A multi-impedance combined transformer

Abstract

A multi-impedance combined transformer of the present application includes a built-in reactor, the built-in reactor includes a single-phase winding, the single-phase winding includes a single-phase upper winding and a single-phase lower winding, and when in use, it can flexibly combine the number and method of the single-phase windings connected to the delta connection formed by the single-phase main coils. Examples: When the single-phase upper / lower windings are respectively connected in series, in parallel or individually to the delta connection, the per-unit value of impedance, inductance and reactance of the circuit can be changed to different degrees, so as to meet the scenario requirements in different situations.

Description

Technical Field

[0001] The present application relates to the technical field of power equipment, and more specifically, to a multi-impedance combined transformer. Background Art

[0002] A transformer is a device that uses the principle of electromagnetic induction to change the AC voltage. Its main functions include: voltage transformation, current transformation, impedance transformation, isolation, voltage stabilization (magnetic saturation transformer), etc. When the transformer is operating normally, there is impedance between winding pairs. When the transformer is operating normally, a smaller impedance voltage is better to avoid excessive voltage drop. When the transformer experiences a short circuit, a larger impedance voltage can limit the short-circuit current and make the transformer subject to less short-circuit power.

[0003] Therefore, according to the operating requirements, a certain impedance should be achieved in the transformer. Short-circuit faults often occur in the power system, causing transformer failures. To improve the short-circuit resistance of the transformer, the power grid increasingly selects high-impedance transformers, and the conventional transformer design cannot economically achieve the required short-circuit impedance. Therefore, an in-built reactor is usually connected in series in the transformer winding to achieve impedance improvement. However, the impedance value of the usually connected in-built reactor is unique. Therefore, the impedance of the transformer is unique. When the capacity of the power grid node where the transformer is located changes, or when the transformer is transferred to other stations, due to the unique impedance combination, the applicable stations of the transformer are limited, resulting in a relatively single application scenario for the transformer and its applicability being reduced. Summary of the Invention

[0004] In view of the above problems, the present application is proposed to provide a multi-impedance combined transformer that can flexibly perform various impedance combinations according to the actual situation, enabling the transformer to meet the scenario requirements under different conditions and improving its applicability.

[0005] The specific solutions are as follows:

[0006] A multi-impedance combined transformer includes a transformer and an in-built reactor;

[0007] The transformer includes a plurality of single-phase main coils, and the in-built reactor includes a plurality of single-phase windings adapted to the single-phase main coils. The single-phase winding includes a single-phase upper winding and a single-phase lower winding;

[0008] Among them, the plurality of single-phase main coils form a delta connection, and in the delta connection, every two single-phase main coils are connected in series through one single-phase upper winding and / or one single-phase lower winding.

[0009] Preferably, when one single-phase upper winding and one single-phase lower winding are connected in series between every two of the single-phase main coils, the single-phase upper winding and the single-phase lower winding are connected in series with each other.

[0010] Preferably, when one single-phase upper winding and one single-phase lower winding are connected in series between every two of the single-phase main coils, the single-phase upper winding and the single-phase lower winding are connected in parallel with each other.

[0011] Preferably, when one single-phase upper winding or one single-phase lower winding is connected in series between every 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 equipotentially connected to the single-phase lower / upper winding of the same phase connected to one end of the single-phase main coil at the other end of the single-phase main coil.

[0012] Preferably, the built-in reactor further includes an upper iron core frame provided at the upper end of the single-phase upper winding, a lower iron core frame provided at the lower end of the single-phase lower winding, a left iron core frame provided at the left end of the single-phase winding, a right iron core frame provided at the right end of the single-phase winding, and a middle iron core frame provided between the single-phase upper winding and the single-phase lower winding. Both ends of the middle iron core frame penetrate through the gap between the single-phase windings and are respectively connected to the left iron core frame and the right iron core frame.

[0013] When the transformer is in operation, by setting the cross-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, the magnetic flux density value of the iron core frame is controlled so that the iron core frame will not become saturated during normal operation of the transformer.

