330kV high-capacity on-load coarse and fine voltage regulation double-coil transformer capable of axially splitting and forcibly guiding oil circulation

Abstract

The invention provides a 330kV high-capacity on-load coarse and fine voltage regulation double-ring transformer capable of axially splitting and forcibly guiding oil circulation. The 330kV high-capacity on-load coarse and fine voltage regulation double-ring transformer comprises an oil tank, a sleeve combination, an oil storage cabinet, cooling equipment, an on-load coarse and fine voltage regulation switch, secondary protection equipment, an iron core, a winding assembly and a lead combination. The winding assembly comprises a double-layer low-voltage winding which is split up and down in the axial direction and a high-voltage winding with a built-in coarse tuning winding and a built-in fine tuning winding which are sequentially arranged from inside to outside. And the coarse tuning winding, the fine tuning 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, the lower double-layer low-voltage winding is a second low-voltage winding, and the two windings are mutually independent and are not electrically connected. Through the overall structural design, the problems of high impedance split coefficient and winding temperature rise of a 330kV high-capacity axial split double-ring transformer in the prior art are effectively solved, and the winding is compact in structure, high in insulation reliability, small in loss, low in noise, high in short circuit resistance and small in size.

Description

Technical Field

[0001] The invention belongs to the technical field of 330kV low-voltage split oil-immersed transformers, and more specifically, relates to a 330kV large-capacity axially split on-load coarse and fine voltage regulating double-turn transformer with forced guided oil circulation. Background Art

[0002] In recent years, with the rise of new energy power generation industries such as wind power and solar power, the market demand for high-voltage and 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 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 of the transformer when the two split low-voltage sides are short-circuited, a high impedance splitting coefficient is often required. In addition, in order to extend the service life of the transformer, a lower winding hot spot temperature rise is often required.

[0003] At present, due to the overcapacity in the transformer market, manufacturers need to actively reduce costs and pursue more compact transformer designs in order to improve the market competitiveness of their products. The common high-splitting coefficient on-load voltage-regulating split transformers currently have a radial split structure, the winding cooling method is self-cooling, and the voltage regulation method is positive and negative regulation. The advantage of the radial split structure is the large split coefficient, and the disadvantage is that the insulation design of the high-voltage winding end is complex, and due to the large number of separately arranged windings, the transformer is large in size and high in cost. The advantage of the positive and negative voltage regulation method is that the voltage regulation winding design is relatively simple, and the disadvantage is that the load loss and short-circuit mechanical force generation value at the minimum tap are usually larger than those under the coarse and fine voltage regulation method. In addition, the forced guided oil circulation cooling method is used in the winding, which can more effectively reduce the winding temperature rise and reduce the use of cooling equipment than the self-cooling method. Summary of the invention

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

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A 330kV large-capacity axially split and forced-guide oil circulation on-load coarse and fine voltage regulating double-turn transformer, comprising an oil tank, a cooling device located outside the oil tank, an oil storage cabinet arranged above the cooling device and communicating with the oil path inside the oil tank, a secondary protection device located above the oil tank, a bushing assembly fixedly mounted on the oil tank, an iron core arranged 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;

[0007] The bushing combination includes: 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 insulating cylinder, a stay, an upper pressure ring and a lower pressure ring; the first low-voltage winding and the second low-voltage winding are axially distributed in an upper and lower direction; the coarse adjustment winding, the fine adjustment winding and the high-voltage main winding are connected in series to form a high-voltage winding; insulating cylinders and stays 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 out-of-phase high-voltage winding; the upper pressure ring and the lower pressure ring are fixedly arranged on the upper and lower sides of the winding assembly;

[0009] The lead wire assembly includes: a first low voltage winding lead wire, a second low voltage winding lead wire, a first connecting lead wire, a second connecting lead wire, a third connecting lead wire, a tap lead wire group, a neutral point lead wire and a middle 330 kV lead wire of the high voltage winding; the tap lead wire group includes a plurality of tap lead wires;

[0010] The bottom of the inner and outer layers of the first low-voltage winding are connected in series through transition transposition, and the top of the inner and outer layers of the second low-voltage winding are connected in series through transition transposition, and the two constitute the low-voltage winding of the transformer; the coarse-adjusting winding, the fine-adjusting winding and the high-voltage main winding are divided into upper and lower parts; the upper coarse-adjusting winding, the upper fine-adjusting winding and the upper high-voltage main winding are connected in series through the first connecting lead to form the upper high-voltage winding; the lower coarse-adjusting winding, the lower fine-adjusting winding and the lower high-voltage main winding are connected in series through 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 a third connecting lead to form an upper and lower parallel structure; each tap lead of the coarse-adjusting winding and the fine-adjusting winding is electrically connected to the corresponding terminals 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 three low-voltage bushings; the middle 330kV lead of the high-voltage winding is connected to the high-voltage bushing.

