JP2001085247A - Gas insulated transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a supporting/fixing device for lead wire of a gas insulated transformer which can ensure a dielectric strength equivalent to or more than that of a conventional one and shorten the working time for supporting/fixing a lead wire. SOLUTION: This supporting/fixing device for lead wire is provided with a pair of shields 5 pinching an insulation supporting plate 2 which crosses a lead wire 1 vertically and supports/fixes it, and each shield is composed of at least two divided shields. Furthermore, the device is provided with a means for connecting electrically the divided shields and a lead wire conductor and a means for tightening/fixing the lead wire 1. As a result, the dielectric strength of the device can be ensured equivalent to or more than that of the conventional device without a reinforced insulation in the lead wire supporting part, and a working time for supporting/fixing wiring of lead wire can be shortened at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas insulated transformer, and more particularly to an improvement in a device for supporting and fixing a lead wire derived from a winding.

[0002]

2. Description of the Related Art In recent years, a gas-insulated transformer using a nonflammable insulating gas (for example, SF6 gas) as an insulating cooling medium has attracted attention from the viewpoint of disaster prevention. Fig. 11 shows the outline of the structure of a general gas-insulated transformer. A winding 21 wound coaxially with the iron core 20 is arranged in a tank (not shown) in which the insulating gas is sealed, and the shape of the iron core 20 is maintained by being tightened by upper and lower iron core fasteners 22. I have. The lead wire 1 is led out of the winding wire 21 and attached to a core clamp 22 for supporting and fixing the lead wire.
It is supported and fixed by 23.

FIG. 12 is a front view of a main part showing a conventional lead wire supporting and fixing device, and FIG. 13 is a side view of FIG. As shown in both figures, the lead wire 1 is disposed with a reinforcing wound insulation 24 provided in a groove of an insulating support plate 2 which intersects perpendicularly with the lead wire 1, and is tied and fixed by an insulating cord 4. The lead wire 1 is composed of a lead wire conductor 1a and an outer lead wire cover 1b. Generally, a wire conductor is used as the lead wire conductor 1a in consideration of flexibility in wiring. In such a structure, reinforcement winding insulation 24
At the interface between the groove and the insulating support plate 2, the reinforcing winding insulation 24 is twisted by tightening, and the small gap g1
This small gas gap g1 is formed because the relative permittivity of the reinforcing wound insulation 24 (for example, polyethylene terephthalate film) and the supporting insulating plate 2 (for example, press board) is about three times larger than that of the insulating gas. It concentrates compared to the part and becomes a weak point on insulation. For this reason, the electric field of the minute gas gap g1 is reduced by increasing the thickness of the reinforcing winding 24 to a predetermined value and increasing the thickness of the reinforcing winding 24 away from the lead wire 1. Further, in order to prevent the occurrence of partial discharge in the minute gas gap g1 and the immediate progress of discharge to the lead wire 1 resulting in complete destruction, the length L of the reinforcing wound insulation 24 is increased to a predetermined value. Creep distance. Next, FIG. 14 is a front view of a main part of a lead wire supporting and fixing device showing another conventional example, and FIG. 15 is a side view of FIG. As shown in both figures, the lead wire 1 is disposed by applying a reinforcing winding insulation 24 to the groove of the insulating support plate 2 which intersects perpendicularly with the lead wire 1, and is fixed by a holding insulation having a groove so as to sandwich the lead wire 1. The plate 10 is joined to the supporting insulating plate 2 with the insulating bolts 12 and the insulating nuts 13 via the joining insulating plate 11, so that the lead wire 1 can be supported and fixed more firmly than the prior art shown in FIGS. ing.

In such a structure, at the interface between the groove where the reinforcing winding insulation 24 and the insulating support plate 2 are in contact with each other, the reinforcing winding insulation 24 is twisted by being tightened, and minute gaps g1 and g2 are formed as in the case of FIG. easy. FIG. 16 is a front view of a main part of a lead wire supporting and fixing device showing another conventional example, and FIG.
FIG. As shown in both figures, the lead wire 1 is disposed on the supporting insulating plate 2 'with the reinforcing winding insulation 24 applied thereto.
It is tied up and fixed. The difference from the conventional example shown in FIGS. 12 and 13 is that the supporting insulating plate 2 'has a simplified structure without a groove. In this case, a wedge-shaped gas cap g3 is formed at the contact portion between the reinforcing winding insulation 24 of the lead wire 1 and the supporting insulating plate 2 ', and in this portion, the electric field is increased due to the difference in the relative permittivity with the surrounding solid insulator. Concentration occurs. Therefore, the electric field of the wedge-shaped gas cap g3 is relaxed by increasing the thickness of the reinforcing wound insulation 24 to a predetermined value. In addition, the length L of the reinforcing wound insulation 24 is increased to a predetermined value to secure a creep distance and maintain a predetermined dielectric strength.

