330kv large capacity on-load tap-changing double-winding transformer with axial split and forced oil circulation

Abstract

The application provides a 330kV large-capacity axial split and forced guiding oil circulation on-load coarse and fine regulation double-circle transformer, which comprises an oil tank, a sleeve assembly, an oil storage tank, cooling equipment, an on-load coarse and fine regulation switch, secondary protection equipment, a core, a winding assembly and a lead assembly. The winding assembly comprises upper and lower axial split double-layer low-voltage windings, an inner coarse regulation winding and a fine regulation winding of a high-voltage winding arranged in sequence from inside to outside. The coarse regulation winding, the fine regulation winding and the high-voltage main winding are connected in series to form a high-voltage winding part of the transformer. The upper double-layer low-voltage winding is a first low-voltage winding, and the lower double-layer low-voltage winding is a second low-voltage winding, which are independent of each other and are not electrically connected. Through the overall structure design, the application effectively solves the problems of high impedance, split coefficient and winding temperature rise of the existing 330kV large-capacity axial split double-circle transformer, and has the advantages of compact winding structure, high insulation reliability, small loss, low noise, strong short-circuit resistance and small transformer size.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of 330kV low-voltage split oil-immersed transformer, and more particularly to a 330kV large-capacity axial split and forced oil circulation on-load coarse and fine voltage regulation double-circle transformer. BACKGROUND

[0002] In recent years, with the rise of wind power, solar power and other new energy power generation industries, the market demand for high-voltage large-capacity low-voltage split transformers is increasing year by year. The split low-voltage side is usually connected to the power supply, and the short circuit condition between the two split low-voltage sides needs to be considered, that is, one low-voltage split side is connected to the power supply, and the other low-voltage split side is short-circuited. In order to improve the short-circuit resistance between the two split low-voltage sides of the transformer, a high impedance split coefficient is often required. In addition, in order to prolong the service life of the transformer, a lower winding hot spot temperature rise value is often required.

[0003] At present, due to the overcapacity of the transformer market, manufacturers need to actively reduce costs and pursue more compact transformer designs to improve product market competitiveness. The commonly used high split coefficient on-load voltage regulation split transformer has an amplitude split structure, the winding cooling method is self-cooling, and the voltage regulation method is positive and negative regulation. The advantages of the amplitude split structure are large split coefficient, and the disadvantages are complex high-voltage winding end insulation design, and large transformer volume and high cost due to the large number of separately arranged windings. The advantages of the positive and negative regulation voltage regulation method are that the design of the voltage regulation winding is relatively simple, and the disadvantages are that the load loss and short-circuit mechanical force value at the minimum tap are usually larger than those in the coarse and fine regulation voltage regulation method. In addition, the forced oil circulation cooling method used in the winding can more effectively reduce the winding temperature rise and reduce the amount of cooling equipment used than the self-cooling method. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the present application provides a 330kV large-capacity axial split and forced oil circulation on-load coarse and fine voltage regulation double-circle transformer, which has the advantages of large split coefficient, low winding temperature rise, high insulation reliability, excellent performance, and small size.

[0005] To achieve the above purpose, the present application provides the following technical solutions:

[0006] A 330kV large-capacity axial split and forced oil circulation on-load coarse and fine voltage regulation double-circle transformer, comprising an oil tank, a cooling device located outside the oil tank, an oil storage tank arranged above the cooling device and communicating with the oil circuit inside the oil tank, a secondary protection device located above the oil tank, a bushing combination fixedly installed on the oil tank, a core arranged inside the oil tank, an on-load coarse and fine voltage regulation switch fixedly installed inside the oil tank, a winding assembly sleeved on the core, and a lead combination for electrical connection;

[0007] The bushing combination comprises 3 high-voltage bushings, 1 high-voltage neutral point bushing and 6 low-voltage bushings.

