Multistage voltage regulation autotransformer

Abstract

The invention belongs to the field of transformers, and relates to an autotransformer adopting a low-current on-load tap changer to realize large-current multi-stage voltage regulation, a three-winding arrangement structure of a main transformer body comprises a main transformer iron core, a main transformer low-voltage winding, a main transformer medium-voltage winding, a main transformer voltage regulation winding and a main transformer high-voltage winding which are arranged from inside to outside, a three-winding arrangement structure of the modulator body comprises a modulation iron core, a modulation excitation winding and a modulation voltage regulation winding which are arranged from inside to outside, a main transformer voltage regulation winding is connected with the modulation excitation winding, a main transformer medium-voltage winding is connected with the tail of a main transformer high-voltage winding and the tail of the modulation voltage regulation winding, and an autotransformer winding connection structure is formed. And the on-load voltage regulation switch is electrically connected with the main transformer voltage regulation winding. According to the invention, the modulation excitation winding is arranged to reduce the current of the voltage regulation winding, the low-current three-phase on-load voltage regulation switch is adopted to realize a large-current multi-stage voltage regulation function, the structure of the autotransformer is more compact, meanwhile, the model specification of the on-load voltage regulation switch is reduced, and the product cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of transformers, and particularly relates to an autotransformer that uses a low-current on-load tap-changer to achieve multi-stage voltage regulation for large current. Background Art

[0002] At present, with the gradual expansion of overseas transformer business, especially in the Americas where the problem of aging power grids is becoming increasingly serious, the stability of power supply has been severely threatened. The demand for transformers has increased significantly, and the market scale has expanded rapidly. In response to the demand characteristics of overseas power transformer products, large-capacity autotransformers are widely used; in addition, due to the diversity of power grid construction, the types of autotransformers are diverse, and most are no-load tap-changing on the primary side and on-load tap-changing on the secondary side. Moreover, the basic voltage level of on-load tap-changing on the secondary side is low, and the number of tap-changing levels is large. In this case, for large-capacity autotransformers, the on-load switches designed conventionally need to select single-phase switches with large current, and each phase needs to be equipped with an on-load switch, resulting in difficulties in selecting on-load switches for autotransformers. At the same time, it also makes the overall structure layout of autotransformers complex, and the product design and manufacturing costs are relatively high, affecting market competitiveness.

[0003] In response to the product characteristics of large-capacity autotransformers in this region, it is necessary to improve the excitation voltage regulation structure of the voltage regulation transformer body, and use a low-current three-phase on-load switch to achieve the function of multi-stage voltage regulation for large current, so as to effectively solve the problems of selecting on-load switches with large current and the layout of space structure, and make the overall structure of the autotransformer more compact. Summary of the Invention

[0004] In order to solve the above technical problems, the invention proposes a structural scheme of an autotransformer that uses a low-current on-load switch to achieve multi-stage voltage regulation for large current. The technical scheme adopted by the invention is as follows: A multi-stage voltage regulation autotransformer includes a main transformer body and a regulating transformer body with a three-winding arrangement structure. The three-winding arrangement structure of the main transformer body includes a main transformer core, a main transformer low-voltage winding, a main transformer medium-voltage winding, a main transformer regulating winding, and a main transformer high-voltage winding arranged in sequence from inside to outside. The three-winding arrangement structure of the regulating transformer body includes a regulating transformer core, a regulating transformer exciting winding, and a regulating transformer regulating winding arranged in sequence from inside to outside. The main transformer regulating winding is connected to the regulating transformer exciting winding, and the main transformer medium-voltage winding is connected to the tails of the main transformer high-voltage winding and the regulating transformer regulating winding to form the winding connection structure of the autotransformer. The current on the voltage regulation side is reduced through the voltage regulation lead connection structure between the main transformer body and the regulating transformer body. Finally, an autotransformer that uses a low-current on-load tap-changer to achieve multi-stage voltage regulation for large current is obtained. The on-load tap-changer is electrically connected to the main transformer regulating winding.

[0005] Preferably, the tails of the three phases of the main transformer medium-voltage winding are electrically connected and externally connected to the neutral point bushing, and the regulating transformer regulating winding is externally connected to the medium-voltage bushing.

[0006] Preferably, the regulating excitation winding is electrically connected to the main transformer voltage regulating winding.

[0007] Preferably, the high-voltage bushing, medium-voltage bushing, neutral-point bushing and low-voltage bushing are fixedly installed on the tank cover.

[0008] In the present invention, the main transformer is short for the main transformer, and the regulating transformer is short for the voltage regulating transformer.

