CN114724828A - Multi-impedance combined transformer - Google Patents

Abstract

The multi-impedance combined transformer comprises a built-in reactor, wherein the built-in reactor comprises a single-phase winding, the single-phase winding comprises a single-phase upper winding and a single-phase lower winding, and the number and the mode of the single-phase windings connected into a triangular connection formed by a single-phase main coil can be flexibly combined when the multi-impedance combined transformer is used. Examples are as follows: when the single-phase upper/lower windings which are connected in series, in parallel or separately are connected in series to be connected in a triangular mode, the impedance per unit value, the inductance and the inductive reactance of the circuit can be changed to different degrees, and therefore the scene requirements under different conditions can be met.

Description

Multi-impedance combined transformer

Technical Field

The application relates to the technical field of power equipment, in particular to a multi-impedance combined transformer.

Background

The transformer is a device for changing alternating voltage by utilizing the principle of electromagnetic induction, and has the main functions of: voltage transformation, current transformation, impedance transformation, isolation, voltage stabilization (magnetic saturation transformer), and the like. When the transformer normally operates, impedance exists between the winding pairs, and when the transformer normally operates, the impedance voltage is smaller and better, so that overlarge voltage drop is avoided. When the transformer is short-circuited, the short-circuit current can be limited by the larger impedance voltage, so that the transformer is subjected to smaller short-circuit power.

It is therefore required to achieve a certain impedance in the transformer according to the operational requirements. In order to improve the short-circuit resistance of the transformer, high-impedance transformers are increasingly selected for power grids, but the conventional transformer design cannot economically achieve the required short-circuit impedance. Therefore, a reactor is usually built in series in the winding of the transformer to increase the impedance. However, impedance values of the series-connected built-in reactors are unique, so that impedance of the transformer is unique, and when the capacity of a power grid node where the transformer is located changes or the transformer is allocated to other stations, the stations to which the transformer can be applied are limited due to unique impedance combination, so that the application scenario of the transformer is single, the transformer cannot be applied to more scenarios, and the applicability is reduced.

Disclosure of Invention

In view of the above problems, the present application is provided to provide a multi-impedance combined transformer, which can flexibly combine multiple impedances according to actual situations, so that the transformer can meet the scene requirements under different situations, and the applicability of the transformer is improved.

The specific scheme is as follows:

a multi-impedance combined transformer comprises a transformer and a built-in reactor;

the transformer comprises a plurality of single-phase main coils, the built-in reactor comprises a plurality of single-phase windings matched with the single-phase main coils, and each single-phase winding comprises a single-phase upper winding and a single-phase lower winding;

the single-phase main coils form a triangular connection, and in the triangular connection, every two single-phase main coils are connected in series through one single-phase upper winding and/or one single-phase lower winding.

Preferably, when one single-phase upper winding and one single-phase lower winding are connected in series between every two single-phase main coils, the single-phase upper winding and the single-phase lower winding are connected in series with each other.

Preferably, when one single-phase upper winding and one single-phase lower winding are connected in series between every two single-phase main coils, the single-phase upper winding and the single-phase lower winding are connected in parallel with each other.

Preferably, when one single-phase upper winding or one single-phase lower winding is connected in series between each two single-phase main coils, the single-phase upper/lower winding is electrically connected to one end of the single-phase main coil, and is equipotentially connected to the other end of the single-phase main coil with the single-phase lower/upper winding connected to the one end of the single-phase main coil in the same phase.

Preferably, the built-in reactor further includes an upper core frame disposed at an upper end of the single-phase upper winding, a lower core frame disposed at a lower end of the single-phase lower winding, a left core frame disposed at a left end of the single-phase winding, a right core frame disposed at a right end of the single-phase winding, and a center core frame disposed between the single-phase upper winding and the single-phase lower winding, and two end portions of the center core frame penetrate through a gap between the single-phase windings and are respectively connected to the left core frame and the right core frame.

When the transformer operates, the sectional areas of the upper iron core frame, the lower iron core frame, the left iron core frame, the right iron core frame and the middle iron core frame are arranged, so that the magnetic flux density value of the iron core frame is controlled, and when the transformer operates normally, the iron core frame cannot be saturated.

