JP7828767B2 - Flange member - Google Patents

Description

Embodiments of the present invention relate to a flange member for fixing a load-operated tap changer to a tank that houses the transformer body together with insulating oil.

For example, as disclosed in Patent Document 1, in oil-immersed static induction equipment such as oil-immersed transformers for high-voltage power receiving and distribution equipment, the transformer body is housed in a tank along with insulating oil. Furthermore, in this type of oil-immersed static induction equipment, the voltage supplied to the transformer body during load, i.e., operation, is adjusted by appropriately switching connection points, such as taps, using an on-load tap changer. This type of on-load tap changer is, for example, called an LTC (on-Load Tap Changer).

Japanese Patent Publication No. 2019-201100

Generally, on-load tap changers are formed in a long, cylindrical shape. Therefore, they are inserted and secured into the tank by being lowered from above through an opening at the top of the tank, suspended by wires or similar means.

However, in recent years, a new type of on-load tap changer has been provided, comprising a main cylindrical section and a sub-cylindrical section with a smaller diameter than the main cylindrical section. When installing such a new type of on-load tap changer inside a tank, the following procedure is followed: first, the head cover of the on-load tap changer is removed; then, the tap changer with the head cover removed is placed inside the tank through the tank's opening; then, the head cover is secured to the tank's opening; and finally, the on-load tap changer inside the tank is lifted through the tank's opening and secured to the head cover.

Thus, when fixing a new type of on-load tap changer, which has a main cylindrical section and a sub-cylindrical section, to a tank, the fixing process becomes significantly more complex. Furthermore, because the on-load tap changer is a heavy object, the lifting position is prone to instability.

Therefore, we provide a flange member that allows a load-operated tap changer, which conventionally required lifting, to be fixed to the tank without the need for lifting.

The flange member according to this embodiment is a flange member for fixing an on-load tap changer to a tank containing the transformer body together with insulating oil. It comprises an inner circumferential portion to which the on-load tap changer is fixed, and an outer circumferential portion fixed to the end of an opening provided at the top of the tank. The flange member is configured such that the on-load tap changer can be inserted into the tank through the opening while the on-load tap changer is fixed to the inner circumferential portion, and the outer circumferential portion can be fixed to the end of the opening while the on-load tap changer is inserted into the tank through the opening.

A schematic cross-sectional view showing an example of the transformer configuration according to this embodiment. This figure schematically shows an example of the configuration of the flange member according to this embodiment. This diagram schematically shows a conventional fixing method for a load-operated tap changer according to a comparative example of this embodiment. This figure schematically shows an example of a method for fixing the on-load tap changer according to this embodiment. This figure schematically shows an example of the state during circulating degassing according to this embodiment.

The following describes one embodiment of the flange member with reference to the drawings. The oil-filled insulated transformer 1 illustrated in Figure 1 is an example of an oil-filled static induction device. Hereinafter, the oil-filled insulated transformer 1 will simply be referred to as "transformer 1". Transformer 1 comprises a metal tank 2 that is a horizontally elongated rectangular box shape. The tank 2 consists of a tank body 2A and a tank cover 2B. The tank body 2A is formed as a long rectangular box with an open top. The tank body 2A also has an insulating oil inlet 2C. The tank cover 2B is formed as a long rectangular plate and closes the open top of the tank body 2A.

The tank 2 contains a transformer body 3, which is an example of an induction device body. The tank 2 is also filled with insulating oil M, such as mineral oil, for insulation and cooling purposes. Within the tank 2, the entire transformer body 3 is immersed in the insulating oil M. The transformer body 3 has a well-known configuration comprising an iron core 3A and a coil 3B. The coil 3B is mounted on the iron core 3A. Furthermore, the transformer body 3 is positioned not in the center of the tank 2, but rather at one end of the tank 2 in its longitudinal direction, in this case, off-center to the left in Figure 1.

Furthermore, although a detailed explanation will be omitted, the transformer 1 may be equipped with various auxiliary components. These auxiliary components include, for example, bushings, conservators, radiators, relays, and pressure relief devices. A bushing is a well-known component used for electrical connections. A conservator is a well-known component that absorbs the expansion and contraction of the insulating oil M due to temperature changes and prevents the deterioration of the insulating oil M due to contact with the outside air. A radiator is a well-known component that cools the transformer 1. A relay is a well-known component that operates a circuit breaker (not shown) to stop the power supply to the transformer body 3 based on the detected amount of decomposition gas generated from the insulating oil M. A pressure relief device is a well-known component that releases decomposition gas and expanded insulating oil M generated from the insulating oil M to the outside. In addition, the transformer 1 may be equipped with various other components that can be mounted on this type of oil-filled static induction equipment.

