Electrical facility

Abstract

The present invention relates to an electrical facility in which an electrical apparatus is housed in a container. The electrical apparatus housed in the container includes a transformer. The container has a first short side surface which is one end in a longitudinal direction, a second short side surface which is the other end in the longitudinal direction and which faces the first short side surface, a first long side surface orthogonal to the first short side surface and the second short side surface, and a second long side surface which is orthogonal to the first short side surface and the second short side surface and which faces the first long side surface. The first short side surface is provided with a door which can be opened and closed. The transformer is disposed along the first short side surface.

Description

Electrical equipment

[0001] The present disclosure relates to an electrical installation in which electrical equipment is housed in a container.

[0002] Patent Document 1 discloses a power supply device including an inverter board. Specifically, the power supply device includes an inverter board disposed in a transportable container. Furthermore, the power supply device includes a transformer connected to the inverter board disposed in another container.

[0003] Japanese Patent No. 4455428

[0004] Consider a case where electrical equipment, including transformers that require periodic inspection, is housed in a single container. In this case, depending on the layout of the transformers housed in the container, it may be difficult to easily inspect, replace, or perform other maintenance on the transformers.

[0005] One object of the present disclosure is to provide electrical equipment that allows for easy maintenance of transformers of electrical equipment housed in a container.

[0006] One aspect of the present disclosure relates to an electrical installation in which electrical equipment is housed in a container. The electrical equipment housed in the container includes a transformer. The container has a first short side at one end in the longitudinal direction, a second short side at the other end in the longitudinal direction and opposite the first short side, a first long side perpendicular to the first short side and the second short side, and a second long side perpendicular to the first short side and the second short side and opposite the first long side. The first short side has an openable door. The transformer is arranged along the first short side.

[0007] According to the present disclosure, the transformer is arranged along the first short side surface having an openable door, so that during maintenance of the transformer, a worker can easily perform maintenance on the transformer by opening the door on the first short side surface without entering the container.

[0008] Fig. 1 is a diagram for explaining an overview of electrical equipment; Fig. 2 is a diagram for explaining a specific example of a container; Fig. 3 is a diagram for explaining a first arrangement example of electrical equipment in a container; Fig. 4 is a diagram for explaining a second arrangement example of electrical equipment in a container; and Fig. 5 is a diagram for explaining a specific example of a container according to another embodiment.

[0009] Electrical equipment according to embodiments of the present disclosure will be described with reference to the accompanying drawings. Elements common to the various drawings will be designated by the same reference numerals, and redundant description will be omitted.

[0010] 1. Overview of Electrical Equipment FIG. 1 is a diagram illustrating an overview of electrical equipment 10. The electrical equipment 10 is composed of a container 20 and in-container electrical equipment 30 (hereinafter simply referred to as electrical equipment 30) housed in the container 20. The electrical equipment 10 is connected to a load 40. For example, the electrical equipment 10 converts high-voltage power supplied from a power grid 35 into power required to drive the load 40 and supplies the converted power to the load 40. Examples of the electrical equipment 10 include power receiving equipment for supplying power to the load 40 in a factory or the like, a rectifier for electrolysis, a power conditioner for solar panels, a power converter for charging a storage battery, and power receiving equipment for a pump facility.

[0011] The container 20 is a transportable container and is installed, for example, outdoors. This eliminates the need for a building or the like to store the electrical equipment 30. Furthermore, by storing the electrical equipment 30 in the container 20, the container 20 can be installed at the installation location of the delivery destination. In this case, the assembly work at the delivery destination is reduced, leading to a shorter construction period and improved quality.

[0012] The container 20 used in the electrical equipment 10 may have various sizes. For example, the container 20 may be a container of a size conforming to ISO standards. The container 20 may also be equipped with an air conditioner for adjusting the temperature and humidity of the air inside the container 20. In this case, an outdoor unit of the air conditioner is attached to the outer surface of the container 20.

[0013] The electric equipment 30 is a device that converts electric power. For example, the electric equipment 30 includes a plurality of electric equipment. Examples of the electric equipment 30 include a high-voltage switchgear (circuit breaker) as the high-voltage equipment 32, a converter transformer as the transformer 31, and a rectifier, chopper device, converter, inverter, or a control device for the low-voltage equipment 33, a container air conditioner, etc. as the low-voltage equipment 33.