Preferably, the single-phase upper winding and the single-phase lower winding respectively comprise two wiring terminals;

the single-phase main coil comprises a lead;

the leads/terminals are used for connecting with each other or with the terminals/leads.

Preferably, the transformer further includes an iron core for forming a magnetic path.

Preferably, the transformer further comprises an oil tank and an oil conservator for storing transformer oil, and the oil conservator is connected with the oil tank.

Preferably, the transformer further comprises an insulating medium for insulating the tank.

By means of the technical scheme, the multi-impedance combined transformer comprises the built-in reactor, the built-in reactor comprises the single-phase winding, the single-phase winding comprises the single-phase upper winding and the single-phase lower winding, and the number and the mode of the single-phase winding connected into the triangular connection formed by the single-phase main coil can be flexibly combined when the multi-impedance combined transformer is used. Examples are as follows: when the single-phase upper/lower windings are respectively arranged in series and out-of-phase, in parallel and in-phase or connected in series to be connected in a triangular manner, the impedance per unit value, the inductance and the inductive reactance of the circuit can be changed to different degrees, so that the scene requirements under different conditions can be met.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

fig. 1 is a circuit diagram of a connection method according to an embodiment of the present disclosure;

FIG. 2 is a circuit diagram of another connection scheme provided by an embodiment of the present application;

FIG. 3 is a circuit diagram of another connection scheme provided by an embodiment of the present application;

fig. 4 is a schematic structural view of a built-in reactor.

Wherein,

11. an A-phase upper winding; 12. a phase A lower winding;

21. b phase upper winding; 22. a B-phase lower winding;

31. a C-phase upper winding; 32. c phase lower winding;

4. mounting a core frame; 5. a lower core frame; 6. a left core frame; 7. a right core frame; 8. and (4) a central iron core frame.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.

At present, the impedance value of a common built-in reactor is unique, so that the impedance of a transformer is unique, when the capacity of a power grid node where the transformer is located changes, or the transformer is allocated to other stations, the stations to which the transformer can be applied are limited due to unique impedance combination, so that the application scene of the transformer is single, the transformer cannot be applied to more scenes, and the applicability is reduced.

Therefore, in order to solve the above problems, the present application provides a multi-impedance combined transformer, which can flexibly combine multiple impedances according to actual conditions, so that the transformer can meet the scene requirements under different conditions, and the applicability of the transformer is improved.

A multi-impedance combining transformer of the present application will be described in detail below. A multi-impedance combined transformer comprises a transformer and an internal reactor, wherein the transformer comprises a plurality of single-phase main coils, the internal reactor comprises a plurality of single-phase windings matched with the single-phase main coils, and the single-phase windings comprise a single-phase upper winding and a single-phase lower winding. The single-phase main coils form a triangular connection, and in the triangular connection, every two single-phase main coils are connected in series through one single-phase upper winding and/or one single-phase lower winding.

According to the technical scheme, the multi-impedance combined transformer comprises the built-in reactor, the built-in reactor comprises the single-phase winding, the single-phase winding comprises the single-phase upper winding and the single-phase lower winding, and the number and the mode of the single-phase winding connected into the triangular connection formed by the single-phase main coils can be flexibly combined when the multi-impedance combined transformer is used, so that the scene requirements under different conditions can be met.

It is understood that the coil is formed by winding an insulated wire in a certain shape. A winding is a combination of multiple coils or groups of coils forming a phase or an entire electromagnetic circuit. In the present embodiment, the coil of the transformer and the coil of the reactor are distinguished by their names, but this does not mean that the coil of the transformer is only a single coil, nor that the coil of the reactor is only formed by combining a plurality of coils, and the coil of the transformer and the coil of the reactor are substantially formed by winding wires.

The currently commonly used ac power system is generally A, B, C three-phase, so the transformer in the embodiment of the present application may include an a-phase main coil, a B-phase main coil and a C-phase main coil, and the built-in reactor may include an a-phase winding, a B-phase winding and a C-phase winding adapted to the transformer. The phase A winding comprises a phase A upper winding 11 and a phase A lower winding 12, the phase B winding comprises a phase B upper winding 21 and a phase B lower winding 22, and the phase C winding comprises a phase C upper winding 31 and a phase C lower winding 32.

