CN117976375A - Transformer core structure design method and power transformer - Google Patents

Abstract

The invention discloses a transformer core structural design method and a power transformer, which comprise a transformer shell and a transformer oil tank internally provided with transformer oil, wherein the transformer shell is provided with a plurality of low-voltage bushings and high-voltage bushings, the low-voltage bushings and the high-voltage bushings are oppositely arranged, the power transformer also comprises an iron core and a winding which are arranged in the transformer, the winding is surrounded by the iron core, one end of the winding is connected with a low-voltage lead, the other end of the winding is connected with a high-voltage lead, the low-voltage lead is connected with the low-voltage bushing, the high-voltage lead is connected with the high-voltage bushing, the transformer shell is also provided with a radiator, the radiator is communicated with the transformer oil tank, the structure of the iron core is an EE iron core formed by butting two E-shaped iron cores, and the winding is arranged between internal gaps of the E-shaped iron cores; this scheme sets up the transformer core into EE type iron core, EI type iron core, UU type iron core and annular iron core to use the silicon steel sheet and other materials except for the silicon steel sheet to make the iron core in order to improve the transmission power of transformer, and can save winding copper line.

Description

Transformer core structure design method and power transformer

Technical Field

The invention belongs to the technical field of power transformers, and particularly relates to a transformer core structure design method and a power transformer.

Background

A power transformer is a stationary electric device that is used to change an ac voltage (current) of a certain value into another voltage (current) of the same frequency or different values. A transformer is a stationary electrical device for transforming ac voltage and current to transmit ac power. The electric energy transmission is realized according to the principle of electromagnetic induction. A power transformer is a stationary electric device that is used to change an ac voltage (current) of a certain value into another voltage (current) of the same frequency or different values. When the primary winding is supplied with alternating current, alternating magnetic flux is generated, and alternating magnetic flux induces alternating electromotive force in the secondary winding through the magnetic conduction of the iron core. The secondary induced electromotive force is related to the number of turns of a secondary winding, namely, the voltage is proportional to the number of turns. The main function is to transmit electrical energy, and thus the rated capacity is its main parameter. The rated capacity is a conventional value representing the power, which is a value representing the amount of transmitted electric power, expressed in kVA or MVA, from which the rated current, which does not exceed the temperature rise limit under prescribed conditions, is determined when the rated voltage is applied to the transformer. The power transformer which saves energy is an amorphous alloy iron core distribution transformer, and has the greatest advantage of extremely low no-load loss value. Whether the no-load loss value can be ensured is a core problem to be considered in the whole design process.

Transformer cores, which are the main magnetic circuit part in transformers. Is generally formed by laminating hot-rolled or cold-rolled silicon steel sheets with high silicon content and insulating paint coated on the surfaces. The iron core and the coil wound on the iron core form a complete electromagnetic induction system. The power transformer transmits power, and the iron core of the traditional power transformer is mostly made of silicon steel sheets depending on the material and the cross section area of the iron core, for example, a set of silicon steel sheets consisting of four C-shaped silicon steel sheets is called ED-shaped silicon steel sheets, the appearance of the transformer made of the ED-shaped silicon steel sheets is flat and wide, the ED-shaped transformer is shorter than the CD-shaped transformer under the condition of the same power, in addition, because the coil is arranged in the middle of the silicon steel sheets, but all coils are wound on one coil, the coil is thicker, so the average turn length is longer, and the copper loss is larger.

Therefore, the invention provides a transformer core structure design method and a power transformer for solving the technical problems.

Disclosure of Invention

In view of the above-mentioned problems with the background art, the present invention has as its object: the transformer core structure design method and the power transformer are provided.

In order to achieve the technical purpose, the invention adopts the following technical scheme:

The utility model provides a transformer core structural design method and power transformer, includes transformer shell and the transformer tank that inside is equipped with transformer oil, be equipped with a plurality of low-voltage bushings and high-voltage bushing on the transformer shell, low-voltage bushing and high-voltage bushing set up relatively, still include the inside iron core and the winding that set up of transformer, the winding is surrounded by the iron core, winding one end is connected with low-voltage lead, and the other end is connected with high-voltage lead, low-voltage lead connects low-voltage bushing, high-voltage lead connects high-voltage bushing, the transformer shell still is equipped with the radiator, radiator and transformer tank intercommunication, the structure of iron core is the EE type iron core that is formed by two E type iron cores butt joint, the winding then sets up between EE type iron core's inside space.

