JPH0544166B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for assembling a split transformer in which a plurality of split unit transformers are connected by a connecting duct having built-in leads.

[Technical background of the invention]

In recent years, transformers have become larger and have a larger capacity. For example, transformers used for 500kV class power transmission have a single unit capacity of 1500/3MVA to 2000/3MVA per unit, which reduces the size for transportation. Due to constraints, the single-phase converter is divided into two or three parts. Furthermore, 1000kV class power transmission transformers also have a structure in which a single-phase transformer is divided into two to four parts.

In order to reduce the work required for on-site assembly of such split transformers, each split unit transformer is transported with its contents assembled, and then transported to the site where the transformer is to be installed, such as a substation. In general, an assembly method is adopted in which each unit transformer is connected in parallel via a connecting duct with built-in leads.

FIG. 1 shows a schematic connection state in a split type transformer. In the figure, 1A and 1B are unit transformers to be connected to each other, and this has an iron core 3 and a winding 4 housed inside a tank 2 together with insulating oil.
Further, 5 is a connection duct, and 6 is a lead provided inside the connection duct 5. When assembling the transformer, the connecting duct 5 is installed across the tanks 2 of each unit transformer 1A and 1B, and the lead 6 provided inside this connecting duct 5 is connected to one unit transformer 1.
The high voltage side terminal portion of the winding 4 in A is connected in parallel to the high voltage side terminal portion of the winding 4 in the other unit transformer 1B. The high voltage side terminal portion of the winding 4 of the other transformer 1B is drawn out to the outside through a bushing pocket 7 provided in the tank 2. Further, the inside of the connecting duct 5 is filled with insulating oil similarly to the tank 2.
Note that the intermediate voltage side terminal portion and the low voltage side terminal portion of each unit transformer 1A, 1B are similarly connected in parallel via a connection duct (not shown).

Therefore, in the unit transformer connection, 500kV
In transformers, insulation can be achieved simply by passing the insulated leads through the connection duct, but in 1000kV class high voltage transformers, multiple layers of insulation surrounding the leads are installed inside the connection duct to provide greater insulation strength. A configuration with a barrier is adopted.

FIG. 2 shows a connection using a connecting duct with multiple barriers. Metal connection duct 5
has a shape in which both ends are open and both ends are bent upward, and this connecting duct 5 connects each unit transformer 1.
Attach the openings at both ends to the connection ports 8 formed in the tanks 2 of A and 1B by tightening bolts. The lead 6 is coated with an insulating coating 9, and is provided inside the connection duct 5 in a bent state according to its shape, and both ends of the lead 6 are provided as windings in the tank 2 of each unit transformer 1A, 1B. Connect to the high voltage side leads 10, 10 of. The insulating barrier 11 has a cylindrical shape made of a rigid pressboard or the like to provide mechanical strength, and is made up of a plurality of straight members 11a and bending members 11b to be bent according to the shape of the connecting duct 5. It is divided and the ends are overlapped and joined. The insulating barriers 11 are provided in multiple sets inside and outside the connecting duct 5 so as to surround the leads 6 in a plurality of sets having different diameters.
Note that the lead 6 and the insulating barrier 11 are held in the connection duct by a holding member (not shown).

When assembling a conventional transformer, the connecting duct 5 is attached to the tank 2 of the unit transformers 1A, 1B, and the lead 6 is passed through the inside of the connecting duct 5 and connected to the high voltage side lead 10 of the winding. The members 11a and 11b of the insulating barrier 11 were sequentially attached and assembled inside the connecting duct 5 through a working opening 12 such as a manhole formed in the connecting duct 5. Note that the lead 6 is connected by an operator who enters inside the tank 2. That is, the lead 6 itself is flexible and can be bent to fit the connection duct 5, but the barrier 11 is not flexible as a whole and is therefore divided to fit the connection duct 5. Conventionally, the insulation barrier 11 is assembled when assembling the transformer.

[Problems with background technology]

However, in this method of assembling a transformer, since there are many members 11a and 11b that constitute the insulation barrier 11 provided in the connection duct 5, it takes time to assemble the insulation barrier 11, and it takes a long time to assemble the transformer. are doing. The pressboard used for the insulating barrier 11 is dried in advance, but if the assembly process takes a long time even after the drying process, the insulating barrier 11 will be in contact with air for a long time, and the insulating barrier 11 will be It has the disadvantage that it absorbs moisture and impairs the reliability of its insulation. In addition, because split type transformers are tested for performance in the assembled state at the factory, then disassembled, transported, and reassembled on site, the number of disassembly and assembly operations is high, and the insulation barrier 11 must be assembled each time. In addition, since the barrier 11 is exposed to the air, there is a risk that the insulation performance of the connection duct 5, that is, the insulation barrier 11, which was confirmed in a factory test, will deteriorate during on-site assembly.

