JP7308787B2 - Oil-immersed transformer and its parts replacement method - Google Patents

Description

The present invention relates to an oil-filled transformer and a method for replacing parts thereof.

Patent document 1 is an example of a conventional oil-filled transformer. In order to prevent the transformer body from moving inside the tank, the transformer body and the lid are connected by connecting bolts, and the connecting bolts are used as tension rods so that the transformer body is attached to the bottom plate of the tank. A structure is disclosed that presses against and secures against the bottom plate.

JP 2015-192140

According to JEC-2200, the expected service life of an oil-immersed transformer is about 30 years at an ambient temperature of 25°C, and it is determined by the degree of deterioration of the tensile strength of the insulating paper of the coil. However, other parts that make up the transformer may reach the time of replacement earlier than this expected life. In particular, covers with bushings and cover gaskets cannot be replaced without first digging up the contents with a crane. In particular, in order to replace the cover of a transformer in which the cover is fixed with studs as in Patent Document 1, it is necessary to open the connection between the bushing and the line wire and remove the connection of the stud that connects the cover and the contents. There is However, at the site, the connection between the stud that connects the cover and the contents, the line wire of the contents, and the bushing cannot be removed at the same time. Therefore, the work from removal to reconnection cannot be performed continuously, resulting in poor workability.

In recent years, efforts to reduce the environmental burden have led to the development of transformers that use biodegradable ester oil as insulating oil. Moisture contained in the insulating paper is one of the causes of deterioration of the insulating paper. Since ester oil has a high saturated moisture content, it can hold a lot of moisture, so it is said that it absorbs the moisture of the insulating paper and contributes to the suppression of deterioration. Therefore, ester oil is expected to have a longer life than mineral oil.

In the future, if the market introduction of transformers that use ester oil increases, it is expected that the frequency of parts replacement will increase due to longer life, so it is necessary to propose a structure that simplifies cover replacement work. There is

SUMMARY OF THE INVENTION An object of the present invention is to provide an oil-filled transformer capable of simplifying parts replacement work.

A preferred example of the present invention includes a cover, a bushing, a tank for containing contents, a stud connecting the cover and the contents, and an adapter fixed to the stud,
The adapter is
The oil-filled transformer has a rectangular ring-shaped support portion capable of supporting the content support jig for supporting the content.

ADVANTAGE OF THE INVENTION According to this invention, the oil-immersed transformer which can simplify the replacement|exchange work of components can be implement|achieved.

Explanatory drawing of the cover exchange work process in a comparative example. The figure which shows the work process in a comparative example. The figure which shows the detail of the connection part of the cover of an oil-immersed transformer, and a stud. FIG. 2 is a diagram showing the stud structure of the oil-filled transformer of Example 1; FIG. 4 is a diagram showing a work process for exchanging the cover of the oil-filled transformer on site according to the first embodiment; FIG. 4 is a diagram showing a state in which a content supporting jig is inserted into the adapter in Embodiment 1; The figure which looked at FIG. 6 from the side. The figure which shows the stud structure of the oil-filled transformer of Example 2. FIG. The figure which shows the adapter structure of Example 3. FIG.

Prior to describing examples of the present invention, comparative examples will be described first. 1 to 3 are diagrams showing comparative examples. The procedure for replacing the cover at the site will be described with reference to FIGS. 1 to 3. FIG. FIG. 1 shows an example of an explanatory diagram of the on-site cover replacement work process for an oil-immersed transformer.

A crane lifts the contents of the oil-filled transformer. (S201)
After being lifted, the operator inserts a sleeper 107 between a cover 105 that covers the top of the oil-filled transformer and a flange of a tank 106 that stores the contents of the oil-filled transformer. (S202)
Here, the sleeper is a support base for preventing deformation of the tank 106 and for stably working.
The connection between the bushing 108, which is the input/output terminal of the oil-filled transformer, and the line wire 109 is removed by the operator. (S203)
The worker once removes the sleeper 107, and the contents are returned into the tank 106 by a crane. (S204)
An operator opens the handhole cover of the cover 105 and disconnects the connection between the cover 105 and the stud 110 . (S205)
The operator removes the old cover 105 . Then, a new cover 105 is attached, the new cover 105 and the stud 110 are connected, and the handhole cover is closed. (S206)
The contents are lifted again by the crane, and the sleeper 107 is inserted by the operator. (S207)
Bushing 108 and line wire 109 are reconnected by the operator. (S208)
The sleeper 107 is removed by the operator and the contents are returned to the original tank by a crane. (S209)

FIG. 2 is a diagram showing the work process (S202) of FIG. 1, which is a comparative example. In the work step (S201), after the contents including the iron core 101, the coil 102, the fastener 103, etc. are lifted by the wire 104, the sleeper 107 is placed between the cover 105 and the flange of the tank 106.

