Stationary induction apparatus

Abstract

To provide a stationary induction apparatus which enables reduction of noise more effectively.SOLUTION: A stationary induction apparatus according to one embodiment of the disclosure includes: a stationary induction apparatus body 2; a housing which houses the stationary induction apparatus body 2; a plurality of reinforcement members 20 provided on an outer side surface 10SP of the housing and configured to reinforce the outer side surface 10SP; and load applying means which constantly applies a load for deforming the outer side surface 10SP of the housing.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to stationary induction machines. [Background technology]

[0002] Conventionally, in order to reduce noise generated by stationary induction devices such as transformers and reactors, the stationary induction devices have been surrounded by soundproof walls. In addition, focusing on the fact that noise from stationary induction devices is caused by vibration due to magnetostriction, noise has also been reduced by attaching vibration-damping material to the housing of the stationary induction device.

[0003] On the other hand, it is known that in a stationary induction device, when the natural frequency of the housing is an even multiple of the excitation frequency, resonance occurs and this resonance becomes a noise source. Therefore, a technology has been proposed to suppress resonance and reduce noise by changing the natural frequency of the housing of the stationary induction device. For example, Patent Document 1 shows a configuration in which "in a transformer in which an iron core is composed of legs and upper and lower yoke portions, a support rod is fixed between the upper yoke portion and the lower yoke portion to adjust the natural frequency of the iron core in the yoke portion." For example, Patent Document 2 discloses a configuration in which a weight for reducing noise is attached to a reinforcing member attached to the side surface of a transformer tank, thereby shifting the resonance frequency of the reinforcing member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 58-70513 [Patent Document 2] JP 2020-170797 A Summary of the Invention [Problem to be solved by the invention]

[0005] The technology of Patent Document 1 adjusts the natural frequency of the iron core housed in the housing, so adjustments are difficult to make after the housing is closed. Furthermore, the technology of Patent Document 2 is a technology for shifting the resonance frequency of a reinforcing member, and does not directly shift the natural frequency of the housing, so there is room for further improvement in the effect of reducing noise due to resonance.

[0006] An object of the present disclosure is to provide a stationary induction device that can more effectively reduce noise. [Means for solving the problem]

[0007] A stationary induction device according to one embodiment of the present disclosure comprises a stationary induction device main body, a housing that houses the stationary induction device main body, a plurality of reinforcing members provided on an outer surface of the housing that reinforce the outer surface, and a load-applying means that steadily applies a load that causes deformation to the outer surface of the housing. Effect of the Invention

[0008] According to one embodiment of the present disclosure, noise from stationary induction equipment can be reduced more effectively. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a diagram illustrating an example of a transformer according to an embodiment of the present disclosure. [Diagram 2] FIG. 4 is a diagram showing an example of a cross-sectional configuration of a reinforcing member. [Diagram 3] 11A and 11B are diagrams illustrating an example of a configuration of a rear side of a reinforcing member. [Figure 4] 10 is a diagram showing a schematic diagram of the relationship between the pressure in the internal space of the reinforcing member and the deformation of the outer surface of the tank. FIG. [Diagram 5] 6A and 6B are diagrams illustrating the relationship between the pressure in the internal space of the reinforcing member and the deformation of the outer surface of the reinforcing member. [Figure 6] 11 is a diagram showing the relationship between the vibration frequency characteristics of a front plate of a tank and the pressure state of an internal space of a reinforcing member. FIG. [Figure 7] FIG. 13 is a diagram showing the vibration state of a membrane on the outer surface of the tank. [Figure 8] FIG. 8 is a diagram showing the relationship between the natural frequency of the membrane vibration in each vibration state shown in FIG. 7 and the pressure in the internal space of the reinforcing member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a preferred embodiment of the present disclosure will be described with reference to the drawings. In the drawings, the dimensions and scale of each part may differ from the actual ones, and some parts may be shown diagrammatically to facilitate understanding. In addition, unless otherwise specified in the following description to the effect that the present disclosure is limited, the scope of the present disclosure is not limited to the embodiments described in the following description. The scope of the present disclosure includes the equivalent scope of the embodiments.

