Stationary induction electrical apparatus

Abstract

To provide a stationary induction electrical apparatus that can accommodate windings and an arrester in a container and actuate them to prevent overvoltage generated at a neutral point.SOLUTION: A stationary induction electrical apparatus of an embodiment has a container, three-phase windings, and an arrester. The container has a closing lid. The three-phase windings are accommodated in the container, and each of which is connected by Δ connection at one end and Y connection at the other end. The arrester is accommodated in the container and attached between the ground point and an ungrounded neutral point terminal of the Y connection.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a stationary induction motor. [Background technology]

[0002] Conventionally, for static induction electric equipment such as power transformers with a voltage of less than 154 kV, when the windings are connected in a delta or Y connection, the neutral point is often ungrounded and not drawn out. When the neutral point is ungrounded, there is no terminal that serves as a reference potential, so when a lightning surge enters the winding, an oscillating voltage may occur in the winding. In this case, an overvoltage 1.5 to 2 times that of the applied part occurs near the neutral point, so insulation reinforcement of the neutral point is required. When a gas-insulated transformer is used, which uses a naturally occurring gas such as N2 as an insulating medium for insulation reinforcement, the insulating medium has lower insulating performance than conventional insulating oil or SF6 gas, and more complex insulation reinforcement and increased insulation distance are required, which may make it difficult to promote the miniaturization and weight reduction of power transformers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2-112211 Summary of the Invention [Problem to be solved by the invention]

[0004] The problem that the present invention aims to solve is to provide a static induction device that can house and operate a winding and an arrester within a container, thereby promoting miniaturization and lightweight design while suppressing overvoltage generated at the neutral point. [Means for solving the problem]

[0005] The stationary induction device of the embodiment has a container, a three-phase winding, and an arrester. The container has a closing lid. The three-phase winding is housed in the container, and one end of each winding is connected in a delta connection and the other end is connected in a Y connection. The arrester is housed in the container and attached between an ungrounded neutral terminal of the Y connection and a ground point. [Brief description of the drawings]

[0006] [Figure 1] FIG. [Diagram 2] FIG. 2 is a configuration diagram of a Δ connection according to the first embodiment. [Diagram 3] FIG. 11 is a configuration diagram of the other Y connection according to the first embodiment. [Figure 4] FIG. 11 is a configuration diagram of a Δ connection according to a second embodiment. [Diagram 5] FIG. 11 is a configuration diagram of a Y connection according to a third embodiment. [Figure 6] FIG. 13 is a configuration diagram of a Y connection according to a fourth embodiment. [Figure 7] FIG. 13 is a configuration diagram of the other Y connection according to the fourth embodiment. [Figure 8] FIG. 11 is a layout diagram of the tank 1 according to the fifth embodiment. [Figure 9] FIG. 11 is a layout diagram of a tank 1 having a partition plate 6 according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, a static induction motor according to an embodiment will be described with reference to the drawings.

[0008] (First embodiment) 1 is a cross-sectional view of a static induction device 100. The static induction device 100 includes, for example, a tank 1, a closing lid 2, an arrester 3, an iron core 4, a winding 5, and a partition plate 6. In the figure, the Z axis is a vertical direction, and the X axis and the Y axis are two horizontal axes. The long axis direction of the iron core 4 is set along the Z axis, and the winding 5 is wound around the long axis direction of the iron core 4. The definitions of the Z axis, the X axis, and the Y direction are the same in the subsequent figures.

[0009] The tank 1 is made of metal. A specific gas is sealed in the tank 1. The specific gas is a naturally occurring gas such as N2 or CO2, or SF6 gas. The specific gas may be a mixture of these gases. The tank 1 is an example of a container.

[0010] The closing lid 2 is provided in the vicinity of the arrester 3 in the tank 1. The closing lid 2 can be opened and closed, and is opened and closed mainly when the stationary induction device 100 is subjected to maintenance.

[0011] The arrester 3 is formed of multiple nonlinear elements that become conductive when a certain voltage or more is applied. The arrester 3 is formed by connecting in series multiple modules, each of which has one or more nonlinear elements connected in parallel. The arrester 3 is provided in the lower part of the tank 1.

[0012] The iron core 4 is made of a magnetic material. When a current is passed through the iron core 4, a magnetic field is generated, and the iron core 4 functions like a magnet.

[0013] The winding 5 is, for example, a copper wire, and is capable of generating a magnetic flux when a current is passed through it.

[0014] Partition plate 6 is a plate that separates tank 1 into upper and lower spaces. In general, the space above partition plate 6 is at a high temperature, and the space below partition plate 6 is at a low temperature. Partition plate 6 is open to the cooling flow paths installed in heating elements including iron core 4 and windings 5, and is used to circulate a large amount of gas inside the heating elements for efficient cooling.

