How to renew equipment in a power receiving and transforming system

Abstract

To provide a device renewal method for a power receiving and transforming system by which a renewal work can be smoothly performed without causing degradation in quality of the power receiving and transforming system.SOLUTION: In a first removing step of a device renewal method, a plurality of existing oil insulation transformers are removed with an oil retaining wall to form a first space while a prescribed number of oil insulation transformers are left. In a first installation step, one or more new switch gears are installed in the first space. In a second removing step, the same number of existing switch gears as the number of the new switch gears are removed to form a second space. In a second installation step, the same number of new switch gears as the number of the existing switch gears removed in the second removing step are installed in a first update space. In a third removing step, the same number of existing switch gears as the number of the new switch gears are removed to form a third space. In a third installation step, the same number of new mold insulation transformers as the number of the existing oil insulation transformers removed in the first removing step are installed in a second update space.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a method for renewing equipment in a power receiving and transforming system. [Background technology]

[0002] Conventionally, power receiving and transforming systems have been known to receive and transform high-voltage electricity from electric power companies and distribute it to various devices within commercial facilities, buildings, and other buildings. These systems consist of switchgear and transformers, which are located in electrical rooms. Conventional switchgears often employ an insulation structure using sulfur hexafluoride (SF6) gas, for example. Transformers often employ an insulation structure using either SF6 gas or oil, for example. SF6 gas is a nonflammable, stable gas and is widely used as an insulating material. However, SF6 gas has an extremely high global warming potential, making its management and disposal complicated. Similarly, oil is also widely used as an insulating material, but its handling and management are complicated due to its status as a hazardous material. Therefore, other insulation methods, such as molding with epoxy resin, have been proposed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-239246 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-93133 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-89202 Summary of the Invention [Problem to be solved by the invention]

[0004] Power receiving and transformer systems are often periodically renovated. Therefore, switchgear and transformers that use SF6 gas or oil as insulating materials, as described above, are sometimes replaced with switchgear and transformers molded with epoxy resin or other materials during renovations. Power receiving and transformer systems are generally designed for redundancy, for example, with two power receiving circuits. Therefore, when existing switchgear and transformers installed in electrical rooms are renovated, each system is typically replaced. In this case, while one system's equipment is shut down during the renovation, the other system continues to supply power, enabling commercial facilities, buildings, and other premises to continue receiving power. However, renovating each system is large-scale, and one system tends to be out of service for a long period of time. In this case, although the other system continues to supply power, there are periods when only one system is available, reducing redundancy and resulting in a temporary degradation of the quality of the power receiving and transforming equipment.

[0005] Therefore, it would be meaningful to provide a method for renewing equipment in a power receiving and transforming system that allows for smooth renewal work without causing a deterioration in the quality of the power receiving and transforming system. [Means for solving the problem]

[0006] An equipment renewal method for a power receiving and transforming system according to an embodiment includes a first removal step, a first installation step, a second removal step, a second installation step, a third removal step, and a third installation step, and the renewal target is a power receiving and transforming system including a plurality of existing oil-insulated transformers arranged in an electrical room and having oil leakage prevention measures implemented by an oil retaining wall, and a plurality of existing switchgears. The first removal step removes the plurality of existing oil-insulated transformers together with the oil retaining wall, leaving a predetermined number, to form a first space in the electrical room. The first installation step installs at least one new switchgear in the first space. The second removal step removes the same number of existing switchgears as the new switchgears installed in the first installation step to form a second space in the electrical room. The second installation step installs the same number of new switchgears as the existing switchgears removed in the second removal step in a first renewal space including at least a portion of the first space and the second space. In the third removal step, the same number of existing switchgears as the new switchgears installed in the second installation step are removed to form a third space in the electrical room. In the third installation step, the same number of new molded insulation transformers as the existing oil-insulated transformers removed in the first removal step are installed in a second renewal space including at least a part of the first renewal space and the third space. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an exemplary schematic plan view showing the configuration of an electrical room before renewal, to which a method for renewing equipment in a power receiving and transforming system according to an embodiment can be applied. [Figure 2] FIG. 2 is an exemplary schematic perspective view showing the configuration of a molded insulated switchgear to be renewed by the equipment renewal method for a power receiving and transforming system according to the embodiment. [Figure 3] FIG. 3 is an exemplary schematic perspective view showing the configuration of a molded insulation transformer that is to be renewed by the equipment renewal method for a power receiving and transforming system according to the embodiment. [Figure 4]FIG. 4 is an exemplary schematic explanatory diagram showing a renewal procedure of a device renewal method for a power receiving and transforming system according to an embodiment. [Figure 5] FIG. 5 is an exemplary schematic plan view showing another equipment layout when the equipment renewal method for a power receiving and transforming system according to the embodiment is applied and renewal is completed. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The configurations of the embodiments described below, as well as the actions and results (effects) brought about by the configurations, are merely examples and are not limited to the following description.