[0008] The winding assembly comprises a first low-voltage winding, a second low-voltage winding, a coarse adjustment winding, a fine adjustment winding, a high-voltage main winding, an insulation cylinder, a stay, an upper pressing ring and a lower pressing ring; the first low-voltage winding and the second low-voltage winding are distributed axially in an up-down manner; the coarse adjustment winding, the fine adjustment winding and the high-voltage main winding are connected in series to form a high-voltage winding; the insulation cylinder and the stay are arranged between the first low-voltage winding and the second low-voltage winding and the main column of the iron core, between the first low-voltage winding and the second low-voltage winding and the high-voltage winding, between the outer side of the high-voltage winding and the side column of the iron core, and between the outer side of the high-voltage winding and the high-voltage winding of different phases; the upper pressing ring and the lower pressing ring are fixedly arranged on the upper and lower sides of the winding assembly.

[0009] The lead combination comprises a first low-voltage winding lead, a second low-voltage winding lead, a first connecting lead, a second connecting lead, a third connecting lead, a tapping lead group, a neutral point lead and a middle 330kV lead of the high-voltage winding; the tapping lead group comprises a plurality of tapping leads.

[0010] The bottom of the inner and outer layers of the first low-voltage winding is connected in series through transition transposition, the top of the inner and outer layers of the second low-voltage winding is connected in series through transition transposition, and the two form a low-voltage winding of the transformer; the coarse adjustment winding, the fine adjustment winding and the high-voltage main winding are each divided into an upper part and a lower part; the upper part of the coarse adjustment winding, the upper part of the fine adjustment winding and the upper part of the high-voltage main winding are connected in series through the first connecting lead to form an upper high-voltage winding; the lower part of the coarse adjustment winding, the lower part of the fine adjustment winding and the lower part of the high-voltage main winding are connected in series through the second connecting lead to form a lower high-voltage winding; the upper high-voltage winding and the lower high-voltage winding are connected through the third connecting lead to form an up-down parallel structure; each tapping lead of the coarse adjustment winding and the fine adjustment winding is electrically connected to a corresponding terminal of a load coarse and fine voltage regulating switch; the neutral point lead is led out from the terminal of the load coarse and fine voltage regulating switch and connected to a high-voltage neutral point bushing; the first low-voltage winding lead and the second low-voltage winding lead are respectively connected to three low-voltage bushings; and the middle 330kV lead of the high-voltage winding is connected to a high-voltage bushing.

[0011] As a preferred technical scheme of the present application, the inner and outer layers of the first low-voltage winding are in a spiral structure and connected at the bottom through transition transposition to form a U-shaped winding structure; the inner and outer layers of the second low-voltage winding are in a spiral structure and connected at the top through transition transposition to form a ∩-shaped winding structure; the coarse adjustment winding is in a continuous structure, the fine adjustment winding is in a knotted structure, and the high-voltage main winding is in an inner screen continuous structure.

[0012] As a preferred technical scheme of the present application, the first low-voltage winding, the second low-voltage winding and the high-voltage winding are each provided with a forced guide oil circulation cooling structure.

[0013] As a preferred technical scheme of the present application, an electrostatic ring and a large-angle ring for increasing the distance between the two low-voltage windings are arranged at a position between the bottom of the first low-voltage winding and the top of the second low-voltage winding.

[0014] As a preferred technical scheme of the present application, the inner surface of the oil tank is provided with a magnetic shield.

[0015] As a preferred technical scheme of the present application, the iron core comprises three main columns, two side columns, a main window iron yoke, a side window iron yoke, a main column pull plate, a side column pull plate, an upper clamp, a lower clamp and a supporting plate; one main column pull plate is arranged on each of the front and rear end faces of the main column; one side column pull plate is arranged on each of the front and rear end faces of the side column; the main window iron yoke is arranged at the upper and lower ends between the two adjacent main columns, and the side window iron yoke is arranged at the upper and lower ends between the main column and the side column; the main column, the main column pull plate, the side column, the side column pull plate, the main window iron yoke and the side window iron yoke are tightly fixed in position by the upper clamp and the lower clamp to form a five-column four-frame structure; the main column is provided with a vertical oil channel and a horizontal oil channel, and the side column, the main window iron yoke and the side window iron yoke are provided with a horizontal oil channel; the outer end face of the side column is provided with a graphite shielding layer; two supporting plates are welded to the lower end faces of the upper clamp on both sides of each main column pull plate and the upper end faces of the lower clamp on both sides of each main column pull plate, and the supporting plates are internally provided with a magnetic shield.