Further limited, the transformer shell is formed by pressing carbon steel plates, and a base with a locking function is arranged at the bottom of the transformer shell. The transformer shell with the structural design is higher in strength, better in protectiveness and better in base supporting performance.

Further defined, a layer of epoxy resin paint is sprayed on the carbon steel plate. The structural design can improve the alkali resistance, the heat resistance and the electrical insulation of the transformer shell by the epoxy resin coating.

Further limited, the structure of the iron core also comprises an EI-shaped iron core formed by butting an E-shaped iron core and an I-shaped iron core, an annular iron core formed by connecting a plurality of iron cores end to end and UU-shaped iron cores in a butting mode.

Further defined, the EE-type core and the EI-type core are made of manganese-zinc magnetic cores. The Mn-Zn magnetic core has the characteristics of high resistivity, low core loss and high Curie temperature.

Further defined, the manganese-zinc core is comprised of 71% Fe ₂O₃, 20% MnO, and 9% ZnO.

Further defined, the UU type iron core is made of silicon steel sheets and silicon steel sheets. The silicon steel sheet and the silicon steel sheet have extremely high magnetic permeability, extremely high saturation magnetic flux density, low resistivity and low cost, and are suitable for manufacturing low-frequency transformers.

Further defined, the toroidal core is made of silicon steel sheet, iron-silicon-aluminum alloy, iron-nickel alloy and molybdenum permalloy. The structural design has the advantages that the magnetic permeability of the Fe-Si-Al alloy is high, the core loss is low, the saturation magnetic flux density of the Fe-Ni alloy is higher than that of the Fe-Si-Al alloy, and the cost is higher than that of the Fe-Si-Al alloy; the saturation magnetic flux density of the molybdenum permalloy is highest among three alloys, the core loss is lowest, the stability is best, and the disadvantage is that the cost is highest.

Further defined, the Fe-Si-Al alloy is composed of 6% Al, 9% Si and 85% Fe, the Fe-Ni alloy is composed of 50% Ni and 50% Fe, and the Mo-Ni alloy is composed of 2% Mo, 81% Ni and 17% Fe.

Further defined, the transformer oil tank is connected with an oil level gauge, the oil level gauge is arranged at the top of the transformer shell, and the oil level gauge is used for monitoring the oil level condition of transformer oil in the transformer oil tank.

The invention has the beneficial effects that:

The power transformer transmission power depends on the material and the cross-sectional area of an iron core, the traditional power transformer iron core is made of silicon steel sheets, the transformer iron core is arranged into an EE type iron core, an EI type iron core, a UU type iron core and an annular iron core, the silicon steel sheets and other materials except the silicon steel sheets are used for manufacturing the iron cores (the silicon steel sheets, the manganese zinc magnetic cores, the iron-silicon-aluminum alloy, the iron-nickel alloy and the molybdenum permalloy) so as to improve the transmission power of the transformer, the lead space of the EE type iron core is large, and winding wiring is convenient. Wide application range, high working frequency, wide working voltage range, high output power and good thermal stability. In addition, compared with the traditional ED type transformer, the connection mode of the iron core and the winding has the advantage of saving winding copper wires.

Drawings

The invention can be further illustrated by means of non-limiting examples given in the accompanying drawings;

FIG. 1 is a schematic diagram of a transformer core design method and an embodiment of a power transformer according to the present invention;

FIG. 2 is a top view of an embodiment of a transformer core design method and a power transformer according to the present invention;

FIG. 3 is a side view of an embodiment of a transformer core design method and a power transformer according to the present invention;

Fig. 4 is a schematic diagram of an EE-type core structure of an embodiment of a transformer core design method and a power transformer according to the present invention;

FIG. 5 is a schematic diagram of the EI-type core structure of an embodiment of a transformer core design method and a power transformer according to the present invention;

FIG. 6 is a schematic diagram of a transformer core structure design method and a toroidal core structure of an embodiment of a power transformer according to the present invention;

fig. 7 is a schematic diagram of a design method of a transformer core structure and a UU-type core structure of an embodiment of a power transformer according to the present invention.

The main reference numerals are as follows: low-voltage bushing 1, high-voltage bushing 2, transformer housing 3, base 4, iron core 5, radiator 6, transformer tank 7, high-voltage lead 8, low-voltage lead 9, winding 10, oil level gauge 11.

Detailed Description

In order that those skilled in the art can better understand the present invention, the following technical solutions of the present invention will be further described with reference to the drawings and the embodiments, and the technical solutions of the embodiments of the present invention will be clearly and completely described. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present invention are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture (as shown in the drawings), and if the particular posture is changed, the directional indicator is changed accordingly.

