Tham luan TCKT cap ngam.pdf

TNG CNG TY IN LC TP HCM

THAM LUN

CP NHT TIU CHUN K THUT

CP NGM TRUNG, H TH, B CH TH S C

06/2013

2

1. Tiu chun cp ngm trung th 22kV

2. Tiu chun cp ngm h th 1kV

3. Mt s cp nht c bn - Cp chng thm - Tng cng lp mn chn kim loi cp trung th - Cp ngm nhm h th - B ch th s c

Ni dung gii thiu

3

1. Li dn in (Cu)

2. Lp mn chn rut dn (bn dn)

3. Lp cch in (XLPE, EPR)

4. Lp mn chn cch in (bn dn)

5. Lp mn chn kim loi (Cu)

6. Lp cht n (PP,)

7. Lp bc phn cch (PVC)

8. Lp gip (thp, Cu, Al)

9. Lp v bc (PVC, PE)

1. Cp ngm trung th 22kV

4

TCKT c TCKT cp nht

Tiu chun TCVN 5935 IEC 60502-2

Th nghim in p xoay

chiu

Thng xuyn 30kV/5 44,4kV/5

(3,5Uo)

in hnh 36kV/4h 50,8kV/4h

(4Uo)

Th phng in cc b

Thng xuyn 19kV (1,5Uo)

20pC

22kV (1,73Uo)

10pC

in hnh

19kV (1,5Uo)

20pC

22kV (1,73Uo)

5pC

Th nghim chng thm nc Khng C (vi loi cp c lp chng thm

1. Cp ngm trung th 22kV

5

2. Cp ngm h th 1kV

1. Li dn in (Cu, Al)

2. Lp cch in (XLPE, EPR)

3. Lp cht n (PP,)

4. Lp bc bn trong (PVC)

5. Lp gip bo v (thp, Cu, Al)

6. Lp v bc (PVC, HDPE)

IEC 60502-1 (Version

2009)

Photo: LS Cable

6

2. Cp ngm h th 1kV

TCKT c TCKT cp nht

Tiu chun TCVN 5935 IEC 60502-1 & TCVN 5935

Th nghim in hnh

in p xoay chiu

1,8kV/4h

2,4kV/4h

(4Uo)

7

3. Cc cp nht c bn

3.1 Cp chng thm trung, h th

Cp chng thm

trung th

Cp chng thm h th

Cu to

- Cu to li c vt liu chng thm (water blocking material)

- Mn chn bn dn ca cch in c thm lp bng bn dn c tnh trng n chng thm nc.

- Cu to li c vt liu chng thm (water blocking material)

Th nghim

Th nghim in hnh:

Th nghim chng thm nc (Water penetration test)

Cha c

8

3. Cc cp nht c bn

3.1 Tng cng lp mn chn kim loi cp ngm trung th

-Lp mn chn kim loi c tc dng ni t an ton v tn dng ngn mch trong trng hp s c. Trong trng hp dng chm t ln, nu tit din lp mn chn kim loi khng ln s gy h hng (chy) cp.

Theo TCKT c,vi cp 22kV 3x240mm2, lp mn chn kim loi c tit din S=11,4mm2 ch chu c dng in chm t 3,3kV trong 0,5s

-Vic chn tit din lp mn chn kim loi phi xt n cc ch tiu kinh t - k thut.

Vd: Theo ICASEA: Thi Lan, cp ngm trung th c lp mn chn kim loi chu c dng s c bng 20% dng s c ngn mch mt pha ln nht, chp nhn ri ro nu c s c gn ngun.

Tng cng bng cch s dng mn chn kim loi bng si ng hoc bng ng kt hp vi si ng

9

Mn chn kim loi bng si ng

Mn chn kim loi bng si ng kt hp vi bng ng

10

3. Cc cp nht c bn


Tnh ton dng in ngn mch cho php trn lp mn chn kim loi ca cp theo tiu chun IEC 60949

i

f

ad SKtI ln...222

adII .

20

12

. 10.20.

cK

32 ..0043.0..069.0.61.01 tMtMtM

FM .10..2 31

3

3

2

2

Tit din dy dn S(mm2)

Thi gian ngn mch t(s)

Nghch o h s nhit in tr (K)

in tr sut ca kim loi 20C 20(.m)

Nhit ban u i(C)

Nhit cui cng f (C)

Hng s nhit khi c(J/K.m3)

H s K (As1/2/mm2)

Dng in ngn mach trong TH on nhit Iad(A)

H s F = 0.7

Hng s nhit khi lp lin k XLPE 2(J/K.m3)

Hng s nhit khi lp lin k PVC 3(J/K.m3)

Nhit tr sut lp lin k mt 2(K.m/W)

Nhit tr sut lp lin k hai 3(K.m/W)

dy lp mn chn kim loi (mm)

H s M

H s M.sqrt(t)

H s khng on nhit

Dng in ngn mach trong TH khng on nhit (A)

11

3. Cc cp nht c bn


Tnh ton dng in ngn mch cho php trn lp mn chn kim loi ca cp theo tiu chun IEC 60949

Tit din cp (mm2) 240 185 150 120 95 70 50 35

MN CHN KIM LOI C (BNG NG)

Tit din lp mn chn KL (mm2)

11.4 10.5 9.9 9.3 8.8 8.1 7.6 7.1

Dng ngn mch ln nht (kA/0,5s)

3.3 3.1 2.9 2.7 2.6 2.4 2.2 2.1

MN CHN KIM LOI TNG CNG (SI NG)

Tit din lp mn chn KL (mm2)