[0011] 1. Embodiment FIG. 1 is a diagram illustrating a schematic diagram of an example of a transformer 1 according to the present embodiment. The transformer 1 is an example of a "static induction device" in the present disclosure. The transformer 1 of this embodiment is installed in a substation, a power distribution facility, etc., and is a device that steps down or steps up the voltage of power transmitted from outside the premises to a predetermined voltage according to the purpose of the transformer 1. As shown in Fig. 1, the transformer 1 of this embodiment includes a tank 10, a plurality of base members 12 that are an example of legs that support the tank 10, and a plurality of reinforcing members 20 that reinforce the strength of the tank 10. Each of the multiple base materials 12 is a member having extremely high rigidity, such as an H-shaped steel, an L-shaped steel, or an I-shaped steel, and is firmly fixed to a foundation, such as a concrete foundation, constructed at the installation site, and the tank 10 is mounted on these base materials 12. Note that a vibration-isolating member such as a vibration-isolating rubber may be provided between the base material 12 and the tank 10.

[0012] The tank 10 is an example of a housing that houses the stationary induction device body 2. The stationary induction device body 2 is a device that includes a winding and an iron core, and is fixed inside the tank 10 by a fixing member (not shown) such as a frame. The tank 10 also houses a magnetic shielding material (not shown) that suppresses leakage of magnetic flux. The transformer 1 of this embodiment is a so-called oil-filled device. That is, the tank 10 is a structure with an enclosed interior, and is filled with insulating oil (not shown), which is an example of an insulating medium. As the insulating oil, an appropriate type of oil such as mineral oil or natural ester is used.

[0013] The tank 10 of this embodiment has a substantially rectangular parallelepiped shape, i.e., a hexahedral shape, and includes a top plate 10SU, a bottom plate 10SD, a front plate 10SF, a back plate 10SB, and a pair of side plates 10SR and 10SL. That is, the outer surface 10SP of the tank 10 is formed by the front plate 10SF, the back plate 10SB, and the pair of side plates 10SR and 10SL. In this disclosure, the "outer surface" refers to a surface that surrounds an axis extending in the height direction of the tank 10. In the illustrated example, the front plate 10SF and the back plate 10SB correspond to a pair of main surfaces having the largest areas in a substantially rectangular parallelepiped, and have an aspect ratio in which the width Bw is larger than the height Bh. That is, the tank 10 of this embodiment has a narrow depth and a long box shape. Although not shown in the drawings, a plurality of terminals to which power lines are connected are provided upright on the upper plate 10SU of the tank 10. The plurality of terminals may be either primary terminals or secondary terminals, or may include both.

[0014] In the following description, the width direction and height direction of the front plate 10SF are defined as the X-axis direction and the Y-axis direction, respectively, and the normal direction of the front plate 10SF is defined as the Z-axis direction.

[0015] In the oil-filled transformer 1, when filling the tank 10 with insulating oil, the inside of the tank 10 is made into a vacuum state, and in this state, the insulating oil is filled into the tank 10. The multiple reinforcing members 20 provided in the transformer 1 are members that reinforce the strength of the outer surface 10SP of the tank 10 in order to suppress deformation of the outer surface 10SP of the tank 10 during the process of making the inside of the tank 10 into a vacuum state. The reinforcing members 20 in this embodiment are rod-shaped members extending across the top plate 10SU and bottom plate 10SD of the tank 10, i.e., rod-shaped members having a length equivalent to the height of the tank 10, and are provided on each of the surfaces of the front plate 10SF, the back plate 10SB, and the pair of side plates 10SR, 10SL, which are the outer side surface 10SP of the tank 10. The number of reinforcing members 20 provided on each surface and the arrangement interval between the reinforcing members 20 are appropriately set according to the strength of that surface.