[0016] As a preferred technical scheme of the present application, the winding assembly further comprises a sleeve plate, an end ring, a cushion block and an oil baffle.

[0017] As a preferred technical scheme of the present application, the upper end of the first low-voltage winding and the upper pressure ring are sequentially stacked from bottom to top with an oil baffle, an end ring, a sleeve plate, a cushion block, an end ring, a sleeve plate and a cushion block; the lower end of the second low-voltage winding and the lower pressure ring are sequentially stacked from top to bottom with an oil baffle, an end ring, a cushion block, a sleeve plate, an end ring, a sleeve plate, a cushion block, a sleeve plate, an end ring and a sleeve plate.

[0018] As a preferred technical scheme of the present application, the upper end of the upper fine adjustment winding and the upper pressure ring are sequentially stacked from bottom to top with an oil baffle, a sleeve plate, a cushion block, a sleeve plate and a cushion block; the lower end of the lower fine adjustment winding and the lower pressure ring are sequentially stacked from top to bottom with a sleeve plate, an end ring, a cushion block and a sleeve plate.

[0019] As a preferred technical scheme of the present application, the tap lead groups of the coarse adjustment winding and the fine adjustment winding of two phases are distributed on the same side of the middle 330kV lead of the high-voltage winding; the tap lead groups of the coarse adjustment winding and the fine adjustment winding of the other phase are distributed on the same side of the lead of the first low-voltage winding and the second low-voltage winding.

[0020] Compared with the prior art, the present application has the following advantages:

[0021] (1) the 330kV large capacity axial split and forced guiding oil circulation on-load coarse and fine regulation double circle transformer of the application, two low voltage windings are designed into upper and lower independent axial split structure, the distance between the two low voltage windings is increased by setting static ring and large angle ring between the two low voltage windings, so that the impedance split coefficient is effectively improved and reliable insulation structure is provided.(2) the 330kV large capacity axial split and forced guiding oil circulation on-load coarse and fine regulation double circle transformer of the application, all windings adopt forced guiding oil circulation cooling structure, which effectively reduces the winding temperature rise.(3) the 330kV large capacity axial split and forced guiding oil circulation on-load coarse and fine regulation double circle transformer of the application, coarse and fine regulation mode is adopted, which effectively reduces the load loss at the minimum tapping, thereby reducing the number of cooling equipment and improving the short circuit resistance of the transformer at the minimum tapping.(4) the 330kV large capacity axial split and forced guiding oil circulation on-load coarse and fine regulation double circle transformer of the application, coarse regulation winding and fine regulation winding are arranged in the high voltage winding, which reduces the number of winding single columns, makes the structure of the device more compact, and reduces the size of the transformer. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0023] Figure 1 is a schematic diagram of the overall structure of the application;

[0024] Figure 2 is a left view of Figure 1 ;

[0025] Figure 3 is a top view of Figure 1 ;

[0026] Figure 4 is a schematic diagram of the core assembly structure of the application;

[0027] Figure 5 is a schematic diagram of the winding arrangement and connection of the application;

[0028] Figure 6 is a schematic diagram of the assembly structure of the winding assembly of the application;

[0029] Figure 7 is a schematic diagram of the lead arrangement of the application.

