2025-11-26
Cable joints utilize either a metal sheath (iron, lead, aluminum, etc.) or a non-metallic sheath (nylon, plastic, etc.), with an insulating casting agent (such as epoxy resin, asphalt, cable oil, etc.) poured inside to form the joint. This type of joint is commonly used in oil-impregnated paper-insulated power cables.
The figure shows a schematic diagram of a 6-35KV oil-impregnated paper-insulated cable intermediate joint. The joint sheath uses a lead sleeve. To ensure good contact between the lead sleeve and the cable's lead sheath, the ground wires at both ends of the cable should be welded to the lead sleeve last.
Figure 6 - Schematic diagram of the intermediate joint structure of a 35KV oil-impregnated paper-insulated cable
1 – Steel strip; 2 – Steel strip clip; 3 – Lead-lined; 4 – Lead sleeve; 5 – Glue injection hole; 6 – Ground wire; 7 – Lead sheath; 8 – Semi-conductive paper; 9 – Cable sheath insulation; 10 – Insulated core wire; 11 – Core wire connection point
In practice, there are also intermediate connectors with non-metallic shells or no shell at all, with only a ground wire connecting the two ends of the connector. The failure rate of this type of intermediate connector is relatively high and it is relatively difficult to measure.
The figure shows a schematic diagram of the terminal joint structure of a 6-35kV oil-impregnated paper-insulated cable.
1—Terminal; 2—Wire core insulation; 3—Insulating sleeve, etc.; 4—Insulating adhesive; 5—Cable sheath insulation; 6—Semi-conductive paper; 7—Non-metallic outer shell; 8—Lead sheath; 9—Steel tape clip; 10—Ground wire; 11—Steel tape