[0009] Advantages of the present invention: The present invention innovatively improves the on-load voltage regulating structure of a large-capacity autotransformer, sets a separate regulating excitation winding, reduces the current of the voltage regulating winding, and can realize the large-current multi-stage voltage regulating function by using a low-current three-phase on-load voltage regulating switch. This structure solves the problem of selecting the on-load voltage regulating switch for large current, reduces the number of on-load voltage regulating switches, saves the space layout, makes the overall structure of the autotransformer more compact, and at the same time reduces the model specifications of the on-load voltage regulating switch, reduces the product cost, and has a wide application prospect for products exported overseas, especially to the Americas. Description of the Drawings

[0010] The drawings are used to provide further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention, but do not constitute a limitation to the present invention. In the drawings: Figure 1 is the external top view of the autotransformer according to the embodiment of the present invention; Figure 2 is the internal top view of the autotransformer according to the embodiment of the present invention; Figure 3 is the schematic diagram of the connection scheme of the main transformer body and the regulating transformer body according to the embodiment of the present invention; In the figure: 1. Medium-voltage bushing, 2. Low-voltage bushing, 3. High-voltage bushing, 4. Neutral-point bushing, 5. Tank cover, 6. On-load voltage regulating switch, 7. Regulating voltage regulating winding, 8. Regulating excitation winding, 9. Regulating iron core, 10. Main transformer high-voltage winding, 11. Main transformer voltage regulating winding, 12. Main transformer medium-voltage winding, 13. Main transformer low-voltage winding, 14. Main transformer iron core, 15. Tank shell, 16. Main transformer body, 17. Regulating transformer body. Detailed Embodiments

[0011] The technical solutions of the present invention will be clearly and completely described below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments.

[0012] Such as Figures 1-3As shown in the figure, an autotransformer with multi-stage voltage regulation includes a main transformer body 16, a regulating transformer body 17, a medium-voltage bushing 1, a low-voltage bushing 2, a high-voltage bushing 3, a neutral-point bushing 4, an on-load tap-changer 6, a tap-changing lead connection structure, a tank structure, external components and an overall assembly structure. The tank structure includes a tank shell 15 and a tank cover 5.

[0013] 1) The main transformer body 16 is arranged in the tank shell 15. The parameter specifications of the main transformer core 14 are set according to the parameters of the autotransformer, and the winding structure and arrangement mode of the main transformer body 16 are set. The main transformer body 16 of the present invention adopts a common three-winding product structure. In each winding, a main transformer high-voltage winding 10, a main transformer medium-voltage winding 12, a main transformer low-voltage winding 13 and a main transformer regulating winding 11 are arranged. The three-winding arrangement structure of the main transformer body 16 adopts an arrangement structure in which the main transformer core 14, the main transformer low-voltage winding 13, the main transformer medium-voltage winding 12, the main transformer regulating winding 11 and the main transformer high-voltage winding 10 are arranged in sequence from the inside to the outside.

[0014] 2) A regulating transformer body 17 is additionally arranged in the tank shell 15. The regulating transformer body 17 adopts a common three-winding arrangement structure. In each winding, a regulating transformer regulating winding 7, a regulating transformer core 9 and a regulating transformer exciting winding 8 are arranged. An arrangement structure in which the regulating transformer core 9, the regulating transformer exciting winding 8 and the regulating transformer regulating winding 7 are arranged in sequence from the inside to the outside is adopted.

[0015] 3) The tap-changing lead connection structure between the main transformer body 16 and the regulating transformer body 17 is as follows: the main transformer regulating winding 11 of the main transformer body 16 is connected to the regulating transformer exciting winding 8 of the regulating transformer body 17, and the main transformer medium-voltage winding 12 of the main transformer body 16 is connected to the tail of the main transformer high-voltage winding 10 and the tail of the regulating transformer regulating winding 7 of the regulating transformer body 17 to form an autotransformer winding connection structure. The tails of the three phases of the main transformer medium-voltage winding 12 of the main transformer body 16 are electrically connected in three phases and externally connected to the neutral-point bushing 4, and the regulating transformer regulating winding 7 of the regulating transformer body 17 is externally connected to the medium-voltage bushing 1.

[0016] 4) The main transformer voltage regulating winding 11 of the main transformer body 16 is arranged on the outer periphery of the main transformer core 14. On the premise of a certain turn potential, by changing the number of turns of the main transformer voltage regulating winding 11, the number of turns of the modulating exciting winding 8 of the modulating body 17 is synchronously adjusted, and then the turn potential of the modulating body 17 is determined. By adjusting the number of turns of the main transformer voltage regulating winding 11 of the main transformer body 16, the voltage and the number of turns of the modulating exciting winding 8 of the modulating body 17 are correspondingly adjusted. Since the modulating exciting winding 8 of the modulating body 17 and the modulating voltage regulating winding 7 are jointly arranged on the outer periphery of the modulating core 9, according to the electromagnetic induction principle, the number of turns of the modulating exciting winding 8 and the number of turns of the modulating voltage regulating winding 7 are determined, and the current flowing through the winding is in a proportional relationship with the number of turns. The modulating voltage regulating winding 7 is connected to the main transformer medium voltage winding 12, and the current flowing through it is the large current of the main transformer medium voltage winding 12; the modulating exciting winding 8 is connected to the main transformer voltage regulating winding 11 of the main transformer body 16, and the current flowing through it is the low current after the modulating exciting winding 8 of the modulating body 17 is excited. By changing the turn ratio of the modulating body 17, the current flowing through the on-load tap-changer 6 is reduced, and the on-load tap-changer 6 is selected by reducing the magnitude of the tap-changing current, realizing the function of voltage regulation using the low-current on-load tap-changer 6.

