JPH09282985A - Opening/closing device for ground potential transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an air-tight piercing portion in a tank and perform opening or closing operation without applying excessive force to contacts by providing a fixed contact and movable contact consisting of a fixed contact piece having a bushing, on a potential transformer side and a fixed contact piece on a power source side. SOLUTION: A fixed contact for one phase comprises an L-shaped fixed contact piece 12 on a potential transformer side and long and short fixed contact pieces 13, 14 on a power source side. A projecting bushing 12c is provided at the reverse of the contact piece 12; and contacts 12a, 12b, on both sides thereof; all of which are electrically conducted to each other. Contacts 13a, 14a disposed at one end of each of the contact pieces 13, 14 are fixed vertically with a predetermined interval to a fixing plate in a manner corresponding to the contacts 12a, 12b, respectively; while terminals disposed at the other end thereof are connected to cables 7, 8 respectively. These contacts serve as contacts on a female side. A U-shaped conductor 16a serving as a contact on a male side is covered with an insulating coating layer 16b, thereby forming a movable contact piece 16. In contrast, the tip of the bushing 12c air-tightly piercing a fixing hole 11a of a tank 11 containing oil therein is connected to a high- voltage cutout 5 via a conducting wire 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground transformer installed on an underground power distribution line, and more particularly to a switchgear thereof.

[0002]

2. Description of the Related Art FIG. 6 is a front view of a conventional ground transformer, and FIG. 7 is a side view showing a power source side thereof. A three-phase transformer body 1 is housed in a tank 2 filled with insulating oil. A protective device is attached to the outer wall, and these are housed in the outer box 3. Six plug units 4 constituting an opening / closing part of the protective device are attached to penetrate the tank in an airtight manner. It is desirable that the mounting position of the plug unit 4 penetrates into the air part of the tank, but it penetrates into the oil in order to keep the height of the outer box 3 low. Further, three high pressure cutouts 5 are mounted above the plug unit 4 so as to penetrate the tank in an airtight manner and project into the air in the tank. Then, in-tank plug units 4 and 4 are connected to each other by a lead wire 6, and further electrically connected to the transformer body 1 through a high-voltage cutout 5 having a built-in current limiting fuse.

On the other hand, for the ground transformer, the primary side cable 7 for three phases branched by a certain multi-circuit switch of the underground supply system is used.
And the primary side cables 8 for three phases branched by other multi-circuit switches having different power supplies are drawn. An elbow type load break connector 9 is attached to the ends of the primary side cables 7 and 8. The load break connector 9 is opened / closed by inserting / removing it into / from the plug unit 4. In addition, 10
Is a secondary side terminal connected to the load.

[0004]

By the way, a ground transformer is often installed on a sidewalk in a city, and inevitably requires miniaturization and high reliability. Focusing on the tank 2 of the above ground transformer, there are as many as six plug units 4 that penetrate the oil-immersed portion of the tank. This is an indispensable structure for downsizing of the tank, but there is a problem that it is desired to reduce the number of penetrations in order to further improve reliability. Further, when the load break connector 9 is inserted and removed during the opening and closing operation, the primary side cables 7 and 8 connected thereto are bent. If it becomes a 6kV class cable, the diameter is 23mm.
Moreover, the bending rigidity is also quite large. Therefore, there is a problem that the load break connector 9 pulled by the cable may be inserted or removed while being inclined, or may be pulled by the cable to cause incomplete contact. An object of the present invention is to provide an opening / closing device for a ground transformer which reduces the airtight penetration portion of a tank and prevents an unreasonable force from being applied to the contact portion during the opening / closing operation.

[0005]

To achieve the above object, the present invention provides a transformer main body housed in an oil-filled tank with a primary side cable rising from the ground attached to an outer wall of the tank. In the above-grounded transformer, the transformer-side fixed contact piece provided with a bushing for air-tightly penetrating the switchgear through the transformer-side contact and the tank, and the fixed contact piece, A fixed contact formed by a power supply side fixed contact piece provided separately with a power supply side contact, and a plug type movable contactor for opening and closing between the transformer side contact and the power supply side contact of the fixed contact. And the primary side cable is connected to the power source side fixed contact piece.

In the above ground transformer switchgear,
The fixed contact includes two transformer-side contacts that are electrically connected to each other, a transformer-side fixed contact piece that is provided, and two power-side contacts that correspond to the transformer-side contacts. It is preferably constituted by a fixed contact piece on the power source side.

According to the above construction, all the fixed contact pieces of the switchgear can be connected outside the tank, and the tank can have only one penetrating portion for each phase. Further, since the primary side cable is connected to the fixed contact piece on the power source side, an unreasonable force due to the cable does not act on the opening / closing operation of the movable contact piece, so that the movable contact piece can be smoothly inserted and removed.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a front view of a ground transformer,
FIG. 2 is a side view showing the power source side. This example is similar to the one described in the related art, in which the primary side cables 7 and 8 for three phases branched from two multi-circuit switches having different power supplies are drawn in, and between the switchgear and the transformer body 1. The high-voltage cutout 5 is connected to the. It should be noted that the same parts as those of the related art are designated by the same reference numerals and the description thereof will be omitted.