Then, after curing with a sheet or the like, the connection between the bushing 108 and the line wire 109 is removed. Curing here means to prevent chips and the like from falling into the tank at the connection between the stud 110 and the cover 105 and the connection between the bushing 108 and the line wire 109 . Refers to laying the sheet under the joint.

In order to remove the cover 105, it is necessary to remove the connection between the cover 105 and the stud 110, but as shown in FIG. When the nut 112 on the upper side is removed while supporting the 105, the contents themselves cannot be supported and fall down.

Therefore, in order to remove the connection with the cover 105, it is necessary to return the contents to the tank 106 once. In this case, after replacing the cover 105 with a new one, the stud 110 and the cover 105 are connected again, the contents are lifted by a crane, the sleeper 107 is rearranged, and the bushing 108 and the line 109 are connected. Therefore, a series of operations from removing the cover 105 to attaching a new cover 105 to connecting the bushing 108 and the line wire 109 cannot be performed continuously, resulting in poor work efficiency.

In this embodiment, after the contents are lifted once, the lifted state of the contents is maintained so that the replacement work of the cover 105 can be continuously performed, thereby improving the efficiency of the on-site replacement work.

Examples are described below with reference to the drawings.

FIG. 4 shows the structure of the stud of the oil-filled transformer of Example 1. As shown in FIG. The oil-filled transformer of Example 1 has an adapter 202 fixed to the stud 110 .

Studs 110 are posts that connect the contents and cover 105 . Here, the content is the content of the transformer, and is a group of parts that constitute the transformer including the coil 102, the iron core 101, the fastener 103, and the line wire 109 housed in the tank.

An adapter 202 having a rectangular annular shape (supporting portion) is provided in which a support jig 201 made of steel or the like is inserted and supported. The adapter 202 and the jig 201 for supporting the contents can maintain the state in which the contents are lifted.

The mounting position of the adapter 202 is determined by inserting the contents supporting jig 201 and determining a position where the coil 102 of the contents does not protrude above the oil level in the tank 106 when the suspended state is maintained. The adapter 202 is fixed at the position of the stud 110 . This is to prevent the coil from being exposed to the outside air and the insulation performance from deteriorating.

FIG. 4 shows the configuration of the connecting portion between the cover 105 and the stud 110 of the oil-filled transformer in this embodiment. The stud 110 penetrates the cover 105 and is connected with a nut 112 to a hanging ear 111 fixed to the cover 105 . That is, the stud 110 and the cover 105 are connected via the hanging ear 111 and the nut 112 . Further, the stud 110 penetrates the adapter 202 of this embodiment, and the jig 201 for supporting the contents is shaped to avoid the stud 110 .

5 and 6, a method of replacing parts of an oil-immersed transformer such as a cover on site will be described. FIG. 5 shows an example of an explanatory diagram of the on-site cover replacement process for an oil-immersed transformer when the structure of the first embodiment is used.

A crane lifts the contents of the oil-filled transformer. (S301)
After being lifted, the worker inserts the contents supporting jig 201 into the support portion of the adapter 202 that can support the contents supporting jig 201 , thereby supporting the adapter 202 . It is installed on the flange of the tank 106 . (S302)
The operator disconnects the bushing 108 and the line wire 109 . (S303)
The worker removes the connection between the cover 105 and the stud 110 . (S304)
An operator removes the old cover 105, attaches a new cover 105, connects the new cover 105 and the stud 110, and attaches the handhole cover. (S305)
Here, the handhole is open for the operator to put his/her hands in to extract oil for maintenance, to change the tap voltage of the transformer, and to operate the tap changer inside. is a hole. A handhole cover is a cover that covers a handhole.

The operator reconnects bushing 108 and line wire 109 . (S306)
Here, the line wire 109 is a lead wire through which current flows through the coil.
The operator removes the contents supporting jig 201 from the supporting portion of the adapter 202 that can support the contents supporting jig, and the contents are returned to the original position in the tank. (S307)

The work of the above workers may be replaced by machines such as cranes.