[0005]

In the lead wire supporting and fixing device 22 described in the prior art, it is necessary to provide a reinforcing wire insulation 24 having a predetermined thickness and length to the lead wire 1 of the supporting portion.
Since the reinforcing wound insulation 24 is formed by winding a large number of insulating films or insulating sheets, there is a problem that the work of supporting and fixing the lead wire 1 is troublesome.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a lead wire supporting portion which does not require complicated insulation reinforcement while maintaining a dielectric strength equal to or higher than that of the related art. An object of the present invention is to provide a lead wire supporting and fixing device which shortens the work time for supporting and fixing a wire.

[0007]

According to the present invention, in order to achieve the above object, a lead wire supporting and fixing device intersects a pair of insulating support plates which vertically intersect with the lead wire and support and fix the lead wire. The shield alone is composed of at least two divided shields, and has means for electrically connecting these divided shields to the lead wires and means for tightening and fixing to the lead wires. Things. The means for electrically connecting the split shield has a needle-shaped protrusion on the lead wire contact surface of the split shield. Further, the means for tightening and fixing the split shield is such that the outer insulating material is wound around a groove provided on the outer periphery of the split shield and fixed to the lead wire, or at a position above and below an opposing portion of the split shield. The opposing portion is tied to the provided through hole through an insulating cord to fix the divided shield to the lead wire.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. Note that the same parts as those in the related art are denoted by the same reference numerals. FIG. 1 is a front view of a main part of a lead wire supporting and fixing device according to a first embodiment of the present invention, and FIG. 2 is a side view of FIG.
FIG. 3 is a perspective view of a split shield constituting the shield of FIG. 1, and FIG. 4 is a sectional view taken along the line AA of FIG. FIG.
2A and 2B, the lead wire 1 is arranged in a groove of the supporting insulating plate 2, and is bound and fixed to the supporting insulating plate 2 by an insulating cord 4 passing through a through hole 3 of the supporting insulating plate 2. A pair of shields 5 is attached to the lead wire 1 so as to sandwich the supporting insulating plate 2. This shield 5 is composed of two divided shields 5a and 5b,
5b is fixed by winding the outer layer insulator 6 composed of an insulating tape or an insulating string, pressing down on the lead wire 1, and fixing. At this time, as shown in FIG. 3 and FIG.
5b has a needle-like projection 7 on the inside facing the lead wire 1. The needle-like projection 7 penetrates the lead wire insulation coating 1a and penetrates the stranded lead wire conductor 1b. The shields 5a and 5b can be set to the same potential as the lead conductor 1b. Further, since the outer insulating material 6 is wound around a portion provided along the groove provided on the outer periphery of the divided shields 5a and 5b, there is no possibility that the outer insulating material 6 will come off and come off. FIG. 5 shows a distribution diagram of equipotential lines in a longitudinal section of the lead wire 1 of the main part of the lead supporting and fixing device described above. Since the shield 5 having the same potential as the lead wire 1 is disposed so as to sandwich the supporting insulating plate 2, the entry of the equipotential line P is reduced between the shields 5, and formed at the interface where the supporting insulating plate 2 and the lead wire 1 are in contact. The electric field of the small gas gap g1 can be reduced. For this reason, the breakdown voltage that leads to dielectric breakdown from the minute gas gap g1 can be made higher than before. Becomes highest part field in this structure is the outer peripheral surface of the shield 5, by increasing the curvature of this portion to an appropriate value, it is possible to relax the electric field, if an insulating quotes _Lee ring shield 5 The breakdown effect can be increased by the coating effect. Therefore, a dielectric strength equal to or higher than that of the related art can be secured. As a method of fixing the divided shields 5a and 5b, a method of binding upper and lower positions to each other through an insulating cord 9 in a through hole 8 provided in the divided shields 5a and 5b as shown in FIG.

FIG. 7 is a front view of a main part of a lead wire supporting and fixing device according to a second embodiment of the present invention, and FIG. 8 is a side view of FIG. The difference from the embodiment of FIGS. 1 and 2 is that the lead wire 1 is supported and fixed to the supporting insulating plate 2 by a holding insulating plate 10 via a bonding insulating plate 11 using insulating bolts 12 and insulating nuts 13. However, since a pair of shields 5 are arranged so as to sandwich the supporting insulating plate 2, the same operation and effect as in the embodiment of FIGS. 1 and 2 can be expected.