When one single-phase upper winding and one single-phase lower winding are connected in series between every two single-phase main coils, the single-phase upper winding and the single-phase lower winding are connected in series, and the single-phase upper winding and the single-phase lower winding are out of phase. Next, the above connection manner is further described with reference to fig. 1, as shown in fig. 1, a C-phase lower winding 32 and a B-phase upper winding 21 which are connected in series with each other are connected in series between the C-phase main winding and the B-phase main winding, a T1 end of the C-phase lower winding 32 is electrically connected to the C-phase main winding, a T2 end of the C-phase lower winding 32 is electrically connected to a T1 end of the B-phase upper winding 21, a T2 end of the B-phase upper winding 21 is electrically connected to the B-phase main winding, a T1 end of the B-phase lower winding 22 is electrically connected to the B-phase main winding, a T2 end of the B-phase lower winding 22 is electrically connected to a T1 end of the a-phase upper winding 11, a T2 end of the a-phase upper winding 11 is electrically connected to the a-phase main winding, a T1 end of the a-phase lower winding 12 is electrically connected to the a-phase main winding, and a T2 end of the C-phase upper winding 31 is electrically connected to the C1 end.

When one single-phase upper winding and one single-phase lower winding are connected in series between every two single-phase main coils, the single-phase upper winding and the single-phase lower winding are connected in parallel, and the single-phase upper winding and the single-phase lower winding are in the same phase. Next, the above connection mode is further explained with reference to fig. 2, as shown in fig. 2, the C-phase upper winding 31 is connected in parallel with the C-phase lower winding 32, the B-phase upper winding 21 is connected in parallel with the B-phase lower winding 22, and the a-phase upper winding 11 is connected in parallel with the a-phase lower winding 12; the C-phase main coil is electrically connected to the T2 ends of the C-phase upper winding 31 and the C-phase lower winding 32, and is also electrically connected to the T1 ends of the B-phase upper winding 21 and the B-phase lower winding 22; the B-phase main coil is electrically connected to the T2 ends of the B-phase upper winding 21 and the B-phase lower winding 22, and is also electrically connected to the T1 ends of the A-phase upper winding 11 and the A-phase lower winding 12; the phase a main coil is electrically connected to the phase a upper winding 11 and the phase a lower winding 12 at the end T2, and the phase a main coil is also connected to the phase C upper winding 31 and the phase C lower winding 32 at the end T1.

When one single-phase upper winding or one single-phase lower winding is connected in series between every two single-phase main coils, the single-phase upper/lower winding is electrically connected to one end of each single-phase main coil, and is equipotentially connected to the other end of each single-phase main coil with the same phase of the single-phase lower/upper winding connected to one end of each single-phase main coil. Next, referring to fig. 3, the above connection manner is further described, as shown in fig. 3, a T2 end of the C-phase upper winding 31 is electrically connected to one end of the C-phase main winding, a T1 end of the C-phase lower winding 32 is equipotentially connected to the other end of the C-phase main winding, and the C-phase main winding is further electrically connected to a T1 end of the B-phase upper winding 21; the T2 end of the B-phase upper winding 21 is electrically connected to one end of the B-phase main coil, the T1 end of the B-phase lower winding 22 is equipotentially connected to the other end of the B-phase main coil, and the B-phase main coil is also electrically connected with the T1 end of the A-phase upper winding 11; the T2 end of the phase-a upper winding 11 is electrically connected to one end of the phase-a main winding, the T1 end of the phase-a lower winding 12 is equipotentially connected to the other end of the phase-a main winding, and the phase-a main winding is also electrically connected to the T1 end of the phase-C upper winding 31.

Table 1 shows that different impedance per unit values, inductance values, and inductance values are obtained by setting different connection modes between the impedance and the transformer under different impedance types. It can be seen that the generated impedance per unit value, inductance value and inductive reactance value are different under different impedance connection modes, so that the scene requirements under different conditions can be met, and the applicability of the method is improved.

TABLE 1

As shown in fig. 4, the internal reactor further includes an upper core frame 4 disposed at the upper ends of all the upper windings, a lower core frame 5 disposed at the lower ends of all the lower windings, a left core frame 6 disposed at the left ends of the a-phase upper winding and the a-phase lower winding, a right core frame 7 disposed at the right ends of the C-phase upper winding and the C-phase lower winding, and a center core frame 8 disposed between all the upper windings and all the lower windings, and both end portions of the center core frame 8 penetrate through a gap between the single-phase windings and are connected to the left core frame 6 and the right core frame 7, respectively. Through the arrangement of the central iron core frame 8, the distribution of magnetic leakage can be effectively limited, and the problem of heating of structural eddy caused by uncontrollable magnetic leakage is avoided; meanwhile, the magnetic leakage is positioned and quantitatively expressed, and the problem of impedance nonlinearity can be effectively relieved.