[0030] In the figure: oil tank 1, magnetic shield 1-1;

[0031] Sleeve assembly 2, high-voltage sleeve 2-1, high-voltage neutral point sleeve 2-2, first low-voltage winding sleeve 2-3; second low-voltage winding sleeve 2-4;

[0032] Oil conservator 3;

[0033] Cooling equipment 4, fin 4-1, fan 4-2, oil pump 4-3;

[0034] On-load tap-changing switch 5;

[0035] Secondary protection equipment 6, pressure relief valve 6-1, gas relay 6-2, oil temperature gauge 6-3, winding temperature gauge 6-4, oil flow relay 6-5, and oil level gauge 6-6;

[0036] Core 7, main column 7-1, side column 7-2, main window iron yoke 7-3, side window iron yoke 7-4, main column pull plate 7-5, side column pull plate 7-6, upper clamp 7-7, lower clamp 7-8, supporting plate 7-9;

[0037] Winding assembly 8, first low-voltage winding 8-1, second low-voltage winding 8-2, fine-tuning winding 8-3, coarse-tuning winding 8-4, high-voltage main winding 8-5, insulating cylinder 8-6, strut 8-7, sleeve plate 8-8, static ring 8-9, large-angle ring 8-10, cushion block 8-11, oil baffle 8-12, end ring 8-13, upper compression ring 8-14, lower compression ring 8-15;

[0038] Lead assembly 9, first low-voltage winding lead 9-1, second low-voltage winding lead 9-2, tapping lead assembly 9-3, neutral point lead 9-4, 330kV middle lead of high-voltage winding 9-5. DETAILED DESCRIPTION

[0039] Embodiments of the present application are described in detail below with reference to the accompanying drawings, in which like or similar elements or elements having the same or similar functions are denoted by the same or similar reference numerals throughout the drawings. The embodiments described below by reference to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0040] In the description of the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0041] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature can include that the first and second features are in direct contact, or can include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature is "on", "above" and "over" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. The first feature is "under", "below" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0042] As shown in the present application, a 330kV large-capacity axial split and forced guiding oil circulation on-load coarse and fine voltage regulation double-circle transformer includes an oil tank, cooling equipment, an oil storage tank, secondary protection equipment, a bushing combination, a core, an on-load coarse and fine voltage regulation switch, a winding assembly and a lead combination. Figures 1-7 The bushing combination is fixedly arranged at the upper portion of the oil tank 1, and the bushing 2 includes three high-voltage bushings 2-1, one high-voltage neutral point bushing 2-2, three first low-voltage winding bushings 2-3 and three second low-voltage winding bushings 2-4.

[0043] The oil storage tank 3 is arranged above the finned radiator 4-1, and is used for storing transformer oil. The oil storage tank 3 is communicated with the internal oil passage of the oil tank 1, and the oil tank 1 is filled with transformer oil. The above is prior art and will not be described in detail. The inner surface of the oil tank 1 is provided with a magnetic shield 1-1, so that the magnetic leakage of the oil tank 1 is reduced, and the stray loss of the oil tank 1 is reduced. The outer side of the magnetic shield 1-1 of the oil tank 1 is further provided with a graphite shielding layer, a surrounding screen and a support bar (not shown), so that the insulation effect of the oil tank 1 is enhanced.

[0044] The cooling equipment 4 includes the finned radiator 4-1, a fan 4-2 and an oil pump 4-3. The cooling equipment 4 is used for heat dissipation of the transformer, and can prolong the service life of the transformer.

[0045] The on-load coarse and fine voltage regulation switch 5 is fixedly arranged in the oil tank 1, and is used for realizing the voltage regulation function of the transformer.

[0046] The secondary protection equipment 6 includes a pressure release valve 6-1, a gas relay 6-2, an oil temperature gauge 6-3, a winding temperature gauge 6-4, an oil flow relay 6-5 and an oil level gauge 6-6. The transformer is protected by the pressure release valve 6-1, the gas relay 6-2 and the oil flow relay 6-5 during operation, and is controlled to start and stop by the oil temperature gauge 6-3 and the winding temperature gauge 6-4. This section is prior art and will not be described in detail.

