2-Mng in (Electrical installation): Mt tp hp thit b in lin quan vi

nhau v mt mc ch sn xut v c mt s c tnh kt hp.

3-Trang b ng ct (Switchgear): Mt tp hp kh c ng ct in chnh v ph

dng cho vn hnh, iu chnh, bo v hoc cho cc mc ch khc nhm kim

sot mng in.

4-T ng ct tng (Main switchtboard): T cha trang b ng ct t c th

kim sot vic cp in cho ton b mng in.

5-T phn phi: (Distribution board): T cha cc trang b ng ct khng phit ng ct tng.

6-Cch in kp (Double insulation): Cch in hai lp, lp nm st b phn

mang in gi l cch in c bn v lp th hai gi l cch in b sung.

7-B phn c tnh dn in h (Exposed conductive part): B phn c tnh

dn in khng |c bao che ca thit b in m con ng|i c th chm vo,

bnh th|ng khng mang in nh|ng c th tr thnh mang in trong iu kins c.

8-B phn c tnh dn in ng ri (Extraneous conductive part): B phn c

tnh dn in ng ring l, khng lin quan n thit b in, cn |c |a v

mt in th, thng th|ng bng in th t.

9-t (Earth): Ton khi t c tnh dn in m in th ca n bt k im

no cng c gi tr quy |c bng khng.

10-in cc t (Earth electrode): Mt vt dn hoc mt nhm vt dn chn

d|i t v tip xc cht ch vi t, t hnh thnh mi ni in c hiu qu

vi ton khi t.


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11-in cc t c lp v in (Electrically independent earth electrode): in

cc t ng cch xa cc in cc khc n mc dng in chm t ln nht c

c hi chy qua in cc ny nh h|ng khng ng k n in th ca cc

in cc khc.

12-in cc t nhn to (Artificial earth electrode): in cc |c ch to

s dng ring cho mc ch ni t.

13-in cc t t nhin (Natural earth electrode): Cc b phn c tnh dn in

ca |ng ng, nh v cng trnh d|i t tip xuc cht ch vi t v |c tn

dng lm in cc t.

14-in tr ca in cc t (Earth electrode resistance): in tr ca mt in

cc t i vi t. in cc t y |c hiu theo nh ngha 10 ca ph lc

ny.

15-Thanh ci hoc u cc ni t chnh (Main earthing bar or terminal): Thanh

ci hoc u cc ni t ca mt ngun cp in hoc ca mt mng in c lin

quan, dng ni tt c cc loi dy bo v k c dy ni ng th chnh, dy

ni t chc nng nu c, ca ngun hoc mng in vi in cc t.

Thanh ci hoc u cc ni t chnh th|ng t trong hp phn b t (Earth

dispatcher) hay cn gi l hp chia t (Earth divider).

16-Dy bo v (Protective conductor): Dy dn dng bo v chng in git

v dng ni mt s trong cc b phn sau y li vi nhau:

- b phn c tnh dn in h;- b phn c tnh dn in ng ri;- thanh ci hoc u cc ni t;- in cc t;- im ni t ca ngun in, hoc mt im trung tnh nhn to.

Dy bo v l tn gi chung ca cc loi dy sau y:

- dy bo v mch;- dy ni ng th chnh;


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- dy ni ng th b sung;- trc ni t;- dy ni t chnh.

17-Dy bo v mch (Circuit protective conductor): Dy bo v ni cc b phn

c tnh dn in h ca mt thit b in vi thanh ci hoc u cc ni tca t cp in cho thit b in hoc vi mt trc ni t xut pht t t .

18-Dy ni ng th chnh (Main equipotential bonding conductor): Dy bo v

ni ng th cho cc |ng ng ci kim loi trong cng trnh cng nghip.

19-Dy ni ng th b sung (Supplementary equipotential bonding conductor):

Dy bo v ni ng th cho cc b phn c tnh dn in ng ri.

