JPS5937832A - Terminal connecting portion for double insulated high voltage 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 [Technical Field of the Invention] The present invention relates to a terminal connection for a double insulated high voltage cable.

[Background of the invention]

As shown in Figure 1, the cross-sectional structure of a double-insulated high-voltage cable for voltages from 3 pairs to 83 KV is shown in Figure 1.
It is formed of two layers: 1) and a sub-insulating layer (2), and a partial shielding layer (3) is provided between these two layers. More specifically, (4) is a conductor, (5) is an inner semiconducting layer, (6) is an outer semiconducting layer, (7) is a metal shielding layer, and (8)
is the presser tape, (9) is the sheath, and usually the main insulation layer (1
) is made of cross-linked polyethylene, the sub-insulating layer (2) is made of polyethylene, the sheath (9) is made of a polyvinyl chloride resin composition, and the metal shielding layer (7) is formed by overlapping copper tape. .

When the double-insulated high-voltage cable shown in Figure 1 is used as an underground distribution line, grounding the metal shielding layer (7) prevents accidents such as power outages due to electrical breakdown of the insulator. It is preventable.

Figure 2 schematically illustrates this case, and the reference numeral 1 is
Shows the same parts as the figure. If the partial shielding layer (8) is placed in a permanently floating state, the sub-insulating layer (2) is designed to temporarily withstand the working voltage even if the main insulating layer (1) breaks down. , the line itself will not cause a ground fault accident. Therefore, if a new cable can be replaced after breakdown occurs in the main insulating layer (1), serious accidents such as power outages can be prevented.

In addition, as schematically shown in Figure 3, if the partial shielding layer (3) is grounded via the circuit breaker Q0, etc., when the main insulation layer (1) breaks down, the circuit breaker 00 is immediately turned off. By switching to the open state, the partial shielding layer (3) shown in FIG.
) in a floating state, serious accidents such as power outages can be prevented.

However, in the case of double-insulated high-voltage cables that adopt the above method, the structure of the terminal connection part is different from that of conventional cables, so the structure of the terminal connection part is different from that of the conventional cable, that is, the main insulation layer and the sub-insulation layer. It was difficult to apply the terminal connection part without distinction as it is.

[Summary of the invention]

The present invention has been made in view of the above points, and provides a terminal connection section for a double-insulated high-voltage cable, which can be reduced in size compared to a normal conventional terminal connection section.

The gist of the first invention is that the cable termination portion is formed by sequentially exposing a conductor, a main insulation layer, a partial shielding layer, a sub-insulation layer and a metal shielding layer from the termination of a double-insulated high-voltage cable. In the terminal connection portion of a double-insulated high-voltage cable, the main insulating layer is covered with a rubber porcelain tube, and the sub-insulating layer is covered with a high dielectric constant heat-shrinkable tube.

In the first invention, the rubber insulator tube may have a lead wire and an embedded electrode for providing electrical continuity between the partial shielding layer and the circuit breaker.

Similar to the object of the first invention, the second invention provides a terminal connection part for a double-insulated high-voltage cable, and the gist thereof is to connect a conductor to a main insulation layer from the terminal end of a double-insulated high-voltage cable. , in the cable terminal portion in which a partial shielding layer, a sub-insulating layer and a metal shielding layer are sequentially exposed, the insulating layer and the sub-insulating layer are covered with a high dielectric constant heat-shrinkable tube. Located at the end connections of double-insulated high-voltage cables.

[Detailed description of the invention]

FIG. 4 is a longitudinal cross-sectional view of the terminal connection part of the double-insulated high-voltage cable of the first invention, in which the terminal end of the double-insulated high-voltage cable is connected to the conductor (
4), main insulating layer (1), partial shielding layer (3), sub-insulating layer (
2) and the metal shielding layer (7) are exposed in this order, and the exposed portion of the main insulating layer (1) is covered with a plug-in rubber insulator tube ◇υshiζ. It is desirable that the plug-in rubber insulator tube αυ has a structure in which the stress cone part @ is hidden.