[0016] The reinforcing member 20 of the present embodiment is an example of the "load applying means" in the present disclosure, and has a function of steadily applying a load that causes deformation to the outer surface 10SP in addition to a function of reinforcing the strength of the outer surface 10SP of the tank 10. The configuration of the reinforcing member 20 will be described in detail below.

[0017] Fig. 2 is a diagram showing an example of the cross-sectional configuration of the reinforcing member 20. Note that this cross section is a plane perpendicular to the Y-axis direction (height direction). Fig. 3 is a diagram showing an example of the configuration of the back side of the reinforcing member 20. As shown in FIG. 2, the reinforcing member 20 is a member in which an internal space 20I is formed, and is made of an appropriate material such as steel, and has the rigidity required for reinforcing the outer surface 10SP of the tank 10. The reinforcing member 20 of this embodiment has an opening 20H that opens the internal space 20I to the outside by being formed in a substantially C-shaped cross section, and the reinforcing member 20 is fixed to the surface of the outer surface 10SP of the tank 10 by welding or the like so that the opening 20H is airtightly closed by the outer surface 10SP of the tank 10. In this mounting state, the airtight internal space 20I is in direct contact with the outer surface 10SP of the tank 10 through the opening 20H, so that the pressure of the internal space 20I is directly and steadily applied to the outer surface 10SP, causing deformation of the outer surface 10SP.

[0018] As shown in FIG. 3, in the reinforcing member 20 of this embodiment, the opening 20H is a single slit-shaped opening extending in the longitudinal direction Da. By providing this reinforcing member 20 on the outer surface 10SP of the tank 10, the pressure of the internal space 20I is applied to the outer surface 10SP across the upper plate 10SU and the bottom plate 10SD. The opening 20H does not have to be a single slit-shaped opening. For example, the opening 20H may be a plurality of through holes arranged at appropriate intervals in the longitudinal direction Da of the reinforcing member 20. In this case, the number, opening shape, and opening area of ​​each through hole are appropriate.

[0019] 1, the reinforcing member 20 is provided with a normally closed valve 23, and this valve 23 is connected to an internal pressure adjustment means 30. Note that the valve 23 is omitted in Fig. 2. The internal pressure adjustment means 30 is a means for adjusting the pressure of the internal space 20I, and includes, for example, a device such as a pump that increases the internal pressure by feeding compressed air into the internal space 20I, or decreases the internal pressure by discharging air from the internal space 20I. In addition, when adjusting the pressure of the internal space 20I to a positive pressure, the pressure may be adjusted by filling it with a substance other than a gas such as air. In this case, the type of substance may be any appropriate type, and may be, for example, a liquid such as water, or a solid such as powder.

[0020] Fig. 4 is a diagram showing a schematic diagram of the relationship between the pressure in the internal space 20I of the reinforcing member 20 and the deformation of the outer surface 10SP of the tank 10. In Fig. 4, "positive pressure load" indicates a state in which the pressure in the internal space 20I is higher than the external pressure. Also, "negative pressure load" indicates a state in which the pressure in the internal space 20I is lower than the external pressure. As shown in "positive pressure load" in FIG. 4, when the pressure in the internal space 20I is higher than the outside, the pressure in the internal space 20I acts on the outer surface 10SP of the tank 10, and a load A1 is applied that presses the tank 10 toward the inside. This load A1 causes the outer surface 10SP to undergo a deformation B1 that causes the outer surface 10SP to dent inward, and the rigidity of the outer surface 10SP of the tank 10 changes due to this deformation B1. Such rigidity is generally referred to as "geometric rigidity" or "differential rigidity." The change in the rigidity of the outer surface 10SP causes the natural frequency of the outer surface 10SP to change. In this embodiment, since the upper end and the lower end of the outer surface 10SP are fixed ends, a force F1 that pulls the upper end and the lower end of the outer surface 10SP at the deformation B1 occurs, and the natural frequency increases.

