Underground cable leakage, what method or instrument can find the leakage cable breakage?

First of all, I will tell me why it is confirmed that it is leakage, the transformer has leakage protection, and it will be automatically adjusted and smashed as soon as there is leakage, and it will be used and jumped after closing, and the leakage will be displayed, and then in order to determine again that it is indeed the cable leakage and not the transformer leakage protection error, we will use the 2500V shake meter to test the leakage cable, and the shake meter is also displayed as 0, so it is determined that it is leakage.

Then we checked the cable, and repaired the breach as soon as we saw it, but we have been reading the entire cable and did not see the break, and the person was tired and sweating, and then used a short circuit to fire the cable, but unfortunately it could not be released, it seemed to be grounded and non-grounded, and it could not be put with a gun discharger, alas! Then use the black wire of the universal meter to ground the red line to connect the leakage of the cable phase wire, a person will knock or shake the cable next to each other, a person looks at the multimeter, if the multimeter shakes at a certain position, it means that the place is leaking, and the result is that the cable is all gone, and then use the most stupid way to find the break, and even open the break and make up again, no. I really don't know what to do, please teach the master how to move, and the little brother is very grateful.

Connect the cable to low-voltage direct current, and then check the current level of the multimeter point by point, depending on the applied voltage and leakage resistance to adjust to the appropriate gear. Try.

Due to poor production conditions, humid air, and frequent movement of electrical equipment in underground coal mines, leakage occurs from time to time. Leakage from the neutral ungrounded system will pose a great threat to people, equipment and even the mine. Therefore, it is necessary to have leakage protection.

Article 423 of the Coal Mine Safety Regulations stipulates that "a leakage detection protection device with leakage locking or a selective leak detection protection device shall be installed on the underground low-voltage feeder. If these two devices are not available, a leak detection device must be installed that automatically cuts off the leakage feeder. ”

At present, most of the leakage protection in small coal mines is not selective, and the leakage relay is generally connected with the total feed switch of the low-voltage power grid in the mining area, once the leakage occurs at a certain point in the power grid, the total feed switch will trip quickly and cut off the power supply of the entire power grid. Therefore, the scope of the power outage is wide and the impact area is large. If you can't quickly find the leakage fault point and restore the power supply as soon as possible, it will prolong the power outage time and have a great impact on production.

Especially when there is a excavation face in the mining area, if the local fan is out of operation for too long, it will lead to the accumulation of harmful gases in the excavation face and its nearby roadway to exceed the limit. When restoring power to local fans and other tunneling equipment, it will cause gas accidents. According to the analysis of some typical accident cases, the vast majority of biogas accidents in China's excavation face are caused by the above reasons.

Therefore, after the leakage of the power grid occurs, it is necessary to quickly find the leakage fault point and restore the normal power supply underground.

Common cable faults in underground are:

1) The cable falls to the ground, or even soaked in water, encounters various mechanical pressure gauges, squeezing, planing, stabbing or smashing, etc., which damage the cable insulation and leakage or short circuit.

2) The bending radius of the armored cable is too small, which makes the armor crack and lead package crack of the cable, resulting in the invasion of moisture or moisture, and the insulation of the cable is damaged and the leakage causes an accident.

3) The cable hanging position is too low, and the cable will be damaged when the tram head or minecart turns off the road; The cable is hung too high, and when the roadway roof is pressed, the cable will be crushed due to the deformation of the bracket.

4) Chicken paws, sheep tails, and exposed joints are one of the main causes of leakage and interphase short circuits.

5) The quality of the cable or cable joint is not up to standard, resulting in a short circuit or disconnection between phases.

6) The cable will be broken by the wire rope of the return column winch or the chain plate of the conveyor.

7) The cable is overheated due to overload operation, and the insulation is damaged by aging insulation.

In order to prevent the occurrence of various cable accidents, in addition to the design and installation should meet the requirements of the technical regulations, it must also be hung according to the regulations; Appropriate height and intensity; In use, regular patrol inspections should be carried out, and protective measures should be taken immediately when there is a situation that may endanger the cable; The insulation resistance should be measured regularly, and preventive insulation performance tests should be carried out according to the regulations, and problems or defects should be found and reported and dealt with in a timely manner; Leakage, overload and short-circuit protection devices must be set correctly and reliably operated.