JPH028525B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to, for example, cross-linked polyethylene insulated vinyl sheathed power cables (hereinafter referred to as CV cables).
Regarding the connection method.

[Prior technology] CV cables are used for 154KV and 275KV lines, but from the standpoint of line reliability, the connection part uses a polyolefin insulator made of the same material as the cable insulator, and is a molded type that is heated and integrated. The connection is optimal and widely used.

[Problem to be solved by the invention] The molded connection part is made by integrally molding a polyolefin insulator by heating, but this heating is usually done from the outside of the insulator, and the insulator near the conductor connection pipe of the connection part is heated. Once the temperature reaches a predetermined temperature, it is maintained at that temperature for a predetermined period of time. In such heating methods, the dimensions of the cable conductor become a problem.
In other words, if the conductor diameter is relatively small, the above method is effective, but if the diameter is large, heat dissipation to the cable conductor becomes large, and the temperature of the insulator near the conductor connection pipe increases to a predetermined temperature. It becomes difficult to do so.

In addition, in a conductor connection method in which cable conductors are pressure-connected with a conductor connection tube, in order to reduce the concentration of electric field on the uneven portions of the surface of the conductor connection tube that have been deformed by pressure connection, for example, a file or the like is used to Shaving the surface of the conductor connection tube smooth was a time-consuming process.

An object of the present invention is to provide a connection method that can effectively prevent heat dissipation to the cable conductor side when heat-molding the connection portion of a CV cable, and that eliminates the trouble of processing the surface of the conductor connection tube. , thereby facilitating the connection of CV cables.

[Means for Solving the Problems] According to the present invention, when molding the insulating layer of the connection part of the CV cable by heating from the outside, a stainless steel made of relatively low thermal conductivity is formed on the connection pipe. The above object is achieved by providing a molded heat insulating layer and performing the heating in this state.

[Example] An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a partial cross-sectional view of one embodiment of a CV cable connection section. First, the ends of each CV cable 6 to be connected are penciled into a predetermined shape, and the cable conductors are pressure-connected using the conductor connecting tube 1. In the conventional method, an internal semiconducting layer is formed directly on the conductor connecting tube 1, but in this embodiment, a molded heat insulating layer made of stainless steel with low thermal conductivity is formed on the conductor connecting tube 1. 2
is disposed, and the internal semiconducting layer 3 is formed thereon.

By providing such a molded heat insulating layer 2,
Generally, an insulating layer 4 made of polyolefin, which is the same material as the CV cable insulator, is formed by extrusion molding, tape lamination winding molding, molded sheet winding molding, or insulator block insertion molding, and is further heated on the outside of the outer semiconductive layer 5. A heat source such as a heater is provided, so that when the insulating layer 4 is heated and molded, heat dissipation toward the cable conductor connecting tube side is effectively blocked, and the insulator temperature can be smoothly raised. In addition, the unevenness on the surface of the conductor connecting tube 1 connected by pressure welding,
Since it is covered with the molded heat insulating layer 2 made of stainless steel, there is no need to smooth the surface of the conductor connecting tube 1. As a result, connection work can be easily carried out in a short time in CV cables having large diameter conductors. Of course, there is no reduction in electrical performance at the cable connection.

Although the present invention is particularly suitable for CV cables having large-diameter conductors, it goes without saying that the present invention is equally applicable to CV cables having small-diameter conductors.

[Effects of the Invention] As described above, the present invention has been achieved by focusing on the heat dissipation to the conductor connecting tube side and the processing of the surface of the conductor connecting tube when connecting cables, and has achieved the above-mentioned advantages. The novel improvement of employing a molded heat insulating layer such as the above achieves the original objective very effectively and has extremely great industrial advantages.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining one embodiment of the present invention.
FIG. 3 is a partial cross-sectional view of a CV cable connection section. 1: Conductor connection pipe, 2: Molded heat insulating layer, 3: Internal semiconductive layer, 4: Insulating layer, 5: External semiconductive layer, 6:
CV cable.

Claims (1)

[Claims] 1. A molded heat insulating layer made of stainless steel with low thermal conductivity is provided on the circumference of the conductor connecting tube that connects the cable conductors, and an internal semiconductive layer,
1. A method for connecting a power cable, comprising providing an insulating layer and an outer semiconductive layer, and then heating the outer layer from the outside to mold the outer layer.