[0021] Also, as shown in "negative pressure load" in Fig. 4, when the pressure in the internal space 20I is lower than the outside, the pressure in the internal space 20I acts on the outer surface 10SP of the tank 10, applying a load A2 that pulls the tank 10 toward the outside. This load A2 causes a deformation B2 in the outer surface 10SP that bulges outward, and this deformation B2 changes the rigidity of the outer surface 10SP of the tank 10, and the natural frequency of the outer surface 10SP also changes. In this embodiment, in the case of "negative pressure load", as in the case of "positive pressure load", a pulling force F1 is generated at the upper end and the lower end of the deformation B2, and as a result, the natural frequency becomes higher.

[0022] Thus, in this embodiment, the reinforcing member 20 constantly applies pressure to the outer surface 10SP of the tank 10, causing deformation of the surface, thereby causing the geometric rigidity of the outer surface 10SP to constantly change, and as a result, the natural frequency of the outer surface 10SP is maintained in a constantly changed state.

[0023] FIG. 5 is a diagram showing a schematic diagram of the relationship between the pressure in the internal space 20I of the reinforcing member 20 and the deformation of the outer surface 20SP of the reinforcing member 20. As shown in FIG. In this embodiment, the outer surface 20SP of the reinforcing member 20 also steadily deforms due to the pressure in the internal space 20I, and the geometric rigidity of the outer surface 20SP steadily changes, so that the natural vibration of the reinforcing member 20 is also maintained in a steadily changed state. Specifically, as shown in "positive pressure load" in Fig. 5, when the pressure in the internal space 20I is higher than the outside, the pressure acts on the outer surface 20SP of the reinforcing member 20, applying a load A1 that presses outward, and the outer surface 20SP is deformed B3 to bulge outward. As a result, the stiffness of the outer surface 20SP of the reinforcing member 20 also changes, and the natural frequency of the reinforcing member 20 changes. 5, when the pressure in the internal space 20I is lower than the outside, the pressure acts on the outer surface 20SP of the reinforcing member 20, and a load A2 is applied to the outer surface 20SP, pulling it inward. This load A2 causes deformation B4 in the outer surface 20SP, causing it to dent inward. As a result, as with the "positive pressure load," the deformation of the outer surface 20SP under the "negative pressure load" also changes the rigidity, and the natural frequency of the reinforcing member 20 changes.

[0024] Fig. 6 is a diagram showing the relationship between the vibration frequency characteristics of the front plate 10SF of the tank 10 and the pressure state of the internal space 20I of the reinforcing member 20. In Fig. 6, "no load" indicates that the pressure in the internal space 20I is the same as the external pressure. The vibration frequency characteristics were obtained by applying vibration to the base material 12 in the Z-axis direction as base excitation with the main body of the transformer 1 configured as shown in Fig. 1 at rest (no excitation vibration).

[0025] As shown in the figure, when comparing the case of "no load" and the case of "negative pressure load", it can be seen that the peak position in the frequency characteristics is shifted. Therefore, the experiment shows that the natural frequency of the front plate 10SF changes when pressure is applied to the front plate 10SF. Note that the same results as for the front plate 10SF are obtained for the frequency characteristics of the rear plate 10SB and the pair of side plates 10SR and 10SL that constitute the remaining outer surface 10SP other than the front plate 10SF. In other words, the natural frequency of each surface changes steadily when pressure is steadily applied by the reinforcing member 20 to each surface that constitutes the outer surface 10SP.