Furthermore, the transformer 1 is equipped with an on-load tap changer 11. The on-load tap changer 11 is a component that adjusts the voltage supplied to the transformer body 3 under load, i.e., during operation, by appropriately switching connection points, such as taps (not shown). Although detailed illustrations are omitted, the on-load tap changer 11 has a configuration in which a tap selector and a switching switch are housed within a sealed body. The on-load tap changer 11 is also configured with its interior filled with insulating oil M.

Furthermore, the load-operated tap changer 11 has a configuration that combines a long main cylindrical section 11A that constitutes its body, and a long sub-cylindrical section 11B with a smaller diameter than the main cylindrical section 11A. Both the main cylindrical section 11A and the sub-cylindrical section 11B extend linearly in the vertical direction. The main cylindrical section 11A and the sub-cylindrical section 11B are also combined in a parallel manner. Additionally, the dimensions of the main cylindrical section 11A and the sub-cylindrical section 11B along their longitudinal directions are approximately or exactly the same.

The on-load tap changer 11 is fixed to the tank cover 2B, which forms the upper surface of the tank 2. Specifically, an opening 2D is provided in the tank cover 2B on the side opposite to the transformer body 3, penetrating the tank cover 2B in the thickness direction. The on-load tap changer 11 is fixed to this opening 2D via a flange member 100. Next, a detailed explanation of the configuration of this flange member 100 will be provided.

As illustrated in Figure 2, the flange member 100 is composed of a flange body portion 101 that is generally elliptical in shape. The flange member 100 also integrally comprises an inner circumference portion 102 and an outer circumference portion 103. The flange body portion 101 comprises at least the space between the inner circumference portion 102 and the outer circumference portion 103. The inner circumference portion 102 constitutes the inner edge of the flange body portion 101. The outer circumference portion 103 constitutes the outer edge of the flange member 101. Furthermore, the flange body portion 101 is shaped to cover at least the upper part of the sub-cylindrical portion 11B of the load-operated tap changer 11.

The inner circumference 102 is formed as a generally circular opening and is located offset from the center of the flange body 101. In this case, the inner circumference 102 is located eccentrically, offset from the center of the flange body 101 towards one end along the long axis of the flange body 101. The outer circumference 103 is provided along the outer edge of the flange body 101. Therefore, the outer circumference 103 is a generally elliptical annular component along the outer edge of the flange body 101.

The inner circumference portion 102 is provided with a plurality of screw holes 102a along its circumferential direction. In this case, the plurality of screw holes 102a are arranged at equal intervals along the circumferential direction of the inner circumference portion 102. An LTC flange 110, described later, is fixed to the upper part of this inner circumference portion 102 by a plurality of screws (not shown). The upper end of the load-operated tap changer 11, described above, is fixed to the lower part of this LTC flange 110 by a plurality of screws (not shown). In this case, the upper end of the main cylindrical portion 11A of the load-operated tap changer 11 is fixed to the lower part of the LTC flange 110. Furthermore, the upper end of the main cylindrical portion 11A of the load-operated tap changer 11 is indirectly fixed to the inner circumference portion 102 of the flange member 100 via the LTC flange 110.

The outer periphery 103 is provided with a plurality of screw holes 103a along its extension direction. In this case, the plurality of screw holes 103a are arranged at equal intervals along the extension direction of the outer periphery 103. This outer periphery 103 is fixed to the end of the opening 2D by a plurality of screws (not shown). That is, the outer periphery 103 of the flange member 100 is directly fixed to the end of the opening 2D of the tank 2. The opening 2D is a generally elliptical opening that is slightly smaller than the flange body 101. However, the shape and size of the opening 2D can be appropriately modified, at least within a range smaller than the flange body 101.

Furthermore, the flange member 100 is equipped with a vent portion 104 in a part of the flange body portion 101. The vent portion 104 is configured to allow gases, such as the decomposition gas of insulating oil M (an example of gas present in the tank 2) and residual gas generated during lubrication, to flow out to the outside.