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

[0012] As a preferred technical solution of the present invention, the first low-voltage winding, the second low-voltage winding and the high-voltage winding are all provided with a forced guided oil circulation cooling structure.

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

[0014] As a preferred technical solution of the present invention, a magnetic shield is relatively arranged on the inner surface of the oil tank.

[0015] As a preferred technical solution of the present invention, the iron core includes 3 main columns, 2 side columns, main window yokes, side window yokes, main column pull plates, side column pull plates, upper clamps, lower clamps and support plates; the main column pull plates are each provided with one on the front and rear end surfaces of the main columns; the side column pull plates are each provided with one on the front and rear end surfaces of the side columns; the main window yoke is arranged at the upper and lower ends between two adjacent main columns, and the side window yoke is arranged at the upper and lower ends between the main columns and the side columns; the main columns, main column pull plates, side columns, side column pull plates, main window yokes and side window yokes are fastened and positioned in a five-column four-frame structure by upper clamps and lower clamps; the main columns are provided with vertical oil passages and horizontal oil passages, and the side columns, main window yokes and side window yokes are provided with horizontal oil passages; the outer end surfaces of the side columns are provided with graphite shielding layers; two support plates are welded on the lower end surfaces of the upper clamps located on both sides of each main column pull plate and the upper end surfaces of the lower clamps located on both sides of each main column pull plate, and magnetic shielding is provided inside the support plates.

[0016] As a preferred technical solution of the present invention, the winding assembly further includes: a sleeve plate, an end ring, a spacer block and an oil baffle.

[0017] As a preferred technical solution of the present invention, an oil baffle plate, an end ring, a sleeve plate, a gasket, an end ring, a sleeve plate and a gasket are stacked in sequence from bottom to top between the upper end of the first low-voltage winding and the upper pressure ring; an oil baffle plate, an end ring, a gasket, a sleeve plate, an end ring, a sleeve plate, a gasket, a sleeve plate, an end ring and a sleeve plate are stacked in sequence from top to bottom between the lower end of the second low-voltage winding and the lower pressure ring.

[0018] As a preferred technical solution of the present invention, an oil baffle plate, a sleeve plate, a pad, a sleeve plate and a pad are stacked in sequence from bottom to top between the upper end of the upper fine-tuning winding and the upper pressure ring; a sleeve plate, an end ring, a pad and a sleeve plate are stacked in sequence from top to bottom between the lower end of the lower fine-tuning winding and the lower pressure ring.

[0019] As a preferred technical solution of the present invention, 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 another phase are distributed on the same side of the leads of the first low-voltage winding and the second low-voltage winding.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The 330kV large-capacity axially split and forced-guided oil circulation on-load coarse and fine voltage-regulating double-turn transformer of the present invention designs the two low-voltage windings into an upper and lower independent axially split structure, and increases the distance between the two low-voltage windings by arranging an electrostatic ring and a large-angle ring between the two low-voltage windings, thereby effectively improving the impedance splitting coefficient and providing a reliable insulation structure. (2) The 330kV large-capacity axially split and forced-guided oil circulation on-load coarse and fine voltage-regulating double-turn transformer of the present invention adopts a forced-guided oil circulation cooling structure for all windings, which effectively reduces the temperature rise of the windings. (3) The 330kV large-capacity axially split and forced-guided oil circulation on-load coarse and fine voltage-regulating double-turn transformer of the present invention adopts a coarse and fine voltage regulation method, 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) In the 330 kV large-capacity axially split and forced oil-circulating on-load coarse and fine voltage regulation double-turn transformer of the present invention, the coarse regulation winding and the fine regulation winding are placed inside the high-voltage winding, which reduces the number of single-row windings, makes the body structure more compact, and reduces the size of the transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 for Figure 1 Left view of

[0025] Figure 3 for Figure 1 A top view of

[0026] Figure 4 It is a schematic diagram of the iron core assembly structure of the present invention;

[0027] Figure 5 A schematic diagram of the winding arrangement and connection of the present invention;

[0028] Figure 6 It is a schematic diagram of the assembly structure of the winding assembly of the present invention;

[0029] Figure 7 It is a schematic diagram of the lead arrangement of the present invention.