[0047]

[0048] ​The iron core 7 is mainly composed of main columns 7-1, side columns 7-2, main window iron yokes 7-3, side window iron yokes 7-4, main column pull plates 7-5, side column pull plates 7-6, upper clamping pieces 7-7, lower clamping pieces 7-8, and supporting plates 7-9. There are three main columns 7-1 and two side columns 7-2, which are arranged on both sides of the iron core 7. Each of the front and rear end faces of the main column 7-1 is provided with a main column pull plate 7-5. Each of the front and rear end faces of the side column 7-2 is provided with a side column pull plate 7-6. The main window iron yokes 7-3 and the side window iron yokes 7-4 are arranged in pairs at the upper and lower parts, respectively. The main window iron yokes 7-3 are arranged at the upper and lower ends between the two main columns 7-1 to seal the head, and the side window iron yokes 7-4 are arranged at the upper and lower ends of the main column 7-1 and the side column 7-2 to seal the tail. The three main columns 7-1, the two side columns 7-2, the main column pull plates 7-5, the side column pull plates 7-6, the main window iron yokes 7-3, and the side window iron yokes 7-4 are fastened into one body by the upper clamping pieces 7-7 and the lower clamping pieces 7-8, forming a five-column four-frame structure. The main column 7-1 is provided with vertical oil channels and horizontal oil channels, the side column 7-2, the main window iron yoke 7-3, and the side window iron yoke 7-4 are provided with horizontal oil channels, and the main column 7-1, the side column 7-2, the main window iron yoke 7-3, and the side window iron yoke 7-4 of the iron core are all arranged in a six-level jointed manner. The outer periphery of the two side columns 7-2 is provided with a screen and a screen support bar (not shown). Two supporting plates 7-9 are welded on the lower end faces of the upper clamping pieces 7-7 on both sides near the main column, and two supporting plates 7-9 are welded on the upper end faces of the lower clamping pieces 7-8 on both sides near the main column. There are a total of 12 supporting plates 7-9, which are arranged inside the supporting plates 7-9. The supporting plates 7-9 are provided with magnetic shielding, which is used to press and support the winding assembly 8, and to reduce the leakage magnetic flux of the upper clamping pieces 7-7 and the lower clamping pieces 7-8, thereby reducing the stray loss. During assembly, the iron core 7 is fixed in the oil tank 1.

[0049] The winding assembly 8 includes a first low-voltage winding 8-1, a second low-voltage winding 8-2, a fine adjustment winding 8-3, a coarse adjustment winding 8-4, a high-voltage main winding 8-5, an insulation cylinder 8-6, a support bar 8-7, a sleeve plate 8-8, an electrostatic ring 8-9, a large-angle ring 8-10, a cushion block 8-11, an oil baffle 8-12, an end ring 8-13, an upper pressing ring 8-14, and a lower pressing ring 8-15. The number of sleeve plates 8-8, end rings 8-13, cushion blocks 8-11, and oil baffles 8-12 is set according to requirements. The upper pressing ring 8-14 and the lower pressing ring 8-15 are arranged at the upper and lower ends of the winding assembly 8 to press and support the related components of the winding assembly 8. The electrostatic ring 8-9 and the large-angle ring 8-10 are arranged between the bottom of the first low-voltage winding 8-1 and the top of the second low-voltage winding 8-2, which can increase the distance between the two low-voltage windings, thereby effectively improving the impedance splitting coefficient and providing a reliable insulation structure.

[0050] The inner and outer layers of the first low-voltage winding 8-1 and the second low-voltage winding 8-2 are in a spiral structure, and are arranged on the outer periphery of the fine adjustment winding 8-3, the coarse adjustment winding 8-4 and the high-voltage main winding 8-5. The first low-voltage winding 8-1 and the second low-voltage winding 8-2 are distributed in an upper and lower axial direction. The first low-voltage winding 8-1 is connected by a transition transposition at the bottom to form a U-shaped winding structure. The second low-voltage winding 8-2 is connected by a transition transposition at the top to form a ∩-shaped winding structure. The first low-voltage winding 8-1 and the second low-voltage winding 8-2 are provided with an insulating cylinder 8-6 and a support bar 8-7 between the fine adjustment winding 8-3, the coarse adjustment winding 8-4 and the high-voltage main winding 8-5. The upper end of the first low-voltage winding 8-1 is sequentially provided with an oil baffle 8-12, an end ring 8-13, a sleeve plate 8-8, a cushion block 8-11, an end ring 8-13, a sleeve plate 8-8 and a cushion block 8-11 from bottom to top between the upper pressure ring 8-14. The lower end of the second low-voltage winding 8-2 is sequentially provided with an oil baffle 8-12, an end ring 8-13, a cushion block 8-11, a sleeve plate 8-8, an end ring 8-13, a sleeve plate 8-8, a cushion block 8-11, a sleeve plate 8-8, an end ring 8-13 and a sleeve plate 8-8 from top to bottom between the lower pressure ring 8-15.