[0009] FIG. 1 is an exemplary schematic plan view showing the configuration of an electrical room 10 before renewal, to which an equipment renewal method for a power receiving and transforming system M according to an embodiment can be applied. The electrical room 10 is, for example, a generally rectangular room with a roof extending in the X and Y directions, forming a space that can be largely isolated from the outside. The electrical room 10 may be equipped with air conditioning equipment, etc., as necessary. For the sake of explanation, FIG. 1 shows the electrical room 10 with an existing switchgear 12 and an existing oil-insulated transformer 16 surrounded by an oil barrier 14, which are the main components of the power receiving and transforming system M and are relatively large pieces of equipment, but does not show other equipment.

[0010] In the example shown in FIG. 1, a plurality of (e.g., six) existing switchgears 12 are arranged in the X direction inside the electrical room 10. Furthermore, a plurality of (e.g., two) existing oil-insulated transformers 16, each having an oil barrier 14 to prevent oil leakage, are arranged in the X direction at positions offset in the Y direction from the existing switchgears 12. The oil barrier 14 is, for example, an isolation wall that rises to a predetermined height from the floor 10a of the electrical room 10. Alternatively, the oil barrier 14 may be a bottomed container-shaped member, a so-called oil pan, installed on the floor 10a. The oil barrier 14 surrounds the existing oil-insulated transformer 16 to prevent insulating oil from leaking from the existing oil-insulated transformer 16. The oil barrier 14 may be provided for each existing oil-insulated transformer 16 as shown in Figure 1, or may be composed of a partition wall of a predetermined height rising from the floor surface 10a so as to separate the area where the existing switchgear 12 is located from the area where the existing oil-insulated transformer 16 is located.

[0011] The power receiving and transforming system M in FIG. 1 is provided with redundancy and includes, for example, two power receiving circuits, a first power receiving circuit 18A (e.g., a main line circuit) and a second power receiving circuit 18B (e.g., a backup line circuit). The first power receiving circuit 18A is configured with three of the six existing switchgears 12A and one of the existing oil-insulated transformers 16 installed in two locations, one of which has been treated for oil leakage with an oil retaining wall 14A. Similarly, the second power receiving circuit 18B is configured with the remaining three of the six existing switchgears 12B and one of the existing oil-insulated transformers 16 installed in two locations, one of which has been treated for oil leakage with an oil retaining wall 14B. By configuring the power receiving and transforming system M to receive high-voltage electricity from the power company using two existing switchgears 12, the quality of the power receiving and transforming system M is improved.

[0012] During normal operation, high-voltage electricity transmitted from the electric power company is supplied, for example, to existing switchgear 12A of first power-receiving circuit 18A and existing switchgear 12B of second power-receiving circuit 18B. The voltage of the high-voltage electricity supplied to existing switchgear 12A is changed by existing oil-insulated transformer 16A and then supplied to the premises of each commercial facility, building, etc. Similarly, the voltage of the high-voltage electricity supplied to existing switchgear 12B is changed by existing oil-insulated transformer 16B and then supplied to the premises of each commercial facility, building, etc.