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

[0031] Bushing combination 2, high-voltage bushing 2-1, high-voltage neutral point bushing 2-2, first low-voltage winding bushing 2-3; second low-voltage winding bushing 2-4;

[0032] Oil storage tank 3;

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

[0034] On-load coarse and fine voltage regulating switch 5;

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

[0036] Iron 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, support plate 7-9;

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

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

[0039] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0040] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0042] like Figure 1-7 As shown, a 330kV large-capacity axially split and forced-guided oil circulation on-load coarse and fine voltage regulating double-turn transformer of the present application includes: an oil tank, a cooling device, an oil storage cabinet, a secondary protection device, a bushing assembly, an iron core, an on-load coarse and fine voltage regulating switch, a winding assembly and a lead assembly.

[0043] The bushing assembly is fixedly arranged on the upper part 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.

[0044] The oil storage cabinet 3 is arranged above the sheet disperser 4-1, and the oil storage cabinet 3 is used to store transformer oil. The oil storage cabinet 3 is connected to the internal oil circuit of the oil tank 1, and the oil tank 1 is filled with transformer oil. The above is the 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, which can reduce the magnetic leakage of the oil tank 1 and reduce the stray loss of the oil tank 1. The outer side of the magnetic shield 1-1 of the oil tank 1 is also provided with a graphite shielding layer, a screen and a stay (not shown), so that the arrangement can enhance the insulation effect of the oil tank 1.

[0045] The cooling device 4 includes a heat sink 4-1, a fan 4-2 and an oil pump 4-3. The cooling device 4 is used to dissipate heat of the transformer and can extend its service life.

[0046] The on-load coarse and fine voltage regulating switch 5 is fixedly arranged in the oil tank 1 , and the on-load coarse and fine voltage regulating switch 5 is used to realize the voltage regulating function of the transformer.

[0047] The secondary protection device 6 includes a pressure relief valve 6-1, a gas relay 6-2, an oil thermometer 6-3, a winding thermometer 6-4, an oil flow relay 6-5 and an oil level meter 6-6. The transformer implements safety protection for transformer operation through the pressure relief valve 6-1, the gas relay 6-2 and the oil flow relay 6-5, and controls the start and stop of the transformer through the oil thermometer 6-3 and the winding thermometer 6-4. This section is all prior art and will not be repeated.

[0048] The iron core 7 is mainly composed of a main column 7-1, a side column 7-2, a main window iron yoke 7-3, a side window iron yoke 7-4, a main column pull plate 7-5, a side column pull plate 7-6, an upper clamp 7-7, a lower clamp 7-8, and a support plate 7-9. There are three main columns 7-1, and two side columns 7-2. The two side columns 7-2 are arranged on both sides of the iron core 7. A main column pull plate 7-5 is arranged on each of the front and rear end surfaces of the main column 7-1. A side column pull plate 7-6 is arranged on each of the front and rear end surfaces of the side column 7-2. Two main window iron yokes 7-3 and side window iron yokes 7-4 are arranged at the upper and lower parts. The main window iron yoke 7-3 is arranged at the upper and lower ends between the two main columns 7-1 for head sealing, and the side window iron yoke 7-4 is arranged at the upper and lower ends of the main column 7-1 and the side column 7-2 for tail sealing. Three main columns 7-1, two side columns 7-2, main column pull plates 7-5, side column pull plates 7-6, main window iron yokes 7-3 and side window iron yokes 7-4 are fastened together by upper clamps 7-7 and lower clamps 7-8 to form a five-column four-frame structure. The main column 7-1 is provided with vertical oil passages and horizontal oil passages, and the side columns 7-2, main window iron yokes 7-3 and side window iron yokes 7-4 are provided with horizontal oil passages. The main columns 7-1, side columns 7-2, main window iron yokes 7-3 and side window iron yokes 7-4 of the iron core are all stacked in a six-level joint manner. The outer peripheries of the two side columns 7-2 are provided with screens and screen stays (not shown). Two support plates 7-9 are welded on the lower end surfaces of the front and rear sides of the upper clamp 7-7 near the main column, and two support plates 7-9 are welded on the upper end surfaces of the front and rear sides of the lower clamp 7-8 near the main column. A total of 12 support plates 7-9 are provided. A magnetic shield is provided inside the support plate, which is used to press and support the winding assembly 8 on the one hand, and reduce the leakage magnetic field incident on the upper clamp 7-7 and the lower clamp 7-8 on the other hand, thereby reducing 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-tuning winding 8-3, a coarse-tuning winding 8-4, a high-voltage main winding 8-5, an insulating tube 8-6, a stay 8-7, a sleeve 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 pressure ring 8-14, and a lower pressure ring 8-15. The number of sleeves 8-8, end rings 8-13, cushion blocks 8-11 and oil baffles 8-12 is set according to demand. The upper pressure ring 8-14 and the lower pressure ring 8-15 are arranged at the upper and lower ends of the winding assembly 8 to compress and support the relevant 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 spiral structures, which are arranged on the periphery of the fine-tuning winding 8-3, the coarse-tuning 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 axially up and down. The first low-voltage winding 8-1 is connected by transition transposition at the bottom to form a U-shaped winding structure. The second low-voltage winding 8-2 is connected by transition transposition at the top to form a ∩-shaped winding structure. An insulating tube 8-6 and a support bar 8-7 are provided between the first low-voltage winding 8-1 and the second low-voltage winding 8-2 and the fine-tuning winding 8-3, the coarse-tuning winding 8-4, and the high-voltage main winding 8-5. An oil baffle plate 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 are fixed in sequence from bottom to top between the upper end of the first low-voltage winding 8-1 and the upper pressure ring 8-14. An oil baffle plate 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 and a cushion block 8-11 are fixed in sequence from top to bottom between the lower end of the second low-voltage winding 8-2 and the lower pressure ring 8-15.

