JP2002245883A - Lead-less bushing in switch or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead-less bushing at the outside of a case in which the exposed charged part positioned at the outside of the insulating cover installed at the cable connection part is eliminated by a simple and inexpensive structure. SOLUTION: These are plural bushings 2 that are fixed protruded at the outside of a case 3 of a switch 1 or the like, and are separated by mutually holding an appropriate insulating space g, and, in the through hole 4a of the insulator tube 4 of each bushing, a central conductor 5 is penetrated and fixed, and at the top end of the outside of the case of the conductor 5, a cable connection terminal 10 is fixed. And an insulating cover 19 is installed on the terminal 10 and the terminal 10 is covered, and further, the exposed parts positioned at the outside of the case of the central conductor 5 are covered with an insulating shrinkable tube 12 applied with adhesive 13 at the inner face 12a of those outer circumference including the central conductor 5, a nut 8 screwed to the conductor, and a part of the cable connection terminal 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a bushing portion of a cased switchgear used for a high-voltage distribution line, and in particular, in a leadless type bushing, does not cause an accident such as an interphase short circuit between adjacent bushings. Related to the structure.

[0002]

2. Description of the Related Art In a high-voltage distribution line, a cased switch for dividing a line is installed on a utility pole at appropriate intervals.
In the switch, a three-phase power supply side and a load side bushing protruding and fixed to the outside of the switch case are connected to their respective wire connection terminals with distribution lines composed of insulated wires to form a high-voltage distribution line. ing. In the above switch, the bushing structure can be roughly classified into a lead type in which a lead wire is previously assembled to a bushing portion at the time of assembly, and a bushing wire at a mounting (use) site without a lead wire at the time of assembly and shipment. There is a leadless type in which a lead wire made of an insulated wire is connected to a connection terminal. And especially in the latter leadless type bushing,
During the installation work of the switch, after connecting the insulated wire to the wire connection terminal, an insulation cover is attached to the terminal which becomes a charged portion in an energized state to prevent the charged portion from being exposed.

[0003]

However, in the conventional leadless type bushing, there is a case where a charged portion located outside the insulating cover, for example, only a part of the center conductor is still exposed. Therefore, the binding wire used for construction and the wire carried by birds for nesting enter through the gap, and inadvertently come into contact with the exposed live part and approach it, and the bushing of the adjacent phase of the switch on the ground side and the switch. There is a risk of causing a ground fault accident or an interphase short circuit accident between the two. Although there is a type that completely covers the charging portion, there is a problem that these structures require a significant design change and that an increase in cost cannot be avoided.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and comprises a plurality of bushings projecting and fixed to a case 3 such as a switch 1 and the like, and spaced apart from each other while appropriately holding an insulating space g. 2, a central conductor 5 is fixed through the through-hole 4a of the insulator tube 4 of each bushing.
An electric wire connection terminal 10 is fixed to the outer end of the case, and an insulating cover 19 is attached to the terminal 10 to cover the terminal 10 and a central portion of the center conductor 5 located outside the case is located outside the case. The conductor 5, the nut 8 to be screwed to the conductor, and the outer peripheral surface thereof including a part of the electric wire connection terminal 10 are attached by an insulating shrink tube 12 formed by applying an adhesive 13 to an inner surface 12a. The present invention proposes a leadless type bushing for a switch or the like.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to FIGS. 2 (2, 2)
Is a leadless type bushing of the cased switch 1, and a three-phase bushing of U-phase, V-phase, and W-phase is adjacent to the side surface 3a on the power supply side and the side surface (not particularly shown) of the case 3 respectively. It is attached to the phase while appropriately holding the insulating space g.

The bushing 2 has a stud bolt type center conductor 5 inserted into a through hole 4a of the insulator tube 4, and is fixedly secured to the outside of the case by a detent nut 6, a spring washer 7, a fastening nut 8, and a flat washer 9. After that, the crimp terminal type wire connection terminal 10 is crimp-connected to the end 5a of the center conductor.

On the inner side of the case, a flange-shaped pressing portion 5b is attached to the inner end surface 4b of the through hole 4a of the porcelain tube 4 by an O-ring 11.
Attached through. In addition, the through hole 4 of the insulator tube 4
The center conductor 5 penetrating through a is a split type that can be divided into two, and has a structure in which the center conductor 5 is integrally connected by a screw connection portion 5c in the through hole 4a.