[Purpose of the invention]

The present invention is an assembly method for connecting unit transformers using a connecting duct having a built-in lead surrounded by an insulating barrier, which provides good assembly work efficiency, reduces the number of assemblies of the insulating barrier, and improves the insulation performance of the insulating barrier. The present invention provides a method for assembling a split type transformer that can maintain the following characteristics.

[Summary of the invention]

The method for assembling a split type transformer of the present invention includes assembling and providing a lead and an insulating barrier inside a connecting duct in advance, and attaching protective covers to openings at both ends of the connecting duct to produce an integrated connecting duct structure, When assembling the transformer, the protective covers are removed from the openings at both ends of the connecting duct, the unit transformer is attached to the tank, and the leads are connected to the winding leads.

[Embodiments of the invention]

The assembly method of the present invention will be described with reference to an embodiment shown in FIGS. 3 and 4. This embodiment is applied to the case where unit transformers are connected in the connection state shown in FIG.

First, the connecting duct structure shown in FIG. 3 is manufactured. That is, the connection duct 5 having the above-described configuration
Prepare. A flow port 13 having a valve 13a is provided in the center of the connecting duct 5. The lead 6 coated with the insulation coating 9 is bent to match the shape of the connection duct 5 and inserted into the connection duct 5.
Next, for example, two sets of insulating barriers 11 having different diameters are placed inside the connection duct 5, and are arranged so as to surround the lead 6 and separate the inside and outside, and a holding member (not shown) such as a spacer is attached to the lead 6. , are appropriately inserted between the insulating barrier 11 and the connection duct 5, and held by the connection duct 5. In this case, the insulating barrier 11 is assembled by first inserting the innermost linear member 11a and then joining the circumferentially divided bent members 11b.
Thereafter, the outer layers are sequentially assembled in the same manner.

Next, the connecting duct 5, the lead 6 built in the connecting duct 5, and the insulating barrier 11 are dried by such means as being housed together in a drying oven, and the insulating barrier 11 is dried.

Next, protective covers 14 made of metal or insulating material are removably attached to the openings at both ends of the connection duct 5 by tightening bolts, and the connection duct 5 is closed.
Close the openings at both ends.

In this way, the lead 6 is inserted into the inside of the connection duct 5.
A connecting duct structure is manufactured in which the connecting duct 5 is integrated with the insulating barrier 11 and the connecting duct 5 is closed with a protective cover 14.

When this connecting duct structure is not used, that is, during storage or transportation, the openings at both ends of the connecting duct 5 are kept closed with the protective cover 14.
In addition, in this case, the flow port 1 provided in the connection duct 5
3 is opened by the valve 13a, and this communication port 13
The air inside the connecting duct 5 is sucked through the connecting duct 5 to create a vacuum state, or the inside of the connecting duct 5 is filled with dry air through the flow port 13.
When assembling a transformer, that is, when assembling a transformer for performance testing at a factory or when assembling a transformer on-site, the above-mentioned connection duct structure is prepared. Then, as shown in FIG. 4, the connection duct structure is constructed by removing the protective cover 14, opening both ends of the connection duct 5, and connecting the connection duct 5 to the tank 2 of each unit transformer 1A, 1B to be connected to each other. The openings at both ends of the connecting duct 5 are attached to the connecting port 8 of the tank 2 by tightening bolts. In this case, since the leads 6 and the insulating barrier 11 are already assembled and provided inside the connecting duct 5, the leads 6 and the insulating barrier 11 are installed inside the connecting duct 5 again after the connecting duct 5 is attached to the tank 2.
There is no need to insert and assemble. Both ends of the lead 6 provided inside the connection duct 5 connect to each unit transformer 1.
It is connected to the high voltage side lead 10 of the winding provided inside the tanks 2 of A and 1B. This work is carried out by a worker entering the tank 2 of the unit transformers 1A, 1B. Thereafter, the inside of the tank 2 of each unit transformer 1A, 1B is evacuated and filled with insulating oil, and a part of this insulating oil is caused to flow from the tank 2 into the inside of the connecting duct 5 to fill it. In this way, unit transformer 1
A and 1B are connected by a connecting duct 5 to assemble the transformer.

