Comparitive Current Ratings , Short Circuit Ratings, Capacitance and Reactance for XLPE Cables

 

Comparative Current Ratings of 650/100 Volts Multicore heavy duty PVC Insulated Cable

& XLPE Insulated Cables. (3,3.5 & 4 Core Unarmoured / Armoured PVC Sheathed Cable

with Aluminium Conductor.

Nominal

Size of

Conductor

3,3.5&4 Core PVC Insulated & Sheathed

cables as per IS-1554(part-1) 1988

3,3.5&4 Core XLPE Insulated & Sheathed

cables as per IS-7098(part-1) 1988

In Ground In Air Approx

Voltage Drop

In Ground In Air Approx

Voltage Drop

Sq.mm Amp Amp mv / amp / mtr Amp Amp mv / amp / mtr
16 60 51 4 73 70 4.2
25 76 70 2.5 94 96 2.7
35 92 86 1.8 113 117 1.9
50 110 105 1.3 133 142 1.4
70 135 130 0.93 164 179 0.99
95 165 155 0.68 196 221 0.72
120 185 180 0.54 223 257 0.58
150 210 205 0.46 249 292 0.48
185 235 240 0.38 282 337 0.39
240 275 280 0.28 326 399 0.31
300 305 315 0.25 367 455 0.26
400 335 375 0.20 420 530 0.21

 

 

Comparison of Short Circuit Rating for 1 Second duration for * PVC & XLPE Insulated

Cables ** with Copper and Aluminium Conductors. (Current in kAmps)

Nominal

Size

PVC Insulated XPLE Insulated
Sq.mm Copper Aluminium Copper Aluminium
1.5 0.173 - 0.21 -
2.5 0.283 - 0.36 -
4 0.46 0.303 0.57 0.38
6 0.690 0.455 0.86 0.57
10 1.15 0.758 1.40 0.94
16 1.84 1.21 2.30 1.5
25 2.88 1.90 3.60 2.40
35 4.03 2.65 5.0 3.3
50 5.75 3.79 7.10 4.70
70 8.05 5.31 10.0 6.6
95 10.90 7.2 13.6 9.0
120 13.80 9.10 17.10 11.30
150 17.3 11.40 21.40 14.2
185 21.3 14.02 26.40 17.50
240 27.6 18.20 34.3 22.6
300 34.5 22.80 42.90 28.3
400 46.00 30.40 57.10 37.7
500 57.5 38 71.4 47.2
630 72.5 47.25 90 59.4
800 92.0 60.0 114.3 75.5
1000 115.0 75 142.9 94.3
* PVC Type ‘A’ Insulation as per IS-5831/’84

** PVC Cables as per IS-1554(part-1)-1988.

** XLPE Cables as per IS-7098(part-1)-1988.

1). Max Conductor Temperature during

operation.                   PVC             XLPE

70ºC            90ºC

 

2). Max Conductor Temperature during

Short Circuit.              160ºC          250ºC

 

Formula relating Short Circuit Rating with duration

It=I sh                Where

t   It = Short Circuit Rating for t Seconds.

t = duration in seconds

Ish = Short Circuit Rating for 1 Seconds.

 

 

CAPACITANCE

Approximate Capacitance (Microfarads/km) 1.1 kV XLPE Cables.

Nominal Area of Conductor in

sq.mm

 

Single Core Two Core Three, three &

Half and Four

Core

Unarmoured Armoured
1.5 0.19 - 0.051 0.15
2.5 0.24 - 0.058 0.18
4 0.29 - 0.065 0.22
6 0.34 - 0.071 0.25
10 0.43 0.32 0.081 0.31
16 0.51 0.38 0.088 0.36
25 0.49 0.38 0.089 0.41
35 0.57 0.44 0.096 0.47
50 0.58 0.46 0.098 0.50
70 0.63 0.51 0.10 0.53
95 0.73 0.59 0.11 0.61
120 0.74 0.61 0.11 0.63
150 0.73 0.61 0.11 0.60
185 0.69 0.59 0.11 0.60
240 0.74 0.64 0.11 0.63
300 0.80 0.69 0.12 0.67
400 0.83 0.70 0.12 0.67
500 0.83 0.71 0.11 0.69
630 0.87 0.75 0.11 0.73

 

800 0.92 0.78 - -
1000 0.95 0.81 - -
Table-5
REACTANCE

Approximate Reactance At 50 Hz (Ohms-/km) 1.1 kV XLPE Cables.

Nominal Area of Conductor in

sq.mm

 

Single Core Multicore
Unarmoured Armoured
1.5 0.155 - 0.107
2.5 0.142 - 0.0985
4 0.132 - 0.0927
6 0.123 - 0.0884
10 0.114 0.134 0.0837
16 0.108 0.125 0.0808
25 0.103 0.120 0.0805
35 0.0986 0.114 0.0783
50 0.0937 0.108 0.0750
70 0.0900 0.102 0.0740
95 0.0865 0.100 0.0724
120 0.0841 0.0968 0.0712
150 0.0839 0.0941 0.0716
185 0.0836 0.0932 0.0718
240 0.0813 0.0900 0.0710
300 0.0795 0.0881 0.0705
400 0.0787 0.0873 0.0704
500 0.0779 0.0859 0.0702
630 0.0785 0.0843 0.0698
800 0.0755 0.0826 -
1000 0.0752 0.0825 -