Common faults and safety requirements of underground distribution cables

What are the common faults of insulated underground distribution cables? Common faults of underground distribution lines include mechanical damage, insulation damage, insulation moisture, insulation aging and deterioration, overvoltage, cable overheating, etc. If these faults occur in the line, it is necessary to cut off the power supply of the faulty cable, find the fault point, check and analyze the fault, and then carry out maintenance and experiment.

What are the safety requirements for insulated cables of underground distribution lines?

The distance between the cable and the building foundation shall ensure that the cable is buried outside the landscape of the building. When the cable enters the building, it shall pass through the official protection, and the protection pipe shall also cross the landscape of the building.

When the cable approaches or crosses the heat pipe, if there are thermal insulation measures, the minimum distance between parallel and cross is 0.5m and 0.15m respectively.

When the UD cable crosses the railway or road, it shall penetrate the pipeline for protection, and the protective pipe shall protrude 2m beyond the track or road.

When cables cross each other, high-voltage cables shall be located under low-voltage cables. If one of the cables is protected by pipes or separated by partitions within 1m before and after crossing, the minimum allowable distance is 0.15m.

The distance between the cable directly buried underground and the grounding of general grounding device is 0.15 ~ 0.5m; Must be separated. The buried depth of cables directly buried underground shall not be less than 0.7m and shall be buried under frozen soil.