20-Trc ni t (Common earthing conductor): Dy ni t c mt hoc hai u

ni vi thanh ci ni t chnh hoc vi l|i in cc t v i dc theo cc dy

t bng in, thit b cng ngh, kt cu thp ca nh x|ng cho ni vo bn

thn n cc dy ni t ca cc i t|ng cn ni t va k.

21-Dy ni t chnh (Main earthing conductor): Dy bo v ni thanh ci hoc

u cc ni t chnh ca mt ngun cp in hoc ca mt mng in vi in

cc t hoc vi mt ph|ng tin ni t ni vi in cc t..

22-Ni ng th (Equipotential bonding): Ni in nhm |a cc b phn c

tnh dn in h ca thit b in v cc b phn c tnh dn in tip cn

|c khng lin quan n thit b in v mt mc in th thc cht bng nhau.

23-Ni t bo v (Protective earthing): Ni vi ton th khi t theo ng yu

cu ca bn tiu chun ny nhm m bo cch ly kp thi thit b |c bo v

khi ngun in nh mt trang b ct t ng khi pht hin |c dng in r ra

v thit b.

24-Ni t chc nng (Functional earthing): Ni t nhm m bo ch lm

vic ca thit b in, cn gi l ni t lm vic.


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25-H thng ni t (Earthing system): Tt c cc dy bo v, thanh ci hoc

u cc ni t, kp ni t v in cc t, k c cc ph|ng tin kim loi bao

che dy km theo cc dy bo v v cc kp ni t ni trn, dng duy tr mt

s b phn no ca mng in c lin quan in th t.

26-H thng (System): H thng bao gm mt ngun in nng n v mt

mng in. Trn quan im ni t, cn phn bit cc h thng cp in ca cc

cng trnh cng nghip theo quan h i vi t ca ngun in nng v ca

mng in trong cc h thng .

a) H thng TN: H thng trong ngun in c mt hoc nhiu hn mtim ni t trc tip, cn cc b phn c tnh dn in h ca mng

in th ni vi im ni t ca ngun in bng cc dy bo v.

C ba loi h thng TN |c nhn dng nh| sau:

- H thng TN-C l h thng trong cc chc nng trung tnh v bov kt hp trong mt dy n dn i khp h thng gi l dy PEN;

- H thng TN-S l h thng c dy trung tnh N v dy bo v tch rigi l dy PE dn i khp h thng;

- H thng TN-C-S l h thng trong cc chc nng trung tnh v bov kt hp trong mt dy n PEN ch trong mt phn ca h thng,

sau tch thnh hai dy ring r (dy trung tnh N v dy bo v PE)

trong phn cn li ca h thng

b) H thng TT: H thng trong ngun in c mt hoc nhiu hn mtim ni t trc tip, cn cc b phn c tnh dn in h ca mng

in th ni vi cc in cc ni t c lp v in i vi cc in cc

ni t ca ngun in.

c) H thng IT: H thng khng c mi ni trc tip gia cc thnh phnmang in v t, cn cc b phn c tnh dn in h ca thit b in

th ni t.


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27-Cc h thng dng tn gi TN, TT v IT (Systems using the designations TN,

TT and IT):

Ch ci th nht th hin quan h i vi t ca ngun in nng:

T: c mt hoc nhiu hn mt im ni t trc tip;

I: tt c cc phn mang in u cch ly vi t hoc c mt im ni vi

t thng qua tng tr ln.

Ch ci th hai th hin quan h i vi t ca cc b phn c tnh dn in

h ca mng in:

T: cc b phn c tnh dn in h ca mng in ni trc tip vi t

ring r, khng ph thuc bt k im ni t no ca ngun in;

N: cc b phn c tnh dn in h ni trc tip vi im ni t ca

ngun in (trong h thng in xoay chiu, im ni t th|ng l im

trung tnh).

28-Tng tr ca mch vng chm t (Earth fault loop impedance): Tng tr ca

mch vng dng in chm t (mch vng pha ti t) khi u v kt thc ti

im ngn mch chm t.