[0051] The fine adjustment winding 8-3 is in a knotted structure, and is arranged at the upper end of the upper coarse adjustment winding 8-4 and the lower end of the lower coarse adjustment winding 8-4. The coarse adjustment winding 8-4 is in a continuous structure, and is arranged between the upper fine adjustment winding 8-3 and the upper high-voltage main winding 8-5, and between the lower fine adjustment winding 8-3 and the lower high-voltage main winding 8-5. The high-voltage main winding 8-5 is in an inner screen continuous structure, and the upper and lower high-voltage main windings 8-5 are arranged between the upper coarse adjustment winding 8-5 and the lower coarse adjustment winding 8-5. The outer sides of the fine adjustment winding 8-3, the coarse adjustment winding 8-4 and the high-voltage main winding 8-5 are provided with an insulating cylinder 8-6 and a support bar 8-7 between the other phase high-voltage windings and the two side columns 7-2. The upper end of the upper fine adjustment winding 8-3 is sequentially provided with an oil baffle 8-12, a sleeve plate 8-8, a cushion block 8-11, a sleeve plate 8-8 and a cushion block 8-11 between the upper pressure ring 8-14. The lower end of the lower fine adjustment winding 8-3 is sequentially provided with a sleeve plate 8-8, an end ring 8-13, a cushion block 8-11 and a sleeve plate 8-8 between the lower pressure ring 8-15.

[0052] The first low-voltage winding 8-1, the second low-voltage winding 8-2, the fine adjustment winding 8-3, the coarse adjustment winding 8-4 and the high-voltage main winding 8-5 are all provided with a forced guide oil circulation cooling structure, which is a prior art and will not be described in detail.

[0053] The lead combination 9 includes a first low-voltage winding lead 9-1, a second low-voltage winding lead 9-2, a tapping lead combination 9-3, a neutral point lead 9-4 and a middle 330kV lead 9-5 of the high-voltage winding. The first low-voltage winding lead 9-1 is located at the upper part of the core 7, and the second low-voltage winding lead 9-2 is located at the lower part of the core 7. The tapping lead combination 9-3 of the regulating winding includes several tapping leads. The upper fine regulating winding, the upper coarse regulating winding and the upper high-voltage main winding are connected in series through a first connecting lead (not shown) to form the upper high-voltage winding. The lower fine regulating winding, the lower coarse regulating winding and the lower high-voltage main winding are connected in series through a second connecting lead (not shown) to form the lower high-voltage winding. The coarse regulating winding 8-3 and the fine regulating winding 8-4 are connected in parallel through a third connecting lead (not shown) near the winding, and then connected to the corresponding terminal pairs of the on-load coarse and fine voltage regulating switch 5 through the tapping lead combination 9-3, so as to realize the voltage regulating function of the transformer. The neutral point lead 9-4 is led out from the terminal of the on-load coarse and fine voltage regulating switch 5.

[0054] The first low-voltage winding lead 9-1 and the second low-voltage winding lead 9-2 are connected to the first low-voltage winding bushing 2-3 and the second low-voltage winding bushing 2-4 respectively. The neutral point lead 9-4 is connected to the high-voltage neutral point bushing 2-2. The middle 330kV lead 9-5 of the high-voltage winding is connected to the high-voltage bushing 2-1.

[0055] The tapping lead combination 9-3 of the coarse regulating winding 8-3 and the fine regulating winding 8-4 of two phases is distributed on the same side of the middle 330kV lead 9-5 of the high-voltage winding. The tapping lead combination 9-3 of the coarse regulating winding 8-3 and the fine regulating winding 8-4 of the other phase is distributed on the same side of the first low-voltage winding lead 9-1 and the second low-voltage winding lead 9-2.

