Method for repairing damage of external shield of medium and high voltage cable

Abstract

The invention discloses a method for repairing the damage of an external shield of a medium and high voltage cable, belongs to the technical field of wires and cables, and is used for cleanly processing the damaged external shield and the surface of an insulator. The method comprises the following steps of: completely wrapping a damage part by using a pressing sheet of an external semi-conductive material; tightly winding the exterior of the damage part by using a polyester belt or a polytetrafluoroethylene belt; putting the repaired damage part into a heating device which is pre-heated to a constant temperature of 118 to 122 DEG C; heating for 4 to 6 minutes under the pressure of 1.1 MPa to 1.3 MPa; and cooling, and then cutting a thicker part to make the appearance smooth. The method has the advantages that: the appearance of the repaired part is almost the same as that of the unrepaired part; the thickness of the external shield can be guaranteed; any influence of the external shield is avoided; the shielding effect of the external shield and the quality of finished cable products are guaranteed; and economical cost is low.

Description

Technical field [0001] The invention belongs to the technical field of wires and cables, and relates to a method for repairing the outer shield of medium and high voltage cables, and is suitable for repairing when the cross-linked polyethylene insulated outer shield is damaged. Background technique [0002] When the outer shielding of medium and high voltage cross-linked polyethylene insulated power cables is damaged, most of them can only be divided into sections. The number of meters out of the sections cannot meet the requirements of customers and must be re-produced and processed. A large backlog of short-segment finished products not only increases the inventory, but also increases the company’s scrap rate and cost; if repairs are necessary, the usual approach is to buy some semi-conductive paint or semi-conductive self-adhesive tape, and apply it directly to the outer surface of the insulation or Wrap the self-adhesive tape directly on the outside of the insulation, which w...

AI Technical Summary

Problems solved by technology

[0002] When the outer shielding of medium and high-voltage XLPE insulated power cables is damaged, most of them can only be segmented. A large backlog of short-segment finished products not only increases the inventory, but also increases the company's scrap rate and cost; if repairs are necessary, the usual way is to buy some semi-conductive paint or semi-conductive self-adhesive tapes, which are directly coated on the outer surface of the insulation or Wrap the self-adhesive tape directly on the outside of the insulation, which will have great disadvantages. Since the outer shielding repair uses semi-conductive paint, the liquid is applied to the solid surface, and the thickness cannot be guaranteed, often failing to meet the standard thickness requirements. Moreover, there are almost no domestic manufacturers of this kind of semi-conductive paint. When needed, they can only be imported from abroad. Not only the time cannot be guaranteed, but also the price is very high.

If the repair method of wrapping tape is used, although the outer shielding and insulation can be combined into one, because the tape and the insulation are in close contact, when using a hair dryer, due to manual operation, the temperature control is not stable enough, and the damaged surface is not heated. Even, overheating will cause the insulation to expand due to heat, which will inevitably be damaged and seriously affect the insulation quality of cable products

If the temperature is lower than the temperature, it cannot ensure that the wrapping tape is completely melted, and it cannot be integrated with the insulation.

Therefore, these two methods can only be used when the outer shield is slightly damaged, and the amount of semi-conductive paint and semi-conductive tape is relatively small, and when the outer shield after insulation suffers a lot of damage, And when the area reaches a certain level, the above two methods cannot meet the design requirements

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