JPH0446515A - cable terminal device - Google Patents

Abstract

PURPOSE:To lessen concentration of an electric field on an earth sheath and prevent troubles such as corona discharge by coating the section from the terminal of the charge part of a high-tension cable to the earth sheath with a high- resistance high-dielectric semiconductor. CONSTITUTION:A conductor 1 is coated with an insulator 2, the insulator 2 is coated with a screen 3 acting as an earth, and the section between the earth sheath 5 of the screen 3 and the terminal 6 of the charge part of a high-tension cable is completely coated with a high-resistance high-dielectric semiconductor tube 7. The semiconductor tube 7 is coated with an insulating tube 4. The equipotential lines around the earth sheath 5 of the screen 3 are sparse and an electric field is less concentrated thereon. Thereby corona discharge is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cable terminal device that alleviates electric field concentration in a ground sheath portion provided on the outer sheath of a high-voltage cable.

(Prior Art) In conventional cable terminal devices, such as the terminals of high-voltage cables, electric field concentration tends to occur in the earth sheath portion, and therefore corona discharge tends to occur.

For example, FIG. 3 shows a cross-sectional view of a conventional cable terminal, and in the figure, (1) is the cable conductor, (
2) is the insulator covering the conductor (1), (3) is the screen surrounding the insulator (2), (4) is the insulating tube, and (5) is the ground covering the insulator (2). Sheath part, (
6) is the live part terminal of the cable.

As shown in FIG. 3, the conventional cable terminal device is
The conductor (1) is surrounded by an insulator (2), the insulator (2) is further covered with a screen (3) that serves as a ground, and the surrounding area is covered with an insulating tube (4). are doing.

Further, FIG. 4 is a sectional view of a cable terminal showing another conventional example that is an improvement on the conventional example shown in FIG. Code (1) in the figure ~
(6) is the same as in Figure 3, and (7) is the insulator (2).
It is a semiconductor tube that covers the

The configuration of the cable terminal device shown in Fig. 4 is almost the same as that shown in Fig. 3, but the characteristic improvement is that the insulator (2) is removed from the screen (3) around the earth sheath part (5). Cover a part with a semiconductor tube (7), and cover the semiconductor tube (7).
7) is further covered with an insulating tube (4).

FIGS. 5 and 6 show stress map diagrams around the earth sheath portion when the cable terminals shown in FIGS. 3 and 4 are used, respectively.

As seen in FIG. 5, equipotential lines (8) are densely packed around the earth sheath portion (5) of the cable terminal in FIG. 3, indicating that electric field concentration occurs.

Compared to this Fig. 5, in Fig. 6, the area around the earth sheath part (5) is covered with a semiconductor tube (7), and the equipotential lines (
Although the density of 8) has been somewhat relaxed, electric field concentration still occurs around the earth sheath part (5).

(Problem to be Solved by the Invention) As described above, in the cable terminal device shown in FIG.
As shown in the figure, there is a problem in that electric field concentration occurs in the earth sheath provided on the outer sheath of the conductor (1), and corona discharge is likely to occur.

Therefore, the conventional cable terminal device shown in Fig. 4 uses an insulator (
Although an improvement has been made by covering 2) with a semiconductor tube (7), as shown in FIG. 6, the electric field concentration has not been completely resolved and the problem of discharge still remains.

This invention was made with the aim of solving the above-mentioned problems, and its purpose is to alleviate the concentration of electric field in the earth sheath provided on the outer sheath of the cable.
The object of the present invention is to provide a cable terminal device that is free from problems such as corona discharge.

[Means to solve the problem]

The cable terminal device according to the present invention is characterized in that the high-voltage cable from the live part terminal to the earth sheath part is covered with a high-resistance and high-dielectric semiconductor member.

[Effect]

In the cable terminal device of the present invention, electric field concentration in the earth sheath part is alleviated by covering the high voltage cable from the live part terminal to the earth sheath part with a semiconductor member.

(Embodiment) A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a cable terminal according to an embodiment of the present invention, and FIG. 2 is a stress map diagram around the earth sheath portion in FIG. 1.

Symbols (1) to (8) in Fig. 1 and Fig. 2 refer to the third
Since it shows the same or equivalent parts as those of the conventional example shown in FIGS. 6 to 6, redundant explanation will be omitted.

As shown in FIG. 1, the configuration of the cable terminal device of this embodiment is such that a conductor (1), which is a cable, is surrounded by an insulator (
2), the insulator (2) is further covered with a screen (3) that serves as a ground, and the screen (3)
) from the periphery of the earth sheath part (5) of the high-voltage cable to the live part terminal (6) of the high-voltage cable is completely covered with a high-resistance and high-frequency semiconductor material, that is, in this case, a semiconductor tube (7). .

The semiconductor tube (7) is further covered with an insulating tube (4).

The cable terminal device configured as described above has a screen (3
It can be seen that the density of the equipotential lines (8) around the earth sheath part of ) is low, and the electric field concentration is completely relaxed.

Comparing this with the conventional example shown in FIGS. 4 and 6, we can see that even though the semiconductor tube (7) covers the constant area of the insulator (2) from the periphery of the screen (3), the electric field is concentrated. mitigation was insufficient. For this reason, it was conventionally thought that the semiconductor tube (7) could not be expected to have much of an effect in alleviating electric field concentration.

However, the present inventors have found that by further extending the semiconductor tube (7) and creating a structure that covers the vicinity of the live part terminal (6), a dramatic effect of alleviating electric field concentration can be obtained.

In this way, in this example, it was possible to alleviate the electric field concentration in the earth sheath at the end of the high voltage cable, so even if members such as earth and CT were installed near the end of the high voltage cable, corona discharge etc. There is no longer a risk of this happening.

〔Effect of the invention〕

As described above, according to the cable terminal device of the present invention, by covering the cable from the live part terminal to the earth sheath part with a semiconductor member, electric field concentration in the earth sheath part is alleviated, so corona discharge etc. It is possible to prevent the occurrence of failures.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a cable terminal according to an embodiment of the present invention, Fig. 2 is a stress map diagram around the earth sheath portion in Fig. 1, and Fig. 3 is a sectional view of a conventional cable terminal. Figure 4 is a sectional view of a cable terminal showing another conventional example, Figure 5 is a stress map diagram around the earth sheath part in Figure 3, and Figure 6 is a stress map diagram around the earth sheath part in Figure 4. It is. (1) is a conductor, (2) is an insulator, (3) is a screen,
(4) is the insulation tube, (5) is the earth sheath part, (6
) is a charging terminal, and (7) is a semiconductor tube.

Claims (1)

[Claims] A cable terminal device in which an earth sheath portion is provided on the outer sheath of a high voltage cable, characterized in that the area from the live terminal of the high voltage cable to the earth sheath portion is covered with a high resistance and high dielectric semiconductor member. Cable termination equipment.