JPS6030171B2 - Method of forming plastic insulated power cable connections - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present method relates to a method of forming a plastic insulated power cable connection, and more particularly to a method of forming a plastic insulated power cable extrusion type connection having an outer semiconducting layer edge.

As a means of connecting plastic insulated power cables such as cross-linked polyethylene insulated power cables, a tape or sheet of the same quality as the cable insulator is wrapped around the cable conductor connection part and then heat-fused and integrated. The so-called heat molding method, which consists of
Although there is an extrusion molding method, if the cable to be connected is of the ultra-high voltage class, for example, 154 KV, 27 arc V class, the latter is more suitable in terms of reliability and electrical characteristics.

For this reason, with the recent increase in the voltage of this type of cable, there is an urgent need to put the latter method into practical use, and its development is currently being actively progressed.

On the other hand, in cable lines, there is a problem in that the voltage induced in the outer semiconducting layer increases as the distance increases, so a so-called insulated follow-on part, which cuts off the outer semiconducting layer, is required as a connection part. Become. However, in the extrusion molding method described above, a means for producing an insulated connection portion has not yet been developed.

The present invention has been made in view of the above points, and includes:
The aim is to provide a method for manufacturing insulated connections in an extrusion molding process.

In other words, ``The gist of the present invention is to cover a cable conductor connecting portion with a mold having a recess formed in the inner surface thereof for forming a protrusion for cutting the edge of an external semiconducting layer on the surface of an insulating reinforcing body, which will be described later. The process of extruding and filling an insulating material of the same quality as the cable insulator into the above-mentioned mold and forming an insulating reinforcing body with protrusions for edge cutting of the external semiconducting layer on the above-mentioned cable conductor connection part; A method for forming a plastic insulated power cable connection part, comprising the steps of: molding an outer semiconducting layer while leaving edge cutting protrusions on the circumference of the body.

Specifically, as a method for forming the external semiconductive layer, for example, first, a crosslinking agent-containing semiconductive rubber is applied around the insulating reinforcing body.

Extruded plastic or semiconductive rubber with crosslinking agent.
Wrap it with plastic tape, apply semiconductive rubber or plastic paint containing a crosslinking agent, or insert semiconductive rubber containing a crosslinking agent. Then, place it in air or an inert gas. There is a method in which the insulating reinforcing body is bonded to the insulating reinforcing body by heating to crosslink it.Next, an embodiment of the forming method of the present invention will be explained with reference to the attached drawings. As shown, the cross-linked polyethylene insulated vinyl sheathed power cable (hereinafter referred to as CV cable) to be connected 1.
The sheaths 2, 2', insulators 3, 3', etc. of 1' are peeled off in a predetermined section at the end, and then the exposed end conductors 4, 4' are connected to a predetermined conductor connection pipe. 5
Further, an internal semiconducting layer 6 is provided on the periphery of the end conductors 4, 4' and the conductor connecting tube 5. The internal semiconductive layer 6 is preferably a molded product obtained by heat-treating a wrapped layer of a semiconductive polyolefin heat-shrinkable tube or a semiconductive polyolefin tape (or sheet). Next, a mold 8 having a recess 7 formed in the inner circumferential direction for forming a protrusion for cutting the edge of the external semiconducting layer on the surface of the insulation reinforcing body, which will be described later, is placed on the insulator 3 of both cables.
3' over the cable conductor connection.

The mold 8 is composed of two halves, and is equipped with a heater 9 on its circumference.Next, the ram device blade 0 and the extruder turtle 1 are directly connected to the mold 8, and the The mold 8 is heated to a predetermined temperature using a heater 9.

Next, using the extruder 1, a crosslinking agent-containing polyethylene insulating material 12 having the same quality as the cable insulators 3 and 3' is extruded and filled into the mold 8.

The extrusion filling is continued until the material tortoise 2 overflows from the overflow hole 3 of the mold 8 and the ram device 10. Next, mold 8 is filled with polyethylene insulation material 1
2 rises to a temperature necessary for crosslinking, and after crosslinking, the mold 8 is cooled to solidify the material 12, and then a predetermined outer semiconducting layer edge cutting protrusion group is formed. The base insulating reinforcing body 15 is molded.

