JP2003309910A - Power circuit device and assembling method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power circuit device and an assembling method capable of attaining low maintenance cost and easy maintenance such as repairs and remodeling even after long-term use. <P>SOLUTION: A powered connection conductor is constructed by fixing a first conductor part 16, a relay conductor 19, a second conductor part 18, and an auxiliary conductor 22 with assembling screws 21, 22 to be constituted, thus facilitating maintenance work such as overhaul, repair, and remodeling. Part of a surface of a hermetically sealed housing for filling the periphery of the connection conductor with insulation gas is formed by an expandable bellows wall surface 25. The extension traveling direction of the bellows wall surface 25 is guided by connection of a bolt with a nut 41. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power circuit device that facilitates maintenance such as repair and modification of a power circuit and a method of assembling the power circuit device.

[0002]

2. Description of the Related Art 10 connected between a power supply terminal and a transformer
A power circuit of 0 kv / 30 MvA class is provided in an insulating gas atmosphere. The power circuit device having such a configuration is a large-scale and expensive device as shown in FIG. FIG. 7 is a diagram showing a power circuit device 55 which switches power from a plurality of substations 51, 52, 53 by a power switching circuit 54 and stably supplies the power to the load side.

This electric power circuit device 55 includes a plurality of substations 5.
This is a circuit that outputs three-phase power selected from 1 to 53 to the transformer 56. Each output terminal 5 of the power switching circuit 54
7, 58 and 59 are connected to terminals 63, 64 and 65 of the transformer 56 via connection conductors 60, 61 and 62, respectively.

The connecting conductors 60 to 62 of the power circuit device 55 having the above-described structure are electrically connected to the output terminals 57 to 58 by a strong mechanical contact at the time of assembly. It is required that repair, modification, and replacement of parts with degraded characteristics be easy. Further, each of the connection conductors 60 to 62 is provided in an insulating gas atmosphere of a predetermined pressure in order to prevent discharge from occurring due to high humidity or temperature change. The insulating gas atmosphere having a predetermined pressure is formed by providing the entire connecting conductors 60 to 62 in the leaf spring pipes 67, 68, 69. The leaf-spring-like pipes 67 to 69 are in the most contracted state when not fixed, and are forcibly used in the expanded state when fixed to form the insulating gas atmosphere.

In the power circuit device having such a structure, when the characteristics of the transformer deteriorate due to long-term use and it is time to replace the transformer 56, the transformer is replaced as follows. First, since the leaf spring-like pipes 67 to 69 are filled with the insulating gas, the gas is vented to remove the leaf spring-like pipes 67 to 69. Next, by removing the ends of the connecting conductors 60 to 62 on the transformer 56 side from the terminals 63 to 65, the transformer 56 becomes free, and the free transformer 56 is replaced with an improved transformer. In this way, maintenance of the transformer is performed.

[0006]

However, since the leaf spring pipes 67 to 69 are forcibly expanded and filled with the insulating gas, they are firmly and airtightly attached to the terminals. There is a possibility of an explosion accident during removal work. Furthermore, the attachment part is destroyed by the removing work, and it is difficult to reuse. Furthermore, since the leaf spring function is deteriorated due to the long-term exposure to the rain, the pipes 67 to 69
Had a problem of safety due to the leakage of the insulating gas remaining in the pipes 67 to 69. Moreover, since such leaf spring-like pipes 67 to 69 are expensive and the power supply cost for electric power is high, a measure for reuse is required. That is, the conventional power circuit device 55
Has a problem that maintenance costs are high and maintenance work such as repair and modification is difficult.

The present invention has been made to solve the above-mentioned conventional problems, and has a low maintenance cost, is easy to attach / detach even after long-term use, and is easy to perform maintenance work such as disassembly, repair, and modification. An object is to provide a method for assembling a circuit device and a power circuit device.

[0008]

In order to achieve the above object, the present invention provides a power circuit device and a method of assembling the power circuit device having the following configurations.

That is, in the power circuit device according to the first aspect, the first terminal to which the power is supplied, the second terminal for receiving the power from the first terminal, the first terminal and the second terminal.
It is characterized in that it is provided with a connecting conductor which is inserted between the terminals and is detachably connected, and an airtight box which hermetically covers the periphery of the connecting conductor and at least a part of which is a bellows wall surface.