[0015] 2 is a configuration diagram of a delta connection according to the first embodiment. In the first embodiment, a wire is drawn from a winding intermediate portion 7 connected to the delta connection, and an arrester 3 is connected to the wire. There are arresters 3A to 3C, but hereinafter, when there is no need to distinguish between them, they will be referred to as arrester 3.

[0016] Winding intermediate portion 7 is a middle portion of winding 5. There are winding intermediate portions 7A to 7C. Hereinafter, they will be referred to as winding intermediate portion 7 when there is no need to distinguish between them.

[0017] Fig. 3 is a configuration diagram of the other Y connection according to the first embodiment. The windings in Fig. 2 and Fig. 3 are wound concentrically around the same iron core for each phase, and convert voltage by magnetic coupling. An arrester 3D is connected to a neutral terminal 8A of the Y connection. The neutral terminal 8 is a point where the neutral points of each phase are connected.

[0018] In the first embodiment, one of the three-phase windings housed in the tank 1 is a Δ connection and the other is a Y connection, and an arrester 3D is attached between an ungrounded neutral terminal 8A of the Y connection and the ground point. The arrester 3 is housed in the tank 1 in the same manner as the three-phase windings. In addition, the arrester 3 is attached between a winding intermediate portion 7 of the Δ connection and the ground point.

[0019] With the configuration of the first embodiment, when a lightning surge penetrates the winding 5 between the Y connection and the neutral terminal 8A, the arrester 3D can suppress the overvoltage generated at the neutral terminal 8A to a certain value or less. The overvoltage can be suppressed by setting the limiting voltage of the arrester 3 to a value lower than the voltage of the lightning surge generated at the neutral terminal 8A and higher than various AC overvoltages. When the arrester 3 suppresses the overvoltage, the lightning surge is reflected at the neutral terminal 8A and causes internal oscillation, and it is possible to suppress the generation of an oscillatory surge with a wave height greater than that of the penetrating lightning surge in the winding 5.

[0020] Furthermore, with the configuration of the first embodiment, in the Δ connection, when a lightning surge enters from a certain terminal, the arrester 3 attached to the winding intermediate portion 7 operates, thereby obtaining the same effect.

[0021] Due to these effects, the configuration of the first embodiment can reduce the risk of dielectric breakdown of the neutral point terminal 8, and can simplify the insulation configuration of the neutral point terminal 8 as compared to conventional devices.

[0022] Second embodiment 4 is a configuration diagram of a Δ-connection according to the second embodiment. The stationary induction electric device 100 of the second embodiment includes, for example, a tank 1 having a closing lid 2, a three-phase built-in Δ-winding housed in the tank 1, in which one end of each winding is connected by a Δ-connection, and an arrester 3 housed in the tank 1 and attached between one or two terminals 9 other than the ground terminal of the winding 5 and a ground point. The terminals 9 include terminals 9A to 9C, but hereinafter, when there is no need to distinguish between them, they will be referred to as terminals 9.

[0023] As in the first embodiment, the clamping voltage of the arrester 3 is set to a value lower than the voltage of a generated lightning surge and higher than various AC overvoltages.

[0024] The built-in Δ winding is a winding that is Δ-connected inside a static induction device, and does not have external terminals, so surges do not enter it from the outside. However, when various surge waves, such as a lightning surge, enter the winding 5 adjacent to the built-in Δ winding, a surge wave is also generated in the Δ-connected winding 5 due to electromagnetic induction. The generated surge wave oscillates inside the winding 5, but surge waves with a wave height above a certain value are suppressed by the arrester 3. By suppressing overvoltage, it is possible to suppress surge waves that enter the winding 5 adjacent to the Δ connection, and the risk of insulation breakdown can be reduced. In addition, the configuration of the insulation reinforcement can be simplified compared to conventional equipment.

[0025] (Third embodiment) 5 is a configuration diagram of a Y-connection according to the third embodiment. The stationary induction electric device 100 of the third embodiment includes, for example, a tank 1 having a closing lid 2, a three-phase winding housed in the tank 1, in which one end of each winding 5 is connected in a Y-connection, and an arrester 3 housed in the tank 1 and attached between a winding intermediate portion 7 of the winding 5 and a ground point.

[0026] As in the first embodiment, the clamping voltage of the arrester 3 is set to a value lower than the voltage of a generated lightning surge and higher than various AC overvoltages set in the winding 5.

