JPH054172Y2 - - Google Patents

Description

[Detailed description of the invention] (Technical field of the invention) The invention relates to improving the conductor shielding layer of CV cables, especially when the contact resistance between the conductor and the semiconducting tape and between the semiconducting tape and the internally extruded semiconducting layer is large. Regarding rubber and plastic insulated cables that prevent

(Technical background of the invention and its problems) Generally, the cable core of a CV cable is composed of a conductor with an internal extruded semiconducting layer and an extruded insulating layer.

In the case of a cable core having such a configuration, when the internal semiconductive layer for shielding the conductor is extrusion coated, a semiconductive tape is interposed between the conductor and the internal extruded semiconductive layer to prevent the extruded semiconductive resin from entering the gaps between the conductor strands.

By the way, in a cable core with such a configuration, when a current flows through the conductor, the extruded insulating layer has a larger coefficient of thermal expansion than the conductor, so the adhesive force between the conductor and the extruded insulating layer decreases, and as a result, the conductor and the semiconducting tape This results in the formation of minute gaps between the layers of the semiconducting tape, or between the semiconducting tape and the internally extruded semiconducting layer, increasing the respective contact resistances and increasing the apparent tan δ of the CV cable. The apparent increase in tan δ not only misleads the diagnosis of deterioration of the insulation of the CV cable, but also causes the internal extruded semiconductive layer to thermally deteriorate, which is disadvantageous as it may lead to deterioration of the insulation.

(Purpose of the invention) The present invention was made with attention to these points, and it is a rubber or plastic insulated cable that does not cause an increase in contact resistance between the conductor and the semiconducting tape, and between the semiconducting tape and the internally extruded semiconductive layer. We aim to provide the following.

(Summary of the invention) The rubber/plastic insulated cable according to the invention consists of a composite tape in which a conductive tape is closely integrated on both sides of a semiconductive tape, wrapped over a conductor, and an internally extruded semiconductive layer on the composite tape. and an extruded insulating layer is provided on the internal extruded semiconductive layer.

(Embodiment of the invention) Hereinafter, the invention will be explained based on the drawings of one embodiment. In the drawing, a semiconducting tape 2 is placed on a conductor 1.
It is the same as conventional rubber or plastic insulated cables in that an internal extruded semiconductive layer 3 and an extruded insulating layer 4 such as cross-linked polyethylene are provided through the cable, and an external semiconductive layer, a shielding layer, and a sheath (not shown) are provided thereon. be.

In the present invention, conductive tapes 5 made of a conductive material such as metal are stuck between the semiconductive tapes 2 made of paper or cloth and on both sides of the semiconductive tapes 2.

Note that although the semiconductive tape 2 is usually wrapped around the conductor 1, it may also be formed by wrapping it vertically.

Next, the function of the semiconductive tape according to the present invention will be described. That is, when a required current flows through the conductor 1, minute gaps are created between the conductor 1 and the semiconductive tape 2, between the layers of the semiconductive tape 2, and between the semiconductive tape 2 and the internally extruded semiconductive layer 3, as in the conventional case. but,
In the present invention, since the conductive tape 5 is attached to both sides of the semiconductive tape 2, that is, the conductor 1 and the semiconductive tape 2, the space between the two layers of the semiconductive tape, and the semiconductive Since the tape 2 and the extruded insulating layer 3 are in electrical contact, there is no fear that the contact resistance between these components will increase as in the conventional case.

(Effects of the invention) As described above, in this invention, a composite tape in which conductive tape is closely integrated on both sides of a semiconductive tape is wrapped over a conductor, so that the conductor can be Even if the adhesive force between the conductor and the extruded insulating layer decreases, the contact resistance between the conductor and the semiconducting tape and between the semiconducting tape and the inner extruded semiconducting layer does not increase. Therefore, the present invention can provide a rubber or plastic insulated cable in which the apparent tan δ of the cable does not become large.

[Brief explanation of the drawing]

The drawing is a partially omitted longitudinal sectional view of the rubber/plastic insulated cable of the present invention. DESCRIPTION OF SYMBOLS 1... Conductor, 2... Semiconductive tape, 3... Internally extruded semiconductive layer, 4... Extruded insulating layer, 5... Conductive tape.

Claims (1)

[Scope of utility model registration request] A composite tape in which conductive tape is tightly integrated on both sides of a semiconductive tape is wrapped over a conductor, an internally extruded semiconductive layer is provided on this composite tape, and an extruded insulating layer is provided on this internally extruded semiconductive layer. A rubber and plastic insulated cable characterized by: