阅读说明：本技术 电力变压器 (Power transformer ) 是由 张凡 庄哲 周童浩 刘华栋 汲胜昌 祝令瑜 于 2021-07-13 设计创作，主要内容包括：本申请涉及一种电力变压器,属于电力设备技术领域。该电力变压器包括：油箱、设置于油箱内的变压器器身以及多个磁屏蔽板,变压器器身包括铁芯以及套设在铁芯上的绕组；各磁屏蔽板设置于变压器器身与油箱的内壁之间；各磁屏蔽板由通过绝缘材料连接的多个磁屏蔽条组成,各磁屏蔽板上开设有通孔。本申请提供的电力变压器,可以提高电力变压器的降噪效果。(The application relates to a power transformer, and belongs to the technical field of power equipment. The power transformer includes: the transformer comprises an oil tank, a transformer body and a plurality of magnetic shielding plates, wherein the transformer body is arranged in the oil tank and comprises an iron core and a winding sleeved on the iron core; each magnetic shielding plate is arranged between the transformer body and the inner wall of the oil tank; each magnetic shield board comprises a plurality of magnetic shield strips connected through insulating materials, and through holes are formed in each magnetic shield board. The application provides a power transformer can improve power transformer's noise reduction effect.)

1. An electrical transformer, characterized in that it comprises: the transformer comprises an oil tank, a transformer body and a plurality of magnetic shielding plates, wherein the transformer body is arranged in the oil tank and comprises an iron core and a winding sleeved on the iron core;

each magnetic shielding plate is arranged between the transformer body and the inner wall of the oil tank;

each magnetic shield board comprises a plurality of magnetic shield strips connected through insulating materials, and through holes are formed in each magnetic shield board.

2. The power transformer of claim 1, wherein the core comprises n core legs and a first yoke and a second yoke fixedly connected to the n core legs, the transformer body comprises n windings in one-to-one correspondence with the n core legs, and each winding is respectively sleeved on the corresponding core leg;

the plurality of magnetic shield panels include a first magnetic shield panel, a second magnetic shield panel, a third magnetic shield panel, a fourth magnetic shield panel, a fifth magnetic shield panel, and a sixth magnetic shield panel;

the first magnetic shielding plate is arranged between the first side of the first iron yoke and the inner wall of the oil tank;

the second magnetic shielding plate is arranged between the second side of the first iron yoke and the inner wall of the oil tank;

the third magnetic shielding plate is arranged between the first side of the second iron yoke and the inner wall of the oil tank;

the fourth magnetic shielding plate is arranged between the second side of the second iron yoke and the inner wall of the oil tank;

the fifth magnetic shielding plate is arranged between the first side of the first winding and the inner wall of the oil tank;

the sixth magnetic shield panel is disposed between the first side of the nth winding and the inner wall of the oil tank.

3. A power transformer according to claim 2, characterized in that the power transformer further comprises: a first insulating plate and a second insulating plate;

a first edge of the first insulating plate is connected to the first magnetic shield plate, and a second edge of the first insulating plate is connected to the third magnetic shield plate;

the first edge of the second insulating plate is connected with the second magnetic shielding plate, and the second edge of the second insulating plate is connected with the fourth magnetic shielding plate;

the first insulating plate and the second insulating plate both comprise the through hole.

4. A power transformer according to claim 2,

an area of the first magnetic shield plate is larger than an area of a first side of the first iron yoke;

an area of the second magnetic shield plate is larger than an area of a second side of the first iron yoke;

an area of the third magnetic shield panel is larger than an area of the first side of the second iron yoke;

an area of the fourth magnetic shield plate is larger than an area of a second side of the second iron yoke;

the area of the fifth magnetic shield panel is larger than the area of the first side of the first winding;

the area of the sixth magnetic shield panel is larger than the area of the first side of the nth winding.

5. The power transformer of claim 1, wherein the core comprises n core legs and a first yoke and a second yoke fixedly connected to the n core legs, the transformer body comprises n windings in one-to-one correspondence with the n core legs, and each winding is respectively sleeved on the corresponding core leg;

the plurality of magnetic shield panels include a seventh magnetic shield panel, an eighth magnetic shield panel, a ninth magnetic shield panel, a tenth magnetic shield panel;

the seventh magnetic shielding plate is arranged between the first sides of the n windings and the inner wall of the oil tank;

the eighth magnetic shield panel is disposed between the second side of the n windings and the inner wall of the oil tank;

the ninth magnetic shielding plate is arranged between the first side of the first winding and the inner wall of the oil tank;

the tenth magnetic shield panel is disposed between the first side of the nth winding and the inner wall of the oil tank.