Next, the mold 8 is removed, and as shown in FIG. 2, the outer semiconductive layer 16 is molded, leaving the edge-cutting protrusions 14 on the periphery of the insulating reinforcing body 15.

The outer semiconductive layer i6 is formed by extruding polyethylene containing a crosslinking agent, then heating it in air or an inert gas to crosslink it, and bonding it to the insulating reinforcement 15. Next, an insulating reinforcing layer 17 is provided on the periphery of the edge-cutting protrusion i4 to prevent surface flashing when an abnormal voltage penetrates.

Practically, the insulation reinforcing layer 17 is formed by heat molding a polyopine insulation compound or by wrapping a polyopine insulation tape. Note that FIG. 3 shows another embodiment of the present invention.

In order to prevent surface flashing of the edge cutting protrusion '4', it is preferable to lengthen the surface insulation distance of this part. At this point, a recess 7' was formed on the inner surface of the mold 8', and a curvature molded body 18 having a predetermined curvature was inserted into the recess 7'.

As the curvature portion molded body 1-8, a multi-segmented semiconductive rubber/plastic molded body or a metal molded body having two or more parts is used. After molding the insulating reinforcing body 15', the mold 8' is removed, and then, if the curved part molded body 18 is made of metal, it is removed, and if it is made of semiconductive rubber or plastic, it is removed as necessary. This is removed, and then an outer semiconducting layer (not specifically shown) is formed in the same manner as in the previous embodiment.

). According to the forming method of the present embodiment carried out in this manner, by preparing a mold in which a recess for forming a protrusion for cutting the edge of the external semiconducting layer is formed in the inner circumferential direction of the mold itself, It is possible to easily manufacture a predetermined insulated connection part.

Moreover, the edge cutting protrusion is an extrusion molded body like the insulating reinforcing body, and therefore not only has excellent electrical performance but also excellent reliability.

Thus, the present invention is accomplished using a slightly modified mold, and is therefore a highly practical forming method.

[Brief explanation of the drawing]

1 and 2 are explanatory views of one embodiment of the method for forming a plastic insulated power cable connection portion of the present invention, and FIG. 3 is an explanatory view of another embodiment of the method of forming a plastic insulated power cable connection portion of the present invention. 1, 1': CV cable, 2, 2': cable sheath,
3, 3': Cable insulator, 4, 4': Cable conductor,
5: conductor connection tube, 6: internal semiconductive layer, 7: recess, 8: mold, 9: heater, 10: ram device, 11: extruder,
12: Insulating material, 13: Overflow hole, 14: Edge cutting protrusion, 15: Insulating reinforcement, 16: External semiconductor lightning layer,
17: Insulating reinforcement layer. Ga'kansai do zusai 3 drawings

Claims (1)

[Scope of Claims] 1. A mold having a recess formed in the inner circumferential direction of the insulating reinforcing body to form a protrusion for cutting the edge of the external semiconducting layer on the surface of the insulating reinforcing body, which will be described later, is placed over the cable conductor connection part. process and
A step of extruding and filling an insulating material of the same quality as the cable insulator into the mold to form an insulating reinforcing body with a protrusion for edge cutting of the external semiconducting layer on the cable conductor connection part, 1. A method of forming a plastic insulated power cable connection comprising the steps of: forming an outer semiconducting layer while leaving an edge cutting protrusion. 2 Extrude semiconductive rubber/plastic containing a crosslinking agent while leaving a protrusion for edge cutting on the circumference of the formed insulation reinforcement, wrap semiconductive rubber/plastic tape containing a crosslinking agent, or wrap semiconductive rubber/plastic containing a crosslinking agent. Either by applying a semiconductive rubber/plastic paint or by inserting a semiconductive rubber/plastic heat shrink tube containing a crosslinking agent, this is then heated in air or an inert gas to crosslink it, and the above insulation is A method of forming a plastic insulated power cable connection as claimed in claim 1 so as to bond it to a reinforcement to form an outer semiconducting layer.