JPH04120381U - Test terminations for rubber and plastic cables - Google Patents

Abstract

(57) [Summary] [Structure] In a conventional water terminal (a cable terminal that is coaxially surrounded by multiple insulating pipes 22 and 24 of different diameters on the outside and circulates pure water), A cable terminal formed on the cable insulator 16 with the high dielectric constant layer 40 exposed is inserted to serve as a test termination. [Effect] Radial dielectric constant grading is formed by the cable insulator 16, the high dielectric constant layer 40, and the dielectric constant difference due to the temperature of pure water, and the withstand voltage performance is improved. Furthermore, when providing the same voltage resistance, the length of the water terminal can be made shorter than before.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This idea is an AC withstanding voltage test for rubber/plastic power cables that uses water. This relates to terminations for both commercial and destructive testing purposes.

0002

[Conventional technology]

An example of water termination is shown in Figure 3. 12 is the entire cable, 14 is the outer semiconducting layer, and 16 is the cable insulation (outer half). (with conductive layer 14 removed), 18 is a cable conductor. A plurality of insulating pipes with different diameters are arranged coaxially on the outside of the cable insulator 16. surround. In this case, for example, two pipes, i.e., with a large number of holes 20, An inner pipe 22 and an outer pipe 24 are used. 26 is the lower metal fitting, 28 is the packing, 30 is the lower shield ring, 32 is the upper part Metal fittings, 34 is packing, 36 is upper shield ring, 38 is high voltage bond wire. Ru.

0003 Pure water is sent into the inner pipe 22. Water fills the inner pipe 22 and the hole 20 from the outside pipe 24, taken out outside the outside pipe 24, and cooled outside. It is also fed into the inner pipe 22 and circulated. A dielectric constant graph based on the difference in temperature between the water in the inner pipe 22 and the water in the outer pipe 24. In other words, pure water takes advantage of the property that its dielectric constant decreases as the temperature increases. , to alleviate electrical stress by flowing pure water outward in a radial direction. .

0004

[Problem that the idea aims to solve]

(1) Water alone is insufficient for stress relief, and external flashovers occur at relatively low voltages. (2) The flash voltage becomes lower as the conductor size becomes larger. When the conductor size is ^2000mm2 , it will flash at 370-380kV.

[0005]

[Means to solve the problem]

As shown in Figures 1 and 2, A cable terminal with a high dielectric constant layer 40 formed on the exposed cable insulator 16, Insert into conventional water terminal to provide test termination.

[0006]

[Effect]

Grades due to differences in dielectric constant between cable insulator 16, high dielectric constant layer 40, and water ing will be carried out.

[0007]

【Example】

The outer semiconducting layer 14 at the end of the cable 12 is scraped off to expose the cable insulation 16. A high dielectric constant layer 40 is provided thereon (FIG. 2). The thickness may be approximately several tens of μm. The high dielectric constant layer 40 is made of paint (trade name Acretan). etc.). The process is the same as the conventional case except that the cable 12 is subjected to the above processing. FIG. 1 shows an example in which the cable 12 is surrounded by two pipes.

[0008] In this case, a high dielectric constant layer is provided on the cable insulation, and the temperature of the water increases the Using the difference in electric constant, grading is performed in the radial direction by dielectric constant, and withstand voltage Characteristics improve.

[0009]

[Effect of the idea]

A cable terminal with a high dielectric constant layer formed on the exposed cable insulation is used as a water terminal. Insert it and use it as a test termination. As mentioned above, radial permittivity grading is formed, improving withstand voltage performance do. Also, if the same voltage resistance is to be achieved, the length of the water terminal should be shorter than before. be able to.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an embodiment of this invention.

FIG. 2 is an explanatory diagram showing only the cable in the embodiment of the invention.

FIG. 3 is an explanatory diagram of a conventional water terminal.

[Explanation of symbols]

12 Cable 14 Cable outer semiconducting layer 16 Cable insulation 18 Cable conductor 20 holes 22 Inner pipe 24 Outside pipe 26 Lower metal fittings 28, 34 Packing 30,36 shield ring 32 Upper metal fittings 38 High voltage bond wire 40 High dielectric constant layer

Claims (1)

[Scope of utility model registration request] Claim 1: A plurality of insulating pipes with different diameters coaxially surround the outside of the exposed cable insulator at the end of the cable, and water is sent inside the innermost pipe, and the water is A high dielectric constant layer is applied on the exposed cable insulation at the test termination of the rubber/plastic cable, which is sequentially moved inside the outer layer pipe and taken out from the inside of the outermost layer pipe. Test termination for rubber/plastic cables.