According to the first aspect of the present invention, the connection conductor, which is inserted between the first terminal and the second terminal and is detachably connected, and the periphery of the connection conductor are airtightly covered, and at least a part thereof is provided. Since it has an airtight box with a bellows wall surface, it is possible to obtain a power circuit device which is inexpensive, easy to attach and detach even after long-term use, and easy to maintain and modify.

A power circuit device according to a second aspect of the present invention is the power circuit device according to the first aspect, wherein one end of the bellows wall surface is airtightly fixed and the other end is detachably attached airtightly. .

According to the invention of claim 2, since the other end side of the bellows wall surface is detachably and airtightly attached, the cost is low, and the bellows is connected only by expanding and contracting from the detachable end portion during maintenance. Since the conductor is exposed, maintenance and modification can be easily performed.

A power circuit device according to a third aspect is the power circuit device according to the first or second aspect, wherein the airtight box is filled with an insulating gas.

According to the invention of claim 3, since the airtight box is filled with the insulating gas, electric power can be stably transmitted without being discharged even in a high humidity season.

A power circuit device according to a fourth aspect is the power circuit device according to the first and second aspects.
Alternatively, in the power circuit device according to 3, the connection conductor is
A first conductor component, one end of which is detachably fixed to the first terminal with a fitting structure and electrically connected thereto, and one end of which is electrically attached to the second terminal with a fitting structure being detachably fixed. Electrically connected second conductor parts and relay conductors electrically connected between the other end sides of the first and second conductor parts, respectively.

According to the fourth aspect of the present invention, the connection conductor has a first conductor part whose one end side is detachably fixed by the fitting structure and a second conductor part whose one end side is detachably fixed by the fitting structure. Since the relay conductors are respectively provided between the conductor component and the other end sides of the first and second conductor components, disassembling and assembling are accurate and quick and reliable electrical connection can be obtained.

A method of assembling the power circuit device according to claim 5 is as follows.
The power circuit device according to claim 1, 2, 3 or 4,
A guide is provided on the wall surface of the bellows so that the bellows wall surface moves in the expansion / contraction direction when the detachable attachment portion becomes a free end.

According to the fifth aspect of the invention, since the guide is provided on the wall surface of the bellows so as to move in the expansion / contraction direction, the expansion / contraction direction does not meander and the bellows does not deform. Therefore, even if it is used for a long period of time, it is easy to move in the expansion / contraction direction.

A method of assembling the power circuit device according to claim 6 is as follows.
A first terminal to which electric power is supplied, a second terminal that receives electric power from the first terminal, and a first terminal and a second terminal that are inserted and detachably connected to each other A method for assembling a coupling structure device for a power circuit, comprising: a connection conductor; and an airtight box that hermetically covers the periphery of the connection conductor and at least a part of which is a bellows wall surface. A connecting conductor assembling step of assembling the connecting conductor between the first terminal and the second terminal in a moved state, and, after assembling the connecting conductor, moving the bellows wall surface in the extending direction to obtain an airtight box as the airtight box. And a step of wearing.

According to the sixth aspect of the present invention, the connecting conductor is assembled in the open state in which the bellows wall surface is moved in the contracting direction. Therefore, the assembling and disassembling work is easy and quick.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of a power circuit device of the present invention will be described with reference to FIG. The same parts as those in FIG. 7 are designated by the same reference numerals, and the detailed description thereof will be omitted because the description is redundant. The power circuit device 1 of this embodiment is the power circuit 2 in which electric power from a selected substation out of the substations 51 to 53 is supplied from the output terminals 57 to 59 to the terminals 63 to 65 of the transformer 56. This power circuit 2 is illustrated with three terminals because the power from the substations 51-53 is three-phase power.

The power transmission paths of the respective phases are composed of detachable connection conductors 3, 4, 5 assembled so as to pass a current to the terminals 63 to 65 of the transformer 56 which receives the electric power from the output terminals 57 to 59. , And at least one end side thereof is detachably attached in an airtight manner so that the periphery of each of the connection conductors 3 to 5 is airtight.

Each of the connecting conductors 3 to 5 is made of a good conductor such as aluminum (Al), and is used for assembly work, repair work,
It is divided into multiple parts to facilitate maintenance work such as remodeling work. The above maintenance work such as assembly work, repair work, and modification work is different from the work of manufacturing all from the base, and, for example, the output terminals 57 to 58 and the terminals 63 to 65 of the transformer 56 are not disassembled and remain. Maintenance work such as assembling work, repair work, and modification work is performed only within the range of the connection conductors 3 to 5. By making each of the connection conductors 3 to 5 into a plurality of parts, the maintenance work can be easily performed even in a relatively narrow area, and highly reliable electrical contact can be achieved.

