Electronic Wire And Cable Construction Precautions

1. Eddy current problems caused by high current power cables

In the construction of power cables, steel brackets are used, steel protection pipes are used, cable clamps and overhead laying are used. Eddy currents can result from any steel (iron) closed circuits that form around power cables. Eddy currents are greater especially in high current power cable systems. During the construction process of power cables, measures must be taken to prevent the formation of steel (iron) closed loops around the cables and to prevent the cables from generating eddy currents.

2. Mechanical damage caused by the rotation of the power cord

Due to the large outer diameter of the power cable, it is difficult to transport and lay, and the power cable has stricter requirements on the turning radius. During the construction of the power cable, if the turning angle is too large, it may cause mechanical damage to the inside of the conductor, and the mechanical damage will be reduced due to the insulation strength of the cable until failure occurs. The cable head was found to be faulty during construction. When making cable heads, all three cable heads are the same length. Due to the limitation of the terrain when connecting with the equipment, the cable head of the neutral phase is too long to form an arch, and the root of the cable head is damaged and discharged. Then, take measures to appropriately shorten the connection length of the middle-phase cable head when connecting the equipment, so that the three-phase cable head is not affected by external force. Practice has proved that the operation effect is good. It can be seen that in the process of cable construction, the torsion force of the cable needs to be reduced as much as possible. The cable bends naturally as it turns and leaves the cable to prevent internal mechanical damage.

3. It is the moisture-proof problem of the power cord

Operational experience shows that the faults of medium and low voltage power cables are mostly the faults of the intermediate joints and terminals of the cables, while the faults of the intermediate joints and terminals are mostly caused by poor sealing and moisture intrusion, resulting in a decrease in the dielectric strength. reduce. The network mostly adopts the tree-like power supply mode, and the number of cable terminals is large. Therefore, plugging and sealing the cable terminal and intermediate joint is one of the important measures to ensure the safe and reliable operation of the cable.

4. It is the grounding problem of medium and low voltage power cables

In the public medium and low voltage power cable network, since the three-phase loads are not equal, if the metal sheathed cable is used, the grounding problem of the metal sheath must be considered, and the grounding problem of the metal sheath must be guaranteed. If any point of the sheath is not grounded, the normal induced voltage shall not be greater than 100V. In my opinion, in the medium and low voltage cable network, all cable joints should be provided with grounding electrodes (nets), and the metal sheath should be reliably grounded.