JPS6031384Y2 - insulation tube - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of an insulating cylinder used as insulating the sheath of an insulated connection part of a cable line or a mini-clad direct connection type terminal connection part.

Generally, in a three-phase power transmission line using a single-core cable, a cable shielding layer is insulated at the cable connection part in order to block current due to sheath induced voltage.

Normally, only a small AC voltage is applied to the insulating part of the shielding layer, but when an abnormal voltage occurs on the line and its traveling wave enters, a considerably large shock voltage is induced in the cable shielding layer. The insulating portion of the shielding layer of the insulated connection must have strong dielectric strength so that it can withstand this impact voltage.

By the way, in recent years, as the power transmission voltage has increased, the abnormal voltage generated in the insulating part of the shielding layer has been increasing, and in order to deal with this abnormal voltage, the insulation of the cable shielding layer has also been made considerably thicker. In this case, there is a disadvantage that the insulated connection portion becomes large.

On the other hand, in order to thin the insulation of the shielding layer, each cable 2,
It has also been attempted to provide a capacitor-type insulating layer 5 between the ends of the conductors 4, 4' which are short-circuited to the shielding layers 3, 3' of 2'; This has the disadvantage that it is troublesome and requires a long time to perform the work.

Also, as shown in Utility Model Publication No. 18994/1973,
A method of embedding opposing metal foils in the insulating tubes that make up the insulating junction box has also been attempted, but in this capacitor formation method, the dielectric material located between the opposing metal foils is the material that forms the insulating tubes. Therefore, it has disadvantages such as low dielectric strength and low capacitance.

That is, considering the purpose for which the cable junction box is usually used, the cable junction box itself has the required dielectric strength, water resistance to prevent water from entering from the outside, and resistance to hydraulic pressure because of the OF cable. The necessary internal pressure strength is required to achieve this.

Therefore, when it comes to selecting an insulating material for the insulating tube that satisfies these three conditions and can increase the capacitance, the materials are naturally limited, and in some cases, it is difficult to obtain the desired capacitance. .

Furthermore, since the lead wires are led out from both ends of the metal foil, there is also the disadvantage that actance increases accordingly.

Note that 6 in the figure indicates a conventional insulating cylinder.

The present invention has been made with attention to these points, and aims to provide an insulating tube that has good high frequency characteristics, is durable, and allows the entire connecting portion to be miniaturized.

Hereinafter, the present invention will be explained based on the drawings of one embodiment.

In FIGS. 2A and 2B, the insulating cylinder 7 according to the present invention includes a hard insulating cylinder 8 and a cylinder wall of the cylinder embedded at a predetermined interval along the length direction. A plurality of capacitors 9 and annular electrodes 10.10 provided on both sides of the cylindrical body 8.
The lead wire 11 electrically connects the capacitors located on both sides between the electrodes 10 and 10' and the electrodes.

The hard insulating cylinder 8 is protected from epoxy, magnetism, and the like.

If the mechanical strength of the insulating cylinder is reduced by embedding the capacitor 9, it is desirable to embed a reinforcing body 12 made of a metal band or the like into the cylinder wall.

This is because embedding the reinforcing body 12 may cause a decrease in creeping pressure resistance.

Condenser 9 should be avoided from mica type capacitors etc., 5
At commercial frequencies from 0 to 60 (H2), 0.1 [μ
F] or exhibits a high impedance characteristic of about 1110 to 1/100 of this, and is considered to have a low impedance for high frequencies.

Although the figure shows an example in which 5 pieces are buried equally in the length direction and 6 pieces are equally distributed in the circumferential direction, this number is determined by the impedance of the line and is not limited to the number shown in the figure.

The electrodes io and io' are made of metal plates, paint, etc., but metal plates are preferable in consideration of electrical resistance.

Each capacitor 9 and the electrodes 10, 10' are electrically connected by soldering or the like using lead wires 11 made of stranded mild steel wires, copper strips, or the like.

The insulating tube constructed as described above is used for the straight connection part of the cable line as shown in Fig. 3, or for the shielding layer of the mini-clad direct connection type cable terminal part as shown in Fig. 4.
Used as insulation for 4.

In the figure, 15 is a cable insulating layer, 16 is a cable conductor, 17 is a sleeve, 18 is a protective tube, 19 is a mini-clad, and 20 is a cable head.

As mentioned above, in this invention, the insulating tube is formed by embedding a separate capacitor in the insulating tube, so when forming the insulating tube, the insulating tube itself has to meet the requirements. It is sufficient to select a material that satisfies specific characteristics such as pressure resistance, dielectric strength, and water resistance.

Therefore, in the present invention, in order to obtain an insulating cylinder with the desired capacitance, especially high frequency characteristics, it is only necessary to appropriately select capacitors that have a wide range of capacitance. By using the insulating tube, the entire cable connection part can be made smaller, and it is also possible to provide a cable shielding and insulating part that allows on-site connection work to be carried out in a short time.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing the insulating connection part of a conventional power cable; It is an explanatory view showing an example of use of the insulating tube concerning. 7... Insulating cylinder, 8... Insulating cylinder, 9
・・・・・・Capacitor, 10.10'・・・・・・
Electrode, 11...Lead wire, 12...Reinforcement body.

Claims (1)

[Claims for Utility Model Registration] 1. A hard insulating cylindrical body, annular electrodes fixed to both ends of the insulating cylindrical body, and a predetermined electrode arranged along the axial direction in the cylindrical wall of the insulating cylindrical body. An insulating tube comprising a plurality of capacitors embedded at intervals of . 2. The insulating cylinder according to claim 1 of the utility model registration, characterized in that a reinforcing member is embedded in the cylinder wall of the insulating cylinder.