Modularized recovery method for high-voltage cross-linked polyethylene insulated cable joint

Abstract

The invention discloses a modular recovery method for a high-voltage cross-linked polyethylene insulated cable joint. The method comprises the following steps of (1) cable stripping and pretreatment, (2) conductor welding, (3) semiconductor shielding recovery, (4) modular joint insulation main body recovery, (5) strip wrapping and (6) appearance recovery. According to the present invention, an original cold and hot compression joint type joint is abandoned, but a modular recovery conductor made of the same material as the cable body, a shielding layer, an insulation layer and an insulation shielding layer are adopted, so that the integration of connector main insulation and cable main insulation is achieved, the cable joint is not affected by thermal expansion and cold contraction, the waterproof performance is good, electric field and thermal field distribution is uniform and stable, and the electrical performance is excellent. The cable joint is long in service life, is convenient to construct, is smaller in influence by a construction site, is high in construction speed and is suitable for installation and maintenance of various cables, cable accident rescue and the like, and therefore the capital construction cost is reduced.

Description

technical field [0001] The invention relates to the technical field of cable intermediate joints, in particular to a modular recovery method for high-voltage cross-linked polyethylene insulated cable joints. Background technique [0002] In the high-voltage cable system of 10KV and above, the metal sheath has an induced voltage and increases with the increase of the cable length. The superposition will endanger personal safety, especially in the event of a short-circuit fault, lightning shock or operating overvoltage in the line, it may break down outer sheath. In addition, if the two ends of the cable shield are directly grounded, a large circulation loss will be generated, which will cause the cable to heat up, reduce the current carrying capacity, and accelerate the thermal aging of the cable. Therefore, when the high-voltage cable line is very long, it is necessary to set up an insulating joint (the metal sheath of the cable at both ends of the joint and the cable insul...

AI Technical Summary

Problems solved by technology

[0003] The high-voltage cable accessories commonly used in China today are hot and cold crimping joints, but the prefabricated accessories are assemblies of different materials, and the space charge is easy to accumulate at the interface of different materials, which makes the local field intensity distorted, and even causes electric tree branching. breakdown

On the other hand, due to the influence of operating temperature, the thermal expansion and contraction properties of different materials are different, which will lead to active interfaces at the material interface, which is susceptible to moisture intrusion and accelerates joint cracking

Moreover, rubber insulating parts are affected by electric and thermal fields during long-term operation, and will relax due to the decrease in elastic modulus, resulting in a decrease in interface pressure and precipitation of additives in rubber insulating parts, which will eventually lead to a decline in insulation performance and pose a safety hazard.

In addition, after the joint is manufactured, it must be fixed and cannot be moved or transferred. Otherwise, the internal components will slip or be misplaced, posing a safety hazard. Or the widening section is specially set up in the cable tunnel for the placement of joints, which greatly increases the infrastructure cost of the cable line

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