JPS5859030A - Method of forming power cable joined section insulated with rubber or plastics - Google Patents

Abstract

PURPOSE:To form the titled joined section with good operativity, by arranging per-molded semiconductive polyolefin units or the like at rising sections of a joined section of a cable insulated with rubber or plastics in molds, and filling a molten polyolefin insulator. CONSTITUTION:The crosslinked polyethylene-sinsulated cables 11 to be joined are subjected to penciling treatment, and after the cable conductors are connected by a conductive connecting pipe 2, an inner semiconductive layer 3 (e.g. a semiconductive and heat-shrinkable polyolefin tube or a heat-shrinkable rubber tube) is provided. The pre-molded semiconductive units 4 (e.g. molded one of a semiconductive polyolefin or rubber) are previously arranged to the inner surface of the molds 5 to cover the cable joined section, the molds 5 are heated to a prescribed temperature, and the polyolefin insultor 9 that is melted at a prescribed temperature is extruded from an extruder 1 to fill the molds and is molded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a connecting portion of a gono or a plastic insulated capeple, and particularly to a method for forming an extrusion molded connecting piece 1 using an extrusion device.

Rubber/plastic insulation type cables, especially cross-linked polyolenoin electric cables, are rated at 154KV.

Since it is applied to 275KV lines and also to long lines, a straight connection part is required accordingly. The most suitable linear connection for an ultra-high voltage cross-linked polyolefin insulated cable cable is a molded type in which heat molding is performed using a polyolefin insulator made of the same material as the cable body. For the mold connection part, polyolefin insulating tape or sheet is laminated and rolled and heat molded, a pre-formed polyolefin insulating block is applied and heat molded, and the same method used to manufacture the cable body is extruded using an extrusion device and heated. There is a method of molding. The extrusion-type mold connection part, which is extrusion-molded using an extrusion device, is free from foreign matter and has excellent reliability. For extrusion-type molded connections, treatment of the outer semiconductive layer is important, and in particular, from the viewpoint of electrical performance, it is necessary to establish a highly reliable method for treating the outer semiconductive layer of the rising portion of the connection.

1] The object of the present invention is to provide a highly reliable and reliable construction method capable of appropriately treating the outer semiconducting layer of an extrusion mold connection.

The gist of the present invention is that when a molten polyolefin insulation material is extruded and filled into a mold covering a rubber/plastic insulated cable connection part using a pusher 1"4, the rising r of the connection part in the mold 'dI (pre-formed semiconducting polyolefin unit or semiconducting rubber located near the end of the outer semiconducting layer of the re-pull)
After arranging the unit, the above molten polyolefin insulation is filled and molded to form an extrusion mold joint nod part.

An embodiment of the present invention will be described with reference to the accompanying drawings.

The cross-linked polyethylene insulated cables 11 on both sides to be connected are subjected to pen cylinder treatment, and after the cable conductors are connected by the conductor 1 and the connecting pipe 2, the internal semiconductive layer 6 is provided.

The inner semiconductive layer 6 is made of a semiconductive heat-shrinkable tube or a semiconductive external heat storage polyolefin tube.

The mold 5 can be removed by lowering the cable connection part, but the inner surface of the metal hole (q5) located at the connecting part (near the outer part of the cable - the terminal part of the conductive layer) A pre-molded semiconductive unit 4 is disposed on the unit.The semiconductive unit 4 is molded from semiconductive polyolefin or semiconductive rubber.

Thereafter, the mold 5 is preheated to a predetermined Y quality, and the extrusion device 1 extrudes and fills the polyolefin insulator 9 melted to a predetermined temperature to form the mold.

In this case, a pressurized medium (air, N gas, Sli'6 gas, silicone oil, etc.) is sealed between the mold 5 and the semiconductive unit 4, or the mold 5 is pressurized. A pressurizing device 1 for pressurizing the semiconductive unit 4 may be built-in.

Furthermore, on the insulator 9 between the semiconductive units on both sides,
A semiconductive heat-shrinkable polyolefin tube or cross-linked semiconductive paint or semiconductive polyolefin is applied and hot molded to form an external semiconductive layer.

In addition, the molten polyolefin insulator 9 (i
- When filling, the inside of the mold 5 may be evacuated in advance and filled with the molten polyolefin insulator 9.

6 is a pressurizing device/deaerator, 7 is a ram/over) 3- Holes 8 and 1o are heaters.

According to the present invention, the following effects can be achieved.

1. It can be carried out without complicating the mold structure and has excellent workability.

2. By using a pre-molded semiconductive unit, the external semiconductive layer of the standing portion of the extrusion mold 1 can be formed in a suitable manner.

[Brief explanation of drawings]

The figure is a 16 longitudinal cross-sectional explanatory diagram showing one embodiment of the present invention. 1: Extrusion device, 2: Conductor connection tube, 3: Internal semiconductive layer, 4
: Semi-conductive unit, 5: Mold, 9: Polyolefin insulator, 11: Cross-linked polyethylene insulated cable. 4-

Claims (1)

[Claims] When filling a mold with molten polyolefin insulation covering the joints of rubber-plastic insulated cables on both sides to be connected, place a pre-formed semi-conductor in the mold at the rising edge of the joint. 1. A method of forming a rubber/glass insulated cable connection part, which comprises arranging a conductive polyolefin unit or a semiconductive rubber unit, and then filling the molten polyolefin insulator and molding.