Multistage voltage regulation autotransformer

Abstract

The utility model 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 utility model, 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] This utility model belongs to the field of transformer technology, specifically relating to an autotransformer that uses a low-current on-load tap changer to achieve high-current multi-stage voltage regulation. Background Technology

[0002] Currently, with the gradual expansion of overseas transformer business, especially in the Americas where the stability of power supply is severely threatened due to increasingly serious problems such as aging power grids, the demand for transformers has increased significantly, and the market size has expanded rapidly. In response to the characteristics of overseas power transformer product demand, large-capacity autotransformers are widely used. Furthermore, due to the diversity of power grid construction, autotransformers are diverse in type, and most are characterized by no-load tap changing on the primary side and on-load tap changing on the secondary side. The on-load tap changing on the secondary side typically has a low basic voltage level and a large number of tap changing stages. In this context, for large-capacity autotransformers, conventionally designed on-load tap changers require high-current single-phase switches, and each phase needs to be equipped with an on-load tap changer. This makes the selection of on-load tap changers for autotransformers difficult, and also complicates the overall structural layout of the autotransformer, increasing product design and manufacturing costs and affecting market competitiveness.

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

[0004] To solve the above-mentioned technical problems, this utility model proposes an autotransformer structure that uses a low-current on-load switch to achieve high-current multi-stage voltage regulation. The technical solution adopted by this utility model is as follows:

[0005] An autotransformer with multi-stage voltage regulation includes a main transformer body and a regulator body with three windings arranged in a three-winding configuration. The main transformer body's three-winding configuration includes, from the inside out, a main transformer core, a main transformer low-voltage winding, a main transformer medium-voltage winding, a main transformer voltage regulating winding, and a main transformer high-voltage winding. The regulator body's three-winding configuration includes, from the inside out, a regulator core, a regulator excitation winding, and a regulator voltage regulating winding. The main transformer voltage regulating winding is connected to the regulator excitation winding, and the main transformer medium-voltage winding is connected to the tail of both the main transformer high-voltage winding and the tail of the regulator voltage regulating winding, forming the autotransformer winding connection structure. The voltage regulating lead connection structure between the main transformer body and the regulator body reduces the voltage regulating side current. Finally, a low-current on-load tap changer is used to achieve high-current multi-stage voltage regulation in the autotransformer. The on-load tap changer is electrically connected to the main transformer voltage regulating winding.

[0006] Preferably, the three-phase electrical connection at the tail of the main transformer's medium-voltage winding is externally connected to the neutral point bushing, and the voltage regulating winding of the transformer is externally connected to the medium-voltage bushing.

[0007] Preferably, the modulation excitation winding is electrically connected to the main transformer voltage regulating winding.

[0008] Preferably, the high-pressure bushing, medium-pressure bushing, neutral point bushing, and low-pressure bushing are fixedly installed on the tank cover.

[0009] In this utility model, "main transformer" is short for "main transformer" and "voltage regulating transformer" is short for "voltage regulating transformer".

[0010] The beneficial effects of this utility model are:

[0011] This utility model innovatively improves the on-load tap-changing structure of a large-capacity autotransformer by setting up a separate regulating excitation winding, reducing the current of the tap-changing winding, and achieving high-current multi-stage tap-changing function by using a low-current three-phase on-load tap-changing switch. This structure solves the selection problem of high-current on-load tap-changing switches, reduces the number of on-load tap-changing switches and saves space, making the overall structure of the autotransformer more compact. At the same time, it reduces the model and specifications of on-load tap-changing switches, lowers product costs, and has broad application prospects for products exported overseas, especially to the Americas. Attached Figure Description

[0012] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0013] Figure 1 This is an external top view of the autotransformer according to an embodiment of the present invention; Figure 2 This is an internal top view of the autotransformer according to an embodiment of the present invention;

[0014] Figure 3 This is a schematic diagram of the connection scheme between the main transformer body and the modulator body according to an embodiment of the present utility model;

[0015] In the diagram: 1. Medium-voltage bushing, 2. Low-voltage bushing, 3. High-voltage bushing, 4. Neutral point bushing, 5. Tank cover, 6. On-load tap changer, 7. Transformer voltage regulating winding, 8. Transformer excitation winding, 9. Transformer 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 core, 15. Tank housing, 16. Main transformer body, 17. Transformer body. Detailed Implementation

[0016] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this utility model, but not all embodiments.

[0017] like Figure 1-3 As shown, a multi-stage voltage-regulating autotransformer includes a main transformer body 16, a regulator 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 voltage regulating lead connection structure, an oil tank structure, external components, and an assembly structure. The oil tank structure includes an oil tank shell 15 and an oil tank cover 5.

[0018] 1) The main transformer body 16 is installed in the tank housing 15. The parameters of the main transformer core 14 are set according to the parameters of the autotransformer, and the winding structure and arrangement of the main transformer body 16 are set. The main transformer body 16 of this utility model adopts a commonly used three-winding product structure. Each winding is equipped with 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 voltage regulating winding 11. 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 voltage regulating winding 11, and the main transformer high-voltage winding 10 are arranged sequentially from the inside to the outside.

[0019] 2) A modulator body 17 is added to the oil tank housing 15. The modulator body 17 adopts a common three-winding arrangement structure. Each winding is equipped with a modulation voltage regulating winding 7, a modulation iron core 9 and a modulation excitation winding 8. The modulation iron core 9, the modulation excitation winding 8 and the modulation voltage regulating winding 7 are arranged in sequence from the inside to the outside.