At least a part of each of the airtight boxes 6 to 8 is, for example, a stretchable bellows (bellows) wall surface, is hermetically sealed by surrounding each of the connection conductors 3 to 5, and one end side is detachable. Is. Each airtight box 6-8, whose one end is detachable, is moved in the contraction direction during maintenance work,
The connection conductors 3 to 5 are exposed to facilitate the work. That is,
The expandable airtight boxes 6 to 8 are used in a stretched state when attached so as to form an airtight atmosphere, and are used in a contracted state during maintenance.

The connection conductors 3 to 5 in the airtight boxes 6 to 8
The surroundings are filled with an insulating gas, eg SF ₆ gas, in order to avoid discharging. Each of the airtight boxes 6 to 8 is provided with guides 9, 10 and 11 so that extension and movement can be stably and easily performed during maintenance of the power circuit 2.

Next, a specific embodiment of the power circuit 2 is shown in FIG.
Will be described with reference to. FIG. 2 is a diagram mainly showing the power circuit 2 of one connecting conductor 3 (4,5).

Each of the connecting conductors 3 (4,5) has a cylindrical first conductor part 16 having a male fitting portion 15 whose one end, for example, the upper end is thin and has a substantially conical shape, and a female fitting portion at the lower end. It is composed of a cylindrical second conductor component 18 having 17 and a relay conductor 19 interposed between the first and second conductor components 16 and 18 and electrically contacting each other. The male fitting portion 15 of the first conductor component 16 has a male and female fitting structure so as to be attachable to and detachable from each of the output terminals 57 to 59, and has a small contact resistance and sufficiently secures a current capacity. Therefore, the fitting part is wide, and the shape and size are selected so that the fitting part is in perfect contact. The fitting structure of each output terminal 57 to 59 is processed into a female coupling conductor 70 shown by a dotted line in FIG.

On the contrary, the terminals 63 to 65 of the transformer 56 fitted to the second conductor component 18 having the female fitting portion 17 are fitted.
2 is shown by a dotted line in FIG. 2, and is processed into a male coupling conductor 71. The male coupling conductor 71 and the female fitting portion 17
The second conductor component 18 having a male and female fitting structure is formed to have a detachable structure, has a small contact resistance, and has a wide fitting portion to secure a sufficient current capacity. The shape and size are selected so that the fitting parts fit together perfectly.

Ensuring sufficient current capacity means substations 51 to 5
3 to have sufficient electrical contact area to carry the current. In this embodiment, the second conductor component 18 has a cylindrical shape, but may have a diameter having a current capacity such as a cylindrical shape. Furthermore, in this embodiment, the mating structure of the first and second conductor parts 16, 18 is electrical connection and fixing. In order to electrically connect and fix the first and second conductor parts 16 and 18, in addition to a fitting structure, a screwing structure, for example, a male fitting part 15 is processed into a bolt shape, and a female coupling conductor 70 is screwed. Has a threaded structure that is processed into a nut shape.
The female fitting portion 17 of the conductor component 18 is processed into a nut shape,
The male coupling conductor 71 may be processed into a bolt shape to have a screwed structure.

The relay conductor 19 provided between the first and second conductor parts 16 and 18 has, for example, a cross section U for electrically connecting and fixing the first and second conductor parts 16 and 18. It is a letter-shaped part. First conductor component 16
From the relay conductor 1 for passing a current from the second conductor component 18 to
9 is aligned in a state of slidingly contacting the contact surfaces of the first and second conductor components 16 and 18, and is detachably fixed, for example, screwed by a screw 21. This U-shaped relay conductor 19
The auxiliary conductor 22 for securing the current capacity is attached to the screw 2
The first head is positioned so as to avoid the first head and is buried, and is detachably fixed, for example, screwed by a screw 23. Although the auxiliary conductor 22 has a U-shaped structure for screwing the relay conductor 19, any other detachable fixing means may be used, and for example, the auxiliary conductor 22 may be formed by a conductor of a mass of conductors.