The opening / closing device is composed of a fixed contact mounted on the outer wall of the tank 11 and a movable contact engaged with the fixed contact. FIG. 3 shows the structure of a fixed contact for one phase, (a)
Is a front view and (b) is a side view. As shown in the figure, there are three fixed contacts for one phase, one set consists of an L-shaped transformer side fixed contact piece 12, a long power side fixed contact piece 13 and a short power side fixed contact. It consists of child pieces 14. The transformer-side fixed contact piece 12 has a contact 12a at one end, a contact 12b at the other end, and a protruding bushing 12c on the back side. These are electrically connected by a conductor. Long power supply side fixed contact piece 13
Has a contact 13a at one end, and the other end forms a terminal for connecting a cable. Short power supply side fixed contact piece 1
4 has a contact 14a at one end and the other end forms a terminal for connecting a cable. Then, on the mounting plate 15, the contact 12a and the corresponding contact 13a, and also the contact 12b.
The three fixed contact pieces 12, 1 are arranged so that the contact point 14a and the corresponding contact point 14a are vertically spaced at predetermined intervals.
3, 14 are arranged. Each of the contacts 12a, 12b, 1
3a and 14a are provided with tulip contacts and form so-called female-side contact portions.

As shown in FIG. 4, the movable contact 16 has a U
The character-shaped conductor 16a is molded with resin to form the insulating coating layer 16
b is formed, and skirt portions 16c are provided around both ends of the conductor 16a, which is the contact portion on the male side, to protect the contact portion. In the switchgear configured in this way, the primary side cables 7 and 8 are connected to the terminal portions provided at the lower ends of the power source side fixed contact pieces 13 and 14 of each phase.

On the other hand, when the fixed contact is attached to the tank 11, the bushing 12 of the transformer side fixed contact piece 12 of each phase is provided.
c penetrates the mounting hole 11a of the tank 11 and projects into the tank. This through portion is sufficiently hermetically sealed.
A terminal provided at the tip of the bushing 12c and a primary side terminal of the high voltage cutout 5 are connected by a conductor wire 17. further,
The primary side lead wire 18 of the transformer body 1 is connected to the secondary side terminal of the high voltage cutout 5. Note that the configuration of the secondary side of the transformer body 1 is not different from that of the conventional technique, and thus the description thereof is omitted.

FIG. 5 shows an electric circuit diagram of the above ground transformer. A series of primary side cables 7 for three phases branched by a certain multi-circuit switch of the underground supply system and a primary side cable 8 for three phases branched by another multi-circuit switch of different power source. The opening / closing unit 110, the bus bar 19, and the opening / closing unit 120 are connected to the. On the other hand, a bushing 12c branches off from the bus bar 19 and is connected to the primary side of the transformer body 1 via the high-voltage cutout 5.

Next, the operation will be described. If the fixed contact of the switchgear is configured as described above, only one bushing 12c for penetrating the tank 11 is required for each phase. It can be reduced to 3 places. Furthermore, since the primary side cables 7 and 8 are connected to the fixed contactor and the mechanical connection between the movable contactor 16 and the primary side cables 7 and 8 is lost, the movable contactor 16 does not receive excessive force. Can be inserted and removed. It is also possible to mechanically connect the movable contactors 16 of each phase of the switchgear by connecting metal fittings in order to simultaneously open and close each of the primary side lines in three phases.

[0014]

As described above, according to the present invention, the number of airtight penetrating portions of the tank can be reduced as compared with the conventional one, and the movable contact operates without being affected by the primary side cable. Can be made.

[Brief description of drawings]

FIG. 1 is a front view of a ground transformer showing an embodiment of the present invention.

FIG. 2 is a side view of FIG. 1;

3A is a front view and FIG. 3B is a side view showing the structure of a fixed contact for one phase.

FIG. 4 is a sectional view of a movable contactor.

FIG. 5 is a circuit diagram of a ground transformer.

FIG. 6 is a front view of a conventional ground transformer.

FIG. 7 is a side view of FIG. 6;

[Explanation of symbols]

 1 Transformer Main Body 11 Tank 12, 13, 14 Fixed Contact Piece 12a, 12b, 13a, 14a Contact Point 12c Bushing 16 Movable Contact Point

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Nakaarai 1440 Nakakuki, Oyama City, Tochigi Prefecture, Takayama Manufacturing Co., Ltd. Oyama Plant (72) Inventor, Eri Okamoto 4-chome, Oshu, Minami-ku, Hiroshima City, Hiroshima Prefecture No. 4-32 Chugoku Electric Manufacturing Co., Ltd. (72) Inventor Toshiki Yokomoto 4-43, Daishu, Minami-ku, Hiroshima City, Hiroshima Prefecture Chugoku Electric Manufacturing Co., Ltd. (72) Inventor Seizo Shirane Hiroshima Prefecture 4-4-3 Oshu, Minami-ku, Hiroshima City Chugoku Electric Manufacturing Co., Ltd.

Claims (2)

[Claims] 1. A ground transformer in which a primary side cable rising from the ground is connected to a transformer main body housed in an oil-filled tank through an opening / closing device attached to the outer wall of the tank.
The switchgear is provided with a transformer-side fixed contact piece provided with a transformer-side contact and a bushing that hermetically penetrates the tank to connect to the transformer body, and a power-source-side contact that is separated from the fixed contact piece. A fixed contact consisting of a power supply side fixed contact piece,
The fixed contact is constituted by a plug-type movable contact that opens and closes between the transformer side contact and the power supply side contact, and the primary side cable is connected to the power supply side fixed contact piece. Switchgear for ground transformers. 2. A transformer-side fixed contact piece provided with two transformer-side contacts electrically connected to each other, and two power supplies provided with power-source-side contacts corresponding to the respective transformer-side contacts. The switchgear for a ground transformer according to claim 1, wherein a fixed contact is formed by the side fixed contact piece.