Furthermore, as illustrated in Figure 1, the LTC flange 110 is fixed to the upper part of the inner circumference 102 of the flange member 100 by multiple screws (not shown). The LTC flange 110 comprises a cylindrical LTC flange body portion 110A and multiple pipe portions 110B. In this case, the LTC flange 110 has three pipe portions 110B. Each of the multiple pipe portions 110B is smoothly bent.

Next, an example of a method for fixing the on-load tap changer 11 to the tank 2 will be described in detail. Specifically, Figure 3 illustrates a conventional method for fixing the on-load tap changer 11 to the tank 2. According to the conventional fixing method, in step A1, the head cover H attached to the upper end of the on-load tap changer 11 is removed, and then the on-load tap changer 11, with the head cover H removed, is housed in the tank 2 through the opening 2D of the tank 2. A through-hole Ha is provided in the center of the head cover H, penetrating the head cover H.

Then, in step A2, the head cover H is fixed to the upper part of the opening 2D of the tank 2. Then, in step A3, the on-load tap changer 11 inside the tank 2 is lifted by the wire W through the opening 2D of the tank 2 and the through-hole Ha in the head cover H. Then, in step A4, the upper end of the on-load tap changer 11, which has been lifted by the wire W, is fixed to the lower part of the head cover H with several screws (not shown).

As described above, conventionally, the on-load tap changer 11 is installed inside the tank 2 using this fixing method. However, this conventional fixing method makes the fixing process extremely complicated. Furthermore, because the on-load tap changer 11, being a heavy object, needs to be lifted by a wire W, the lifted state tends to be unstable.

Therefore, in this embodiment, a fixing method utilizing the flange member 100 described above is adopted. Specifically, Figure 4 shows an example of a fixing method for the on-load tap changer 11 according to this embodiment. According to the fixing method according to this embodiment, first, in step B1, the upper end of the on-load tap changer 11 is fixed to the lower part of the LTC flange 110 with a plurality of screws (not shown), thereby indirectly fixing the upper end of the on-load tap changer 11 to the inner circumference 102 of the flange member 100 via the LTC flange 110. Then, in step B2, with the on-load tap changer 11 indirectly fixed to the inner circumference 102 of the flange member 100 via the LTC flange 110, the on-load tap changer 11 is suspended by a wire W and inserted into the tank 2 through the opening 2D of the tank 2. Then, in step B3, with the load-operated tap changer 11 inserted into the tank 2 through the opening 2D of the tank 2, the lower part of the outer circumference 103 of the flange member 100 is directly fixed to the upper part of the end of the opening 2D of the tank 2 by multiple screws (not shown).

As described above, according to the fixing method of this embodiment, by utilizing the flange member 100 with the above-described configuration, the on-load tap changer 11 can be installed inside the tank 2 without requiring the on-load tap changer 11 to be lifted.

According to the flange member 100 of this embodiment illustrated above, the load-operated tap changer 11 is fixed to the inner circumference 102, and the load-operated tap changer 11 is configured to be insertable into the tank 2 through the opening 2D of the tank 2. Furthermore, with the flange member 100, the lower part of the outer circumference 103 of the flange member 100 is configured to be fixed to the upper part of the end of the opening 2D of the tank 2, while the load-operated tap changer 11 is inserted into the tank 2 through the opening 2D of the tank 2.

By utilizing the flange member 100 configured in this way, the load-operated tap changer 11, which previously required lifting, can be fixed inside the tank 2 without the need for lifting. The load-operated tap changer 11 may also be directly fixed to the inner circumference 102 of the flange member 100.

Furthermore, the on-load tap changer 11 is a new type of on-load tap changer comprising a main cylindrical portion 11A that constitutes its body, and a sub-cylindrical portion 11B with a smaller diameter than the main cylindrical portion 11A. The flange body portion 101 of the flange member 100, which forms the space between the inner circumference 102 and the outer circumference 103, is shaped to cover the upper part of the sub-cylindrical portion 11B, which is a significantly different part of this new type of on-load tap changer 11 compared to conventional designs. In other words, the flange member 100 according to this embodiment is configured to adequately accommodate the new type of on-load tap changer 11 comprising the main cylindrical portion 11A and the sub-cylindrical portion 11B; in this case, it has an eccentrically elliptical shape.