[0014] The load 40 is connected to the output side of the electrical equipment 30 through the container 20. Examples of the load 40 include a device that operates on a DC power source (e.g., an electrolytic cell, etc.), a device that is driven by an inverter, etc.

[0015] 1, the load 40 is provided outside the container 20, but this is not limiting. The load 40 may be provided inside the container 20. Furthermore, the electrical equipment 30 may include an electric motor drive device. In this case, the load 40 may be an electric motor that is driven by AC power output from the electric motor drive device.

[0016] 2. Example of a Container Figure 2 is a diagram illustrating a specific example of a container 20. As shown in Figure 2 (A), the container 20 has a generally rectangular parallelepiped shape and has a first short side surface 21 at one end in the longitudinal direction, a second short side surface 22 at the other end in the longitudinal direction and facing the first short side surface 21, a first long side surface 23 perpendicular to the first short side surface 21 and the second short side surface 22, and a second long side surface 24 perpendicular to the first short side surface 21 and the second short side surface 22 and facing the first long side surface 23. The first short side surface 21, the second short side surface 22, the first long side surface 23, and the second long side surface 24 are surfaces that are approximately perpendicular to the ground.

[0017] The first short side surface 21 is provided with an openable / closable door 21A. The second short side surface 22 is provided with an openable / closable door 22A. The first long side surface 23 is provided with an openable / closable door 23A. The second long side surface 24 is provided with an openable / closable door 24A. (B) in FIG. 2 is a view of the container 20 as seen from above. In the example shown in (B) in FIG. 2, the right direction of the paper is the X direction, and the upward direction is the Y direction. In this case, the short sides of the container 20 are parallel to the Y direction, and the long sides of the container 20 are parallel to the X direction. The doors 21A, 22A, 23A, and 24A each open, for example, in the direction shown in (B) in FIG. 2. The doors 23A and 24A are, for example, foldable double doors, and are configured so that large equipment can be carried inside by widening the opening width. The doors 23A and 24A are not limited to foldable double doors, but may be multiple double doors or sliding doors. The container 20 may also be configured to include at least the door 21A on the first short side surface 21.

[0018] 3. Examples of Electrical Equipment Arrangement 3-1. First Example FIG. 3 is a diagram illustrating a first example of the arrangement of electrical equipment 30 in a container. Specifically, (A) in FIG. 3 is a plan view of the equipment arrangement when the container 20 is viewed from above, showing an example of the connections of the electrical equipment 30 stored in the container 20. (B) in FIG. 3 is a perspective view showing an example of the arrangement of the electrical equipment 30 stored in the container 20. The electrical equipment 30 is arranged in a space surrounded by the first short side surface 21, the second short side surface 22, the first long side surface 23, and the second long side surface 24. The X direction in FIG. 3 is the direction from the first short side surface 21 to the second short side surface 22, the Y direction is the direction from the first long side surface 23 to the second long side surface 24, and the Z direction is the direction from the ground upward. Here, the electrical equipment 30 includes a transformer 31, high-voltage equipment 32, and low-voltage equipment 33. As shown in FIG. 3A, the high-voltage equipment 32 is connected to the power grid 35 via a conductor 70 and is further connected to a high-voltage terminal 31A of the transformer 31 via a conductor 71. The low-voltage terminal 31B of the transformer 31 is connected to the low-voltage equipment 33 via a conductor 72. The high-voltage terminal 31A is a three-phase AC terminal. For example, the high-voltage terminal 31A is composed of a first-phase high-voltage terminal U, a second-phase high-voltage terminal V, and a third-phase high-voltage terminal W. The low-voltage terminal 31B is a three-phase AC terminal. For example, the low-voltage terminal 31B is composed of a first-phase low-voltage terminal u, a second-phase low-voltage terminal v, and a third-phase low-voltage terminal w.