6. A power transformer according to claim 5,

the seventh magnetic shield panel has an area larger than an area of the first side of the n windings;

the area of the eighth magnetic shield panel is larger than the area of the second side of the n windings;

the area of the ninth magnetic shield panel is larger than the area of the first side of the first winding;

the area of the tenth magnetic shield panel is larger than the area of the first side of the nth winding.

7. The power transformer of claim 1, further comprising: a plurality of electrical shielding plates;

each electric shielding plate is arranged between the magnetic shielding plate and the inner wall of the oil tank.

8. The power transformer of claim 7, wherein the electrical shield includes the through-holes therein.

9. The power transformer according to claim 1, 3 or 8, wherein the aperture of the through-hole and the penetration rate of the through-hole are determined according to a noise sound pressure frequency and a sound transfer function of the power transformer.

10. A power transformer according to claim 9, characterised in that the sound transfer function is:

wherein, ω is 2 pi f,

rho is the density of the oil in the tank, c is the speed of sound of the oil in the tank, and f is the sound source in the transformerFrequency, D is the distance from the first shielding plate to the inner wall of the second shielding plate/oil tank, the motion viscosity coefficient of mu transformer oil, D is the pore diameter of the micropores, and S_thruIs the total area of the first shield plate, S_totalThe total area of the microporous plate, g, is the gravitational acceleration.

Technical Field

The invention relates to the field of power equipment, in particular to a power transformer.

Background

With the enhancement of environmental awareness and health awareness, the vibration and noise problems of transformers have been paid high attention by environmental protection departments, power supply departments, and transformer manufacturers. The vibration and noise of the power transformer mainly come from the vibration of the winding and the iron core, wherein the vibration of the winding is mainly generated by the leakage magnetic flux and the lorentz force generated on the winding by the winding current.

In the existing power transformer, a component capable of reducing the generation of lorentz force is generally arranged outside a winding to reduce the vibration of the transformer winding, so that the vibration reduction and the noise reduction of the power transformer are realized.

However, such a power transformer can only reduce noise generated by vibration of the winding, and cannot reduce other noise in the transformer, and its noise reduction effect is limited.

Disclosure of Invention

In view of the above, it is necessary to provide a power transformer capable of improving the noise reduction effect of the power transformer.

An electrical transformer, comprising: the transformer comprises an oil tank, a transformer body and a plurality of magnetic shielding plates, wherein the transformer body is arranged in the oil tank and comprises an iron core and a winding sleeved on the iron core;

each magnetic shielding plate is arranged between the transformer body and the inner wall of the oil tank;

each magnetic shield board comprises a plurality of magnetic shield strips connected through insulating materials, and through holes are formed in each magnetic shield board.

In one embodiment, the iron core comprises n iron core columns and a first iron yoke and a second iron yoke which are fixedly connected with the n iron core columns, the transformer body comprises n windings which correspond to the n iron core columns one by one, and each winding is respectively sleeved on the corresponding iron core column;

the plurality of magnetic shield panels include a first magnetic shield panel, a second magnetic shield panel, a third magnetic shield panel, a fourth magnetic shield panel, a fifth magnetic shield panel, and a sixth magnetic shield panel;

the first magnetic shielding plate is arranged between the first side of the first iron yoke and the inner wall of the oil tank; the second magnetic shielding plate is arranged between the second side of the first iron yoke and the inner wall of the oil tank; the third magnetic shielding plate is arranged between the first side of the second iron yoke and the inner wall of the oil tank; the fourth magnetic shielding plate is arranged between the second side of the second iron yoke and the inner wall of the oil tank; the fifth magnetic shielding plate is arranged between the first side of the first winding and the inner wall of the oil tank; the sixth magnetic shield plate is disposed between the first side of the nth winding and the inner wall of the oil tank.

In one embodiment, the power transformer further comprises: a first insulating plate and a second insulating plate;

the first edge of the first insulating plate is connected with the first magnetic shield plate, and the second edge of the first insulating plate is connected with the third magnetic shield plate;

the first edge of the second insulating plate is connected with the second magnetic shielding plate, and the second edge of the second insulating plate is connected with the fourth magnetic shielding plate;

the first insulating plate and the second insulating plate both comprise through holes.

In one embodiment, the area of the first magnetic shield panel is larger than the area of the first side of the first iron yoke; the area of the second magnetic shield plate is larger than the area of the second side of the first iron yoke; the area of the third magnetic shield panel is larger than the area of the first side of the second iron yoke; the area of the fourth magnetic shield plate is larger than the area of the second side of the second iron yoke; the area of the fifth magnetic shield panel is larger than the area of the first side of the first winding; the area of the sixth magnetic shield panel is larger than the area of the first side of the nth winding.

In one embodiment, the iron core comprises n iron core columns and a first iron yoke and a second iron yoke which are fixedly connected with the n iron core columns, the transformer body comprises n windings which correspond to the n iron core columns one by one, and each winding is respectively sleeved on the corresponding iron core column;

the plurality of magnetic shield panels include a seventh magnetic shield panel, an eighth magnetic shield panel, a ninth magnetic shield panel, a tenth magnetic shield panel;

the seventh magnetic shielding plate is arranged between the first sides of the n windings and the inner wall of the oil tank; the eighth magnetic shielding plate is arranged between the second side of the n windings and the inner wall of the oil tank; the ninth magnetic shielding plate is arranged between the first side of the first winding and the inner wall of the oil tank; the tenth magnetic shield panel is disposed between the first side of the nth winding and the inner wall of the oil tank.

In one embodiment, the area of the seventh magnetic shield panel is larger than the area of the first side of the n windings; the area of the eighth magnetic shield panel is larger than the area of the second side of the n windings; the area of the ninth magnetic shield panel is larger than the area of the first side of the first winding; the area of the tenth magnetic shield panel is larger than the area of the first side of the nth winding.

In one embodiment, the power transformer further comprises: a plurality of electrical shielding plates; each electric shielding plate is arranged between the magnetic shielding plate and the oil tank.

In one embodiment, the electrical shield includes a through hole therein.

In one embodiment, the aperture of the through-hole and the penetration rate of the through-hole are determined according to the noise sound pressure frequency and the sound transfer function of the power transformer.

In one embodiment, the sound transfer function is:

wherein, ω is 2 pi f,

rho is the density of oil in the oil tank, c is the sound velocity of the oil in the oil tank, f is the frequency of the sound source in the transformer, D is the distance from the first shielding plate to the second shielding plate/inner wall of the oil tank, mu is the motion viscosity coefficient of the transformer oil, D is the pore diameter of the micropores, S_thruIs the total area of the first shield plate, S_totalThe total area of the microporous plate, g, is the gravitational acceleration.

The beneficial effects brought by the technical scheme provided by the embodiment of the application at least comprise:

the power transformer that this application embodiment provided includes: the oil tank, set up transformer ware body and a plurality of magnetic screen board in the oil tank, wherein, transformer ware body includes the iron core and overlaps the winding of establishing on the iron core, and each magnetic screen board sets up between the inner wall of transformer ware body and oil tank, and each magnetic screen board comprises a plurality of magnetic screen strips that connect through insulating material, and has seted up the through-hole on each magnetic screen board. The power transformer that this application embodiment provided through set up the magnetic screen board between the inner wall of transformer ware body and oil tank, can provide the magnetic circuit for the magnetic leakage that transformer winding produced, can reduce the magnetic leakage flux through the winding to can reduce the noise that winding vibration produced. Meanwhile, the through holes are formed in the magnetic shielding plate, so that the magnetic shielding plate, fluid in the oil tank and the inner wall of the oil tank form an acoustic resistance structure, noise can be restrained from a propagation path of the noise, the energy transfer efficiency of the noise in the transformer is reduced, and the noise reduction effect of the transformer can be improved.

Drawings

Fig. 1 is a top view of a structure of a power transformer provided in an embodiment of the present application;

fig. 2 is a schematic structural diagram of a power transformer according to an embodiment of the present disclosure;

fig. 3 is another schematic structural diagram of a power transformer according to an embodiment of the present disclosure;

fig. 4 is a top view of another structure of a power transformer according to an embodiment of the present disclosure.