[0056] In use, the three first low-voltage winding bushings 2-3 and the three second low-voltage winding bushings 2-4 are connected to the input power supply. The high-voltage bushing 2-1 and the high-voltage neutral point bushing 2-2 output the power supply, that is, the low-voltage input and the high-voltage output. Obviously, the input and output of the power supply can also be reversed when needed.

[0057] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the above examples do not limit the present application in any form, and any technical solutions obtained by equivalent replacement or equivalent transformation fall within the protection scope of the present application.

Claims

1. A 330kV high-capacity axially split and forced-guided oil circulation on-load coarse and fine voltage regulating double-winding transformer, comprising an oil tank, a cooling device located outside the oil tank, an oil conservator disposed above the cooling device and communicating with the internal oil circuit of the oil tank, a secondary protection device located above the oil tank, a bushing assembly fixedly installed on the oil tank, an iron core disposed inside the oil tank, an on-load coarse and fine voltage regulating switch fixed inside the oil tank, a winding assembly sleeved on the iron core, and a lead assembly for electrical connection, characterized in that: The bushing assembly includes: 3 high-pressure bushings, 1 high-pressure neutral point bushing, and 6 low-pressure bushings. The winding assembly includes: a first low-voltage winding, a second low-voltage winding, a coarse-adjustment winding, a fine-adjustment winding, a high-voltage main winding, an insulating cylinder, a support bar, an upper pressure ring, and a lower pressure ring; the first low-voltage winding and the second low-voltage winding are axially distributed vertically; the coarse-adjustment winding, the fine-adjustment winding, and the high-voltage main winding are connected in series to form a high-voltage winding; the insulating cylinder and the support bar are provided between the first low-voltage winding and the second low-voltage winding and the main column of the iron core, between the first low-voltage winding and the second low-voltage winding and the high-voltage winding, between the outer side of the high-voltage winding and the side column of the iron core, and between the high-voltage winding and the out-of-phase high-voltage winding; the upper pressure ring and the lower pressure ring are fixedly disposed on the upper and lower sides of the winding assembly; The lead assembly includes: a first low-voltage winding lead, a second low-voltage winding lead, a first connecting lead, a second connecting lead, a third connecting lead, a tap lead group, a neutral point lead, and a 330kV lead in the middle of the high-voltage winding; the tap lead group includes several tap leads. The bottom layers of the inner and outer layers of the first low-voltage winding are connected in series via transition transposition, and the top layers of the inner and outer layers of the second low-voltage winding are connected in series via transition transposition, forming the low-voltage winding of the transformer. The coarse adjustment winding, the fine adjustment winding, and the high-voltage main winding are all divided into upper and lower parts. The upper coarse adjustment winding, the upper fine adjustment winding, and the upper high-voltage main winding are connected in series via the first connecting lead to form the upper high-voltage winding. The lower coarse adjustment winding, the lower fine adjustment winding, and the lower high-voltage main winding are connected in series via the second connecting lead to form the lower high-voltage winding. The upper high-voltage winding and the lower high-voltage winding are connected by the third connecting lead to form an upper and lower parallel structure; each tap lead of the coarse adjustment winding and the fine adjustment winding is electrically connected to the corresponding terminal of the on-load coarse and fine voltage regulating switch; the neutral point lead is led out from the terminal of the on-load coarse and fine voltage regulating switch and connected to the high-voltage neutral point bushing; the first low-voltage winding lead and the second low-voltage winding lead are respectively connected to the three low-voltage bushings; the middle 330kV lead of the high-voltage winding is connected to the high-voltage bushing.

2. The 330kV large-capacity axially split and forced guided oil circulation on-load coarse and fine voltage regulating double-coil transformer according to claim 1, characterized in that, The inner and outer layers of the first low-voltage winding are spiral structures and are connected at the bottom through transition transposition to form a U-shaped winding structure; the inner and outer layers of the second low-voltage winding are spiral structures and are connected at the top through transition transposition to form a ∩-shaped winding structure. The coarse adjustment winding has a continuous structure, the fine adjustment winding has a tangled structure, and the high-voltage main winding has an inner-screen continuous structure.