[0019] The high-voltage equipment 32 is a device that supplies high-voltage AC power supplied from the power grid 35 through the conductor 70 to the transformer 31. The high-voltage equipment 32 is, for example, a high-voltage distribution panel. Examples of high-voltage distribution panels include switchgears, disconnectors, lightning arresters, voltage transformers (VTs), current transformers (CTs), and protective relays that receive signals from the voltage transformers and current transformers and operate the switchgears. The transformer 31 is a device that transforms the high-voltage AC power supplied from the high-voltage equipment 32 into low-voltage AC power suitable for specific low-voltage equipment 33 and supplies the AC power to the low-voltage equipment 33. The transformer 31 is also referred to as a transformer panel. The low-voltage equipment 33 is a device that generates DC power or AC power required to drive the load 40 based on the low-voltage AC power supplied from the transformer 31 and supplies the DC power or AC power to the load 40 through the conductor 73. The low-voltage equipment 33 includes, for example, one or more electrical devices. Examples of the low-voltage equipment 33 include a rectifier, a chopper device, a self-excited converter and inverter, and a control panel that controls the self-excited converter and inverter. The low-voltage equipment 33 is also referred to as a power conversion device. Note that, in the example shown in (A) in FIG. 3, the power system 35 and the load 40 are arranged in a position in the X direction from the container 20, but this is not limiting.

[0020] 3B, according to the electrical equipment 10, the transformer 31 is arranged along the first short side surface 21. As a result, during maintenance such as inspection or replacement of the transformer 31, a worker can easily perform maintenance on the transformer 31 in the X direction by opening the door 21A on the first short side surface 21 without entering the container 20.

[0021] Furthermore, we consider which of the high-voltage terminal 31A and the low-voltage terminal 31B of the transformer 31, which are arranged along the first short side surface 21, should be arranged facing the first short side surface 21. Generally, the current capacity of the wiring of the transformer 31 is set to be larger for the conductor 72 on the low-voltage terminal 31B side than for the conductor 71 on the high-voltage terminal 31A side. In other words, the cross-sectional area of ​​the conductor 72 connecting the transformer 31 and the low-voltage device 33 is larger than the cross-sectional area of ​​the conductor 71 connecting the transformer 31 and the high-voltage device 32. The smaller the cross-sectional area of ​​the conductor, the easier the wiring work and the lower the material costs. Considering the wiring work and wiring length between the transformer 31 and the low-voltage device 33, it is desirable to arrange the high-voltage terminal 31A of the transformer 31 facing the first short side surface 21 and shorten the wiring length of the conductor 72.

[0022] According to the electrical equipment 10, the transformer 31 is disposed so that the high-voltage terminal 31A faces the first short side surface 21. By disposing the low-voltage terminal 31B on the low-voltage device 33 side, the length of the conductor 72 between the low-voltage terminal 31B and the low-voltage device 33 can be shortened. This facilitates the wiring work between the transformer 31 and the low-voltage device 33. Therefore, the time required for assembling the electrical equipment 10 is reduced. Furthermore, the shortened wiring length of the conductor 72 reduces the resistance loss of the conductor 72 between the low-voltage terminal 31B and the low-voltage device 33. It is desirable that the outlet on the high-voltage device 32 side of the conductor 71 connecting the high-voltage device 32 and the high-voltage terminal 31A be provided at the top of the surface of the high-voltage device 32 facing the transformer 31. It is desirable that the inlet on the low-voltage equipment 33 side of the conductor 72 connecting the low-voltage equipment 33 and the low-voltage terminal 31B be located on the side of the low-voltage equipment 33 facing the transformer 31, or in a location close to the transformer 31 on the side of the low-voltage equipment 33 facing the high-voltage equipment 32.

[0023] Furthermore, in the electrical equipment 10, as shown in FIG. 3B , the high-voltage equipment 32 is arranged along the second long side surface 24, and the low-voltage equipment 33 is arranged along the first long side surface 23. In this case, a maintenance space 39 having a gap G may be provided between the low-voltage equipment 33 and the high-voltage equipment 32. The gap G has a dimension in the Y direction that allows a worker to enter the maintenance space 39. This dimension is, for example, 600 mm or more. As a result, a worker can enter the maintenance space 39 by opening the door 22A on the second short side surface 22 and perform maintenance on the high-voltage equipment 32 in the Y direction in the maintenance space 39. Furthermore, by opening the door 24A on the second long side surface 24, the worker can perform maintenance on the high-voltage equipment 32 from the opposite side in the Y direction. Therefore, maintenance of the high-voltage equipment 32 can be easily performed from two sides. Furthermore, by opening the door 22A on the second short side surface 22, a worker can enter the maintenance space 39 and perform maintenance on the low-voltage equipment 33 from the opposite side in the Y direction in the maintenance space 39. By opening the door 23A on the first long side surface 23, a worker can perform maintenance on the low-voltage equipment 33 toward the Y direction in the maintenance space 39. Therefore, maintenance of the low-voltage equipment 33 can be easily performed from two sides. Furthermore, by opening the door 22A on the second short side surface 22, a worker can enter the maintenance space 39 and perform maintenance on the transformer 31 from the opposite side in the X direction in the maintenance space 39 in the maintenance space 39. Therefore, the efficiency of maintenance of the electrical equipment 30 stored in the container 20 is improved.