Connection conductor 3 (4,5) having such a structure
Are installed in an atmosphere of insulating gas so that each airtight box 6
The airtight container according to 8 is configured as follows. Since each of the airtight boxes 6 to 8 is provided for maintenance work such as repair and modification, it is desirable to select a size necessary for the work. In the airtight container in this embodiment, about half is made up of the airtight boxes 6 to 8, and the other half is made up of a fixed cylindrical container 73.

Next, an embodiment of the airtight container by the expandable airtight boxes 6 to 8 will be described. That is, the expandable airtight box 6
~ 8, when attached to form an airtight atmosphere,
It is used in a stretched state and in a contracted state during maintenance. It is desirable that at least a part of the airtight boxes 6 to 8 be formed by the bellows wall surface 25. At both ends of the cylindrical bellows wall surface 25, an annular mounting plate 26,
It is fixed airtight to 27. One annular mounting plate 2
7 is aligned with the support 74 of the transformer 56 and is detachably fixed, for example, by a screw 28.

The annular mounting plate 26 is used for the cylindrical container 7
It is aligned with the end of 3 and is detachably fixed, for example, by a screw. At the end of the cylindrical container 73, the following coupler 30 is provided for detachably attaching the cylindrical bellows wall surface 25. This coupler 30 has a structure in which annular mounting plates 31, 32 and 33 are superposed. The annular mounting plate 31 is aligned and fixed to the end of the cylindrical container 73. An annular mounting plate 32 is aligned with the annular mounting plate 31 so as to be detachably and airtightly fixed, for example, screwed by a screw 35.

The annular mounting plate 32 includes an annular mounting plate 33.
Are aligned, detachably and airtightly fixed, for example, screwed by screws 36. An annular mounting plate 26 to which the bellows wall surface 25 is attached is aligned with the annular mounting plate 33 so as to be detachably and airtightly fixed, for example, screwed with a screw 37.

In the above-mentioned embodiment, a good sealing effect can be obtained by interposing an O-ring at the place to be fixed airtightly. The airtight fixing points are, for example, between the opposing surfaces of the annular mounting plates 31 and 32, and the annular mounting plate 32.
And between the opposing surfaces of the annular mounting plates 33 and 26, between the opposing surfaces of the annular mounting plate 27 and the support plate 74, and the like.

By loosening the screw 37 and freeing the annular mounting plate 26 from the annular mounting plate 33, the connecting conductor 3
(4, 5) is exposed to facilitate maintenance work. At this time, the bellows wall surface 25 becomes movable in the contracting direction (opening direction). However, since the bellows wall surface 25 is expandable and contractible, the orbit when it moves moves to the left and right. Guides are provided for such left and right movements of the bellows wall surface 25 to make it difficult to move the bellows wall surface 25 in the expansion and contraction direction.

This guide is, for example, a track guide mechanism 42 formed by coupling a bolt 40 and a nut 41. By disposing the track guide mechanism 42 at a plurality of positions, for example, four positions, with respect to one bellows wall surface 25, it is possible to easily perform balanced expansion and contraction movement. By connecting the bolt 40 to the rotary shaft of the motor and rotating the bolt 40, the bellows wall surface 25 can be automatically opened and closed. The trajectory guide mechanism 42 may be provided at one place.

That is, the airtight box is a bellows wall surface 25, annular mounting plates 26, 27, 33, 32, 31, support 74,
The output terminals 57 to 59 shown in FIG. Insulating gas is enclosed in the airtight box so that the connecting conductor 3 (4,
An insulating gas atmosphere is formed around 5). Each terminal 63 of the transformer 56 including the male coupling conductor 71 shown in FIG.
2 to 65 are shown in a state of being supported by the support 76 in FIG.

The power circuit device 1 configured as described above is
A side view in which three-phase electric power is arranged for one transformer 56 is shown in FIG. 3, and a top view thereof is shown in FIG.

In the above-described embodiment, an embodiment in which the fitting portion of the first conductor component 16 is a male type and the fitting portion of the second conductor component 18 is a female type has been described. The fitting portion of the conductor component 16 may be female and the fitting portion of the second conductor component 18 may be male, or the first and second conductor components 1 may be formed.
The fitting portions of both 6 and 18 may be male or female.