3. The 330kV large-capacity axially split and forced guided oil circulation on-load coarse and fine voltage regulating double-coil transformer according to claim 1, characterized in that, The first low-voltage winding, the second low-voltage winding, and the high-voltage winding are all equipped with a forced-guided oil circulation cooling structure.

4. The 330kV large-capacity axially split and forced guided oil circulation on-load coarse and fine voltage regulating double-coil transformer according to claim 1, characterized in that, An electrostatic ring and a large-angle ring are provided between the bottom of the first low-voltage winding and the top of the second low-voltage winding to increase the distance between the two low-voltage windings.

5. The 330kV large-capacity axially split and forced guided oil circulation on-load coarse and fine voltage regulating double-coil transformer according to claim 1, characterized in that, The inner surface of the oil tank is magnetically shielded.

6. The 330kV large-capacity axially split and forced guided oil circulation on-load coarse and fine voltage regulating double-coil transformer according to claim 5, characterized in that, The iron core includes 3 main columns, 2 side columns, a main window yoke, a side window yoke, a main column tie plate, a side column tie plate, an upper clamp, a lower clamp, and a support plate. The main column tie plate is provided on each of the front and rear end faces of the main column; The side column bracing plate is provided on each of the front and rear end faces of the side column; The main window yoke is located at the upper and lower ends between two adjacent main columns, and the side window yoke is located at the upper and lower ends between the main column and the side column; The main column, the main column tie plate, the side column, the side column tie plate, the main window yoke, and the side window yoke are fastened and positioned as a five-column four-frame structure by the upper clamp and the lower clamp; The main column is provided with vertical oil channels and horizontal oil channels, and the side columns, the main window yoke, and the side window yoke are provided with horizontal oil channels; The outer end face of the side column is provided with a graphite shielding layer; Two support plates are welded to the lower end faces of the upper clamping member on both sides of each main column pull plate and the upper end faces of the lower clamping member on both sides of each main column pull plate. The magnetic shielding is provided inside the support plates.

7. The 330kV large-capacity axially split and forced guided oil circulation on-load coarse and fine voltage regulating double-coil transformer according to claim 1, characterized in that, The winding assembly also includes: a bushing, an end ring, a spacer, and an oil baffle.

8. The 330kV large-capacity axially split and forced guided oil circulation on-load coarse and fine voltage regulating double-coil transformer according to claim 7, characterized in that, The oil baffle plate, end ring, sleeve plate, pad block, end ring, sleeve plate, and pad block are stacked sequentially from bottom to top between the upper end of the first low-voltage winding and the upper pressure ring; the oil baffle plate, end ring, pad block, sleeve plate, end ring, sleeve plate, pad block, sleeve plate, end ring, and sleeve plate are stacked sequentially from top to bottom between the lower end of the second low-voltage winding and the lower pressure ring.

9. The 330kV large-capacity axially split and forced guided oil circulation on-load coarse and fine voltage regulating double-coil transformer according to claim 7, characterized in that, The oil baffle, sleeve plate, pad block, sleeve plate and pad block are stacked sequentially from bottom to top between the upper end of the upper fine adjustment winding and the upper pressure ring; The lower end of the lower fine-tuning winding and the lower pressure ring are provided with the sleeve plate, end ring, pad block and sleeve plate stacked from top to bottom.

10. The 330kV large-capacity axially split and forced guided oil circulation on-load coarse and fine voltage regulating double-coil transformer according to claim 1, characterized in that, The tap lead groups of the coarse adjustment winding and the fine adjustment winding of the two phases are distributed on the same side of the 330kV lead in the middle of the high voltage winding; The tap groups of the coarse adjustment winding and the fine adjustment winding of the other phase are distributed on the same side of the leads of the first low-voltage winding and the second low-voltage winding.

Images