[0051] The fine adjustment winding 8-3 is a tangled structure, placed 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 a continuous structure, placed 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 an inner screen continuous structure, and the upper and lower high-voltage main windings 8-5 are placed 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, other phase high-voltage windings and the two side poles 7-2 are all provided with insulating tubes 8-6 and stays 8-7. An oil baffle plate 8-12, a sleeve plate 8-8, a cushion block 8-11, a sleeve plate 8-8, and a cushion block 8-11 are fixed in sequence from bottom to top between the upper end of the upper fine-tuning winding 8-3 and the upper pressure ring 8-14. A sleeve plate 8-8, an end ring 8-13, a cushion block 8-11, and a sleeve plate 8-8 are fixed in sequence from top to bottom between the lower end of the lower fine-tuning winding 8-3 and 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 guided oil circulation cooling structure, which is the prior art and will not be described in detail.

[0053] The lead assembly 9 includes: a first low-voltage winding lead 9-1, a second low-voltage winding lead 9-2, a tap lead assembly 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 iron core 7, and the second low-voltage winding lead 9-2 is located at the lower part of the iron core 7. The tap lead assembly 9-3 of the voltage regulating winding includes a plurality of tap leads. The upper fine adjustment winding, the upper coarse adjustment winding and the upper high-voltage main winding are connected in series through a first connecting lead (not shown) to form an upper high-voltage winding. The lower fine adjustment winding, the lower coarse adjustment winding and the lower high-voltage main winding are connected in series through a second connecting lead (not shown) to form a lower high-voltage winding. After the coarse adjustment winding 8-3 and the fine adjustment winding 8-4 are connected in parallel near the windings through a third connecting lead (not shown), they are then electrically connected to the corresponding terminals of the on-load coarse and fine voltage regulating switch 5 through a tapping lead set 9-3 to achieve the transformer voltage regulation function. The neutral point lead 9-4 is led out from the terminals 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 tap lead group 9-3 of the coarse adjustment winding 8-3 and the fine adjustment winding 8-4 of the two phases is distributed on the same side of the middle 330kV lead 9-5 of the high voltage winding. The tap lead group 9-3 of the coarse adjustment winding 8-3 and the fine adjustment 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] When 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, low voltage input and high voltage output. Obviously, when necessary, the connection method can be reversed to the above method, and the input and output power can be reversed.