Furthermore, the flange member 100 is equipped with a vent portion 104 on the flange body portion 101. Here, the flange body portion 101 of the flange member 100 is fixed so that its outer edge, the outer peripheral portion 103, overlaps the upper end of the opening 2D of the tank 2. Therefore, a stepped portion is formed by the lower surface of the flange body portion 101 and the inner peripheral surface of the opening 2D of the tank 2. This stepped portion is prone to accumulating gases such as decomposition gases of the insulating oil M generated in the tank 2 and residual gases generated during lubrication. According to the flange member 100 of this embodiment, such gases in the tank 2 can be smoothly discharged through the vent portion 104. This prevents excessive accumulation of gases such as decomposition gases of the insulating oil M and residual gases generated during lubrication in the tank 2.

Furthermore, the aforementioned venting section 104 can also be utilized during circulating degassing, where the insulating oil M in the tank 2 is circulated while being degassed. Specifically, as illustrated in Figure 5, circulating degassing is performed by connecting a well-known circulating degassing device 200 to the transformer 1. The circulating degassing device 200 is connected to the venting section 104 of the flange member 100 and the insulating oil inlet 2C of the tank 2 via a circulation hose 201. When the circulating degassing operation begins, the circulating degassing device 200 draws the insulating oil M from the tank 2 through the venting section 104 and removes air bubbles and impurities contained in the insulating oil M using a well-known removal device. The circulating degassing device 200 then returns the insulating oil M, from which air bubbles and impurities have been removed, back into the tank 2 through the insulating oil inlet 2C.

As described above, the circulating degassing device 200 circulates the insulating oil M in the tank 2, degassing the insulating oil M and removing impurities contained in the insulating oil M. During circulating degassing by the circulating degassing device 200, the vent portion 104 provided in the flange member 100 functions as a valve that allows the insulating oil M to flow out of the tank 2. Therefore, the transformer 1 can perform circulating degassing of the insulating oil M by utilizing the vent portion 104 of the flange member 100, even without a valve, i.e., an insulating oil outlet, for flowing the insulating oil M out of the tank 2.

This embodiment is not limited to the one described above, and various modifications and extensions can be made without departing from its essence. For example, the on-load tap changer is not limited to the on-load tap changer 11 having the main cylindrical portion 11A and sub-cylindrical portion 11B described above, and on-load tap changers with various configurations can be applied. Furthermore, the shape and size of the flange body portion 101 can be appropriately modified, for example, depending on the configuration and size of the on-load tap changer to be applied.

Furthermore, the position, shape, and size of the inner circumference 102 of the flange body 101 can be appropriately modified according to the configuration and size of the load-operated tap changer, the shape and size of the flange member 100, and other factors. Similarly, the position, shape, and size of the ventilation portion 104 of the flange body 101 can be appropriately modified according to the shape and size of the flange member 100, for example.

Furthermore, when painting the surface of the flange member 100, it is preferable to avoid painting the inner circumference 102 and the outer circumference 103, and instead paint only the parts of the flange body 101 other than the inner circumference 102 and the outer circumference 103.

The embodiments of the present invention have been described above. These embodiments are presented merely as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as described in the claims.

In the drawing, 2 represents the tank, 2D represents the tank opening, 3 represents the transformer body, 11 represents the on-load tap changer, 11A represents the main cylindrical section, 11B represents the sub-cylindrical section, 100 represents the flange member, 101 represents the flange body section, 102 represents the inner circumference section, 103 represents the outer circumference section, and 104 represents the ventilation section.

Claims (4)

A flange member for fixing a load-operated tap changer to a tank that houses the transformer body together with insulating oil,
The aforementioned on-load tap changer is used to secure a head cover that is fixed to an opening provided at the top of the tank, and is designed to be lifted up.
The inner circumference portion to which the on-load tap changer is fixed,
An outer peripheral portion fixed to the end of the opening ,
Equipped with,
The outer circumference is provided with a plurality of screw holes,
A flange member configured such that the on-load tap changer is fixed to the inner circumference and the on-load tap changer can be inserted into the tank through the opening, and the outer circumference can be fixed to the end of the opening by a plurality of screws while the on-load tap changer is inserted into the tank through the opening. The on-load tap changer comprises a main cylindrical portion that constitutes its body, and a sub-cylindrical portion having a smaller diameter than the main cylindrical portion.
The flange member according to claim 1, wherein the flange body portion forming the space between the inner circumference portion and the outer circumference portion has a shape that covers the upper part of the sub-cylindrical portion of the load tap changer. The flange member according to claim 2, wherein the flange body portion is provided with a vent portion for releasing gas from the tank to the outside. The flange member according to claim 3, wherein, during circulating degassing, the vent portion functions as a valve for draining insulating oil from the tank.