[0026] FIG. 7 is a diagram showing the vibration state of the membrane vibration on the outer surface 10SP of the tank 10. As shown in FIG. It is known that the frequency of the excitation vibration of the stationary induction device body 2 is an even multiple of the frequency of the power applied thereto, and the frequency band of the excitation vibration is relatively narrow. Meanwhile, the excitation vibration generates a membrane vibration on the outer surface 10SP of the tank 10, causing the surface to undulate. The natural frequency of the membrane vibration is roughly equal to the frequency of the excitation vibration. In FIG. 7, vibration state A, vibration state B, vibration state C, and vibration state D show cases where the natural frequencies are 82.1 Hz, 94.5 Hz, 127.7 Hz, and 144.8 Hz, respectively, and the higher the natural frequency, the more waves the membrane vibration contains.

[0027] FIG. 8 is a diagram showing the relationship between the natural frequency of the membrane vibration and the pressure in the internal space 20I of the reinforcing member 20 in each vibration state shown in FIG. As shown in the figure, when comparing the "no load" case with the "negative pressure load" case, it can be seen that the natural frequency shifts by about 2 Hz to about 3 Hz in all vibration states. This shift in the natural frequency is sufficiently larger than the band of the excitation vibration. Therefore, in the "no load" state, when resonance occurs due to the frequency of the excitation vibration coinciding with the natural frequency of the outer surface 10SP of the tank 10, by changing the internal space 20I of the reinforcing member 20 from the "no load" state to the "negative pressure load" or "positive pressure load" state, the natural frequency of the outer surface 10SP can be maintained in a state steadily shifted outside the band of the excitation vibration, and the resonance can be steadily suppressed. And, by suppressing the resonance in this way, the noise is reduced.

[0028] In the transformer 1 of this embodiment, the natural frequency of the reinforcing member 20 also changes steadily due to the pressure in the internal space 20I of the reinforcing member 20, so that the deviation of the natural frequency of the tank 10 to which the reinforcing member 20 is fixed becomes larger. The greater the deviation between the natural frequency of the tank 10 and the frequency of the excitation vibration, the weaker the resonance becomes, and therefore the noise caused by the resonance can be more effectively suppressed.

[0029] Generally, the natural frequency of the tank 10 differs for each individual transformer 1, but the natural frequency of the tank 10 does not change after shipment. Therefore, in this embodiment, the pressure in the internal space 20I of each reinforcing member 20 is adjusted in advance before the shipment of the transformer 1, and noise generation after installation is suppressed. Specifically, in the adjustment process, before the transformer 1 is shipped, the stationary induction device main body 2 is energized to operate the stationary induction device main body 2, and noise caused by excitation vibration is measured. Next, if the noise is equal to or greater than a predetermined level, the pressure in the internal space 20I of each reinforcing member 20 is adjusted by the internal pressure adjusting means 30 to a value at which resonance of the tank 10 is suppressed.

[0030] As a result of the pressure adjustment, the pressure in the internal space 20I of the reinforcing members 20 provided in each of the front plate 10SF, the back plate 10SB, and the pair of side plates 10SR and 10SL constituting the outer surface 10SP may be different. Also, the pressure in the internal space 20I may be different among the multiple reinforcing members 20 provided in each of the front plate 10SF, the back plate 10SB, and the pair of side plates 10SR and 10SL. Furthermore, the pressure in the internal space 20I of the reinforcing member 20 may be adjusted to either a positive pressure or a negative pressure, so long as it causes deformation in the outer surface 10SP of the tank 10 and the outer surface 20SP of the reinforcing member 20.

[0031] In addition, in the maintenance work after the installation of the transformer 1, the pressure in the internal space 20I of each reinforcing member 20 may be adjusted by the internal pressure adjusting means 30 to the pressure at the time of shipment.

[0032] Furthermore, a system may be configured that includes a transformer 1, an internal pressure adjustment means 30, a sensor that measures the pressure in the internal space 20I of each reinforcing member 20, and a control means that adjusts the pressure in the internal space 20I of each reinforcing member 20 to the pressure at the time of shipment by controlling the internal pressure adjustment means 30 based on the measurement results of the sensor. According to this system, even in a situation where the pressure in the internal space 20I of each reinforcing member 20 fluctuates depending on the environment, for example, when the transformer 1 is installed in an environment with a large temperature difference throughout the day or year, the fluctuation in pressure can be suppressed.