[0013] In another example, high-voltage electricity transmitted from the electric power company is configured to be supplyable to the existing switchgear 12B of the first power-receiving circuit 18A and the second power-receiving circuit 18B, and is then supplied only to the existing switchgear 12A, from which it is supplied to the existing oil-insulated transformer 16A and the existing oil-insulated transformer 16B, and is then supplied from the existing oil-insulated transformer 16A and the existing oil-insulated transformer 16B to the premises of each commercial facility, building, etc. Similarly, high-voltage electricity may be supplied only to the existing switchgear 12B from the existing switchgear 12B to the existing oil-insulated transformer 16A and the existing oil-insulated transformer 16B, and is then supplied from the existing oil-insulated transformer 16A and the existing oil-insulated transformer 16B to the premises of each commercial facility, building, etc. It is also possible to supply electricity to all of the premises of commercial facilities, buildings, etc. from existing oil-insulated transformer 16A, or to supply electricity to all of the premises of commercial facilities, buildings, etc. from existing oil-insulated transformer 16B. Since it is unlikely that existing switchgear 12A, existing switchgear 12B, existing oil-insulated transformer 16A, and existing oil-insulated transformer 16B will malfunction simultaneously, by providing two power receiving and transforming circuits consisting of first power receiving circuit 18A and second power receiving circuit 18B, even if a malfunction occurs in one of the devices, electricity can still be supplied to the premises of each commercial facility, building, etc. from a functioning device. By configuring in this way so that electricity can always be supplied from multiple systems, redundancy is ensured to improve the quality of power receiving and transforming system M.

[0014] 1, the existing switchgear 12 is shown schematically, but is a switchgear of a well-known configuration, for example, a rectangular housing that houses electrical equipment such as a circuit breaker, busbars, instrument current transformers, and external cables. The inside of the housing of the existing switchgear 12 is a substantially sealed space, and as described above, it is filled with, for example, SF6 gas or the like to maintain insulation.

[0015] FIG. 2 is an exemplary schematic perspective view showing the configuration of a molded insulated switchgear 22, which is a new switchgear to be installed in place of the existing switchgear 12 when implementing the equipment renewal method for a power receiving and substation system according to this embodiment. Like the existing switchgear 12, the molded insulated switchgear 22 houses electrical devices such as circuit breakers, bus bars, instrument current transformers, and external cables inside a rectangular housing K1. The molded insulated switchgear 22 differs from the existing switchgear 12 in that the electrical devices such as the circuit breakers, bus bars, and external cables are individually configured as molded components 22a that are individually covered and sealed with an insulating resin material (molding material) such as epoxy resin. Because each electrical device is individually configured as a molded component 22a, the housing K1 is not filled with SF6 gas or the like. Therefore, the molded insulated switchgear 22 does not require gas monitoring devices such as gas pressure gauges that were required to manage SF6 gas and the like in the existing switchgear 12, and has a structure that contributes to simplifying the equipment, making it more compact, and improving maintainability. Note that Figure 2 shows a state in which part of the wall of the housing K1 has been removed in order to illustrate the interior.

[0016] Similarly, while the existing oil-insulated transformer 16 is shown diagrammatically in Figure 1, it is a transformer with a well-known configuration, for example, in which the primary and secondary iron cores and windings are housed in a container, and the container is filled with oil (insulating oil) to maintain insulation. The housing that constitutes the existing oil-insulated transformer 16 may also be filled with SF6 gas or the like. In the existing oil-insulated transformer 16, the windings form the electric circuit, and the iron core forms the magnetic circuit. Also, heat dissipation fins are provided on the side walls, etc., for heat dissipation.