The work process (S302) will be described below with reference to FIGS. 6 and 7. FIG.

FIG. 6 shows a state in which the contents supporting jig 201 is installed on the flange of the tank 106 after lifting the contents. After the parts have been replaced, the oil-filled transformer has the structure shown in FIG.

In order to maintain the state of the contents lifted in the work step (S301), as shown in FIG. be.

In this embodiment, as shown in FIGS. 6 and 7, four studs are used, but the number of studs may be four or more.

In this embodiment, the cover 105 is used as an example of the parts to be replaced. However, the present invention can be applied not only to the cover 105 but also to the case where the gasket (sealing material) attached to the cover 105 and the bushing 108 are replaced with new ones.

6 and 7, unlike the comparative example, even if the connecting portion between the cover 105 and the stud 110 is removed, the contents do not fall down and the suspended state is maintained by the contents supporting jig. , the connecting portion between the bushing 108 and the line wire 109 and the connecting portion between the cover 105 and the stud 110 can be removed and reconnected to a new one continuously. Furthermore, compared to the comparative example of FIG. 1, the number of times of crane work can be reduced, so the work can be simplified.

FIG. 8 shows the structure of the stud of the oil-filled transformer of Example 2. As shown in FIG. Descriptions of the same configurations as those of the first embodiment are omitted, and different points are described.

The stud structure of the oil-filled transformer of the second embodiment has a structure in which the stud 110 is split. It has a structure that can be inserted and the contents can be maintained in a suspended state. When the stud 110 penetrates the adapter 202 as in the first embodiment, the jig 201 for supporting the contents must be shaped to avoid the stud. On the other hand, in the case of the present embodiment, there is no such restriction on the shape, and the flexibility of the shape of the jig 201 for supporting the contents is high.

FIG. 9 shows the structure of the adapter of Example 3. As shown in FIG. Descriptions of the same configurations as those of the first embodiment are omitted, and different points are described.

The adapter structure of Example 3 is a structure in which two adapters 401 are arranged on the left and right sides from one stud 110 and the studs 110 do not pass through the adapters 401 . Therefore, it is possible to insert not only one but also a plurality of jigs 201 for supporting contents.

Moreover, unlike the first embodiment, there is no restriction on the shape of the jig 201 for supporting the contents, and the degree of freedom of the shape of the jig 201 for supporting the contents is high as in the case of the second embodiment. Furthermore, according to this embodiment, since a plurality of jigs 201 for supporting the contents can be inserted, the load can be distributed and the contents of the oil-filled transformer can be supported more stably.

In the above examples, soybean oil, which is a natural ester oil, was used as the insulating oil, but rapeseed oil, which is a natural ester oil, or mineral oil may also be used.

101 Iron core 102 Coil 103 Fastener 104 Wire 105 Cover 106 Tank 107 Sleeper 108 Bushing 109 Line wire 110 Stud 111 Hanging ear 112 Nut 201 Content supporting jig 202 Adapter 401 Adapter of Example 3

Claims (6)

a cover, a bushing, a tank containing contents, a stud connecting the cover and the contents, and an adapter fixed to the stud,
The adapter is an oil-filled transformer having a rectangular ring-shaped support portion capable of supporting a content supporting jig for supporting the content. In the oil-filled transformer according to claim 1,
Said contents are
a coil;
iron core and
An oil-filled transformer including line wires that connect with the coil. In the oil-filled transformer according to claim 1,
An oil-filled transformer in which the stud passes through the adapter. In the oil-filled transformer according to claim 1,
An oil-filled transformer in which the adapter and the stud are fixed by welding. In the oil-filled transformer according to claim 1,
An oil-immersed transformer in which a plurality of said adapters are fixed to said studs. An oil container having a cover, a bushing, a tank for containing a content, a stud connecting the cover and the content, and an adapter fixed to the stud and having a support portion capable of supporting a jig for supporting the content. A method for replacing parts of a transformer,
the contents are removed from the tank;
the insert supporting jig is inserted into the supporting portion of the adapter;
parts are replaced
the insert support jig is removed from the support portion of the adapter;
A method for replacing parts in an oil-filled transformer in which the contents are returned to the tank.

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