[0020] 3) The voltage regulating lead connection structure between the main transformer body 16 and the modulator body 17 is as follows: the main transformer voltage regulating winding 11 of the main transformer body 16 is connected to the modulator excitation winding 8 of the modulator body 17. 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 modulator voltage regulating winding 7 of the modulator body 17, forming an autotransformer winding connection structure. The tail of the main transformer medium voltage winding 12 of the main transformer body 16 is electrically connected in three phases and externally connected to the neutral point bushing 4. The modulator voltage regulating winding 7 of the modulator body 17 is externally connected to the medium voltage bushing 1.

[0021] 4) The main transformer voltage regulating winding 11 of the main transformer body 16 is located on the outer periphery of the main transformer core 14. Under the premise of a constant turn potential, the number of turns of the modulation excitation winding 8 of the modulator body 17 is adjusted synchronously by changing the number of turns of the main transformer voltage regulating winding 11, thereby determining the turn potential of the modulator body 17. By adjusting the number of turns of the main transformer voltage regulating winding 11 of the main transformer body 16, the voltage and number of turns of the modulation excitation winding 8 of the modulator body 17 are adjusted accordingly. Since the modulation excitation winding 8 and the modulation voltage regulating winding 7 of the modulator body 17 are both located on the outer periphery of the modulator core 9, the number of turns of the modulation excitation winding 8 and the modulation voltage regulating winding 7 are determined according to the principle of electromagnetic induction. The current flowing through the winding is proportional to the number of turns. The voltage regulating winding 7 is connected to the medium-voltage winding 12 of the main transformer, and the current flowing through it is the large current of the medium-voltage winding 12. The voltage regulating winding 8 is connected to the voltage regulating winding 11 of the main transformer body 16, and the current flowing through it is the low current after excitation of the voltage regulating winding 8 of the transformer body 17. By changing the turns ratio of the transformer body 17, the current flowing through the on-load tap changer 6 is reduced. By reducing the magnitude of the voltage regulating current, the selection of the on-load tap changer 6 is achieved, thus realizing the function of voltage regulation using a low-current on-load tap changer 6.

[0022] 5) After the main transformer body 16 is assembled, install the special positioning structure for the main transformer body 16 to reliably fix the main transformer body 16 to the oil tank housing 15; after the modulator body 17 is assembled, install the special positioning structure for the modulator body 17 to reliably fix the modulator body 17 to the oil tank housing 15.

[0023] 6) An on-load tap changer bracket is installed on the main transformer core clamp of the main transformer body 16. An on-load tap changer 6 is installed on the bracket, and the on-load tap changer 6 is connected to the tap changer terminals according to the lead connection structure. The on-load tap changer 6 is connected to the main transformer regulating winding 11 of the main transformer body 16. Due to the reduced current in the main transformer regulating winding 11, a low-current on-load tap changer 6 can be selected to achieve the voltage regulation function, reducing the required specifications of the on-load tap changer 6 and making the overall structure of the autotransformer more compact.

[0024] 7) According to the connection structure scheme of the main transformer body 16 and the regulator body 17, make the lead wire connection between the two bodies, and the connection of the high voltage, medium voltage and low voltage side lead wires, and reliably connect them with the corresponding bushings.

[0025] 8) Install and fix the high-pressure bushing 3, medium-pressure bushing 1, neutral point bushing 4 and low-pressure bushing 2 on the tank cover 5, and reliably seal the tank cover 5 with the tank shell 15.

[0026] 9) Install the external components of the autotransformer. The autotransformer assembly is now complete.

[0027] Figure 1 , 2In the middle, the top of the on-load switch 6 is located above the tank cover 5, and the other positions of the on-load switch 6 are located in the tank housing 15. The component connected to the top of the on-load switch 6 is the switch operation drive shaft, which is connected to the switch mechanism box. The switch mechanism box is located on the outside of the tank housing 15.

[0028] Figure 3 The letters in the table represent the tap numbers of the corresponding windings: Y - the first tap number of the low-voltage winding 13 of the main transformer; y - the last tap number of the low-voltage winding 13 of the main transformer; H - the first tap number of the high-voltage winding 10 of the main transformer; X - the first tap number of the voltage regulating winding 7 of the transformer; H0-X0 are the neutral point tap numbers of the high-voltage winding and the medium-voltage winding of the main transformer; and k - the contact number of the on-load tap changer 6.

[0029] In this embodiment of the utility model, all technical features not described in detail are existing technologies or conventional technical means, and will not be repeated here.

[0030] Finally, it should be noted that the above embodiments are merely specific implementations of this utility model, used to illustrate the technical solution of this utility model, and not to limit it. The protection scope of this utility model is not limited thereto. Those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the technical scope disclosed in this utility model; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be covered within the protection scope of this utility model.

Claims

1. A multi-stage voltage-regulating autotransformer, comprising a main transformer body (16) and a regulator body (17) with a three-winding arrangement, characterized in that, The three-winding arrangement structure of the main transformer body (16) includes the main transformer core (14), the main transformer low-voltage winding (13), the main transformer medium-voltage winding (12), the main transformer voltage regulating winding (11), and the main transformer high-voltage winding (10) arranged sequentially from the inside out. The three-winding arrangement structure of the modulator body (17) includes the modulator core (9), the modulator excitation winding (8), and the modulator voltage regulating winding (7) arranged sequentially from the inside out. The main transformer voltage regulating winding (11) is connected to the modulator excitation winding (8). The main transformer medium-voltage winding (12) is connected to the tail of the main transformer high-voltage winding (10) and the tail of the modulator voltage regulating winding (7), forming an autotransformer winding connection structure. The on-load tap changer (6) is electrically connected to the main transformer voltage regulating winding (11).

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

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

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

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