Conductor material of power cable
Copper conductor shall be used for power cables used in the following situations
- Motor excitation, important power supply, mobile electrical equipment, etc. should be connected with high reliability circuit
- Working environment such as vibration place, explosion risk or corrosion to aluminum;
- Fire resistant cable
- Close to high temperature equipment
- Crowded places
- Nuclear power plant conventional island and production related ancillary facilities.
In addition to the fact that the product only has copper conductor and copper conductor should be selected as above, copper conductor, all aluminum conductor or aluminum alloy conductor can be selected as conductor material of cable. Aluminum alloy conductor is not suitable for cables with voltage level above 1kV
The structure and performance parameters of cable conductor shall comply with the provisions of current national standards: electric τ copper round wire (GB / t3953), electric t round aluminum wire (GB / t3955), conductor of cable (GB / t3956), aluminum alloy wire for cable conductor (B / t30552).
Insulation level of power cable
The phase to phase rated voltage of power cable conductor in AC system shall not be lower than the working line voltage of using circuit
The selection of rated voltage between power cable conductor and insulation shield or metal sheath in AC system shall meet the following requirements
- When the neutral point is directly grounded or grounded through low resistance system, the action of grounding protection shall not exceed 1 min, and when the fault is removed, it shall not be lower than 100% of the working phase voltage of the use circuit;
- For the power supply system with single-phase ground fault more than lmin, it should not be lower than 133% of the working phase voltage of the use circuit; when the single-phase ground fault may last more than & H or the safety requirements of generator circuit are high, 173% of the working phase voltage of the use circuit should be adopted
The withstand voltage level of cables in AC system shall meet the requirements of system insulation coordination.
The insulation level of DC transmission cable should be able to withstand withstand voltage test of polarity reversal, DC and impact superposition, etc.; XLPE insulated cable should have the characteristics of restraining space charge accumulation and forming local high field strength to adapt to DC electric field operation