[0017] FIG. 3 is an exemplary schematic perspective view showing the configuration of a new molded insulation transformer 30 to be installed in place of the existing oil-insulated transformer 16 when implementing the equipment renewal method for a power receiving and transforming system according to this embodiment. Like the existing oil-insulated transformer 16, the new molded insulation transformer 30 includes, for example, a housing K2 housing a plurality of primary and secondary iron cores and windings. Heat dissipation fins K3 are also provided on the side walls. The new molded insulation transformer 30 differs from the existing oil-insulated transformer 16 in that the primary and secondary iron cores and windings are configured as molded components 30a that are covered and sealed with an insulating resin material (molding material) such as epoxy resin. Because the windings wound around the iron cores are integrally molded with epoxy resin to form the molded component 30a, the container and oil filling for insulation required for the existing oil-insulated transformer 16 are unnecessary. Therefore, the new molded insulation transformer 30 does not require the monitoring devices and other equipment required for the existing oil-insulated transformer 16 to prevent oil leakage and for maintenance purposes, and the oil barrier 14 that was previously installed around the transformer is also unnecessary. As a result, the new molded insulation transformer 30 has a simpler structure, is more compact, and is easier to maintain than the existing oil-insulated transformer 16. Furthermore, the space required for installing the new molded insulation transformer 30 can be significantly reduced. This significantly increases the flexibility in the location of equipment in the limited space of the electrical room 10. The housing K2 of the new molded insulation transformer 30 may be filled with a gas that does not require special maintenance, such as dry air. Note that Figure 3 shows the interior of the housing K2 with some of its walls removed.

[0018] 4 is an exemplary and schematic explanatory diagram showing the renewal procedure of the equipment renewal method of the power receiving and transforming system M according to the embodiment. An example will be described in which the process (step S) in the equipment renewal method of the embodiment is composed of, for example, nine steps (S0 to S8).

[0019] The power receiving and transforming system M shown in step 0 (S0) has the same configuration as that shown in Fig. 1, for example, and is provided with redundancy as described above. In the state of step S0, for example, six existing switchgears 12 are available using the existing switchgears 12A and 12B, and two existing oil-insulated transformers 16 are available using the existing oil-insulated transformers 16A and 16B, which have been provided with oil leakage prevention measures using oil retaining dikes 14 (14a, 14B). In other words, the power receiving and transforming system M is configured with two power receiving circuits, ensuring redundancy. Renewal work begins from this state.

[0020] In step 1 (S1), first, the power supply from the existing switchgear 12 is switched to only the existing oil-insulated transformer 16B, and electricity is supplied to all commercial facilities, buildings, and other premises from the existing oil-insulated transformer 16B. In other words, preparations for renewal are made while maintaining the previous redundancy of receiving high-voltage electricity from the electric company through six existing switchgears 12. Next, the existing oil-insulated transformer 16A, to which electricity supply has been stopped, and the oil retaining wall 14A installed for the existing oil-insulated transformer 16A are removed (first removal step). In other words, in the first removal step, multiple existing oil-insulated transformers 16, except for a predetermined number, are removed together with the oil retaining wall 14, forming a first space 20 in the electrical room. In this case, the first space 20 includes the installation area of ​​the oil retaining wall 14A and its surrounding area, making it possible to secure a large free space.

[0021] Subsequently, in step 2 (S2), at least one mold-insulated switchgear 22 is installed in the formed first space 20 (first installation step). In the first installation step, for example, the same number of mold-insulated switchgears 22 as the existing switchgears 12A of the first power-supply circuit 18A (see FIG. 1) are installed somewhere in the first space 20. In the case of FIG. 4, three mold-insulated switchgears 22 are installed at positions equivalent to the installation position of the oil barrier 14 (existing oil-insulated transformer 16), but they may also be arranged, for example, closer to or in contact with the wall surface 10b of the electrical room 10.

[0022] Subsequently, in step 3 (S3), the same number of existing switchgears 12A as the molded insulated switchgears 22 installed in the first installation step are removed to form a second space 24 in the electrical room 10 (second removal step). In this case, the second space 24 includes the installation area of ​​the existing switchgears 12A and a surrounding area including part of the first space 20, making it possible to secure a large free space.