Description of reference numerals:

10: an oil tank; 20: a magnetic shield panel; 30: an iron core; 40: a winding; 50: an insulating plate; 60: an electrical shield plate.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

With the continuous expansion of densely populated areas and the increase in demand and density of electricity, the distance between an electric power substation and an urban business district or a residential district is continuously shortened, and the capacity of the substation is gradually increased. With the enhancement of environmental awareness and health awareness, the vibration and noise problems of transformers have been paid high attention by environmental protection departments, power supply departments, and transformer manufacturers. In recent years, the national grid has been increasingly demanding on the noise level of power transformers, and therefore, higher demands have been made on the noise reduction technology of power transformers.

The vibration and noise of the power transformer mainly come from the winding and the iron core in the power transformer, and the vibration of the winding is mainly caused by the lorentz force, so that the power transformer in the prior art is generally provided with a component which can be used for reducing the generation of the lorentz force outside the winding, thereby reducing the vibration of the transformer winding, and further realizing the vibration and noise reduction of the power transformer. However, this kind of power transformer can only reduce the noise generated by the vibration of the winding, and cannot reduce other noise in the transformer, and the noise reduction effect is limited.

The power transformer that this application embodiment provided includes: the oil tank, set up transformer ware body and a plurality of magnetic screen board in the oil tank, wherein, transformer ware body includes the iron core and overlaps the winding of establishing on the iron core, and each magnetic screen board sets up between the inner wall of transformer ware body and oil tank, and each magnetic screen board comprises a plurality of magnetic screen strips that connect through insulating material, and has seted up the through-hole on each magnetic screen board. The power transformer that this application embodiment provided through set up the magnetic screen board between the inner wall of transformer ware body and oil tank, can provide the magnetic circuit for the magnetic leakage that transformer winding produced, can reduce the magnetic leakage flux through the winding to can reduce the noise that winding vibration produced. Meanwhile, the through holes are formed in the magnetic shielding plate, so that the magnetic shielding plate, fluid in the oil tank and the inner wall of the oil tank form an acoustic resistance structure, noise can be restrained from a propagation path of the noise, the energy transfer efficiency of the noise in the transformer is reduced, and the noise reduction effect of the transformer can be improved.

The following describes the technical solutions of the present application and how to solve the above technical problems with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments. Embodiments of the present application will be described below with reference to the accompanying drawings.

Fig. 1 is a top view of a structure of a power transformer provided in an embodiment of the present application, where the power transformer includes: the transformer comprises an oil tank 10, a transformer body and a plurality of magnetic shielding plates 20, wherein the transformer body is arranged in the oil tank 10 and comprises an iron core 30 and a winding 40 sleeved on the iron core 30; each magnetic shield plate 20 is arranged between the transformer body and the inner wall of the oil tank 10; each magnetic shield panel 20 is composed of a plurality of magnetic shield strips connected by an insulating material, and through holes are opened in each magnetic shield panel 20.

The magnetic shielding plate 20 is composed of a plurality of magnetic shielding strips, the magnetic shielding strips are made of magnetic conductive materials, and the magnetic shielding strips are connected with each other through insulating materials.

Optionally, the magnetic shielding strip can be formed by pressing a plurality of layers of guiding silicon steel sheets capable of conducting magnetism, and insulating paint is coated on each layer of guiding silicon steel sheet.

Alternatively, the insulating material used for connecting the magnetic shield strips may be epoxy resin.

Optionally, fixing holes are formed around or in the middle of the magnetic shielding plate 20, and the fixing holes can be suspended on the inner wall of the transformer oil tank 10 through positioning pillars.

In practical application, the multilayer guidance silicon steel sheets coated with the insulating varnish are pressed into magnetic shielding strips, epoxy resin is poured into gaps among the prepared magnetic shielding strips to form magnetic shielding plates 20, then the magnetic shielding plates 20 are provided with a plurality of through holes, and finally the magnetic shielding plates 20 are hung on the inner wall of the transformer oil tank 10.