[0017] 5) After the main transformer body 16 is assembled, install the special positioning structure for the main transformer body 16, and fixedly install the main transformer body 16 and the oil tank shell 15 reliably; after the modulating body 17 is assembled, install the special positioning structure for the modulating body 17, and fixedly install the modulating body 17 and the oil tank shell 15 reliably.

[0018] 6) Install an on-load tap-changer support on the main transformer core clamp of the main transformer body 16, install the on-load tap-changer 6 on the on-load tap-changer support, and connect the on-load tap-changer 6 and the tap-changing shunt according to the lead connection structure scheme. The on-load tap-changer 6 is connected to the main transformer voltage regulating winding 11 of the main transformer body 16. Since the current of the main transformer voltage regulating winding 11 is reduced, a low-current on-load tap-changer 6 can be selected to realize the voltage regulation function, reducing the selection specification of the on-load tap-changer 6 and making the overall structure of the autotransformer compact.

[0019] 7) According to the connection structure scheme between the main transformer body 16 and the modulating body 17, connect the leads between the two bodies, and connect the outgoing leads of the high voltage, medium voltage, and low voltage sides, and connect them reliably to the corresponding bushings.

[0020] 8) Install and fix the high voltage bushing 3, medium voltage bushing 1, neutral point bushing 4, and low voltage bushing 2 on the oil tank cover 5, and seal the oil tank cover 5 and the oil tank shell 15 reliably.

[0021] 9) Install the external components of the autotransformer, and the overall assembly of the autotransformer is completed.

[0022] Figure 1 、 2Among them, the top of the on-load tap-changer 6 is located above the tank cover 5, and other positions of the on-load tap-changer 6 are located in the tank housing 15. The component externally connected to the top of the on-load tap-changer 6 is the switch operation drive shaft, which is connected to the switch mechanism box through the switch operation drive shaft, and the switch mechanism box is located outside the tank housing 15.

[0023] Figure 3 The letters in it represent the tap labels corresponding to the windings. Y is the first tap label of the low-voltage winding 13 of the main transformer, y is the last tap label of the low-voltage winding 13 of the main transformer, H is the first tap label of the high-voltage winding 10 of the main transformer, X is the first tap label of the regulating voltage winding 7 of the regulating transformer, H0-X0 are the neutral tap labels of the high-voltage winding and the medium-voltage winding of the main transformer, and k is the contact label of the on-load tap-changer 6.

[0024] In the embodiments of the present invention, the technical features not described in detail are all prior arts or conventional technical means, and will not be elaborated here again.

[0025] Finally, it should be noted that the above embodiments are only specific implementation manners of the present invention, used to illustrate the technical solutions of the present invention, rather than limiting it. The protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any person skilled in the art within the technical scope disclosed by the present invention can modify the technical solutions recorded in the foregoing embodiments, or can easily think of changes, or perform equivalent replacements on some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the protection scope of the present invention.

Claims

1. An autotransformer with multi-stage voltage regulation, comprising a main transformer body (16) and a regulating transformer body (17) with a three-winding arrangement structure, characterized in that, The three-winding arrangement structure of the main transformer body (16) includes a main transformer iron core (14), a main transformer low-voltage winding (13), a main transformer medium-voltage winding (12), a main transformer regulating winding (11), and a main transformer high-voltage winding (10) arranged in sequence from the inside to the outside. The three-winding arrangement structure of the regulating transformer body (17) includes a regulating transformer iron core (9), a regulating transformer exciting winding (8), and a regulating transformer regulating winding (7) arranged in sequence from the inside to the outside. The main transformer regulating winding (11) is connected to the regulating transformer exciting winding (8). The main transformer medium-voltage winding (12) is connected to the tails of the main transformer high-voltage winding (10) and the regulating transformer regulating winding (7) to form an autotransformer winding connection structure. The on-load tap-changer (6) is electrically connected to the main transformer regulating winding (11).

2. The autotransformer with multi-stage voltage regulation according to claim 1, characterized in that, The three-phase electrical connection of the tail of the main transformer medium-voltage winding (12) is externally connected to the neutral point bushing (4), and the regulating transformer regulating winding (7) is externally connected to the medium-voltage bushing (1).

3. The autotransformer with multi-stage voltage regulation according to claim 1, characterized in that, The regulating transformer exciting winding (8) is electrically connected to the main transformer regulating winding (11).

4. The autotransformer with multi-stage voltage regulation according to claim 1, wherein The high-voltage bushing (3), the medium-voltage bushing (1), the neutral point bushing (4), and the low-voltage bushing (2) are fixedly installed on the tank cover (5).

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