[0023] In step 4 (S4), new mold insulation type switchgears 26 are installed in the first renewal space 24A, which includes at least a part of the first space 20 and the second space 24, in the same number as the existing switchgears 12A removed in the second removal step (S3) (second installation step). In the example shown in FIG. 4, the mold insulation type switchgears 26 are installed so as to be aligned in the Y direction with the mold insulation type switchgears 22 that have already been renewed and installed. As a result, the mold insulation type switchgears 22, 26 are arranged in the Y direction (second arrangement direction), which is different from the arrangement direction (first arrangement direction) of the existing equipment group (existing switchgears 12A, 12B) that was arranged in the X direction in step 1. In this way, a layout in which the arrangement direction of the mold insulation type switchgears 22, 26 is easily changed by, for example, 90° can be realized.

[0024] Next, in step 5, the same number of existing switchgears 12B as the molded insulated switchgears 26 installed in the second installation step (S4) are removed to form a third space 28 in the electrical room 10 (third removal step). In the case of Fig. 4, removal of all of the existing switchgears 12 is completed in step 5. In this case as well, the third space 28 includes the installation area of ​​the existing switchgears 12B and its surrounding area, making it possible to secure a large free space.

[0025] Then, in step 6 (S6), new molded insulation-type transformers 30 in the same number as the existing oil-insulated transformers 16 removed in the first removal step (S1) are installed in the second renewal space 28A, which includes the first renewal space 24A and at least a part of the third space 28 (third installation step). In the case of Fig. 4, one new molded insulation-type transformer 30 is installed in the third space 28, that is, at the position where the existing switchgear 12B was installed, in the -Y direction of the existing oil-insulated transformer 16B and above the existing oil-insulated transformer 16B in the figure.

[0026] In this way, during the renewal work from step 0 to step 6, six switchgears (the existing switchgear 12 and the molded insulated switchgear 22, or the molded insulated switchgear 22 and the molded insulated switchgear 26) are always available for one existing oil-insulated transformer 16 or one new molded insulated transformer 30, and redundancy can be maintained. Furthermore, when the molded insulated switchgear 22 is newly installed in step 2 (S2), the six existing switchgears 12 that were previously in operation are available for use. In other words, with all six switchgears in a state where they can operate normally, it is possible to perform an operation confirmation test of the newly installed molded insulated switchgear 22 at any time. As a result, sufficient redundancy can be ensured even during an operation confirmation test of the molded insulated switchgear 22. Similarly, when the mold insulation type switchgear 26 is newly installed in step 4 (S4), the newly installed mold insulation type switchgear 22, whose operation has been confirmed, and the three existing switchgears 12 that were previously in operation are available for use. In other words, with all six switchgears in a state where they can operate normally, operation confirmation tests of the newly installed mold insulation type switchgear 26 can be performed at any time. Therefore, sufficient redundancy can be ensured even during operation confirmation tests of the mold insulation type switchgear 26. As a result, it becomes possible to always receive power transmission from the power company through two systems of switchgear, and the quality of the power receiving and transformation system M can be maintained. In other words, it is possible to supply power in the same state as before the renewal work, and it is possible to avoid a situation in which the power receiving and transformation system M receives power transmission from the power company through only one system of switchgear, resulting in low quality. Furthermore, with regard to the newly installed molded insulated transformer 30, it will be possible to carry out operation confirmation tests, etc. at any time while still being able to use the existing oil-insulated transformer 16B that was previously in operation, thereby similarly ensuring redundancy and maintaining the quality of the power receiving and transforming system M.

[0027] As the final step, power supply is switched from the molded insulation-type switchgear 22 and / or molded insulation-type switchgear 26 to the newly installed molded insulation-type transformer 30 renewed in step 6, and the remaining existing oil-insulated transformer 16B is shut down. In this state, as in step 7 (S7), the existing oil-insulated transformer 16B and oil barrier 14B are removed (fourth removal step). That is, as in the first removal step, a fourth space 32 is formed in the electrical room 10. In this case, the fourth space 32 includes the installation area of ​​the oil barrier 14B and its surrounding area, making it possible to secure a large free space.

