JPS58161214A - Power cable - 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 an electric power cable, and particularly to an electric power cable having a novel structure that combines a plastic tape-wrapped OF cable and a plastic extrusion-coated chamber cable.

In recent years, with the rise in feed tK pressure, various studies have been conducted on the insulation structure of power cables, but the main ones are those that have a laminate structure by laminating insulating paper tape and polyolefin tape such as polyethylene or polypropylene, or At present, paper made by mixing polyolefin fibers into kraft paper is being pursued.At present, when ordinary power cape paper is used as an insulator, ε-2,8, tan δ
Ch = 0.08' (to obtain r, the plastic fraction must be 4
Since these components are constantly immersed in oil, it is almost impossible to solve the numerous problems such as swelling and dissolution of plastics due to oil or securing oil passages. Furthermore, from a manufacturing point of view, it is inevitable that the cost will be high since the raw material stage must be considered.

Furthermore, with only extruded insulation such as plastics such as XLPE, there are many problems such as insulation reliability problems of thick insulation, manufacturing technology problems, and countermeasures against expansion of the insulator under load.
It is extremely difficult to put cables of Kv or higher into practical use.

In view of the above-mentioned circumstances, the present invention provides an electric cable that has a relatively simple structure, that is, a plastic tape-wrapped OF cable and a plastic extrusion-covered chamber capeple, which can be used in a wide range of applications.

Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows a first embodiment of the invention, in which a conductor 1 is provided with an internal semiconducting layer 2 made of an extruded coating of conductive plastic and an insulating layer 3 made of extruded plastic such as polyethylene. The extrusion coating layer of these plastics can be constructed by extrusion between two layers, and if necessary, the plastic is crosslinked. A plastic tape-wrapped, oil-immersed insulating layer 4 is provided on the outside of such an extruded insulating coating layer 3, and after applying an external shielding layer 5t, a metal sheath 6 with an oil passage on the inner surface is provided, and a polychloroprene is coated on the outside thereof. Alternatively, an external protective coating 7 made of vinyl chloride resin or the like is provided. Further, the insulating oil, such as silicone oil, which does not swell the plastic is pressurized from the oil passage inside the metal sheath.

FIG. 2 shows another embodiment, in which an internal semiconductive layer 2 made of an extruded coating of conductive plastic and an insulating layer 3 made of an extruded coating of an oil-soluble plastic such as polyethylene are provided on the conductor 1. An extruded coating layer 8 of oil-resistant plastic such as tetrafluoroethylene resin or polypropylene resin is provided as a rough layer, and a tape-wound insulating layer 4 of oil-resistant plastic such as tetrafluoroethylene resin is coated with a hydrocarbon such as dodecylbenzene on the outside. an outer shielding layer 5, a metal sheath 6 with oil passages on its inner surface, and a protective coating 7 such as polychloroprene or vinyl chloride resin.
is provided. Further, insulating oil is pressurized from the oil passage inside the metal sheath.

In these cases, plastics with excellent electrical properties such as polyethylene, polyzolopyrene, polypentene, and tetrafluoroethylene resins are used for the plastic extrusion insulation layer and the plastic tape-wrapped insulation layer. The layers are optionally crosslinked.

Figure 3 shows a conductor 1 having an oil passage in the center, with an internal semiconductive layer 2 such as carzen paper or metallized paper, and an oil-resistant plastic tape such as tetrafluoroethylene resin, polypropylene, or polypentene on top of the conductor 1. A winding layer 4 is provided and impregnated with a non-polar insulating oil such as dodecylbenzene, and an extruded coating insulating layer 3 of the same oil-resistant resin as described above is provided on the outside thereof,
This is an electrical cable in which a shielding layer 5, a metal sheath 6, and an anticorrosion layer 7 are sequentially provided on the outside of the conductor, and the insulating oil is pressurized from an oil passage inside the conductor.

In Figures 1 and 3, even if polyethylene is used as a silicone plastic, there is no risk of the insulating layer completely dissolving due to the presence of an insulating oil such as silicone oil, which is difficult to dissolve completely in the plastic, but dodecylbenzene When a nonpolar insulating oil such as polyethylene is used, it will dissolve the nonpolar insulator such as polyethylene, not only in plastic tape but also in extrusion-coated plastic, as shown in FIG.

The intermediate part must be extruded and coated with an oil-resistant plastic such as tetrafluoroethylene resin, which has a short-cutting effect. Contrary to the structure shown in FIG. 3, it will be easily understood as another modification that the extruded coating layer is placed on the outside and the tape-wrapped layer is placed on the inside.