The reason is that the main insulating layer (1) is destroyed and the partial shielding layer (3)
Even if the terminal becomes a high voltage part, the live parts (referring to the partial shielding layer (3) and the stress cone part @, which are charged to high voltage when the main insulating layer is destroyed) should not be exposed, and the secondary parts at the terminal should not be exposed. This is to reduce the size of the insulating layer. The sub-insulating layer is covered with high dielectric constant heat shrinkable tube α■,
One end of the tube α■ covers a partial shielding layer (3), and the other end covers a metal shielding layer (7). The chip α
It is desirable that the joint between the end of the partial shielding layer (3) and the rubber insulator tube αυ in ■ be covered with an insulating heat-shrinkable tube α→ so that the partial shielding layer (3) is not exposed to the outside. .

The other end of the high dielectric constant heat shrinkable tube α→ is connected to the metal shielding layer (7) to which the grounding wire aυ is connected,
And sheath it with tape or heat shrink tube (9)
Waterproofing treatment is applied across the area.

In the present invention, a rain cover Q71 may be provided on the outside of the high dielectric constant heat shrinkable tube.

In the present invention, the high dielectric constant heat-shrinkable tube is made of a resin composition in which carbon black is blended with polyolefin such as polyethylene or ethylene-vinyl acetate copolymer. The terminal connection part of the present invention is cross-linked with an agent, etc., and then the diameter of the tube is expanded while being heated above the melting point, and the tube is cooled while maintaining its shape, thereby imparting heat shrinkability. This heat-shrinkable tube is shrunk by heating and coated on the sub-insulating layer.

The dielectric constant of the high dielectric constant heat shrinkable tube is 30 to io.

The specific resistance thereof is preferably 10 8 Ω to 1 glO Ω.

FIG. 5 is a longitudinal cross-sectional view showing another embodiment of the first invention, and is a terminal connection section applied when the partial shielding layer (3) is grounded via a circuit breaker etc. (FIG. 3). be. in this case,
Since it is necessary to take out the lead wire from the partial shielding layer, a metal electrode α (support) is embedded in a part of the lower part of the rubber insulator tube aυ (partial shielding layer (3) side), and the two semiconducting layers and the metal layer (3) in the partial shielding layer (3) consisting of the metal layer provided therebetween (in Fig. 5, the contact (1)
8) ) is connected or contacted, and the - blade side is electrically connected to the circuit breaker via lead wire (■).

In the above embodiment, the lead wire is insulated,
Preferably something that is not flexible. The reason is that the main insulating layer (1
) is destroyed and the partial shielding layer (3) becomes a high pressure part,
This is because it ensures a sufficient distance from the earth electrode and also ensures sufficient voltage strength.

FIG. 6 is a longitudinal sectional view of the terminal connection part of the double insulated high voltage cable of the second invention, in which a high dielectric constant heat shrink tube (211) is used as the main insulating layer (1 )
It is coated with The sub-insulating layer (2) is also the main insulating layer (1
) is covered with a high-permittivity heat shrinkable tube α similar to that of ), and the ends of both tubes α and ) are connected at the mutually ζ partial shielding layer (8), and the connecting portion is For the same reason as the first invention, it is covered with an insulating heat shrink tube α→.

The other end of the tube α-bar and the metal shielding layer (7)
is subjected to waterproofing treatment [phase] as in the second invention, and the other end of the tube (21) is connected to the cable conductor (4).
Covered with insulating heat shrink tubing to prevent water from entering.

In the present invention, any number of rain covers may be provided on the outside of the high dielectric constant heat shrinkable tubes a3 and (21).

FIG. 7 is a partial cross-sectional view of the vicinity of the partial shielding layer of another embodiment of the second invention. This embodiment is a terminal connection part applied when the partial shielding layer (3) is grounded via a circuit breaker etc. (Fig. 3), so the partial shielding layer (3) is connected to the lead wire circle and embedded It is covered with an insulating ring (c) provided with an electrode Q91, and the partial shielding layer (3) is electrically connected to the circuit breaker via the lead wire (20) and the embedded electrode 09). FIG. 8 is a perspective view of the insulating ring (23). The insulation ring (c) is made of an insulating thermal insulation tube (goods).
Both ends are waterproofed.