Therefore, in the assembly method of the present invention, the connecting duct structure is manufactured as described above, and when assembling the transformer in a factory, the connecting duct structure is opened and the unit transformers 1A and 1B are connected through the connecting duct 5, and The connecting duct structure with the connecting duct 5 closed is stored and transported to the site together with the unit transformer, and at the site, the connecting duct structure is opened and the connecting duct 5 containing the lead 6 and the insulation barrier 11 is connected to the unit. It connects transformers 1A and 1B. By first manufacturing a connection duct structure that integrates the connection duct 5, lead 6, insulation barrier 11, etc., the connection duct 5 and the like are covered with a protective cover against the connection duct structure when assembling the transformer at the factory.
4 can be used to connect the unit transformers 1A and 1B without disassembling or reassembling the entire unit. Also, when assembling the transformer on-site, simply removing the protective cover 14 from the connecting duct structure connects the connecting duct 5.
Unit transformer 1 as it is without reassembling etc.
Can be attached and connected to A and 1B. Therefore, by using a connection duct structure in which the connection duct 5, lead 6, insulation barrier 11, etc. are assembled together, the assembly work for connecting the unit transformers 1A and 1B is almost eliminated when assembling the transformer. In particular, since the troublesome work of assembling the insulation barrier 11 is eliminated, the assembly work of the transformer can be greatly simplified and the working time can be shortened, and the chances of the insulation barrier 11 coming into contact with the outside air during the assembly of the transformer can be minimized. Therefore, it is possible to suppress as much as possible the insulating barrier 11 from absorbing moisture and deteriorating its insulation performance. Furthermore, the connection duct structure has a protective cover 1 covering the connection duct 5 when not in use.
4, the insulating barrier 11 inside the connecting duct 5 is prevented from coming into contact with the outside air, thereby preventing the insulating property from deteriorating due to moisture absorption of the insulating barrier 11. Note that if the inside of the connection duct 5 is vacuumed or filled with dry air, the insulating barrier 11 can be maintained in a better condition. Also,
If the protective cover 14 is made of metal, it can easily withstand the pressure when the inside of the connecting duct 5 is evacuated and the external mechanical force during transportation.

The method of assembling a split type transformer of the present invention can also be effectively applied to the case where a connecting duct 15 is provided between the lower part of the tank 2 in each unit transformer 1A, 1B to connect them, as shown in FIG.

Note that the insulating barriers provided inside the connection duct 5 or 15 may be provided in one set instead of in multiple layers.

〔Effect of the invention〕

As explained above, the method for assembling the split type transformer of the present invention involves assembling and providing leads and an insulating barrier inside a connecting duct, and integrating these into a connecting duct with openings at both ends of the connecting duct closed with protective covers. The structure is manufactured in advance, the connecting duct structure is transported, and each unit transformer is connected using the connecting duct at the site. This simplifies the assembly work when assembling the transformer, and also reduces the number of times the insulation barrier needs to be assembled once. This prevents the insulation properties of the insulation barrier from deteriorating due to moisture absorption during work. Furthermore, since the connection duct structure closes the connection duct during storage or transportation, it is possible to prevent the insulation barrier from deteriorating due to moisture absorption. Therefore, it is possible to improve the workability of assembling the transformer, and to maintain good insulation by the insulation barrier at the connection portion of the unit transformer.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an example of the connection state of unit transformers in a split type transformer, Fig. 2 is a sectional view showing an example of the connection part of a conventional unit transformer, and Fig. 3
4 and 4 respectively show one embodiment of the present invention, FIG. 3 is a cross-sectional view showing the connecting duct structure, FIG. 4 is a cross-sectional view showing the connecting duct connected to the unit transformer, and FIG. FIG. 5 is an explanatory diagram showing another example of the connection state of the unit transformer. 1A, 1B...unit transformer, 2...tank, 3
... Iron core, 4 ... Winding wire, 5 ... Connection duct, 6 ...
... Lead, 10 ... Winding lead, 11 ... Insulation barrier, 11a ... Straight member, 11b ... Bent member, 13 ... Distribution port, 14 ... Protective cover, 15
...Connection duct.

Claims (1)

[Claims] 1 At least two divided unit transformers,
In the method for assembling a split transformer in which the leads and the insulation barrier are housed and arranged inside the connection duct, and after drying them together, the connection is performed. A connection duct structure is manufactured by attaching protective covers to the openings at both ends of the duct, the connection duct structure is prepared at the time of assembling the transformer, the protection covers are removed, the openings at both ends of the connection duct are opened, and the connection duct is opened. A method for assembling a split type transformer, characterized in that openings at both ends of the unit transformer are attached to the tank of each unit transformer, and the leads are connected to winding leads inside the tank of each unit transformer.