The power transformer that this application embodiment provided includes: the oil tank 10, set up transformer ware body and a plurality of magnetic shield panel 20 in the oil tank 10, wherein, transformer ware body includes iron core 30 and the winding 40 of cover on iron core 30, and each magnetic shield panel 20 sets up between the inner wall of transformer ware body and oil tank 10, and each magnetic shield panel 20 comprises a plurality of magnetic shield strips that connect through insulating material, and has seted up the through-hole on each magnetic shield panel 20. According to the power transformer provided by the embodiment of the application, the magnetic shielding plate 20 is arranged between the transformer body and the inner wall of the oil tank 10, so that a magnetic path can be provided for leakage flux generated by the transformer winding 40, the leakage flux passing through the winding can be reduced, and the noise generated by the vibration of the winding 40 can be reduced. Meanwhile, the through holes are formed in the magnetic shielding plate 20, so that the fluid in the magnetic shielding plate 20 and the oil tank 10 and the inner wall of the oil tank 10 form an acoustic resistance structure, noise can be suppressed from a noise propagation path, the noise in the transformer is prevented from being propagated, and the noise reduction effect of the transformer can be improved.

Meanwhile, by providing the magnetic shield plate 20 between the transformer body and the inner wall of the oil tank 10, eddy currents in the oil tank 10 due to magnetic flux leakage can be suppressed, and heat generation and vibration of the oil tank 10 can be reduced.

Fig. 2 is a structural diagram of a power transformer according to an embodiment of the present application, and as shown in fig. 2, an iron core 30 includes n iron core legs, and a first iron yoke and a second iron yoke fixedly connected to the n iron core legs, a transformer body includes n windings 40 corresponding to the n iron core legs one to one, and each winding 40 is respectively sleeved on the corresponding iron core leg.

The plurality of magnetic shield panels 20 include a first magnetic shield panel 20, a second magnetic shield panel 20, a third magnetic shield panel 20, a fourth magnetic shield panel 20, a fifth magnetic shield panel 20, and a sixth magnetic shield panel 20;

the first magnetic shield panel 20 is disposed between the first side of the first iron yoke and the inner wall of the oil tank 10; the second magnetic shield panel 20 is disposed between the second side of the first iron yoke and the inner wall of the oil tank 10; the third magnetic shield panel 20 is disposed between the first side of the second iron yoke and the inner wall of the oil tank 10; the fourth magnetic shield panel 20 is disposed between the second side of the second iron yoke and the inner wall of the oil tank 10; the fifth magnetic shield panel 20 is disposed between the first side of the first winding 40 and the inner wall of the oil tank 10; the sixth magnetic shield panel 20 is disposed between the first side of the nth winding 40 and the inner wall of the oil tank 10.

Wherein the area of the first magnetic shield panel 20 is larger than the area of the first side of the first iron yoke; the area of the second magnetic shield panel 20 is larger than the area of the second side of the first iron yoke; the area of the third magnetic shield panel 20 is larger than the area of the first side of the second iron yoke; the area of the fourth magnetic shield panel 20 is larger than the area of the second side of the second iron yoke; the area of the fifth magnetic shield panel 20 is larger than the area of the first side of the first winding 40; the area of the sixth magnetic shield panel 20 is larger than the area of the first side of the nth winding 40.

The magnetic shield panels 20 having the above-described area size are disposed at the above-described positions, so that the magnetic flux leakage of the windings can be greatly reduced, the generation of the lorentz force can be reduced, and the noise caused by the vibration of the windings can be reduced.

In practical applications, the magnetic shield panel 20 arrangement shown in fig. 2 is mainly used for three-phase and two-phase power transformers, that is, the magnetic shield panel 20 arrangement shown in fig. 2 is mainly used for transformers with 2 or 3 core legs of the iron core 30. As shown in fig. 2, in the arrangement of the magnetic shield panels 20, when three phases are balanced, leakage flux generated by the harmonic other than 3n (n is 1,2, …) passes through the shield return cores 30 arranged laterally above and below the winding 40, and the rest of the leakage flux passes through the shield return cores 30 on both sides, and when three phases are unbalanced, leakage flux generated by the unbalanced part and 3n (n is 1,2, …) harmonic returns to the core 30 through the shields on both sides, and leakage flux generated by the harmonic other than 3n (n is 1,2, …) of the balanced part returns to the core 30 through the shields arranged laterally above and below the winding 40.

In one embodiment, as shown in fig. 2, the power transformer further comprises: a first insulating plate 50 and a second insulating plate 50; a first edge of the first insulating plate 50 is connected to the first magnetic shield plate 20, and a second edge of the first insulating plate 50 is connected to the third magnetic shield plate 20; the first edge of the second insulating plate 50 is connected to the second magnetic shield panel 20, and the second edge of the second insulating plate 50 is connected to the fourth magnetic shield panel 20; the first insulating plate 50 and the second insulating plate 50 each include a through hole thereon.