- Trong h thng TN, dng chm t i t im ngn mch chm t cathit b in theo dy bo v ti thanh ci ni t ca mng in ri theo

|ng dn kim loi ca dy bo v tr v im trung tnh ni t ca my

bin p. T y, dng chm t chy trong dy qun bin p ti u ra ri

theo dy pha cp in i t my bin p n im ngn mch chm t.

- Trong h thng TT v IT, dng chm t i t im ngn mch chm tca thit b in theo dy bo v ti thanh ci ni t ca mng in ri

theo |ng dn trong t v im trung tnh ni t ca my bin p. T

y, dng chm t chy trong dy qun bin p ti u ra ri theo dy

pha cp in i t my bin p n im ngn mch chm t.


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mang in vi nhau, hoc 600V xoay chiu hoc 900V mt chiu gia

dy mang in vi t.

- in p cao: l in p bnh th|ng v|t qu in p thp. in p t 3kVn 24kV xoay chiu, tn s cng nghip, th|ng gi l trung p, trn

quan im ni t bo v cng thuc dy in p cao.

34-MCC (Motor control center): Cc t h p kim sot ph ti, ch yu l ng

c in, kt hp vi hp nt n ti ch. Dy t MCC th|ng c mt hoc hai t

aptomat tng c trang b iu khin, o l|ng, bo v, tn hiu. Cc t cn li

chia ra nhiu ngn xp t trn xung d|i; mi ngn dnh cho mt l ph ti.

Bn trong mi ngn, c aptomat hoc cu chy, cng tc t v trang b iu

khin, o l|ng, bo v, tn hiu.

35-Thit b dng in d| (Residual current device): Thit b t ng ct mch

theo dng r khi c chm t, gi tt l RCD.

36-H thng iu khin v gim st s dng my tnh (Computer-based control

and monitoring system): H thng iu khin v gim st cc qu trnh cng

ngh da trn k thut vi x l.

37-Thit b iu khin (Controller): Thit b iu khin da trn k thut vi x

l.

38-M un I/O (I/O module): M un vo/ra dng nhn tn hiu t bn ngoi

vo x l hoc |a lnh iu khin t bn trong ra ngoi .

39-T ni dy cp ra (Marshalling cabinet): T cha cc hng kp ni trung gian

gia mt bn l cp ni vi cc m un I/O v mt bn l cp ni vi cc t

MCC hoc vi cc hp ni c lin quan vi cc cm bin v cc b tc ng ti

ni sn xut

40-Chm in gin tip (Indirect voltage touch): Tip xc vi cc b phn c

tnh dn in h ca thit b in b chm do hng cch in |c coi l

chm in gin tip.


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Ph lc B ca tcxdvn............


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Phn loi ni lp t h thng ni ttheo mc nguy him

Ni lp t h thng ni t thit b |c phn loi theo mc nguy him v in

nh| sau:

1-Ni nguy him l ni c mt trong cc yu t sau:

a) m.hoc c bi dn in ( m t|ng i ca khng kh v|t qu 75%trong thi gian di hoc c bi dn in bm vo dy dn v lt vo trong

thit b in);

b) nn nh dn in (bng kim loi, t, b tng, ct thp, gch...);c) nhit cao (nhit khng kh v|t qu 35oC trong thi gian di hn

mt ngy m);

d) nhng ni ng|i c th ng thi tip xc vi mt bn l cc kt cu kimloi ca nh x|ng, my mc, thit b cng ngh v.v... ni t v vi

mt bn l cc b phn kim loi h ca thit b in.

2-Ni c bit nguy him l ni c mt trong cc yu t sau:

a) rt m (( m t|ng i ca khng kh xp x 100%, th hin trn,t|ng, sn nh v vt trong nh c ng s|ng);

b) mi tr|ng c hot tnh ho hc (th|ng xuyn hay trong thi gian di ccha hi, kh, cht lng c th to nn cc cht n mn, nm mc dn n

ph hu cch in v v cc b phn mang in ca thit b in);

c) ng thi c hai hoc nhiu hn hai yu t ca ni nguy him nu trongmc 1.

3-Ni t nguy him l ni khng thuc hai loi trn.


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tcxdvn 319 2004 noi dat thiet bi

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