JPS61273809A - 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 [Industrial Application Field] The present invention relates to a power cable in which an insulating layer and a semiconducting layer have different colors to facilitate their identification.

[Prior Art] A power cable such as a C-cable (cross-linked polyethylene power cable) consists of an inner semi-conducting layer, an insulating layer, and an outer semi-conducting layer arranged concentrically around a conductor.
These insulating layers and semiconducting layers are formed by extrusion.

[Problems to be Solved by the Invention] By the way, since the semiconductive layer of the conventional power cable described above is a mixture of rubber, plastic, and carbon black, it naturally has a black color. Therefore, when the insulating layer is also black, it becomes difficult to distinguish between the insulating layer and the semiconducting layer, and there is a problem in that it becomes difficult to perform cable terminal processing and connection processing.

Here, examples of the insulating layer exhibiting black color include crosslinked polyethylene mixed with carbon black.

0.2 to 5.0 carbon black to cross-linked polyethylene
The fact that the insulator mixed with % by weight is effective as an insulator for DC cables is as already proposed by the applicant (Japanese Patent Application No. 59-150'-091520, Japanese Patent Application No. 59-150'2
99), if a black semiconducting layer is used in such a case, the above-mentioned problem arises.

It was against this background that this invention was made.
Therefore, by making the insulating layer and the semiconducting layer different colors, we aim to make them easier to identify, thereby providing a power cable with improved workability. shall be.

] [Means for solving the problems] ′, In order to solve the above problems, this invention has the following features:
The insulating layer is made of crosslinked polyethylene mixed with carbon black, and the semiconductive layer is made of rubber and/or plastic mixed with conductive zinc white. Further, the amount of carbon black in the insulating stone is 0.2 to 5.0% by weight, and the amount of conductive zinc white in the semiconductive layer is 100 to 400 parts by weight.

[Function] - According to the above configuration, while the insulating layer is black, the semiconducting layer is non-black, so these can be easily identified and workability can be improved. .

[Example] The present invention will be explained in detail below.

First, a description will be given of the semiconductive mixture forming the inner semiconductive layer and/or the outer semiconductive layer, that is, rubber and plastic mixed with conductive zinc white.

Conductive zinc white is made by doping zinc oxide with 01OI~5.0% aluminum oxide and mixing it in powder form.
It is fired at high temperature in a reducing atmosphere. and,
100 to 400 parts by weight of this conductive zinc white is mixed with a base polymer such as polyethylene, ethylene propylene rubber, or ethylene vinyl acetate copolymer to form a semiconductive mixture. In this case, if the amount of conductive zinc white mixed with the base polymer is less than 100 parts by weight, semiconductivity cannot be obtained, and if it is more than 400 parts by weight, it becomes mechanically extremely brittle (
(See Japanese Patent Application No. 1983-015124).

If necessary, processing aids such as crosslinking agents, anti-aging agents, and lubricants may be added to the above semiconductive mixture.
good. Further, although the original color of the semiconductive mixture containing conductive zinc white is grayish white, it can be colored into a desired color by adding an appropriate pigment.

Next, as an insulating layer, carbon black was used at 0°2-5
．． It has already been mentioned that cross-linked polyethylene mixed with 0% by weight is used and that this exhibits a black color.

The power cable according to this embodiment is effective for both AC and DC, but when used as a DC cable, the insulation layer is Cross-linked Bolier with carbon black.

,, Body/Inner semiconductive layer/Constructed of crosslinked polyethylene with carbon black and general crosslinked polyethylene, conductive,
Polyethylene insulating layer (black) / cross-linked polyethylene insulation layer (white) / outer semiconductive layer or conductor / ゛・;::pa inner semi-conductive layer / cross-linked polyethylene insulation layer (white) / carbon It is also effective to have a structure of black-containing crosslinked polyethylene insulating stone (black)/outer semiconducting layer, and in such a case, only the semiconducting layer in contact with the black insulating layer may be the non-black semiconducting layer.

[Experiment example] Carbon black (SAF carbon) was used as the insulating layer.
．． In addition to using crosslinked polyethylene containing 8% by weight, ethylene-
100 parts by weight of vinyl acetate copolymer (manufactured by Mitsui Polychemical Co., Ltd., Evaflex #260), 200 parts by weight of conductive zinc white (manufactured by Hakusui Chemical Co., Ltd., conductive zinc white 23K), and 1.2 parts by weight of dicumyl peroxide. A three-layer capacitor having a conductor cross-sectional area of 200 mm and an insulating layer 13III11 was prepared using a semiconducting mixture containing 0.2% and 0.2% of an anti-aging agent (Santonox R, manufactured by Monsando).

In addition, for comparison, a power cable having a conventional semiconducting layer made of a semiconducting mixture containing carbon black and having the same structure as above was fabricated.

Table 1 shows the results of DC breakdown voltage, polarity reversal breakdown voltage, and cable terminal processing workability for these power cables. As can be seen from this table, the product of the present invention greatly improves the workability of terminal processing without impairing the electrical properties (DC cable properties) due to the inclusion of carbon black in the insulator.

[Effects of the Invention] As explained above, in this invention, the semiconductive layer is made of rubber or plastic mixed with conductive zinc white, and the semiconductive layer is made non-black. The layers can be easily identified. As a result, it is possible to improve the workability of voltage cable terminal processing and connection processing.

Claims (2)

[Claims] (1) In a power cable in which an inner semiconducting layer, an insulating layer, and an outer semiconducting layer are sequentially provided around a conductor, the insulating layer is made of crosslinked polyethylene mixed with carbon black, and the semiconducting layer is conductive. An electric power cable characterized in that it is made of rubber and/or plastic mixed with zinc white. (2) The amount of carbon black in the insulating layer is 0.2 to 5
．． 2. The power cable according to claim 1, wherein the amount of conductive zinc white in the semiconductive layer is 100 to 400 parts by weight.