[0057] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A 330kV large-capacity axially split and forced-guided oil circulation on-load coarse and fine voltage regulating double-turn transformer, comprising an oil tank, a cooling device located outside the oil tank, an oil storage cabinet 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 assembly fixedly mounted on the oil tank, an iron core arranged inside the oil tank, an on-load coarse and fine voltage regulating switch fixed in the oil tank, a winding assembly sleeved on the iron core, and a lead assembly for electrical connection, characterized in that: The bushing combination includes: 3 high-voltage bushings, 1 high-voltage neutral point bushing and 6 low-voltage bushings; 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 insulating cylinder, a stay, an upper pressure ring and a lower pressure ring; the first low-voltage winding and the second low-voltage winding are axially distributed in an upper and lower direction; 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 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 high-voltage winding and the out-of-phase high-voltage winding; the upper pressure ring and the lower pressure ring are fixedly arranged on the upper and lower sides of the winding assembly; The lead wire assembly includes: a first low-voltage winding lead wire, a second low-voltage winding lead wire, a first connecting lead wire, a second connecting lead wire, a third connecting lead wire, a tap lead wire group, a neutral point lead wire and a middle 330kV lead wire of a high-voltage winding; the tap lead wire group includes a plurality of tap leads; The bottom of the inner and outer layers of the first low-voltage winding are connected in series through transition transposition, and the top of the inner and outer layers of the second low-voltage winding are connected in series through transition transposition, and the two constitute the low-voltage winding of the transformer; the coarse-adjusting winding, the fine-adjusting winding and the high-voltage main winding are divided into upper and lower parts; the upper coarse-adjusting winding, the upper fine-adjusting winding and the upper high-voltage main winding are connected in series through the first connecting lead to form an upper high-voltage winding; the lower coarse-adjusting winding, the lower fine-adjusting winding and the lower high-voltage main winding are connected in series through the second connecting lead to form a lower high-voltage winding group; 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 of the tap leads of the coarse adjustment winding and the fine adjustment winding is electrically connected to the corresponding terminals of the on-load coarse and fine voltage regulating switch; the neutral point lead is led out from the on-load coarse and fine voltage regulating switch terminal 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-guide oil circulation on-load coarse and fine voltage regulation double-turn transformer according to claim 1 is characterized in that: The inner and outer layers of the first low-voltage winding are spiral structures and are connected at the bottom by 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 by transition transposition to form a ∩-shaped winding structure; The coarse adjustment winding is a continuous structure, the fine adjustment winding is a tangled structure, and the high-voltage main winding is an inner-screen continuous structure.

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

4. The 330kV large-capacity axially split and forced-guide oil circulation on-load coarse and fine voltage regulation double-turn transformer according to claim 1 is characterized in that: An electrostatic ring and a large-angle ring for increasing the distance between the two low-voltage windings are arranged between the bottom of the first low-voltage winding and the top of the second low-voltage winding.

5. The 330kV large-capacity axially split and forced-guide oil circulation on-load coarse and fine voltage regulation double-turn transformer according to claim 1 is characterized in that: The inner surface of the oil tank is relatively provided with a magnetic shield.

6. The 330kV large-capacity axially split and forced-guide oil circulation on-load coarse and fine voltage regulation double-turn transformer according to claim 5 is characterized in that: The iron core includes 3 main columns, 2 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 support plate; The main column pull plate is provided with one each on the front and rear end surfaces of the main column; The side pillar pull plate is provided with one piece on each of the front and rear end surfaces of the side pillar; The main window iron yoke is arranged at the upper and lower ends between two adjacent main pillars, and the side window iron yoke is arranged at the upper and lower ends between the main pillar and the side pillar; 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 fastened and positioned into a five-column four-frame structure by the upper clamp and the lower clamp; The main column is provided with a vertical oil passage and a horizontal oil passage, and the side column, the main window iron yoke and the side window iron yoke are provided with a horizontal oil passage; The outer end surface of the side column is provided with the graphite shielding layer; Two supporting plates are welded to the lower end surfaces of the upper clamp located on both sides of each main column pull plate and the upper end surfaces of the lower clamp located on both sides of each main column pull plate, and the magnetic shield is arranged inside the supporting plates.

7. The 330kV large-capacity axially split and forced-guide oil circulation on-load coarse and fine voltage regulation double-turn transformer according to claim 1 is characterized in that: The winding assembly also includes: a sleeve plate, an end ring, a spacer block and an oil baffle.

8. The 330kV large-capacity axially split and forced-guide oil circulation on-load coarse and fine voltage regulation double-turn transformer according to claim 7 is characterized in that: The oil baffle plate, end ring, sleeve plate, pad, end ring, sleeve plate and pad are stacked in sequence 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, sleeve plate, end ring, sleeve plate, pad, sleeve plate, end ring and sleeve plate are stacked in sequence 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-guide oil circulation on-load coarse and fine voltage regulation double-turn transformer according to claim 7 is characterized in that: The oil baffle plate, sleeve plate, cushion block, sleeve plate and cushion block are stacked in sequence from bottom to top between the upper end of the upper fine-tuning winding and the upper pressure ring; The sleeve plate, the end ring, the spacer block and the sleeve plate are stacked in sequence from top to bottom between the lower end of the lower fine-tuning winding and the lower pressure ring.

10. The 330kV large-capacity axially split and forced-guide oil circulation on-load coarse and fine voltage regulation double-turn transformer according to claim 1 is 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 middle 330kV lead of the high voltage winding; The tap lead set of the coarse adjustment winding and the fine adjustment winding of another phase is distributed on the same side of the leads of the first low-voltage winding and the second low-voltage winding.

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