[0027] When a lightning surge is applied to the Y-connected winding 5, the arrester 3 can suppress the voltage wave height generated inside the winding 5. By suppressing the voltage wave height, it is possible to suppress insulation breakdown inside the winding. Furthermore, the configuration of the insulation reinforcement can be simplified compared to conventional devices.

[0028] (Fourth embodiment) Fig. 6 is a configuration diagram of a Y-connection according to the fourth embodiment. Fig. 7 is a configuration diagram of the other Y-connection according to the fourth embodiment. The stationary induction electric device 100 of the fourth embodiment includes, for example, a tank 1 having a closing lid 2, a three-phase winding housed in the tank 1, one end of each winding being connected in a Δ-connection or a Y-connection, and an arrester 3 housed in the tank 1 and attached to a terminal 9 drawn out from a winding intermediate portion 7 of the winding 5. Although a Y-connection is shown in Figs. 6 and 7, a Δ-connection may also be used.

[0029] The arrester 3 is attached to the Y-connected or Δ-connected winding 5 by drawing out terminals from the winding intermediate portion 7. As in the first embodiment, the clamping voltage of the arrester 3 is set lower than the voltage of a generated lightning surge and higher than various AC overvoltages.

[0030] When a lightning surge is applied to the winding 5, the arrester 3 can suppress the voltage wave height generated inside the winding 5. By suppressing the voltage wave height, it is possible to suppress insulation breakdown inside the winding. In addition, the configuration of the insulation reinforcement can be simplified compared to conventional devices.

[0031] Fifth embodiment 8 is a layout diagram of the tank 1 according to the fifth embodiment. In the stationary induction device 100 of the fifth embodiment, the tank 1 accommodates an iron core 4, a winding 5, and an arrester 3. The arrester 3 attached to the winding 5 is installed below the vertical middle of the tank 1.

[0032] The higher inside the tank 1, the higher the temperature. Since the arrester 3 is made of semiconductor elements, the higher the temperature, the shorter its lifespan. By installing the arrester 3 at the bottom of the tank 1, the temperature of the arrester 3 can be suppressed, and its lifespan can be extended.

[0033] 9 is a layout diagram of tank 1 with partition plate 6 according to the fifth embodiment. Partition plate 6 is for forcibly circulating a specific gas, which is an insulating cooling medium, through iron core 4 and windings 5. Since the temperature above partition plate 6 is high and the temperature below partition plate 6 is low, by providing arrester 3 below partition plate 6, the life of arrester 3 can be extended.

[0034] According to at least one of the embodiments described above, by housing and operating the winding and arrester within a container, it is possible to provide a static induction device that promotes size and weight reduction and can suppress overvoltage generated at the neutral point.

[0035] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These 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 modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0036] 1...tank, 2...closing cover, 3...arrester, 4...iron core, 5...winding, 6...partition plate, 7...winding middle part, 8...neutral terminal, 9...terminal, 100...static induction device

Claims

1. A container having a closing lid; a three-phase winding housed in the container, one end of each winding being connected in a delta connection and the other end being connected in a star connection; an arrester housed in the container and attached between an ungrounded neutral terminal of the wye connection and a ground point; Stationary induction appliance.

2. A container having a closing lid; a three-phase winding housed in the container, one end of each winding being connected in a delta connection and the other end being connected in a star connection; and an arrester housed in the container and attached between the intermediate portion of the delta connection and a ground point. Stationary induction appliance.

3. A container having a closing lid; a three-phase built-in Δ winding housed in the container, the three-phase built-in Δ winding being connected in a Δ connection, one terminal of which is grounded; an arrester housed in the container and attached between one or two terminals other than the ground terminal of the winding and a ground point; Stationary induction appliance.

4. A container having a closing lid; a three-phase winding housed in the container, the three-phase winding having one end connected in a Y-connection; an arrester housed in the container and attached between the intermediate portion of the winding and a ground point; Stationary induction appliance.

5. A container having a closing lid; a three-phase winding housed in the container, the three-phase winding having one end connected in a delta connection or a star connection; an arrester housed in the container and attached to a terminal drawn out from an intermediate portion of the winding; Stationary induction appliance.

6. The limiting voltage of the arrester is set to a value lower than the voltage of a lightning surge occurring at the neutral point and higher than various AC overvoltages. A static induction device according to any one of claims 1 to 5.

7. The container is filled with natural gas or SF6 gas, The arrester is attached to the lower part of the container. A static induction device according to any one of claims 1 to 5.

8. The container is filled with natural gas or SF6 gas, The arrester is attached below the gas partition plate in the container. A static induction device according to any one of claims 1 to 5.

9. The closing lid is provided near the arrester.

8. The static induction motor according to claim 7.

10. The closing lid is provided near the arrester. The static induction motor according to claim 8.

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