In practical application, through set up a plurality of through-holes on two insulation boards 50, be connected the both sides of one of them insulation board 50 with first magnetism shielding board 20 respectively simultaneously and be connected with third magnetism shielding board 20, the both sides of another insulation board 50 are connected with second magnetism shielding board 20 and fourth magnetism shielding board 20 respectively, can increase the quantity of through-hole on the basis of magnetism shielding board 20, and then can be further prevent that the noise in the transformer from spreading away to can improve the noise reduction of transformer effect. Meanwhile, compared with the case where the first magnetic shield panel and the third magnetic shield panel are connected by the magnetic shield panel 20, the insulating panel 50 can save cost under the same noise reduction effect.

Fig. 3 is another structural diagram of a power transformer according to an embodiment of the present application, and as shown in fig. 3, another arrangement manner of the magnetic shielding plates 20 is provided, where the iron core 30 includes n iron core legs, and a first iron yoke and a second iron yoke fixedly connected to the n iron core legs, the transformer body includes n windings 40 corresponding to the n iron core legs one to one, and each winding 40 is respectively sleeved on the corresponding iron core leg;

the plurality of magnetic shield panels 20 include a seventh magnetic shield panel 20, an eighth magnetic shield panel 20, a ninth magnetic shield panel 20, a tenth magnetic shield panel 20;

the seventh magnetic shield panel 20 is disposed between the first side of the n windings 40 and the inner wall of the oil tank 10; the eighth magnetic shield panel 20 is disposed between the second side of the n windings 40 and the inner wall of the oil tank 10; the ninth magnetic shield panel 20 is disposed between the first side of the first winding 40 and the inner wall of the oil tank 10; the tenth magnetic shield panel 20 is disposed between the first side of the nth winding 40 and the inner wall of the fuel tank 10.

Wherein the area of the seventh magnetic shield panel 20 is larger than the area of the first side of the n windings 40; the area of the eighth magnetic shield panel 20 is larger than the area of the second side of the n windings 40; the area of the ninth magnetic shield panel 20 is larger than the area of the first side of the first winding 40; the area of the tenth magnetic shield panel 20 is larger than the area of the first side of the nth winding 40. The magnetic shield panels 20 having the above-described area size are disposed at the above-described positions, so that the magnetic flux leakage of the windings can be greatly reduced, the generation of the lorentz force can be reduced, and the noise caused by the vibration of the windings can be reduced. Meanwhile, the arrangement of the magnetic shield panel 20 as shown in fig. 3 can be applied to a single-phase, two-phase, or three-phase power transformer in which leakage flux returns to the core 30 through the magnetic shield panel 20. That is, the arrangement of the magnetic shield panel 20 as shown in fig. 3 is applied to a transformer in which the core leg of the core 30 is 1,2, or 3.

Fig. 4 is another top view of the structure of the power transformer provided in the embodiment of the present application, and as shown in fig. 4, the power transformer further includes: a plurality of electrical shield plates 60; each of the electric shield plates 60 is disposed between the magnetic shield plate 20 and the inner wall of the fuel tank 10, and each of the electric shield plates 60 includes a through hole.

Alternatively, the electrical shield 60 is made of a good conductor material.

Optionally, the electric shielding plate 60 has fixing holes formed around or in the middle thereof, and the fixing holes may be suspended on the inner wall of the transformer oil tank 10 by positioning posts.

Alternatively, the electrical shielding plates 60 may include a first electrical shielding plate 60, a second electrical shielding, a third electrical shielding plate 60, and a fourth electrical shielding plate 60. There are two types of arrangement of the electric shield plate 60 based on the arrangement of the magnetic shield plate 20 in fig. 2 and 3.

The first arrangement of the electric shielding plate 60 is as follows: the first electric shielding plate 60 is disposed between the insulating plate 50 and the inner wall of the fuel tank 10, the second electric shielding plate 60 is disposed between the second insulating plate 50 and the inner wall of the fuel tank 10, the third electric shielding plate 60 is disposed between the fifth magnetic shielding plate 20 and the inner wall of the fuel tank 10, and the fourth electric shielding plate 60 is disposed between the sixth magnetic shielding plate 20 and the inner wall of the fuel tank 10.