[0024] 3-2. Second Example FIG. 4 is a diagram illustrating a second arrangement example of the in-container electrical equipment 30A (hereinafter simply referred to as the electrical equipment 30A). The electrical equipment configured in the second arrangement example of the electrical equipment 30A is referred to as the electrical equipment 10A. In the electrical equipment 10A, the power system 35 and the high-voltage equipment 51 in the external equipment 50 are connected by a conductor 70. Furthermore, in the electrical equipment 10A, the high-voltage equipment 51 and the electrical equipment 30A installed inside the container 20A are connected by a conductor 71. Furthermore, in the electrical equipment 10A, the electrical equipment 30A and the load 40 are connected by a conductor 73. The high-voltage equipment 51 corresponds to, for example, the high-voltage equipment 32 in the first arrangement example described above. The electrical equipment 30A is installed in the container 20A instead of the electrical equipment 30 in the first arrangement example described above. Here, the electrical equipment 30A includes a transformer 31 and low-voltage equipment 332. Specifically, (A) in FIG. 4 is a diagram (plan view) of the arrangement of the equipment when the container 20A is viewed from above, showing an example of the connection of the electrical equipment 30A stored in the container 20A. (B) in FIG. 4 is a perspective view showing an example of the arrangement of the electrical equipment 30A stored in the container 20A. The electrical equipment 30A is arranged in a space surrounded by the first short side surface 212, the second short side surface 222, the first long side surface 232, and the second long side surface 242. The X, Y, and Z directions shown in FIG. 4 are the same as those in FIG. 3. As shown in (A) in FIG. 4, the high-voltage terminal 31A of the transformer 31 is connected to high-voltage equipment 51 stored in external equipment 50 (e.g., another container) of the container 20A, and the low-voltage terminal 31B of the transformer 31 is connected to low-voltage equipment 332. The high-voltage terminal 31A is a three-phase AC terminal, as in the first arrangement example described above. For example, the high-voltage terminal 31A is composed of a first-phase high-voltage terminal U, a second-phase high-voltage terminal V, and a third-phase high-voltage terminal W. The low-voltage terminal 31B is a three-phase AC terminal. For example, the low-voltage terminal 31B is composed of a first-phase low-voltage terminal u, a second-phase low-voltage terminal v, and a third-phase low-voltage terminal w.

[0025] The low-voltage equipment 332 includes, for example, a power conversion device 33A and a chopper device 33B. The power conversion device 33A is a device that converts the transformed AC power output from the transformer 31 into DC power. The power conversion device 33A may include a control panel. The control panel may be connected to a higher-level device that issues instructions to the control panel. The chopper device 33B is a device that performs chopper control to generate power of a voltage required to drive the load 40 based on the DC power generated by the power conversion device 33A. The power conversion device 33A is, for example, physically and electrically disposed between the chopper device 33B and the transformer 31.

[0026] In the electrical equipment 10A, as shown in FIG. 4B , the transformer 31 is arranged along the first short side surface 21, and the AC input of the power conversion device 33A constituting the low-voltage equipment 332 is connected to the low-voltage terminal 31B of the transformer 31. The DC output of the power conversion device 33A is connected to the input of the chopper device 33B, and the output of the chopper device 33B is connected to a load 40 outside the container 20A. The low-voltage equipment 332 is arranged along the first long side surface 232. In this case, a maintenance space 39A having a gap G2 may be provided between the low-voltage equipment 332 and the second long side surface 242. The gap G2 has a dimension in the Y direction that allows a worker to enter the maintenance space 39A. The power conversion device 33A and the chopper device 33B are arranged side by side in the X direction in the order shown in FIG. 4B . As in the first arrangement example described above, the transformer 31 is arranged so that the high-voltage terminal 31A faces the first short side surface 212. This allows a worker to easily perform maintenance on the transformer 31 in the X direction by opening the first short side surface 212, without entering the container 20A. Furthermore, the low-voltage terminal 31B of the transformer 31 is arranged on the input terminal side of the power conversion device 33A. This allows the cross-sectional area of ​​the conductor 72 between the low-voltage terminal 31B and the power conversion device 33A to be increased, and the length of the conductor 72 to be shortened, as in the first arrangement example described above. Furthermore, during maintenance of the low-voltage equipment 332, a worker can easily perform maintenance on the low-voltage equipment 332 in the Y direction by opening the first long side surface 232, without entering the container 20A. Furthermore, a worker can easily perform maintenance on the low-voltage equipment 332 from the maintenance space 39A from the opposite side in the Y direction.