[0014] Preferably, the single-phase upper winding and the single-phase lower winding each include two connection terminals;

[0015] The single-phase main coil includes leads;

[0016] The leads / connection terminals are used to connect to each other or to connect to the connection terminals / leads.

[0017] Preferably, the transformer further includes an iron core for forming a magnetic path.

[0018] Preferably, the transformer further includes an oil tank and an oil conservator for storing transformer oil, and the oil conservator is connected to the oil tank.

[0019] Preferably, the transformer further includes an insulating medium for insulating the oil tank.

[0020] With the above technical solution, a multi-impedance combined transformer of the present application includes a built-in reactor, the built-in reactor includes a single-phase winding, the single-phase winding includes a single-phase upper winding and a single-phase lower winding, and when in use, it can flexibly combine the number and method of the single-phase windings connected to the delta connection formed by the single-phase main coils. For example: when the single-phase upper / lower windings are respectively set in series with each other and in different phases, in parallel with each other and in the same phase, or a single single-phase upper / lower winding is connected in series to the delta connection, the per-unit impedance value, inductance, and inductive reactance of the circuit can be changed to different degrees, so as to meet the scenario requirements in different situations. Description of the Drawings

[0021] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0022] Figure 1 is the circuit diagram of a connection method provided by an embodiment of the present application;

[0023] Figure 2 is the circuit diagram of another connection method provided by an embodiment of the present application;

[0024] Figure 3 is the circuit diagram of another connection method provided by an embodiment of the present application;

[0025] Figure 4 is the structural schematic diagram of the built-in reactor.

[0026] Among them,

[0027] 11. A-phase upper winding; 12. A-phase lower winding;

[0028] 21. B-phase upper winding; 22. B-phase lower winding;

[0029] 31. C-phase upper winding; 32. C-phase lower winding;

[0030] 4. Upper iron core frame; 5. Lower iron core frame; 6. Left iron core frame; 7. Right iron core frame; 8. Middle iron core frame. Detailed Embodiments

[0031] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0032] At present, the impedance value of the usual built-in reactor is unique, so the impedance of the transformer is unique. When the capacity of the power grid node where the transformer is located changes, or when the transformer is transferred to other sites, due to the unique impedance combination, the applicable sites of the transformer are limited, resulting in a relatively single application scenario of the transformer, unable to be applied to more scenarios, and the applicability is reduced.

[0033] Therefore, to solve the above problems, the present application provides a multi-impedance combination transformer, which can flexibly perform various impedance combinations according to the actual situation, so that the transformer meets the scenario requirements under different conditions and improves its applicability.

[0034] Next, a multi-impedance combination transformer of the present application will be introduced in detail. A multi-impedance combination transformer includes a transformer and a built-in reactor. The transformer includes a plurality of single-phase main coils, and the built-in reactor includes a plurality of single-phase windings adapted to the single-phase main coils. The single-phase winding includes a single-phase upper winding and a single-phase lower winding. Among them, a delta connection is formed between the plurality of single-phase main coils, and in the delta connection, every two single-phase main coils are connected in series through one single-phase upper winding and / or one single-phase lower winding.

[0035] It can be seen from the above technical solutions that a multi-impedance combination transformer according to an embodiment of the present application includes a built-in reactor. The built-in reactor includes a single-phase winding, and the single-phase winding includes a single-phase upper winding and a single-phase lower winding. During use, it can flexibly combine the number and manner of the single-phase windings connected to the delta connection formed by the single-phase main coils, so as to meet the scenario requirements under different conditions.

[0036] It can be understood that a coil is wound with an insulated wire in a certain shape. A winding is a combination of multiple coils or coil groups that form a phase or the entire electromagnetic circuit. In this embodiment, for the purpose of distinguishing the windings of the transformer and the reactor, such a distinguishing name is used. However, this does not mean that the transformer has only a single coil, nor does it mean that the winding of the reactor is only composed of multiple coils combined. In fact, the coils of the transformer and the windings of the reactor are both wound with wires.

