Relevant specifications and standards when selecting cable models
1. Cable selection
(1) Copper conductors should be selected for control cables, public facilities with high safety, fire-resistant cables and power cables with higher working temperature.
(2) The number of cable cores can be flexibly selected according to the application and the current-carrying conditions of the cable. Choose according to the relevant standards of GB50217. The DC power supply circuit should use a two-core cable, if necessary, a single-core cable can be used.
(3) The withstand voltage rating of the cables in the AC system should meet the requirements of system insulation coordination. The insulation level of the DC transmission cable should be able to withstand voltage tests such as polarity reversal, DC and impact superposition, and the cross-linked polyethylene cable used should have the ability to inhibit space charge accumulation and form high local field strength. . Adapt to DC electric field operation. characteristic.
(4) According to the use environment of the cable, choose the style of the insulation layer purposefully. PVC insulated cables are not suitable for high temperature (above 100°C) or low temperature (below -20°C). Under the maximum operating current, the temperature of the core wire of the cable shall not exceed the allowable value determined by the service life of the cable. Determine the ambient temperature to ensure the continuous allowable current carrying capacity of the cable. If the cable is placed in the air or in a cable tray, the highest average temperature of the hottest month should be obtained.
2. The choice of cable path should meet the following requirements
(1) Avoid cables subject to mechanical external force, overheating, corrosion and other dangers.
(2) When meeting the safety requirements, please shorten the cable length.
(3) Easy to install and maintain.
(4) Avoid digging
(5) When laying cables directly, if the cables are under high voltage or there is a danger of mechanical damage, steel tape armored cables should be used.
(6) The cable shall meet the requirements of the allowable bending radius of the cable under any laying method and all path conditions of the cable.