[0027] In this way, when all of the electrical equipment 30 can be housed in the container 20, the electrical equipment 10 is provided in which the electrical equipment 30 in the container 20 is arranged as shown in the first arrangement example described above. This improves the efficiency of maintenance of the electrical equipment 30. On the other hand, when the low-voltage equipment 332 to be housed in the container 20A is large and the high-voltage equipment 51 cannot be housed in the container 20A due to size restrictions of the container 20A, the electrical equipment 10A is provided in which the electrical equipment 30A in the container 20A is arranged as shown in the second arrangement example described above. This improves the efficiency of maintenance of the electrical equipment 30A.

[0028] 4. Other Embodiments FIG. 5 is a diagram illustrating a specific example of a container 20 according to other embodiments. As shown in FIG. 5A, the container 20 may include an insertion / removal mechanism 60 that allows the transformer 31 to be inserted or removed. In this case, the insertion / removal mechanism 60 is deployed when the transformer 31 is inserted or removed, as shown in FIG. 5B. More specifically, the insertion / removal mechanism 60 is deployed so that the transformer 31 can be transported between the door 21A of the first short side surface 21 and the installation surface 90 of the container 20. On the other hand, as shown in FIG. 5A, the insertion / removal mechanism 60 is stored when the transformer 31 is not being inserted or removed. An example of the insertion / removal mechanism 60 is a rail. In this way, by providing the insertion / removal mechanism 60 to the container 20, the transformer 31 can be easily inserted or removed from the container 20, even when work such as replacing the transformer 31 is required. This improves the efficiency of maintenance of the transformer 31.

[0029] Furthermore, the transformer 31 may be provided with transportable wheels 31C. This further facilitates the loading and unloading of the transformer 31 from the container 20. The loading and unloading mechanism 60 is composed of, for example, a pair of rails 61 (also simply referred to as rails 61) fixed to the floor surface 29 inside the container 20 and extending parallel to the X direction, a portable rail 62, and a platform 63. Specifically, as shown in FIG. 5B , when the door 21A of the container 20 is open during loading and unloading of the transformer 31, the platform 63 is installed on the installation surface 90 on the opposite side of the first short side surface 21 in the X direction, and the rail 62 is installed on the platform 63. The rail 62 is installed on an extension of the rail 61, connected in the negative (negative) X direction. In other words, the top surfaces of the rails 61 and 62 are on the same X-Y plane. The transformer 31 is configured to be movable on the rails 61 and 62 by the wheels 31C. The base 63 is a base that supports the rail 62 .

[0030] An example of carrying in the transformer 31 will be described. When carrying in the transformer 31, a worker places the wheels 31C of the transformer 31 on the rails 62 using equipment such as a crane or forklift (not shown) (see (B) in FIG. 5). Then, the worker moves the transformer 31 in the X direction from the rails 62 to the rails 61 using the wheels 31C, and uses a wheel stopper (not shown) to fix the transformer 31 to a predetermined position on the rails 61 inside the container 20 (see (A) in FIG. 5). Then, the worker removes the rails 62 and the platform 63. After carrying the transformer 31 into the container 20, the worker connects the necessary conductors to the high-voltage terminal 31A and the low-voltage terminal 31B of the transformer 31.

