Power cables, as a part of power lines, are widely used due to their low failure rate, safety and reliability, and flexible outgoing lines. However, once they fail, the repair process is quite difficult and the risks are high. Therefore, special attention should be paid during the maintenance and testing processes.
When detecting cable faults, the following points should be noted:
1. Preparations before work
Power cable outage work should be recorded in the first type of work ticket, while non-outage work should be recorded in the second type of work ticket. Before the work, one should carefully review the relevant path diagrams, arrangement diagrams, and drawings of concealed works. It is necessary to carefully check the names of the cables and whether the labels match those written in the work ticket. Only after the safety measures are correct and reliable can the work begin.
2. Precautions at Work
During work, it is necessary to identify the cables that need to be repaired. The cables that need to be repaired can be classified into two types:
(1) Cables with terminal head malfunctions and obvious fault points on the surface of the cable body. These faulty cables have obvious signs of failure and are easy to identify.
(2) Cables whose surfaces do not expose any faulty points.
For such faulty cables, in addition to checking the data and verifying the cable names, a cable identification instrument must also be used to identify them, so as to distinguish them from other operating live cables. Especially when there are numerous cables in the same section, it is particularly important to strictly distinguish the cables to be repaired from the other live cables. At the same time, this can effectively prevent accidents caused by wrongly hanging cable labels and misidentifying cables, leading to the accidental cutting of live cables. When cutting the cable, reliable safety protection measures must be in place. Before cutting the cable, it must be confirmed that it is the cable that needs to be cut and that the cable is not live. Then, a grounded iron pick with a wooden handle (preferably an epoxy resin handle) should be inserted into the cable core before work can begin. The person holding the wooden handle should wear insulating gloves and stand on an insulating pad. Special attention should be paid to ensuring good grounding of the iron pick. During work, if the cable needs to be moved, it should be done carefully. Do not act rashly to prevent damage to other operating cables. The cable head must be installed according to the process requirements to ensure quality and eliminate potential accident hazards. After the cable is repaired, the phases at both ends of the cable should be carefully checked. The original phase color markings should be removed first, and then the correct phase color markings should be put on to prevent confusion between the new and old phase colors.
3. Precautions during high-voltage tests
The high-voltage test of cables should strictly follow the “Electric Power Safety Work Procedures”. Even in the case of poor working conditions on site, the safety requirements cannot be reduced in the slightest. The division of labor must be clear, and safety precautions should be detailedly arranged. The test site should be equipped with enclosed barriers or fences, with the “Stop, High Voltage Hazard!” sign hanging outward, and someone should be on duty. Especially, the other end of the cable must also be guarded by someone, and communication should be kept畅通 to prevent unexpected incidents. The test equipment and wiring should comply with safety requirements， and the operation must be standardized. During the test， attention should be concentrated， and the operators should stand on insulating mats. Before changing the wiring or at the end of the test， the test power supply should be disconnected， discharged， and the high-voltage part of the equipment should be short-circuited and grounded. During high-voltage direct current tests， the cable should be discharged to ground several times and short-circuited and grounded at each interval or at the end of the test， and then it can be touched.
4. Other Important Notes
When opening the cover of a cable well or cable trench, measures should be taken to prevent traffic accidents. Fences should be set up around the well, and clear warning signs should be placed. Obstacles to prevent vehicles from entering should also be installed. At night, the cable well should be illuminated to prevent pedestrians or vehicles from falling into the well. Before entering the cable well, the foul air inside should be removed. Workers inside the well should wear safety helmets and take measures for fire prevention, waterproofing, and prevention of falling objects from heights. A dedicated person should be on duty at the well opening.
Post time: Jun-23-2026