The second arrangement of the electric shield 60 is: the first electric shielding plate 60 is disposed between the seventh magnetic shielding plate 20 and the inner wall of the fuel tank 10, the second electric shielding plate 60 is disposed between the eighth magnetic shielding plate and the inner wall of the fuel tank 10, the third electric shielding plate 60 is disposed between the ninth magnetic shielding plate 20 and the inner wall of the fuel tank 10, and the fourth electric shielding plate 60 is disposed between the tenth magnetic shielding plate 20 and the inner wall of the fuel tank 10.

In both the first and second arrangements of the electric shielding plates 60, the area of the first electric shielding plate 60 is greater than or equal to that of the seventh magnetic shielding plate 20, the area of the second electric shielding plate 60 is greater than or equal to that of the eighth magnetic shielding plate, the area of the third electric shielding plate 60 is greater than or equal to that of the ninth magnetic shielding plate 20, and the area of the fourth electric shielding plate 60 is greater than or equal to that of the tenth magnetic shielding plate 20.

In practical application, the electric shielding plate 60 is arranged between the magnetic shielding plate 20 and the inner wall of the oil tank 10, the electric shielding plate 60 can generate magnetic resistance force, the direction of leakage magnetic flux can be changed, the leakage magnetic flux which does not pass through the iron core 30 and the magnetic shielding enters the iron core 30 or the magnetic shielding plate 20 again, the problem of magnetic leakage is further inhibited, and the vibration of the winding 40 caused by the magnetic leakage can be further reduced. Further, the through holes are further formed in the electric shielding plate 60, so that the number of the through holes is further increased on the basis of the magnetic shielding plate 20 and the insulating plate 50, and the noise in the transformer can be further prevented from being transmitted, thereby further improving the noise reduction effect of the transformer.

In one embodiment, the aperture of the through-holes and the penetration rate of the through-holes on the magnetic shield plate 20, the insulating plate 50, and the electric shield plate 60 are determined according to the noise sound pressure frequency and the sound transfer function of the power transformer.

Wherein the sound transfer function is:

wherein ω is 2 π f,

rho is the density of oil in the oil tank, c is the sound velocity of the oil in the oil tank, f is the frequency of the sound source in the transformer, D is the distance from the first shielding plate to the second shielding plate/inner wall of the oil tank, mu is the motion viscosity coefficient of the transformer oil, D is the pore diameter of the micropores, S_thruIs the total area of the first shield plate, S_totalThe total area of the microporous plate, g, is the gravitational acceleration.

It should be noted that the determination of the aperture of the through hole and the perforation rate of the through hole is within the process range, and then is determined according to the noise sound pressure frequency and the sound transfer function of the power transformer, wherein the aperture range of the through hole in the process is as follows: 0.3 mm-10 mm, and the perforation rate of the through hole is 5% -90%.

In practical application, according to the actual noise sound pressure frequency distribution of the transformer, determining a main attenuation frequency band of the noise sound pressure frequency distribution, and then adjusting an aperture value and a perforation rate value within the range of the aperture of the through hole and the perforation rate of the through hole in the process, so that the minimum value of the sound transfer function is close to the main attenuation frequency band of the noise sound pressure frequency distribution, and finally obtaining the aperture of the through hole and the perforation rate of the through hole.

The power transformer that this application embodiment provided includes: the oil tank 10, set up transformer ware body and a plurality of magnetic shield panel 20 in the oil tank 10, wherein, transformer ware body includes iron core 30 and the winding 40 of cover on iron core 30, and each magnetic shield panel 20 sets up between the inner wall of transformer ware body and oil tank 10, and each magnetic shield panel 20 comprises a plurality of magnetic shield strips that connect through insulating material, and has seted up the through-hole on each magnetic shield panel 20. According to the power transformer provided by the embodiment of the application, the magnetic shielding plate 20 is arranged between the transformer body and the inner wall of the oil tank 10, so that a magnetic path can be provided for leakage flux generated by the transformer winding 40, the leakage flux passing through the winding can be reduced, and the noise generated by the vibration of the winding 40 can be reduced. Meanwhile, the through holes are formed in the magnetic shielding plate 20, so that the magnetic shielding plate 20, the fluid in the oil tank 10 and the inner wall of the oil tank 10 form an acoustic resistance structure, noise can be suppressed from a propagation path of the noise, the energy transfer efficiency of the noise in the transformer is reduced, and the noise reduction effect of the transformer can be improved.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.