[0028] Finally, in step 8 (S8), the new molded insulation transformer 34 is installed in the formed fourth space 32 (fourth installation step). In the case of Figure 4, the new molded insulation transformer 34 is installed at a position equivalent to the installation position of the oil barrier 14B (existing oil-insulated transformer 16B).

[0029] By performing the renewal work through the above process (steps), the existing equipment can be replaced with new equipment. During this renewal work, as described above, the six switchgears that were installed to ensure redundancy and whose normal operation can be confirmed can be maintained in a constantly available state. Furthermore, conventional renewal work could only be performed in a limited short time, such as at night or on days when the commercial facility or building is closed, which tended to lengthen the work schedule. On the other hand, the renewal work based on the equipment renewal method of this embodiment can be performed during the period when the commercial facility or building is in use, for example, during daytime hours on weekdays, while ensuring redundancy. As a result, the entire renewal work can be performed efficiently in a short time while ensuring redundancy. In other words, the renewal work can be performed smoothly without causing a deterioration in the quality of the power receiving and transforming system M.

[0030] Furthermore, by sequentially changing the installation positions in this manner, for example, it is possible to easily realize a new layout in which the layout of the existing switchgear 12 and the existing oil-insulated transformer 16 shown in step 0 is rotated by 90 degrees, as shown in step 8. The angle of change in the layout is not limited to 90 degrees and can be easily changed to any angle, making it easy to change the specifications of the electrical room 10. Also, while FIG. 4 shows an example in which the mold insulation type switchgear 22 and the mold insulation type switchgear 26 are linearly arranged along the Y direction, this arrangement is not limited to this. For example, the mold insulation type switchgear 26 may be arranged in the X direction relative to the mold insulation type switchgear 22 arranged in the Y direction, resulting in a substantially L-shaped arrangement. In this case as well, it is easy to change the specifications of the electrical room 10.

[0031] Furthermore, for example, when installing a new molded insulation transformer 30 in the third space 28 in the third installation step (S6), it may be installed in a position substantially in contact with the wall surface 10b of the electrical room 10, as shown in FIG. 5. Similarly, when installing a new molded insulation transformer 34 in the fourth space 32 in the fourth installation step (S8), it may be installed in a position substantially in contact with the wall surface 10b of the electrical room 10. As described above, the new molded insulation transformer 30 and the new molded insulation transformer 34 do not require the conventional oil retaining wall 14, and can be made smaller by omitting structures to prevent oil leakage and measuring instruments for management. As a result, they can be easily placed close to the wall surface 10b, etc. As a result, as shown in Fig. 5, it is possible to form a fifth space 36, which is a large free space in which the mold insulation type switchgear 22, the mold insulation type switchgear, the new mold insulation type transformer 30, and the new mold insulation type transformer 34 are not placed. In the fifth space 36, for example, it is possible to add the mold insulation type switchgear 22, the new mold insulation type transformer 30, etc., or to install other equipment, and the space in the electrical room 10 can be used more effectively through the renewal work.

[0032] As shown in FIG. 5 , the fifth space 36 can be used as a large work space during the next renewal work. For example, before removing the mold insulation-type switchgear 22 and mold insulation-type switchgear 26 installed during the next renewal work, the same number of new switchgears as the existing switchgears (in this case, the mold insulation-type switchgear 22 and mold insulation-type switchgear) can be installed and a connection confirmation test can be performed. As a result, all switchgears (the mold insulation-type switchgear 22 and mold insulation-type switchgear) can be replaced at once while ensuring redundancy, which enables more efficient and shorter renewal work. Furthermore, the fifth space 36 can be used to easily change to another layout while ensuring redundancy. During the current renewal work, the mold insulation-type switchgear 22 and mold insulation-type switchgear 26 can also be positioned so that they contact the wall surface 10b of the electrical room 10. In this case, the fifth space 36 can be further enlarged, further improving the flexibility in layout selection and the workability of the renewal work.