[0037] The currently widely used AC power system is generally three-phase of A, B, and C. Therefore, 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. Among them, the A-phase winding further includes an A-phase upper winding 11 and an A-phase lower winding 12, the B-phase winding further includes a B-phase upper winding 21 and a B-phase lower winding 22, and the C-phase winding further includes a C-phase upper winding 31 and a C-phase lower winding 32.

[0038] When one of the single-phase upper windings and one of the single-phase lower windings are connected in series between every two of the single-phase main coils, the single-phase upper winding and the single-phase lower winding are connected in series with each other, and the single-phase upper winding and the single-phase lower winding here are out of phase. Next, in combination with Figure 1 the above connection method will be further described. As Figure 1 shown, a C-phase lower winding 32 and a B-phase upper winding 21 connected in series with each other are connected in series between the C-phase main coil and the B-phase main coil. The T1 end of the C-phase lower winding 32 is electrically connected to the C-phase main coil, the T2 end of the C-phase lower winding 32 is electrically connected to the T1 end of the B-phase upper winding 21, the T2 end of the B-phase upper winding 21 is electrically connected to the B-phase main coil, the T1 end of the B-phase lower winding 22 is electrically connected to the B-phase main coil, the T2 end of the B-phase lower winding 22 is electrically connected to the T1 end of the A-phase upper winding 11, the T2 end of the A-phase upper winding 11 is electrically connected to the A-phase main coil, the T1 end of the A-phase lower winding 12 is electrically connected to the A-phase main coil, and the T2 end of the A-phase lower winding 12 is electrically connected to the T1 end of the C-phase upper winding 31.

[0039] When one of the single-phase upper windings and one of the single-phase lower windings are connected in series between every two of the single-phase main coils, the single-phase upper winding and the single-phase lower winding are connected in parallel with each other, and the single-phase upper winding and the single-phase lower winding here are in phase. Next, in combination with Figure 2 the above connection method will be further described. As Figure 2 shown, 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 the C-phase main coil 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 the B-phase main coil is also electrically connected to the T1 ends of the A-phase upper winding 11 and the A-phase lower winding 12; the A-phase main coil is electrically connected to the T2 ends of the A-phase upper winding 11 and the A-phase lower winding 12, and the A-phase main coil is also electrically connected to the T1 ends of the C-phase upper winding 31 and the C-phase lower winding 32.

[0040] When one of the single-phase upper windings or one of the single-phase lower windings is connected in series between every 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 equipotentially connected to the other end of the single-phase main coil with the single-phase lower / upper winding of the same phase connected to the one end of the single-phase main coil. Next, in combination with Figure 3 the above connection method will be further described. As Figure 3As shown, the T2 terminal of the upper winding 31 of phase C is electrically connected to one end of the main coil of phase C, the T1 terminal of the lower winding 32 of phase C is equipotentially connected to the other end of the main coil of phase C, and the main coil of phase C is also electrically connected to the T1 terminal of the upper winding 21 of phase B; the T2 terminal of the upper winding 21 of phase B is electrically connected to one end of the main coil of phase B, the T1 terminal of the lower winding 22 of phase B is equipotentially connected to the other end of the main coil of phase B, and the main coil of phase B is also electrically connected to the T1 terminal of the upper winding 11 of phase A; the T2 terminal of the upper winding 11 of phase A is electrically connected to one end of the main coil of phase A, the T1 terminal of the lower winding 12 of phase A is equipotentially connected to the other end of the main coil of phase A, and the main coil of phase A is also electrically connected to the T1 terminal of the upper winding 31 of phase C.

[0041] Table 1 shows that under different impedance types, by setting different connection methods of the impedance to the transformer, different per-unit impedance values, inductance values and reactance values can be obtained. It can be seen that under different impedance connection methods, the generated per-unit impedance values, inductance values and reactance values are different, so as to meet the scenario requirements in different situations and improve its applicability.