Reference numeral 12 denotes a state in which the center conductor 5 is fastened and fixed to the porcelain tube 4, and the above-mentioned detent nut 6, spring washer 7, fastening nut 8, flat washer 9, wire connection terminal 10
A heat-shrinkable rubber- or resin-based shrinkable tube that is applied so as to cover the outer periphery of a tube is used. However, at this time, an adhesive 13 is further applied to the inner surface 12a of the tube so that the adhesion to the object to be coated can be further improved during the application.

Reference numeral 14 denotes a silicone rubber or resin-based filler for sealing, and reference numeral 15 denotes a flange-like mounting flange 4c of the insulator tube 4.
, And the bushing 2 is connected to the case 3
Is attached to the side surface 3a of the main body. Reference numeral 16 denotes an O-ring interposed between the pressing portion 4d of the flange and the outer surface 3a of the case 3.

Reference numeral 17 denotes a cup-shaped shielding body made of rubber such as EPR (butyl rubber having tracking resistance).
a, a cap-shaped shielding portion 17b for shielding the groove 4f of the porcelain tube 4 is formed on the front side, and an annular mounting projection 17c for mounting an insulating cover is formed on the rear side.
Further, on the upper side, a split portion 17e for attachment from the peripheral surface 17d to the center attachment hole 17a is formed.
7 is inserted into the center conductor 5 from above with the mounting hole 17a opened in the left and right sides from the split portion 17e.
It is fixed to the center conductor by a screw 18.

Reference numeral 19 denotes a mounting projection 17c of the shield 17.
This is an insulating cover made of rubber such as EPR (tracking resistant butyl rubber) attached to the electric wire connection terminal 10 so as to cover the outer peripheral surface of the electric wire connection terminal 10 serving as a charged portion so that the charged portion is not exposed.

Reference numeral 20 denotes an insulated wire which is tightened and connected to the wire connection terminal 10 with a screw 21. The charging portion in the bushing portion is attached to the shield 17 of the insulating cover 19, and is attached to the cover and the outer periphery of the lock nut 6, the spring washer 7, the tightening nut 8, and a part of the wire connection terminal 10. With the shrink tube 12 attached, there is no exposure of the charged portion.

[0013] This type of leadless bushing is not limited to a switch, but can be used for electric equipment in a case such as a transformer.

[0014]

As described above, the outer peripheral surface of the center conductor, which is located outside the insulating cover and a part of which is a charged portion, is disposed as described above.
Because of the simple structure of covering the charged part by attaching an insulating shrinkable tube, it does not involve a significant design change, and does not cause a cost increase or a reduction in workability.

[0015] Further, an adhesive is further applied to the inner surface of the shrinkable tube to be adhered to enhance the adhesion to the object to be coated (object) during the shrinkage adherence, so that it does not inadvertently come after being adhered. Insulation coating work can be performed simply and reliably.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a leadless type bushing according to an embodiment of the present invention.

FIG. 2 is a sectional view showing the entire bushing.

FIG. 3 is a side view of the cased switch with the insulating cover removed with the leadless type bushing of the present invention attached thereto.

FIG. 4 shows a front view (a), a left side view (b), a rear view (c), an AA sectional view (d), and a BB sectional view (e) of the shield.

FIG. 5 is a front view of an insulating shrinkable tube.

[Explanation of symbols]

 Reference Signs List 1 switch 2 bushing 3 case 3a side surface 5 center conductor 12 insulating contraction tube 12a inner surface 19 insulating cover g insulating space

Claims (1)

[Claims] 1. A plurality of bushings (2) protruding and fixed to the outside of a case (3) such as a switch (1) and separated from each other while appropriately holding an insulating space (g). The center conductor (5) is inserted into the through hole (4a) of the insulator pipe (4).
, And a wire connection terminal (10) is fixed to the outer end of the conductor (5) outside the case, and an insulating cover (19) is attached to the terminal (10). And the exposed portion of the center conductor (5) located outside the case includes the center conductor (5), a nut (8) screwed to the conductor, and a part of the wire connection terminal (10). A leadless type bushing in a switch or the like, wherein an outer peripheral surface is applied by an insulating shrink tube (12) obtained by applying an adhesive (13) to an inner surface (12a).