PREFLIX HIGH TENSION CABLES

Preflix is one of the most preferred brands with plentiful fixing throughout the country. The range of products includes Power Cables, HT XLPE, LT XLPE & PVC Cables, Instrumentation Cables, House wires and Flexibles. With ever evolving modern techniques, the traditional paper insulated cables and thermoplastic insulated cables are substituted with cross linked XLPE (Polyethylene). The XLPE is better in terms of electrical, mechanical and thermal properties and the weight and dimensions are relatively lower.

ADVANTAGES OF PREFLIXCABLES

    Easy Termination & Joints

     Short circuit ratings are higher

     Better Electrical, Mechanical & Thermal Property

     Superior Electrical Strength Retention

PREFLIX manufactures following voltage grade cables as per IS: 7098 (Part 2), IEC -60502 and BS -6622.

   1) 6.35/11 KV (E) , 11/11 KV (UE) , 12.7/22 KV (E),
   19/33 KV (E), 33/33 KV (UE) Cables.
   2) 12.7/22 KV  Cables (22 KV Earth)
   3) 11/11 KV i.e. 11 KV (UE) Cables
   4) 6.6/6.6 KV Cables [ 6.6 KV (UE) & 11 KV (E) ]
   5) 3.8 /6.6. KV Cables
   6) 3.3 KV (E) and (UE) Unscreened / Screened Cables.
   SIZE
   50 Sq.mm  to 1000 Sq.mm in Single Core Cables.
   25 Sq.mm to 400 Sq.mm in Multi  Cores Cables.

Flame Retardant (FR), Flame Retardant Low Smoke (FRLS) and Flame Retardant Zero Halogen (FRZH) Sheathed HT XLPE cables are also manufactured.

The XLPE cables are manufactured on sophisticated triple Extrusion line, in highly quality conscious environment with Testing and Inspection from raw material to finished cables. The assurance of quality is further ensured by ISI certification on cables.

Estimated Voltage  Drops in
PVC /XLPE Aluminum Cables Of A.C System

Nominal area Of conductor
( sq.mm)

P. V .C  Cable

XLPE Cable

Single phase

Three phase

Single phase

Three phase

1.5

43.44

37.62

46.34

40.13

2.5

29.04

25.15

30.98

26.83

4

17.78

15.40

18.98

16.44

6

11.06

9.58

11.80

10.22

10

7.40

6.41

7.88

6.82

16

4.58

3.97

4.90

4.24

25

2.89

2.50

3.08

2.67

35

2.10

1.80

2.23

1.94

50

1.55

1.30

1.65

1.44

70

1.10

0.94

1.15

1.00

95

0.79

0.68

0.83

0.70

SELECTION CRITERIA OF MV/ HV CABLE SIZE FOR PRIMARY DISTRIBUTION SCOPE

The conductor size in the cables for any installation is also governed by its ability to carry short circuit current of system. For L.V Distribution cable may be selected on the basis of continuous load current. But in case of MV /HV distribution it is always safer to select the cable on the basis of ability of conductor to carry expected short circuit current. Short circuit current rating of cable should in line with short circuit capacity of demanding apparatus such as circuit breakers, Transformer & Reactor etc. beside its capacity to carry desired load current . Short circuits rating of cables each size are given in relevant tables & have been calculated on the basis of IEC -949 & IEC -986 & on the following assumption

A) Temperature of conductor just prior to short circuit

i) With XLPE Insulation – 90 Deg. C
ii) With PVC Insulation – 70 Deg. C

B) Maximum permissible conductor temperature during short circuit

i) With XLPE Insulation -250 Deg. S
ii) With PVC Insulation – 160 Deg. C

C) Volumetric specified heat of the conductor

i) With Aluminum conductor – 2.5 x 10 -3 J/Deg. C/MM3
ii) With Copper conductor – 3.45 x 10 -3 J/Deg. C/MM3

D) Reciprocal of temperature co –efficient of resistance of resistance at 9 Deg. C

i) With Aluminum conductor -228
ii) With copper conductor – 234.5

Short Circuit current rating at different duration may be calculated as
Ish ( for t duration ) = Ish ( for 1 sec .) /t
Ish for 1 Sec .Duration is given in relevant tables in KA
t = Time duration required tobe calculated of short circuit in sec.

Estimated Voltage Drops in
PVC/XLPE Aluminum Cable of A.C System

Nominal area of conductor

PVC CABLE

XLPE CABLE

Single phase

Three phase

Single phase

Three phase

120

0.63

0.55

0.66

0.56

150

0.52

0.46

0.55

0.48

185

0.42

0.37

0.44

0.40

240

0.34

0.30

0.35

0.30

300

0.28

0.26

0.30

0.26

400

0.24

0.22

0.24

0.22

500

0.23

0.20

0.23

0.20

630

0.20

0.18

0.21

0.18

800

0.90

–

0.20

–

1000

0.18

–

0.18

–

Above voltage drops (volts/km/amps) shall be multiplied with rated current & length of cable in K.M to calculated total voltage drops in particular length and size cables.

SELECTION CRITERIA OF H.V. /MV CABLES FOR PRIMARY DISTRIBUTION

REQUIRED DATAS
 FOR EXAMPLE
1      Nominal system voltage at H.T.side 11 KV
2     Short Circuit level for H.T. system 2.5 KA
3     Fault withstands time for H.T.  CBs 0.5 Sec
4     Formula for calculating H.T. cable size

With aluminum cond. /XLPE Insulated cable = Ish x √t / 0.094 = 25 x √0.5 / 0.094 = 188 Hence nearest higher size 240mm is required
With Cooper cond. /XLPE Insulted cable = Ish x √t / 0.143 = 25 x √0.5 / 0.143 = 124 Hence nearest higher size 150 mm is required

SECTION DOWNLOAD
3.3 KV SINGLE CORE & THREE CORE, XLPE INSULATED, ARMOURED CABLES – NON SCREENED
3.3 KV SINGLE CORE & THREE CORE, XLPE INSULATED, ARMOURED CABLES – SCREENED
3.8-6.6 KV SINGLE CORE XLPE INSULATED ARMOURED, UNARMOURED CABLE & 3.8-6.6 KV THREE CORE XLPE INSULATED ARMOURED CABLE
6.6-6.6 & 6.35-11 KV SINGLE CORE XLPE INSULATED ARMOURED, UNARMOURED CABLE & 6.6-6.6 & 6.35-11 KV THREE CORE XLPE INSULATED
ARMOURED CABLE
11-11 KV SINGLE CORE XLPE INSULATED ARMOURED, UNARMOURED CABLE & 11-11 KV THREE CORE XLPE INSULATED ARMOURED CABLE
12.7-22 KV SINGLE CORE XLPE INSULATED ARMOURED, UNARMOURED CABLE & 12.7-22 KV THREE CORE XLPE INSULATED ARMOURED CABLE
19.33 KV SINGLE CORE XLPE INSULATED ARMOURED, UNARMOURED CABLE & 19.33 KV THREE CORE XLPE INSULATED ARMOURED CABLE