Whether our colleagues in electrical design or factory electrical maintenance can not open the topic of cable selection, we often see that the AAC Cable selection size of the same equipment under the same power will be different in the work, some may be less than one or two levels, and some friends may be confused by which right? Why do you choose different? Today we will learn how to choose the cable and how to consider it from? What is the effect of temperature on the selection of cables?
1、 Cable selection
(1) Select cable according to temperature rise
We all know that when the conductor passes through the load current, the temperature of the conductor will rise, the conductor has insulation layer, and the conductor temperature shall not exceed the maximum temperature allowed for a long time by the conductor insulation, and the conductor will be damaged after exceeding.
(2) According to mechanical strength
When laying, the conductor has a minimum section allowed according to the laying mode and the distance between the support point and the distance.
(3) Select according to economic conditions
That is, choose the most economical way.
(4) Select by line voltage drop
We all know that when the current passes through the conductor, the voltage drop will be generated in the line due to the existence of line impedance. If the voltage drop is too large, the voltage at the end of the line, that is, the load end is too low, which will cause the equipment to fail to work or affect the equipment life. Therefore, it is required that the voltage drop cannot be too large, so the cable section should be selected reasonably.
(5) Cable selection shall meet the requirements of load protection
When the circuit is in fault, the protective device should act according to the specified time, whether it can operate reliably or not has a great relationship with the cable section. Therefore, we should consider the requirements of reliable action when choosing the ACSR Cable.
(6) Select cable according to the requirements of thermal stability
In case of failure of cable or electrical equipment, the cable shall meet the requirements of thermal stability, and the size of cable section shall be considered in order to meet this requirement. The maximum cross section is the final result by combining the above conditions.