Furthermore, the description of "first," "second," etc. in this disclosure is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

As shown in fig. 1-4, the invention relates to a transformer core structural design method and a power transformer, which comprises a transformer shell 3 and a transformer oil tank 7 filled with transformer oil, wherein a plurality of low-voltage bushings 1 and high-voltage bushings 2 are arranged on the transformer shell 3, the low-voltage bushings 1 and the high-voltage bushings 2 are oppositely arranged, the power transformer further comprises an iron core 5 and a winding 10 which are arranged in the transformer, the winding 10 is surrounded by the iron core 5, one end of the winding 10 is connected with a low-voltage lead 9, the other end of the winding 10 is connected with a high-voltage lead 8, the low-voltage lead 9 is connected with the low-voltage bushings 1, the high-voltage lead 8 is connected with the high-voltage bushings 2, the transformer shell 3 is further provided with a radiator 6, the radiator is communicated with the transformer oil tank 7, the structure of the iron core 5 is an EE-type iron core formed by butt joint of two E-type iron cores, and the winding 10 is arranged between internal gaps of the EE-type iron core.

The installation method of the EE type iron core in the scheme comprises the following steps:

Firstly, stacking two groups of iron cores of a transformer, namely, cross stacking the two groups of iron cores, staggering the two groups of iron cores, respectively expanding the two E-shaped iron cores to two sides, and enabling the two ends of the E-shaped iron cores to present a central line; placing two groups of iron cores 5 so that the two groups of iron cores intersect at the center line position; the positions of the two groups of iron cores 5 are adjusted to enable the two groups of iron cores 5 to be symmetrically intersected, the gap between the two groups of iron cores 5 in a stacked mode is uniform, the fork inductance is small, and the magnetic circuit passing is facilitated; and then the iron core 5 is firmly fixed by using an iron wire or a plastic binding belt so as to ensure the stability of the lamination, and finally, the coil is wound on the iron core 5.

In addition, during the lamination of the iron cores 5, it should be noted that the laminated iron cores 5 must be kept clean and dry so as not to cause electrical breakdown or corrosion, and during the lamination and winding of the iron cores 5, it should be noted that the lamination direction and the winding order are required to ensure the normal transmission and quality of the electric energy; when winding the coil, attention is paid to the size of the gap between the cores 5 and the tightness of the winding; after the stacking is completed, necessary tests are performed to ensure the quality and reliability of the stacking.

The installation method of the EI-shaped iron core, the UU-shaped iron core and the annular iron core is basically consistent with the installation method of the EE-shaped iron core, wherein the annular iron core is formed by stacking a plurality of small iron sheets, the EI-shaped iron core is formed by stacking a plurality of groups of E-shaped sheets and I-shaped sheets, and the UU-shaped iron core is formed by stacking a plurality of groups of U-shaped sheets.

Preferably, the transformer housing 3 is formed by pressing a carbon steel plate, and a base 4 with a locking function is arranged at the bottom of the transformer housing 3. The transformer shell with the structural design is higher in strength, better in protectiveness and better in base supporting performance.

Preferably, a layer of epoxy resin paint is sprayed on the carbon steel plate. The structural design can improve the alkali resistance, the heat resistance and the electrical insulation of the transformer shell by the epoxy resin coating.

As shown in fig. 5, preferably, the structure of the iron core 5 further includes an EI-shaped iron core formed by butting an E-shaped iron core and an I-shaped iron core, an annular iron core formed by connecting a plurality of iron cores 5 end to end, and two U-shaped iron cores are butted to form a UU-shaped iron core; the EI-type iron core has compact structure, small volume, high working frequency, wide working voltage range, tight air gap coil top end coupling and low loss, and the loss is inversely related to the temperature, so that the continuous rise of the temperature can be prevented; the UU-type iron core has the characteristics of small impedance deviation, large output current, high inductance and capability of inhibiting higher harmonic waves; the annular iron core has the characteristics of large output current, small loss, voltage resistance, high inductance and low price.

Preferably, the EE-type core and the EI-type core are made of manganese-zinc core. The Mn-Zn magnetic core has the characteristics of high resistivity, low core loss and high Curie temperature.

Preferably, the manganese-zinc core is composed of 71% Fe ₂O₃, 20% MnO and 9% ZnO.

