Matters needing attention in the operation of power cable in power distribution room - Database & Sql Blog Articles

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1. The power cable line shall operate under the specified current carrying capacity allowed for long-term passage. If the core wire is overheated for a long time, the core cable is overheated, and the overall temperature of the cable rises, which may cause the cable terminal head and the intermediate joint box to burst, which may cause the cable insulation moisture to deteriorate, resulting in thermal breakdown. Therefore, the cable load current and the skin temperature cannot be ignored. Monitoring, for cables used in parallel, take care to prevent the end of the cable from overheating due to uneven load distribution.

2. The cable distribution line should not use the reclosing device, which can cause the cable distribution circuit breaker to trip the cable fault, such as the internal short circuit of the terminal head, the internal short circuit of the middle head, and other permanent faults. In this case, if the reclosing is After the action or trip test, it will inevitably expand the accident and threaten the stable operation of the system. Therefore, the cable distribution line should not use a reclosing device.

3. After the cable distribution line circuit breaker trips, do not ignore the cable inspection. First of all, it is necessary to find out whether there is any fault in the equipment carried by the line. Such as various forms of short circuit of the equipment, but also to check the appearance of the cable changes, for example, whether the outdoor terminal of the cable is flooded and caused an explosion, and whether the intermediate terminal head of the indoor terminal is short-circuited due to overheating of the joint causes the insulation heat to burst and burst. Whether there is excavation on the ground of the cable path, so that the cable is damaged. If necessary, it should be further checked by trial.

4. Pay special attention to the direct buried cable: 1 The ground near the cable path cannot be excavated casually. 2 Cable path ground is not allowed to stack heavy objects and corrosive substances, temporary buildings. 2 Cable path piles and protection facilities are not allowed to move or dismantle. 4 Cables entering the building shall not leak water.

5. The cable is deactivated for a period of time and cannot be easily put into use without testing. The reason for this requirement is that the cable is deactivated for a period of time, the moisture is absorbed, and the insulation is affected. Generally, the power failure is more than one week, but the cable with less than one month should be shaken before the operation is restarted. Compared with the previous test record, the cable should not be reduced by 30%. Otherwise, the DC withstand voltage test must be performed. The test voltage can be Half of the preventive test voltage. If the power outage exceeds the test period, a preventive test must be performed according to the standard.