FIG. 9 is a front view of a main part of a lead wire supporting and fixing device according to a third embodiment, and FIG. 10 is a side view of FIG. This embodiment also differs from the embodiment of FIGS. 1 and 2 in the method of supporting and fixing the lead wire 1, but since the pair of shields 5 are arranged so as to sandwich the supporting insulating plate 2, the lead wire 1 and the supporting insulating plate The electric field with a wedge-shaped gas gap g3 formed at the position where 2 'is in contact is greatly relaxed as compared with the prior art.
Thus by performing the shape optimization and insulating Cote _Lee ring of the shield 5, it can be secured conventional equal or dielectric strength.

[0011]

According to the present invention, in a device for supporting and fixing a lead wire of a gas insulated transformer, a pair of shields can be easily arranged and fixed on the lead wire so as to sandwich a supporting insulating plate for supporting the lead wire. The same or higher dielectric strength can be secured. Therefore, it is possible to provide a lead wire supporting and fixing device which does not require a complicated reinforcing insulation as in the prior art, that is, shortens the work time for supporting and fixing the lead wire.

[Brief description of the drawings]

FIG. 1 is a front view of a main part of a lead wire supporting and fixing device according to a first embodiment of the present invention.

FIG. 2 is a side view of the lead wire supporting and fixing device according to the first embodiment of the present invention.

FIG. 3 is a perspective view of a split shield according to the first embodiment of the present invention.

FIG. 4 is a sectional view taken along line AA of FIG. 1;

5 is an equipotential line distribution diagram in a vertical cross section of the lead wire in the longitudinal direction of FIG.

FIG. 6 is a shield cross-sectional view showing another method of fixing the split shield according to the first embodiment of the present invention.

FIG. 7 is a front view of a main part of a lead wire fixing device according to a second embodiment of the present invention.

FIG. 8 is a side view of a lead wire supporting and fixing device according to a second embodiment of the present invention.

FIG. 9 is a front view of a main part of a lead wire supporting and fixing device according to a third embodiment of the present invention.

FIG. 10 is a side view of a lead wire supporting and fixing device according to a third embodiment of the present invention.

FIG. 11 is a front view showing an example of the content main body of a general gas-insulated transformer.

FIG. 12 is a sectional view of a main part of a conventional lead wire supporting and fixing device.

FIG. 13 is a side view of a conventional lead wire supporting and fixing device.

FIG. 14 is a sectional view of a main part of another conventional lead wire supporting and fixing device.

FIG. 15 is a side view of another conventional device for supporting and fixing a lead wire.

FIG. 16 is a sectional view of a main part of still another conventional lead wire supporting and fixing device.

FIG. 17 is a side view of still another conventional lead wire supporting and fixing device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Lead wire, 2, 2 '... Support insulating plate, 3 ... Through-hole, 4
... Insulation cord, 5 ... Shield, 5a, 5b ... Split shield, 6
... exterior insulator, 7 ... needle-like projection, 8 ... through hole, 9 ... insulating string, 10 ... holding insulating plate, 11 ... joining insulating plate, 12 ... insulating bolt, 13 ... insulating nut, 20 ... iron core, 21 ... Winding, 22: iron core clamp, 23: lead wire support and fixing device, 24: reinforcement winding insulation.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Seigo Watanabe 1-1-1 Kokubuncho, Hitachi City, Ibaraki Prefecture F-term in Kokubu Works, Hitachi, Ltd. (Reference) 5E043 AA02 AB01 EA05 EA06 EA08 5E044 DA08 5E058 CC17

Claims (4)

[Claims] 1. A lead wire supporting device in which a winding wound around an iron core is housed in a tank filled with insulating gas, and a lead wire derived from the winding is supported and fixed via an insulating support plate. In the gas insulated transformer provided with, the lead wire supporting device has a pair of shields arranged so as to sandwich an insulating support plate that intersects perpendicularly to the lead wire and supports and fixes the lead wire. A gas-insulated transformer comprising: a unitary shield composed of at least two divided shields; and means for electrically connecting these divided shields to a lead wire and means for tightening and fixing the shield to the lead wire. 2. The gas insulated transformer according to claim 1, wherein said means for electrically connecting said divided shields has a needle-like projection on a lead wire contact surface of said divided shield. 3. The device according to claim 1, wherein said means for tightening and fixing said split shield is configured such that an outer insulating material is wound around a groove provided on an outer peripheral surface of said split shield and fixed to said lead wire. A gas-insulated transformer as described. 4. The means for tightening and fixing the split shield is such that the facing portion is tied through through holes provided at positions above and below the opposing portion of the split shield to fix the split shield to the lead wire. The gas-insulated transformer according to claim 1, wherein