JPH0753221Y2 - Solid type submarine power cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a solid type submarine power cable provided with a lead cover having an oval cross section.

(Prior art and problem to be solved) Since the solid type power cable has no oil tank, the temperature of the conductor and the insulating layer rises due to the load on the power cable, and the high viscosity solid insulation impregnated in the insulating layer. When the oil expands and the load disappears and the temperature of the conductor and insulating layer becomes low, the solid insulating oil contracts. The expansion and contraction of such insulating oil is repeated locally and locally because the insulating oil has a high viscosity.

When such a solid type power cable is used as a submarine cable, for example, in a shallow sea area of about 150 m or less, the expansion of the insulating oil causes the lead cover to balance with the holding force of the reinforcing tape such as stainless steel or bronze provided on the outside. However, even if the insulating oil contracts, the external pressure from seawater is small, so the lead coating does not contract, and even if repeated external force is applied to the internal insulating layer, it does not damage the insulating layer. Also, it does not damage the lead cover.

However, when the water depth exceeds 150 m, the external pressure due to seawater increases, and the lead cover also expands and contracts following the expansion and contraction of the insulating oil due to load fluctuations, which damages the internal insulation layer,
Also, since the lead cover is also circular, concentrated strain occurs due to expansion and contraction,
It will be damaged by repeated strain. If it is notable, seawater pressure will cause vertical lead wrinkles, which will not disappear anymore and lead to damage to the lead covers or damage to the internal insulating core. .

In order to avoid the above-mentioned phenomenon, in the deep-sea solid type submarine power cable, the conductor is formed into an elliptical shape, the insulating layer is wound on the conductor, and the elliptical lead coating is applied. By configuring in this way, the ratio of the ellipse to the expansion and contraction of the insulating oil, that is, the ratio of major axis / minor axis (eg 1.1)
Because the lead cover is kept in a constant range with a constant outer circumference, the oval → circle → oval is repeated to absorb the amount of expansion and contraction of the insulating oil, so there is no damage to the insulating layer and lead There will be no concentrated distortion on the object.

However, providing an iron wire sheath on the outside of such an elliptical lead cover not only makes the work difficult, but also makes it difficult to handle the cable after the sheath. Further, the cable has an oval shape during and after the installation, which causes a problem that the cable is damaged due to concentration of external force.

(Means for Solving the Problems) The present invention provides a solid type submarine power cable which solves the above-mentioned problems, and is characterized in that the outer shape of a lead cover having a circular cross section provided on a cable core has a cross sectional outer shape. Has a circular plastic coating layer and has an iron wire exterior on the outside.

(Operation) In the solid type submarine power cable of the present invention described above, the plastic coating layer having a circular cross section is provided on the outer side of the oval lead sheath, and the iron wire sheath is provided on the outer side thereof. Can be carried out in the same way as
Further, the external force does not concentrate on the cable during and after the installation due to the oval shape.

(Embodiment) FIG. 1 is a cross-sectional view of a concrete example of the solid type submarine power cable of the present invention.

In the drawings, (1) is an oval conductor, (2) is kraft insulating paper, a composite insulating tape in which insulating paper and a plastic film such as polypropylene are laminated and integrated, an ethylene-propylene copolymer film, or a mixture thereof. An oval insulating layer that is wound and impregnated with high viscosity insulating oil,
(3) is a shielding layer formed by winding a carbon paper, a metal tape, a copper woven cloth tape, etc., and (4) is a lead cover having an oval cross section.

On both sides orthogonal to the major axis of such an oval lead cover (4),
A spacer (5) for making the outer shape of the plastic coating layer (6) to be circular thereon is arranged, and a plastic coating layer (6) such as polyethylene is extrusion-coated thereon.
At this time, a press winding tape may be applied on the spacer (5) if necessary. The material of the spacer (5) is
A plastic made of the same material as that of the plastic coating layer (6) to be applied thereon is preferable, but since it is the spacer (5) for making the outer shape of the plastic coating layer (6) circular, it is not particularly limited. Absent. Further, without using such a spacer (5), the plastic coating layer may be extruded to the outside of the elliptical lead cover (4) and then extruded with an uneven thickness to form the plastic coating layer (6).

The outer side of the plastic coating layer (6) formed in the circular outer shape is coated with an iron wire sheath (7) by a conventional means to form a solid type submarine power cable.

FIG. 2 is a cross-sectional view of another embodiment of the solid type submarine power cable of the present invention.

This concrete example is different from the concrete example shown in FIG.
The structure of the cable core inside is different. In this example, a circular conductor (11) such as a compressed circular conductor generally used for power cables is used, and a circular insulating layer (12) and a shielding layer (13) are provided on the circular conductor (11) to form a cable core. I am configuring. Then, on the outside of the cable core, internal spacers (8) for making the lead cover (4) to be oval on the cable core are arranged at opposite positions on the cable core, and metal tape, copper woven cloth tape, or These tapes and a semiconductive tape as a cushion layer are wound together and fixed by a conductive tape (9), and an oval lead cover (4) is applied on the fixed tape. The plastic coating layer (6) having a circular outer shape is provided on the outer side of the elliptical lead cover (4), and the iron wire sheath (7) is further provided on the outer side thereof as in the specific example of FIG.

In the specific example of FIG. 1, since the elliptical insulating layer (2) is formed on the elliptical conductor (1), its manufacturing technique is difficult, and not only special equipment is required, but also electrical In general, the lines of electric force are concentrated in the smallest part of the elliptical conductor, and it is unavoidable that this becomes a weak point.

However, in the specific example of FIG. 2, since the circular insulating layer (2) is formed on the circular conductor (1), it is possible to manufacture with the conventional technology and equipment, and electrically It has a uniform radial pattern, eliminating local weaknesses. For this purpose, it is necessary to electrically connect the shield layer (13) on the insulating layer (12) and the elliptical lead cover (4), and the conductive tape (9) is placed on the inner spacer (8). ), The shield layer (13) and the elliptical lead cover (4) are electrically connected via the conductive tape (9). At this time, it is preferable that the inner spacer (8) is also electrically conductive so as to be more surely electrically connected.

(Effect of the Invention) As described above, according to the solid type submarine power cable of the present invention, the outer circular plastic coating layer is provided on the outer side of the elliptical lead cover, and the iron wire exterior is provided on the outer side thereof. Moreover, since the cable has an oval shape during and after the installation, the cable will not be damaged by the concentration of external force.

[Brief description of drawings]

1 and 2 are cross-sectional views of specific examples of the solid type submarine power cable of the present invention. 1 ... Oval conductor, 11 ... Circular conductor, 2,12 ... Insulating layer,
3,13 ... Shielding layer, 4 ... Oval lead coating, 5 ... Spacer,
6 ... Plastic coating layer, 7 ... Iron wire exterior, 8 ... Inner spacer, 9 ... Conductive tape.

Claims (2)

[Scope of utility model registration request] 1. A solid type submarine power cable characterized in that a plastic coating layer having a circular cross section is provided on the outside of a lead cover having an oval cross section provided on a cable core, and an iron wire sheath is provided on the outside thereof. . 2. A plastic coating layer having a circular outer shape is provided on both sides orthogonal to the major axis of the elliptical lead cover, by disposing spacers for rounding the outer shape of the plastic coating layer provided thereon. The solid type submarine power cable according to claim 1.