[0033] As described above, the transformer 1 of this embodiment comprises a stationary induction device main body 2, a tank 10 that houses the stationary induction device main body 2, and a plurality of reinforcing members 20 that are provided on the outer surface 10SP of the tank 10 and reinforce the outer surface 10SP, and each of the plurality of reinforcing members 20 functions as a load-applying means that steadily applies a load that causes deformation to the outer surface 10SP of the tank 10. According to this configuration, each of the multiple reinforcing members 20 functions as a load applying means, and the natural frequency of the tank 10 can be steadily shifted from the frequency that resonates with the excitation vibration by deformation of the outer surface 10SP of the tank 10. This makes it possible to effectively reduce noise caused by resonance, compared to a configuration in which only the natural frequency of the reinforcing members 20 is changed.

[0034] In the transformer 1 of this embodiment, each of the multiple reinforcing members 20 steadily applies a load to the outer surface 10SP of the tank 10 by the pressure of the internal space 20I formed therein. According to this configuration, by adjusting the pressure in the internal space 20I of the reinforcing member 20, the load applied to the outer surface 10SP of the tank 10, that is, the natural frequency of the tank 10, can be easily adjusted.

[0035] In the transformer 1 of this embodiment, a load that causes deformation on the outer surface 20SP of each of the multiple reinforcing members 20 is steadily applied by the pressure in the internal space 20I. According to this configuration, the natural frequency of not only the tank 10 but also the reinforcing member 20 provided therein changes steadily, so that the noise caused by this resonance can be more effectively suppressed.

[0036] In the transformer 1 of this embodiment, each of the reinforcing members 20 has an opening 20H that opens the internal space 20I to the outside, and the opening 20H is air-tightly closed by the outer surface 10SP of the tank 10. According to this configuration, a load can be easily applied to the outer surface 10SP of the tank 10 simply by attaching the reinforcing member 20 so that the outer surface 10SP of the tank 10 closes the open portion 20H.

[0037] 2. Variations The following are examples of modified forms that can be added to the above-described embodiment. Two or more forms selected from the following examples may be combined as appropriate within the scope of not being mutually contradictory.

[0038] (1) The "load applying means" in the present disclosure may be provided in the tank 10 separately from the reinforcing member 20. In this case, one example of the configuration of the load applying means is a configuration in which the load applying means includes a main body of an appropriate three-dimensional shape and size having an internal space 20I and an opening 20H that opens the internal space 20I to the outside, and the main body is provided on the outer surface 10SP of the tank 10 so that the opening 20H is airtightly closed by the outer surface 10SP of the tank 10.

[0039] (2) The “static induction device” in this disclosure is not limited to the transformer 1, but may be other devices such as a reactor. [Explanation of symbols]

[0040] 1...transformer, 2...stationary induction equipment body, 10...tank, 10SP...outer surface, 20...reinforcing member, 20H...open portion, 20I...internal space, 20SP...outer surface, 23...valve, 30...internal pressure regulating means.

Claims

1. A stationary induction device body; A housing for housing the stationary induction device body; A plurality of reinforcing members provided on an outer surface of the housing to reinforce the outer surface; a load applying means for steadily applying a load that causes deformation to an outer surface of the housing; A stationary induction device comprising:

2. the load applying means includes the plurality of reinforcing members, Each of the plurality of reinforcing members steadily applies the load to the outer surface of the housing by pressure in an internal space formed therein.

2. The stationary induction machine of claim 1.

3. A load that causes a shape to be applied to the outer surface of each of the plurality of reinforcing members is steadily applied by the pressure in the internal space.

3. The stationary induction machine of claim 2.

4. Each of the reinforcing members has an opening that opens the internal space to the outside, and the opening is airtightly closed by an outer surface of the housing.

3. The stationary induction machine of claim 2.

Images