54.3 48.5 42.5 32.5 25.5 18.5 13 9

Dng ngn mch ln nht (kA/0,5s)

11.6 10.4 9.1 7.0 5.5 4.0 2.8 1.9

12

3. Cc cp nht c bn


Cc lu

Ni t 2 u lp mn chn kim loi m bo an ton: -Nu khng c ni t 2 u, in p cm ng trn lp mn chn kim loi ca c th ln n mc gy nguy him cho con ngi i vi ng cp c chiu di ln hoc trong trng hp c xung ng ct, xung ngn mch

-V d 1: on cp 3x240mm2 di 2500m c Vc 50V khi mang ti cc i 450A

-V d 2: on cp 3x240mm2 di 200m c Vc 526V khi c xung ng ct hoc xung ngn mch 10kA

Trng hp ti max Trng hp xung ng

ct hoc ngn mch

Dng in ti I(A) 450 10000

ng knh li cp (mm) 17.5 17.5

Chiu dy cch in XLPE (mm) 5.5 5.5

Chiu dy lp mn chn kim loi (mm) 0.127 0.127

Khong cch gia hai li cp (mm) 28.754 28.754

ng knh trung bnh ca lp mn chn KL (mm) 28.6270 28.6270

Cm khng ca lp mn chn trn 1 v chiu di X(/m) 4.38E-05 2.63E-04

Chiu di cp L(m) 2500 200

in p cm ng trn mn chn kim loi U=X.L.I (V) 50.00 525.69

13


Cc lu

i vi on cp i t trm trung gian ra li ni: Gim in tr ni t (ti tr s 1) gip tn (chia s) dng in s c t ng dy ni chy vo cp

*V d: trong trng hp Inm = 20kA, R mn chn KL theo tiu chun c = 4,55

-Nu Rt = 10 Inmt = 6,25kA; Inmcp = 13,75kA

-Nu Rt = 4 Inmt = 10,64kA; Inmcp = 9,36kA

3. Cc cp nht c bn

Chiu di on cp t

trm - tr s 1 (m) 200 400 600 800 1000 1500 2000

R mn chn KL theo TCKT c (bng ng) ()

0.30 0.66 1.05 1.48 1.97 3.18 4.55

R mn chn KL tng cng

(si ng) () 0.06 0.14 0.24 0.42 0.68 1.40 2.65

14

3. Cc cp nht c bn 3.2 Cp ngm h th li nhm

Chng trnh ngm ha ca EVNHCMC 2012 2015: 100km cp ngm trung th, 135 km cp ngm h th, mc u t 1.000 t ng/nm vic s dng cp nhm h th s gip tit kim ng k mc u t.

So snh cp li ng v nhm - So snh k thut:

Tnh dn in

nh hng ca nhit n in tr cp

Tui th ca cp nhm v ng

bin dng v mi ni

Lc cng ca cp

Tham kho S tay Vt l c s - N.I.Koskin & M.G.Sirkevich.

Building Wire & Cable Handbook - Southwire.

STT Cc thng s K hiu n v ng

Nhm

1 in tr sut (20oC) 10-6.cm 1.7 2.8

2 H s nhit in tr (20oC)

10-3.oK-1 3.9 4.9

3 Khi lng ring (20oC)

d g/cm3 8.9 2.7

4 Nhit dung ring (20oC)

cp kJ/kg/oK 0.39 0.88

5 Nhit nng chy Tnc oC 1083 658.3

6 H s n di l 10-6.oK-1 16.7 22.9

7 ng sut lc cng (**)

Lb/in2 50000 16000

15

3. Cc cp nht c bn 3.2 Cp ngm h th li nhm

So snh cp li ng v nhm - So snh gi thnh:

Kt lun: Qua phn tch, so snh v k thut v kinh t, vic chn cp ngm nhm h th thay cho cp ngm ng h th vi tiu ch m bo cc yu cu trong vn hnh h thng in v sn xut kinh doanh, cho thy vn u t cho phn cp ngm h th trong d n ngm ha li in ti Thnh ph H Ch Minh gim ng k (2.9 ln).

STT Loi cp VT S

lng n gi

So snh

gi ng nhm

Cp ng 0.6/1kV

1 CXE/DSTA-3x95+1x70 - 0.6/1kV m 1 923,900 2.94

2 CXE/DSTA-3x120+1x95 - 0.6/1kV m 1 1,159,100 2.93

Cp nhm-0.6/1kV

1 AXE/DSTA-3x185+1x120 - 0.6/1kV m 1 314,500 0.34

2 AXE/DSTA-3x240+1x150 - 0.6/1kV m 1 395,900 0.34

16

3. Cc cp nht c bn 3.3 B ch th s c cp ngm trung th

-Tc dng; Nhanh chng khoanh vng s c, tng tin cy h thng (gim SAIDI, SAIFI)

-Tiu chun p dng: IEEE 495 : IEEE Guide for Testing Faulted Circuit Indicators.

-Cu to:

+ B x l tn hiu,

+ Bin dng in v

+ B n bo s c.

- Chc nng:

+ Pht hin v phn bit s c

Ngn mch pha-pha

(trip curent: 225 700A)

Ngn mch pha-t

(trip curent: 20 160A)

+ Ch th bng cc tn hiu c v n nhy khc nhau v mu sc hoc tn s nhp nhy.

Fault indicator

F 5 6 7 8 A B C D E

N P

N P

Cu ch F3

n Led

+ -4A

2A

B bo s c

S1

S2

PE

S1

S2

PE

S1

S2

PE

17

TNG CNG TY IN LC TP HCM

CHN THNH CM N !

06/2013

Documents

Tham luan TCKT cap ngam.pdf