Voltage designation
The rated voltage of the cable for a given application shall be suitable for the operating conditions in the system in which the cable is used,and is expressed in the form of Uo/ U(Um)kV.
Where:
Uo-The rated power-frequency voltage between conductor and screen or metallic-sheath,for which the cable designed;
U-The rated power-frequency voltage between conductors, for which the cable designed:
Urn-The maximum value of the "hight system voltage " for which the equipment may he operated.
Rated voltaged of cable applied in three phrase system are given in table
U | Um | Uo | |
First class | Second class | ||
1 | 1.2 | 0.6 | 0.6 |
3 | 3.6 | 1.8 | 3.6 |
6 | 7.2 | 3.6 | 6 |
10 | 12 | 6 | 8.7 |
15 | 17.5 | 8.7 | 12 |
20 | 24 | 12 | 18 |
35 | 42 | 21 | 26 |
Note:The first class cable suitable for one single-phrase earth-fault time does not exceed 1 min each time and Max. time not exceed 8 hours.and not exceed 125 hours in all in one year.
The second class cable suitable fir more earth-fault time and more better insulation performance.
Production Range of cable
Type | No. of cores | Nominal Cross sectional area m2 |
Copper conductor | ||
VLV22
| 1* | 10-800 |
2 | 4-400 | |
3 | 4-630 | |
4 | 4-500 | |
3+1 | 4-630 | |
5 | 4-500 | |
4+1 | 4-500 | |
3+2 | 4-500 | |
*The armoured single-core cables are used for D.C system only. As for A.C system non-magnetic armoured material should be used. Or magnetic isolation measures should be applied. | ||