[0042] Table 1

[0043]

[0044] As Figure 4 As shown, the built-in reactor further includes an upper iron core frame 4 provided at the upper ends of all upper windings, a lower iron core frame 5 provided at the lower ends of all lower windings, a left iron core frame 6 provided at the left ends of the upper winding of phase A and the lower winding of phase A, a right iron core frame 7 provided at the right ends of the upper winding of phase C and the lower winding of phase C, and a middle iron core frame 8 provided between all upper windings and all lower windings. The two end portions of the middle iron core frame 8 penetrate the gaps between the single-phase windings and are respectively connected to the left iron core frame 6 and the right iron core frame 7. Through the setting of the middle iron core frame 8, the distribution of leakage magnetic flux can be effectively limited, avoiding the problem of structural eddy current heating caused by uncontrollable leakage magnetic flux; at the same time, localizing and quantitatively expressing the leakage magnetic flux can effectively alleviate the impedance non-linearity problem.

[0045] When the transformer is operating, by setting the cross-sectional areas of the upper iron core frame 4 and the lower iron core frame 5, the magnetic flux density value of the middle iron core frame 8 can be controlled. When the transformer is operating normally, the iron core frame will not be saturated, thereby reducing the iron loss and improving the working efficiency of the transformer.

[0046] The single-phase upper winding and the single-phase lower winding each include two connection terminals, and the single-phase main coil includes leads. The leads are used to connect to each other and can also be connected to the connection terminals. Understandably, the connection terminals are the same, that is, they can be used to connect to each other and can also be used to connect to the leads.

[0047] The transformer also includes an iron core, an oil tank, an oil conservator and an insulating medium. Among them, the iron core is used to form a magnetic path, and the oil tank can serve as the outer shell of the transformer and has a certain heat dissipation function; the oil conservator plays the role of storing oil and supplementing the transformer oil in the oil tank to ensure that the oil tank is full of oil, reduce the contact surface between the oil and the air, and prevent the transformer oil from being accelerated oxidized and affected with damp; the insulating medium plays the role of fixing the leads and insulating from the outer shell. The transformer body is sleeved on the iron core through coils to realize the transformation of voltage and current.

[0048] Finally, it should also be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprises", "comprising" or any other variation thereof is intended to cover a non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0049] The orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0050] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

[0051] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not 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

1. A multi-impedance combined transformer, characterized in that, It includes a transformer and a built-in reactor; The transformer includes a plurality of single-phase main coils, the built-in reactor includes a plurality of single-phase windings adapted to the single-phase main coils, and the single-phase winding includes a single-phase upper winding and a single-phase lower winding; Among them, a delta connection is formed among the plurality of single-phase main coils, and in the delta connection, every two single-phase main coils are connected in series through one single-phase upper winding and / or one single-phase lower winding; 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 the single-phase main coil, and is isopotentially connected to the other end of the single-phase main coil with the single-phase lower / upper winding of the same phase connected to one end of the single-phase main coil.

2. The transformer according to claim 1, characterized in that, 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.

3. The transformer according to claim 1, characterized in that, 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.

4. The transformer according to claim 1, characterized in that, The built-in reactor further includes an upper iron core frame arranged at the upper end of the single-phase upper winding, a lower iron core frame arranged at the lower end of the single-phase lower winding, a left iron core frame arranged at the left end of the single-phase winding, a right iron core frame arranged at the right end of the single-phase winding, and a middle iron core frame arranged between the single-phase upper winding and the single-phase lower winding. The two end portions of the middle iron core frame penetrate through the gap between the single-phase windings and are respectively connected to the left iron core frame and the right iron core frame.

5. The transformer according to claim 4, characterized in that, When the transformer is in operation, by setting the cross-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, the magnetic flux density value of the iron core frame is controlled, and the iron core frame will not be saturated during the normal operation of the transformer.

6. The transformer according to claim 1, characterized in that, The single-phase upper winding and the single-phase lower winding respectively include two wiring terminals; The single-phase main coil includes a lead wire; The lead wire / wiring terminal is used for connecting to each other or connecting to the wiring terminal / lead wire.

7. The transformer according to claim 1, characterized in that, The transformer further includes an iron core for forming a magnetic path.

8. The transformer according to any one of claims 1 to 7, characterized in that, The transformer further includes an oil tank and an oil conservator for storing transformer oil, and the oil conservator is connected to the oil tank.

9. The transformer according to claim 8, wherein The transformer further includes an insulating medium for insulation.

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