〔Effect of the invention〕

Since the terminal connection portion of the double-insulated high-voltage cable according to the second and second inventions has the above-described structure, a system capable of preventing cable accidents as shown in FIG. 2 or 3 is a cable line system. Applicable to

Furthermore, since a high dielectric constant heat shrinkable tube is used, it is compact and has good workability when forming an end connection portion.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a double-insulated high-voltage cable, Figure 2 is a schematic diagram of the partial shielding layer floating and the metal shielding layer being grounded, and Figure 3 is the partial shielding layer connected to a circuit breaker, etc. Fig. 4 is a longitudinal sectional view of the terminal connection part of the double insulated high voltage cable of the first invention, and Fig. 5 is a schematic diagram of the case where the metal shielding layer is grounded through the cable. A vertical cross-sectional view showing an embodiment,
Fig. 6 is a longitudinal sectional view of the terminal connection part of the double insulated high voltage cable of the second invention, Fig. 7 is a partial sectional view of another embodiment of the second invention, and Fig. 8 is a perspective view of the insulating ring. It is. (1) Main insulating layer, (2) Sub insulating layer, (3)
...Partial shielding layer, (4)...Conductor, (5)...Inner semiconducting layer, (6)...Outer semiconductor layer, (7)...Metal shielding layer, (8)... Presser tape, (9)・Sheath, αO・
- Breaker, αυ... Plug-in rubber insulator tube, (6) - Stress cone part, α3shi1)... High dielectric constant heat shrink tube, α4) (22) (24)... Insulating Heat shrink tube, Q uniform...ground wire, 0 powder, embedded electrode, (20)...
Lead wire, (23)...Insulation ring. Yoshi1 Figure 7t2 Figure 7r3 Fertility'1r4 Figure 5

Claims (8)

[Claims] (1) At the end of a double-insulated high-voltage cable where the conductor, main insulation layer, partial shielding layer, sub-insulation layer, and metal shielding layer are sequentially exposed from the end of the cable, the main insulation layer is covered with a rubber insulator tube. and the sub-insulating layer is covered with a high dielectric constant heat-shrinkable tube. (2) A terminal connection portion for a double-insulated high-voltage cable according to claim (1), wherein a stress cone portion connected to the partial shielding layer is provided in the end portion of the rubber insulator tube on the partial shielding layer side. (3) The rubber insulator tube is provided with a lead wire for establishing electrical continuity between the partial shielding layer and the circuit breaker, and an embedded electrode for connecting the lead wire and the partial shielding layer. )
Terminal connections for double-insulated high-voltage cables as described in . (4) The terminal connection portion of a double-insulated high-voltage cable according to claim (2), wherein the lead wire is an insulated wire having sufficient rigidity. (5) The dielectric constant of high dielectric constant heat shrinkable tube is 30 to 100
A terminal connection portion for a double-insulated high-voltage cable according to claim (1). (6) At the end portion of a double-insulated high-voltage cable in which a conductor, a main insulating layer, a partial shielding layer, a sub-insulating layer, and a metal shielding layer are sequentially exposed from the terminal end of the cable, the main insulating layer and the sub-insulating layer A terminal connection part of a double-insulated high-voltage cable characterized by being covered with a high-permittivity heat-shrinkable tube. (7) The dielectric constant of high dielectric constant heat shrinkable tube is 30 to 100.
A terminal connection portion for a double-insulated high-voltage cable according to claim (6). (8) The partial shielding layer is covered with an insulating ring provided with a lead wire for establishing electrical continuity between the partial shielding layer and the circuit breaker, and an embedded electrode for connecting the lead wire and the partial shielding layer. A terminal connection portion of a double-insulated high-voltage cable according to claim (6).