[0031] The removal of the transformer 31 is performed in the reverse order of the delivery of the transformer 31. Specifically, when removing the transformer 31, a worker opens the door 21A on the first short side surface 21 and removes the conductors connected to the high-voltage terminal 31A and the low-voltage terminal 31B of the transformer 31. The worker then installs a platform 63 on the installation surface 90 on the opposite side of the first short side surface 21 in the X direction, and installs a rail 62 on the platform 63 (see (B) in FIG. 5 ). To make the transformer 31 movable, the worker removes the car stopper (not shown) attached to the transformer 31. The worker then moves the transformer 31 from the rail 61 to the rail 62 on the opposite side in the X direction. After pulling out the transformer 31 a predetermined distance in the −X direction from the first short side surface 21 (see (B) in FIG. 5 ), a worker removes the transformer 31 from the rails 62 using equipment such as a crane or forklift (not shown). The rails 62 and the platform 63 may be stored inside the container 20 except when the transformer 31 is being carried in or out. For example, the rails 62 and the platform 63 may be stored in the space between the pair of rails 61, the space between the rails 61 and the first long side surface 23, the space between the rails 61 and the second long side surface 24, or the like.

[0032] The loading / unloading mechanism 60 may be provided for loading / unloading the low-voltage equipment 33 and the high-voltage equipment 32, respectively. In this case, the loading / unloading mechanism 60 is deployed so that the low-voltage equipment 33 can be transported between the door 23A of the first long side surface 23 and the installation surface 90 of the container 20. The loading / unloading mechanism 60 is also deployed so that the high-voltage equipment 32 can be transported between the door 24A of the second long side surface 24 and the installation surface 90 of the container 20. This makes it easy to load / unload the low-voltage equipment 33 and the high-voltage equipment 32 into / from the container 20. This reduces the construction period for the electrical equipment 10 and improves the efficiency of maintenance.

[0033] 10, 10A...electrical equipment, 20, 20A...container, 21...first short side, 21A...door, 22...second short side, 22A...door, 23...first long side, 23A...door, 24...second long side, 24A...door, 29...floor, 30, 30A...electrical equipment, 31...transformer, 31A...high voltage terminal, 31B...low voltage terminal, 31C...wheel, 32...high voltage equipment, 33...low voltage equipment , 33A...power conversion device, 33B...chopper device, 35...power system, 39, 39A...maintenance space, 40...load, 60...loading / unloading mechanism, 61...pair of rails, 62...rail, 63...frame, 90...installation surface, 212...first short side, 222...second short side, 232...first long side, 242...second long side, 332...low-voltage equipment, G...gap, G2...gap

Claims

1. Electrical equipment that houses electrical devices in a container, The aforementioned electrical equipment includes a transformer and low-voltage equipment, The aforementioned container is The first short side, which is one end in the longitudinal direction, The other end in the longitudinal direction, and the second short side facing the first short side, A first long side perpendicular to the first short side and the second short side, A second long side that is perpendicular to the first short side and the second short side, and that faces the first long side, It has, The first short side and the first long side are equipped with openable and closable doors. The transformer is positioned along the first short side, The low-voltage equipment is connected to the low-voltage terminal of the transformer and is arranged along the first long side. The low-voltage equipment includes a power converter that converts the transformed AC power output from the transformer into DC power. Electrical equipment characterized by the following features.

2. The electrical equipment according to claim 1, The transformer is arranged such that the high-voltage terminals face the first short side. Electrical equipment characterized by the following features.

3. The electrical equipment according to claim 1, The aforementioned electrical equipment further includes high-voltage equipment, The low-voltage equipment is connected to the low-voltage terminal of the transformer and is arranged along the first long side. The high-voltage equipment is connected to the high-voltage terminals of the transformer and is arranged along the second long side. The second short side is equipped with an openable door, A maintenance space is provided in the gap between the low-voltage equipment and the high-voltage equipment. Electrical equipment characterized by the following features.

4. (delete)

5. The electrical equipment according to claim 1, The low-voltage device further includes a chopper device that performs chopper control to generate power of a voltage necessary to drive a load connected to the output side of the container, based on the DC power. The power conversion device is positioned between the chopper device and the transformer. Electrical equipment characterized by the following features.

6. The electrical equipment according to claim 1, The high-voltage terminals of the transformer are connected to high-voltage equipment housed in the external equipment of the container. Electrical equipment characterized by the following features.

7. The electrical equipment according to claim 1, The transformer is equipped with transportable wheels, The container is equipped with a loading / unloading mechanism that allows the transformer to be loaded and unloaded. The aforementioned retraction mechanism is deployed when the transformer is to be retracted or extended, and retracted when the transformer is not to be retracted or extended. Electrical equipment characterized by the following features.