The characteristic effects of the present invention are as shown in FIG. 1 or 2.
When the inner layer is an insulating layer made of extruded plastic coating and the outer layer is an insulating layer wrapped in oil-impregnated plastic tape, the minimum dielectric strength can be maintained no matter how much the former t' deteriorates.

In addition, although cross-linked polyethylene electrical cables for ultra-high voltage (thick wall) still lack stability, in the present invention, the internal insulating layer (medium thickness) is manufactured by applying technology for cross-linked polyethylene electrical cables of 77KV to 154 KV class, which has already been established. The low dielectric constant and low dielectric loss characteristics can be utilized. Furthermore, in the present invention, since the outer insulating layer is composed of a plastic tape-wrapped and oil-immersed insulating layer, the outer insulating layer can be
It is expected that the electrical properties of the cable will improve. Furthermore, the amount of thermal expansion is reduced and the thermomechanical properties are improved compared to a cable in which the entire insulation is made up of only an extruded insulation layer.

In addition, in the present invention, as in the above embodiment, the oil-immersed insulating layer portion is also composed of a plastic tape-wrapped layer, so that the reduction in ε and tanδ is even greater than in the case of a tape-wound insulating layer made of semi-synthetic paper. In addition, compared to cables using semi-synthetic paper, it has the advantage that it takes less time to dry because it is a plastic tape, and the tape material is on the shoulder side.

Furthermore, from the viewpoint of manufacturing the cable, it can be manufactured using ordinary materials and by combining almost all conventional techniques, and the cable connection work is easy.

Furthermore, as shown in Fig. 3, in the case of a power cable in which the entire inner layer is an oil-immersed plastic tape-wrapped insulating layer and an extruded covering insulating layer is the outer layer, no matter how much the extruded covering layer deteriorates, the oil-impregnated tape-wrapped insulating layer remains intact. The minimum dielectric strength is fully guaranteed, and although the stability of ultra-high voltage (thick-walled) cross-linked polyethylene is affected, the production technology for cross-linked polyethylene cables of the 77 KV to 154 KV class, which has established manufacturing technology, can be applied as is, so the cost is low. By taking advantage of the dielectric constant and low electric loss characteristics, 'e! Since all hydraulic pressure is applied, the electrical properties of the cable, including the extruded coating, are even better than those with just extruded coating, and since an oil-immersed tape-wrapped insulating layer is also used, it is possible to use only extruded coating. Thermal expansion is reduced compared to insulated cables, the thermomechanical properties are improved, there is no breakage due to internal groove irregularities as with conventional cross-linked polyethylene cables, and internal oil cooling is possible compared to conventional technology. Compared to a cable made of an oil-impregnated semi-synthetic paper tape insulation layer, it uses plastic in the insulation layer and does not have a cellulose component, so it is possible to lower ε and tan δ, and it does not use special materials like semi-synthetic paper tape. Reducing the cable cost also has the effect of shortening the drying time of the insulating layer.

Here, the results of a comparative test of the electric cable according to the present invention, a conventional cross-linked polyethylene electric cable (OV cable), and a paper-insulated OF cable are as follows.

However, the conductor cross-sectional area of the cable is 2000mm", 275
It is a KV electric cable.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, FIG. 2 is a cross-sectional view showing another embodiment, and FIG. 3 is a cross-sectional view showing still another embodiment. DESCRIPTION OF SYMBOLS 1... Conductor, 2... Inner semiconducting layer, 3... Plastic extrusion coating insulating layer, 4... Plastic tape-wrapped insulating layer, 5... Outer shielding layer, 6... Metal Sheath, 7... Intestine coating, 8... Oil-resistant plastic extrusion coating layer Patent applicant: Fujikura Electric Wire Co., Ltd.

Claims (2)

[Claims] (1) An insulating layer consisting of an extruded plastic covering insulating layer and an oil-immersed insulating layer wrapped in plastic tape is provided on the outside of the conductor. An electric cable characterized by adding (2) Are oil-resistant plastics used for the extruded insulating layer and the tape-wrapped, oil-immersed insulating layer? tPf electrical cable according to claim 1, using a hydrocarbon insulating oil as the insulating oil (3) An extruded coating insulating layer of oil-bathable plastic on the outside of the conductor and an oil-impregnated insulating layer wrapped with oil-resistant plastic tape. An insulating layer and an oil-blocking layer made of oil-resistant plastic between the two are provided, and the hydraulic pressure of the insulating oil is applied to the oil-immersed insulating layer through the oil passage inside the conductor or inside the metal sheath. Electric power cable.