When the transformer operates, the sectional areas of the upper iron core frame 4 and the lower iron core frame 5 are arranged, so that the magnetic flux density value of the middle iron core frame 8 is controlled, and when the transformer operates normally, the iron core frames cannot be saturated, thereby reducing iron loss and improving the working efficiency of the transformer.

The single-phase upper winding and the single-phase lower winding respectively comprise two wiring terminals, and the single-phase main coil comprises a lead. The lead wires are used for being connected with each other and can also be connected with the wiring terminal. It will be appreciated that terminals are equally applicable, both to interconnection and to connection with leads.

The transformer also comprises an iron core, an oil tank, an oil conservator and an insulating medium, wherein the iron core is used for forming a magnetic path, and the oil tank can be used as a shell of the transformer and has a certain heat dissipation effect; the oil conservator plays a role in storing and supplementing transformer oil in the oil tank so as to ensure that the oil tank is full of oil, reduce the contact surface between the oil and air and prevent the transformer oil from being oxidized and damped; the insulating medium serves to fix the lead and insulate the housing. The transformer body is sleeved on the iron core through the coil, and the transformation of voltage and current is realized.

Finally, it should also be noted that, in this document, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The terms "upper", "lower", "inner", "outer", "front", "rear", "both ends", "one end", "the other end", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, the embodiments may be combined as needed, and the same and similar parts may be referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A multi-impedance combined transformer is characterized by comprising a transformer and a built-in reactor;

the transformer comprises a plurality of single-phase main coils, the built-in reactor comprises a plurality of single-phase windings matched with the single-phase main coils, and the single-phase windings comprise single-phase upper windings and single-phase lower windings;

the single-phase main coils form a triangular connection, and in the triangular connection, every two single-phase main coils are connected in series through one single-phase upper winding and/or one single-phase lower winding.

2. The transformer of claim 1, wherein said single-phase upper winding and said single-phase lower winding are connected in series when one said single-phase upper winding and one said single-phase lower winding are connected in series between each two of said single-phase main windings.

3. The transformer of claim 1, wherein said single-phase upper winding and said single-phase lower winding are connected in parallel with each other when one said single-phase upper winding and one said single-phase lower winding are connected in series between each two of said single-phase main windings.

4. The transformer of claim 1, wherein when one of the single-phase upper winding and the single-phase lower winding is connected in series between each two of the single-phase main coils, the single-phase upper/lower winding is electrically connected to one end of the single-phase main coil and is connected to the other end of the single-phase main coil at the same potential as the single-phase upper/lower winding connected to the one end of the single-phase main coil.

5. The transformer according to claim 1, wherein the built-in reactor further includes an upper core frame provided at an upper end of the single-phase upper winding, a lower core frame provided at a lower end of the single-phase lower winding, a left core frame provided at a left end of the single-phase winding, a right core frame provided at a right end of the single-phase winding, and a center frame provided between the single-phase upper winding and the single-phase lower winding, and both end portions of the center frame penetrate through a gap between the single-phase windings and are connected to the left core frame and the right core frame, respectively.

6. The transformer of claim 5, wherein the transformer is operated by setting sectional areas of the upper core frame, the lower core frame, the left core frame, the right core frame and the center core frame so that the magnetic flux density of the core frames is controlled, and the core frames are not saturated during normal operation of the transformer.

7. The transformer of claim 1, wherein the single-phase upper winding and the single-phase lower winding respectively comprise two connection terminals;

the single-phase main coil comprises a lead;

the leads/terminals are used to connect to each other or to the terminals/leads.

8. The transformer of claim 1, further comprising a core for forming a magnetic path.

9. The transformer of any one of claims 1 to 8, further comprising an oil tank and a conservator for storing transformer oil, the conservator being connected to the oil tank.

10. The transformer of claim 9, further comprising a dielectric for insulating the insulating medium.

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