Further, in the above embodiment, the connection conductor 3
Regarding (4,5), first and second conductor parts 16, 1
Although the case composed of 8, the relay conductor 19 and the auxiliary conductor 22 has been described, the flanges 44 and 45 are integrally provided on the facing surfaces of the first and second conductor components 16 and 18 as shown in FIG. A configuration in which a relay conductor with a flange 46 is inserted between the flanges 44 and 45 and fixed by a screw 47 may be adopted. The flanged relay conductor 46 may also be configured by providing a flangeless relay conductor 48 as shown in FIG. 6 by providing three or more fastening portions with screws 47. In the embodiments shown in FIGS. 5 and 6, since the flanges 44 and 45 project, if there is a possibility of discharging when a high voltage is transmitted, it is desirable to process the corners into curved surfaces.

Next, an embodiment of the power circuit 2 will be described with reference to FIG. An example of the power circuit 2 when the power of 130 kv / 35 MvA is supplied from the substation to the power circuit 2 is as follows. The first conductor component 16 is a cylindrical aluminum rod having a diameter of 80 mm and a length of 400 mm. The second conductor component 18 is a cylindrical aluminum rod having a diameter of 130 mm and a length of 250 mm. The size of the cylindrical bellows wall surface 25 is made of aluminum having a diameter of 500 mm and a length of 230 mm. Output terminals 57 to 59 of the first conductor component 16
The length of the sliding contact portion with is 80 mm. Second conductor component 18
The length of the sliding contact portion with the terminals 63 to 65 is 50 mm. The length of the relay conductor 19 is 150 mm. The insulating gas is
SF6, which is an incombustible gas, is desirable, and the pressure is preferably 3 to 5 atmospheres.

Next, regarding the maintenance process of the power circuit 2 shown in FIG. 2, an embodiment of disassembling will be described with reference to the process chart of FIG. 7, and an embodiment of assembling will be described with reference to the process chart of FIG. The description of the same parts as those in FIG. 1 and FIG.

First, the disassembling method will be described. Confirm that the breaker is set to the open state (P-1). Screw 3
Insulating gas is leaked to the outside in the process of freeing the annular mounting plate 26 attached to the bellows wall surface 25 after starting to loosen (P-2). After the airtight Hakouchi becomes normal pressure,
The annular mounting plate 26 of the bellows wall surface 25 which has become free is moved in the contracting direction (downward) along the guides 9 to 11,
The bellows wall surface 25 opens. As a result, the connection conductor 3 (4,
5) is exposed (P-3). Next, the screw 23 is loosened and the auxiliary conductor 22 is disassembled (P-4). Next, screw 21
Is loosened, and the relay conductor 19 is disassembled (P-5).

Next, the male fitting portion 15 fitted to the coupling conductor 70 is pulled out to remove the first conductor component 1.
6 is dismantled (P-6). Next, the second female structure
The connection conductors 3 to 5 are easily disassembled by pulling out the conductor component 18 from the coupling conductor 71 of the transformer 56 (P-7).

Next, the assembling method will be described with reference to FIG. By rotating the guides 9 to 11, the bellows wall surface 25 is
It is moved in the contracting direction, that is, the opening direction (P-11). The first conductor component 16 is inserted into the female fitting portion of the coupling conductor 70 and temporarily fixed with the male fitting portion 15 facing upward (P-1).
2). In this state, the female fitting portion 17 of the second conductor component 18
Is moved downward, fitted into the coupling conductor 71 of the transformer 56, and temporarily fixed (P-13).

Temporarily fixed first and second conductor parts 1
Relay conductor 1 at the position (P-14) fitted between 6 and 18
9 is the first and second conductor parts 16 and
It is fixed at 18. As a result, the first and second conductor parts 16 and 18 do not fall off from the terminals 57 to 59 and 63 to 65 shown in FIG. 1 even if there is vibration or earthquake (P-15).

Further, the auxiliary conductor 22 is inserted into the relay conductor 19 and fixed by the screw 23 (P-16). afterwards,
The bolt 40 is rotated to move the bellows wall surface 25 in the extending direction, and the annular mounting body 26 is airtightly fixed to the annular mounting body 33 with the screw 37 to form an airtight box (airtight container) (P-17).

Thereafter, an insulating gas such as S is placed in the airtight box.
After enclosing F ₆ (P-18) and making the surroundings of the connecting conductors 3 to 5 an insulating gas atmosphere, power transmission is started.

In the above embodiment, the embodiment in which the first conductor component 16 is incorporated first has been described, but the second conductor component 18 may be incorporated first. Furthermore, in the above embodiment, the power circuit device that supplies the power from the substation to the transformer has been described, but the present invention can be applied to any circuit as long as it is a power circuit provided in an insulating gas atmosphere.