[0033] In the above-described embodiment, an example has been shown in which the switchgear after renewal is the molded insulation type switchgear 22 or the molded insulation type switchgear 26. In this case, the molded insulation type switchgear 22 or the molded insulation type switchgear 26 can be made smaller and have a simpler configuration than the existing switchgear 12, and can be renewed into a highly reliable switchgear that contributes to improved management and maintainability, a reduction in replacement parts, and a reduction in running costs. In addition, for the purpose of performing renewal that involves changing the layout in a short period of time while ensuring redundancy, it is not necessary to replace the existing switchgear 12 with a molded insulation type switchgear, and it is also possible to arrange the same switchgear as before in a new layout, and the same effect as in this embodiment can be obtained.

[0034] Furthermore, in this embodiment, the power receiving and substation system M has been described as having six switchgears and two transformers, but the number of switchgears and transformers is not limited to this and can be changed as appropriate, while still achieving the same effects as in this embodiment. Furthermore, the number of switchgears replaced at one time during renewal work can be changed as appropriate. Furthermore, if there are three or more transformers, the number of transformers replaced at one time during renewal work may be more than one, while still achieving the same effects as in this embodiment.

[0035] Although the embodiments of the present invention have been described above, the above embodiments are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The above embodiments are included within the scope and spirit of the invention, as well as within the scope of the inventions and their equivalents as set forth in the claims. [Explanation of symbols]

[0036] 10 Electrical Room 10b Wall 12, 12A, 12B Existing switchgear 14,14A,14B Oil dike 16, 16A, 16B Existing oil-insulated transformers 18A 1st power receiving circuit 18B Second power receiving circuit 20 First Space 22,26 Molded insulated switchgear 22a, 30a molded parts 24 Second Space 24A First Update Space 28 Third Space 28A Second Update Space 30,34 Newly installed molded insulation transformer 32 4th Space 36 5th Space M Power receiving and transforming system

Claims

1. 1. A method for renewing equipment in a power receiving and transforming system including a plurality of existing oil-insulated transformers that are arranged in an electrical room and have oil leakage prevention measures implemented by an oil barrier, and a plurality of existing switchgears, comprising: a first removal step of removing the plurality of existing oil-insulated transformers together with the oil barrier, leaving a predetermined number of the existing oil-insulated transformers, to form a first space in the electrical room; a first installation step of installing at least one new switchgear in the first space; a second removal step of removing the same number of existing switchgears as the new switchgears installed in the first installation step to form a second space in the electrical room; a second installation step of installing new switchgears in a first renewal space including at least a part of the first space and the second space, the number of which is equal to the number of the existing switchgears removed in the second removal step; a third removal step of removing the same number of the existing switchgears as the new switchgears installed in the second installation step to form a third space in the electrical room; a third installation step of installing new molded insulation transformers in a second renewal space including at least a part of the first renewal space and the third space, the number of which is equal to the number of the existing oil-insulated transformers removed in the first removal step; A method for renewing equipment in a power receiving and transforming system, including:

2. 2. The equipment renewal method for a power receiving and transforming system according to claim 1, wherein the third installation step installs the new molded insulation transformer in the third space.

3. 2. The equipment renewal method for a power receiving and transforming system according to claim 1, wherein the third installation step installs the new molded insulation transformer in the second renewal space in a position where the new molded insulation transformer is substantially in contact with a wall surface of the electrical room.

4. 4. The equipment renewal method for a power receiving and substation system according to claim 1, wherein the first installation step and the second installation step arrange and install the new switchgear in a second arrangement direction different from a first arrangement direction of the plurality of existing switchgears.

5. 5. The equipment renewal method for a power receiving and transforming system according to claim 1, wherein the first installation step and the second installation step install a molded insulated switchgear as the new switchgear.

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