As shown in fig. 7, the UU type core is preferably made of a silicon steel sheet and a silicon steel sheet. The silicon steel sheet and the silicon steel sheet have extremely high magnetic permeability mu i of about 60000, extremely high saturation magnetic flux density of 0.6T-1.9T, low resistivity and low cost, and are suitable for manufacturing low-frequency transformers.

As shown in fig. 6, the toroidal core is preferably made of silicon steel sheet, sendust, ferronickel and permalloy. The magnetic permeability of the Fe-Si-Al alloy is 26-125H/m, the core loss is low, the saturation magnetic flux density of the Fe-Ni alloy is higher than that of the Fe-Si-Al alloy, and the cost is higher than that of the Fe-Si-Al alloy; the saturation magnetic flux density of the molybdenum permalloy is highest in three alloys, the magnetic permeability is 14-550H/m, the core loss is lowest, the stability is best, and the defect is that the cost is highest.

Preferably, the Fe-Si-Al alloy is composed of 6% of aluminum, 9% of silicon and 85% of iron, the Fe-Ni alloy is composed of 50% of nickel and 50% of iron, and the Mo-Ni alloy is composed of 2% of molybdenum, 81% of nickel and 17% of iron.

Preferably, the transformer oil tank 7 is connected with an oil level gauge 11, the oil level gauge 11 is arranged at the top of the transformer shell 3, and the oil level gauge 11 is used for monitoring the oil level condition of transformer oil in the transformer oil tank 7.

The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims of this invention, which are within the skill of those skilled in the art, can be made without departing from the spirit and scope of the invention disclosed herein.

Claims (10)

1. A transformer core structure design method and a power transformer are characterized in that: including transformer shell (3) and inside transformer tank (7) that are equipped with transformer oil, be equipped with a plurality of low-voltage bushings (1) and high-voltage bushing (2) on transformer shell (3), low-voltage bushing (1) and high-voltage bushing (2) set up relatively, still include iron core (5) and winding (10) that the transformer inside set up, winding (10) are surrounded by iron core (5), winding (10) one end is connected with low-voltage lead (9), and the other end is connected with high-voltage lead (8), low-voltage lead (9) connect low-voltage bushing (1), high-voltage lead (8) connect high-voltage bushing (2), transformer shell (3) still are equipped with radiator (6), radiator (6) and transformer tank (7) intercommunication, the structure of iron core (5) is the type iron core that is formed by two E type iron cores butt joints, winding (10) then set up between EE type iron core's inside space.

2. The transformer core structural design method and the power transformer according to claim 1, wherein: the transformer shell (3) is formed by pressing carbon steel plates, and a base (4) with a locking function is arranged at the bottom of the transformer shell (3).

3. The transformer core structural design method and the power transformer according to claim 2, wherein: and a layer of epoxy resin paint is sprayed on the carbon steel plate.

4. The transformer core structural design method and the power transformer according to claim 1, wherein: the structure of the iron core (5) further comprises an EI-shaped iron core formed by butt joint of an E-shaped iron core and an I-shaped iron core, an annular iron core formed by connecting a plurality of iron cores (5) end to end and UU-shaped iron cores formed by butt joint of two U-shaped iron cores.

5. The transformer core structural design method and the power transformer according to claims 1 and 4 are characterized in that: the EE type iron core and the EI type iron core are made of manganese-zinc magnetic cores.

6. The transformer core structural design method and the power transformer according to claim 1, wherein: the manganese-zinc magnetic core is composed of 71% of Fe ₂O₃, 20% of MnO and 9% of ZnO.

7. The transformer core structural design method and the power transformer according to claim 4, wherein: the UU type iron core is made of silicon steel sheets and silicon steel sheets.

8. The transformer core structural design method and the power transformer according to claim 4, wherein: the annular iron core is made of silicon steel sheets, iron-silicon-aluminum alloy, iron-nickel alloy and molybdenum permalloy.

9. The transformer core structural design method and the power transformer according to claim 8, wherein: the Fe-Si-Al alloy is composed of 6% of aluminum, 9% of silicon and 85% of iron, the Fe-Ni alloy is composed of 50% of nickel and 50% of iron, and the Mo-P alloy is composed of 2% of molybdenum, 81% of nickel and 17% of iron.

10. The transformer core structural design method and the power transformer according to claim 1, wherein: the transformer oil tank (7) is connected with an oil level gauge (11), the oil level gauge (11) is arranged at the top of the transformer shell (3), and the oil level gauge (11) is used for monitoring the oil level condition of transformer oil in the transformer oil tank (7).