According to the above-described embodiment, since the connecting conductor is composed of a plurality of parts and at least a part of the airtight box wall for forming the insulating gas atmosphere is composed of the bellows wall surface, it is possible to disassemble, repair, or install a new transformer. Maintenance work such as replacement and modification can be performed easily and quickly at low cost.

[0052]

As described above, according to the present invention, the maintenance cost is low, the attachment / detachment is easy even after a long period of time, and the maintenance such as repair and modification is easy.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of a power circuit device according to the present invention.

FIG. 2 is an explanatory diagram for specifically explaining the power circuit of FIG.

FIG. 3 is a diagram for explaining a mounted state of the power circuit of FIG.

FIG. 4 is a plan view of FIG.

FIG. 5 is a view for explaining another embodiment of the connection conductors 3, 4, 5 of FIG.

6 is a view for explaining another embodiment of the connection conductors 3, 4, 5 of FIG.

FIG. 7 is a diagram for explaining an embodiment of a disassembling process by the method of assembling the power circuit device according to the present invention in the order of processes.

FIG. 8 is a view for explaining the embodiment of the method for assembling the power circuit device according to the present invention in the order of steps.

FIG. 9 is a diagram for explaining a conventional power circuit device.

[Explanation of symbols]

1 ... Power circuit device, 2 ... Power circuit, 3, 4, 5 ... Connection conductor, 6, 7, 8 ... Airtight box, 9, 10, 11 ... Guide, 1
5 ... Male fitting part, 16 ... First conductor part, 17 ... Female fitting part, 18 ... Second conductor part, 19, 48 ... Relay conductor,
21, 23, 35, 36, 37, 47 ... Screw, 22 ... Auxiliary conductor, 25 ... Bellows wall surface, 26, 27, 31, 3
2, 33, 35, 36 ... Annular mounting plate, 30 ... Coupler,
40 ... Bolts, 41 ... Nuts, 42 ... Orbit guide mechanism, 4
4, 45 ... Flange, 46 ... Relay conductor with flange, 5
1, 52, 53 ... Substation, 56 ... Transformer, 57, 5
8, 59 ... Output terminals, 63, 64, 65 ... Terminals, 70 ...
Female fitting part, 73 ... Cylindrical container, 74 ... Support, 76 ...
support.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasuhiko Fujiki             66-2 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture             Engineering Co., Ltd. F-term (reference) 5G017 FF02 FF07                 5G375 BA09 BA26 DB05 DB35

Claims (6)

[Claims] 1. A first terminal to which electric power is supplied, a second terminal which receives electric power from the first terminal, and a first terminal and a second terminal which are inserted and removed. An electric power circuit device comprising: a freely connected connecting conductor; and an airtight box that hermetically covers the periphery of the connecting conductor and at least a part of which is a bellows wall surface. 2. The power circuit device according to claim 1, wherein one end side of the bellows wall surface is airtightly fixed, and the other end side is detachably attached airtightly. 3. The power circuit device according to claim 1, wherein the airtight box is filled with an insulating gas. 4. A first conductor component, one end of which is detachably fixed to the first terminal in a fitting structure and electrically connected to the first terminal, and the other end of the connecting conductor is fitted to the second terminal. A second conductor component that is detachably fixed and electrically connected by a structure, and a relay conductor that is electrically connected between the other end sides of the first and second conductor components, respectively. The power circuit device according to claim 1, 2 or 3, wherein 5. The bellows wall surface is provided with a guide so as to move in the expansion and contraction direction when the detachable attachment part becomes a free end. Power circuit device. 6. A first terminal to which electric power is supplied, a second terminal which receives electric power from the first terminal, and a first terminal and a second terminal which are inserted and removed between the first terminal and the second terminal. A method of assembling a coupling structure device for a power circuit, comprising: a connection conductor freely connected; and an airtight box that hermetically covers the periphery of the connection conductor and at least a part of which is a bellows wall surface. A connecting conductor assembling step of assembling the connecting conductor between the first terminal and the second terminal in a state where the wall surface is moved in the contracting direction; and, after assembling the connecting conductor, moving the bellows wall surface in the extending direction to perform the airtightness. A method of assembling a power circuit device, comprising a step of airtightly attaching as a box.