JPS5857278A - Method of producing plastic insulated power cable connector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a plastic insulated cable connection.

As a means of connecting plastic insulated cable cables, such as cross-linked polyethylene insulated cable cables, a tape or sheet made of the same material as the cable insulator is wrapped around the cable conductor connection part, and then heat-fused and integrated. The so-called heat molding method involves installing a predetermined mold over the coupler conductor connection part, and extruding the same material as the cable insulator into the mold using an extrusion device. However, if the cable to be connected is of an ultra-high voltage class such as 154 Kv or 27 S Kv 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 in progress.

The present invention has been made in view of the above-mentioned points, and its purpose is to provide a manufacturing method that can stably manufacture a desired connection portion.

That is, the gist of the present invention is that when crosslinking and/or cooling the insulation reinforcement extruded on the cable conductor connection part under pressure, the present invention also applies to the vicinity of the cable end on the side of the insulation reinforcement part. The aim is to perform bridging and/or cooling treatment of the insulation reinforcement part while applying the same pressure as that of the insulation reinforcement part.

Next, an embodiment of the present invention will be described with reference to FIG. 1 of the attached drawings. First, the covering layer of the crosslinked polyethylene insulating capeple 1, 1' to be connected is sequentially coated over a predetermined section at the end. After stripping the steps, the end conductors 2 and 7 exposed in this way are connected with a predetermined conductor connecting tube 6, and semiconductive rubber/glass is further applied around the conductors 2 and 2' and the conductor connecting tube 3. An internal semiconducting layer 4 made of heat shrink tubing is provided.

Next, a predetermined mold 5 is installed around these as shown in the figure, and a predetermined extrusion device 6 and ram device 7 are directly connected to the mold 5.

Next, the mold 5 is preheated by a heater (this is attached to the mold 5 in advance) 8, and then a cable insulator 9 is inserted into the mold 5 using an extrusion device 6. ': Filled with cross-linking agent type polyethylene compound wood 10 made of the same material as 2. The filling takes place in a reed, in which the overflow of the compound 10 can be confirmed by the ram device 7.

Next, the heater 8 of the mold 5 is activated to raise the temperature of the conopound 10 to the temperature required for crosslinking,
Air, inert gas, silicone is applied between the mold 5 and the conopound 10 by the pressurizing device 11, and between the auxiliary pressurizing cylinders 12, 12' arranged on both sides of the mold 5 and the cables 1, 1'. A pressurizing medium 13 such as oil is poured to pressurize the compound 1o and the cable 1.1'.

Next, the power supply to the heater 8 is stopped while the pressure is maintained, and the compound 1o is further cooled and solidified to form a predetermined insulation reinforcement body 1.
Mold 4.

In addition, when forming the predetermined external semiconducting layer 15 on the circumference of the insulation reinforcement body 14, after the insulation reinforcement body 14 is extruded,
Once the mold 5 is removed, the surface of the insulating reinforcement 14 is finished, and the external semiconducting layer 15 is provided on it, then the mold 5 is attached again, and this is then cross-linked under pressure in the same manner as described above. , which is accomplished by cooling.

Incidentally, when a molten material is extruded and filled into a mold, the material expands due to heating during extrusion and adheres tightly to the inner surface of the mold, so even if a pressurized medium is poured between the mold and the material in this state, the material will not melt. The medium may not be able to spread all over the space between them, and as a result, the entire material may not be able to be pressurized uniformly, but in such cases, pressurization with the pressurizing medium for crosslinking treatment may be omitted (in addition, In this case, only the pressure is applied based on the expansion of the material due to heating during the crosslinking process.) It may be applied only during the cooling process.

Pressurization by a pressurizing medium during cooling treatment is performed by utilizing the gap created between the mold and the material due to contraction of the material during cooling, but this pressurization is performed when the material temperature is 14
It is best to carry out at a temperature of 0°C to 120°C. This is because, as shown in Figure 2, the volume of the material changes the most when the temperature is between 120°C and 90°C. Therefore, if pressure is not started before this point, voids may occur in the insulation reinforcement or cracks may occur. This is not a good idea as it may cause the person to enter the room.

Now, according to the manufacturing method of this embodiment carried out in this way,
Since the insulation reinforcement part extruded on the cable conductor connection part is cross-linked and/or cooled under pressure, the generation of voids can be effectively suppressed, resulting in a connection part with excellent electrical properties. can be manufactured.

Furthermore, since the above-mentioned cross-linking and/or cooling treatment is performed while applying pressure to the vicinity of the cable end on the side of the insulation reinforcement part, deformation of the cable, which is a concern, can be suppressed. can.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the method for manufacturing a plastic insulated capacitor connection part according to the present invention, and FIG. 2 is a diagram showing the relative specific volume-temperature characteristics of polyethylene. 1.1': Crosslinked polyethylene insulated capeple, 2.
2': Cable conductor, 6: Conductor connecting tube, 4: Internal semiconductive layer, 52 molds, 6: Extrusion device, 7: Ram device, 8: Heater, 9.9': Cable insulator, 10: 11: Pressure device, 12.12': Auxiliary pressure cylinder, 13: Pressure medium, 14: Insulating reinforcement.

Claims (1)

[Claims] 1. When crosslinking and/or cooling the insulation reinforcement part extruded on the cable conductor connection part under pressure, the insulation reinforcement part is While applying the same pressure as the insulation reinforcement part, bridge the insulation reinforcement part and (
or) A method for manufacturing a plastic insulated cable connection part, which is characterized by performing a cooling treatment. 2. Auxiliary pressure cylinders are provided on both sides of the mold used for extrusion forming the insulation reinforcement, and a pressure medium is filled between the mold and the insulation reinforcement to apply pressure to the insulation reinforcement, 2. A method for manufacturing a plastic insulated cable connection part according to claim 1, wherein pressure is applied to the cable by filling a pressure medium between the auxiliary pressure cylinder and the cable.