Three-phase transformer on-load switch and three-phase transformer system

Abstract

The present invention provides a three-phase transformer on-load switch and a three-phase transformer system, which converts the current of the transformer into a transition voltage through a transition circuit; changes the impedance of the voltage regulating circuit connected to the sub-circuit through a selection circuit to change the impedance of the voltage regulating circuit and the transformed voltage corresponding to the transition voltage; and reduces the voltage oscillation generated by the sub-circuit when the impedance of the voltage regulating circuit connected to the sub-circuit is changed through the selection circuit through a protection module. The present invention reduces the voltage regulation oscillation of the transformer during the voltage regulation process and improves safety.

Description

Technical Field

[0001] The present invention relates to the field of voltage transformation technology, and in particular to a three-phase voltage transformation on-load switch and a three-phase voltage transformation system. Background Art

[0002] In the related art, three single-phase switches are used to solve the insulation problem of the transformer. However, during the high-voltage impulse test or other voltage regulation processes, huge voltage fluctuations are easily caused at the end of the voltage regulating coil of the transformer, and even safety problems may occur. Summary of the invention

[0003] In view of this, an object of the present invention is to provide a three-phase transformer on-load switch and a three-phase transformer system to reduce the voltage regulation oscillation of the transformer during the voltage regulation process and improve safety.

[0004] In the first aspect, an embodiment of the present invention provides a three-phase transformer on-load switch, including three sub-circuits; the three sub-circuits are respectively connected to the first phase circuit, the second phase circuit and the third phase circuit of the transformer; the sub-circuits include a transition circuit, a selection circuit, a voltage regulating circuit and a protection module; the transition circuit, the selection circuit and the voltage regulating circuit are connected in sequence; the transition circuit is connected to the transformer; the protection module is arranged at both ends of the voltage regulating circuit; the transition circuit is used to convert the current of the transformer into a transition voltage; the selection circuit is used to change the impedance of the voltage regulating circuit connected to the sub-circuit, so as to change the impedance of the voltage regulating circuit and the transformed voltage corresponding to the transition voltage; the protection module is used to reduce the voltage oscillation when the impedance of the voltage regulating circuit connected to the sub-circuit is changed by the selection circuit and the sub-circuit generates voltage oscillation.

[0005] In combination with the first aspect, an embodiment of the present invention provides a first possible implementation scheme of the first aspect, wherein the above-mentioned selection circuit and the voltage regulating circuit are connected in a delta connection axial split manner; the selection circuit includes a first selection switch and a second selection switch connected in series; the selection circuit includes a voltage regulating circuit including a first coil and a second coil; the first selection switch is connected to the negative pole of the tap of the first coil; the second selection switch is connected to the negative pole of the tap of the second coil; the positive pole of the tap of the first coil is connected to the positive pole of the tap of the second coil.

[0006] In combination with the first possible implementation of the first aspect, an embodiment of the present invention provides a second possible implementation of the first aspect, wherein the above-mentioned transition circuit includes a first transition resistor and a second transition resistor connected in series; the first transition resistor is connected to the first selection switch; and the second transition resistor is connected to the second selection switch.

[0007] In combination with the first possible implementation of the first aspect, an embodiment of the present invention provides a third possible implementation of the first aspect, wherein the above-mentioned protection module includes a three-phase lightning arrester and an insulating bracket; the three-phase lightning arrester is respectively connected to the positive and negative poles of the tap of the first coil, and the positive and negative poles of the tap of the second coil.

[0008] In combination with the third possible implementation of the first aspect, an embodiment of the present invention provides a fourth possible implementation of the first aspect, wherein the above-mentioned three-phase lightning arrester is respectively connected to the positive and negative poles of the tap of the first coil, and the positive and negative poles of the tap of the second coil through three-phase connecting leads.

[0009] In combination with the third possible implementation of the first aspect, the embodiment of the present invention provides a fifth possible implementation of the first aspect, wherein the above-mentioned insulating bracket includes a supporting wooden bracket; the supporting wooden bracket is used to release the oscillating voltage.

[0010] In combination with the fifth possible implementation of the first aspect, an embodiment of the present invention provides a sixth possible implementation of the first aspect, wherein the above-mentioned supporting wooden bracket includes a set number of threaded holes; the three-phase lightning arrester is fixed to the supporting wooden bracket by bolts corresponding to the threaded holes.

[0011] In combination with the sixth possible implementation of the first aspect, an embodiment of the present invention provides a seventh possible implementation of the first aspect, wherein the above-mentioned supporting wooden bracket includes a plurality of wooden boards; the plurality of wooden boards are connected by riveting to form a supporting wooden bracket.

[0012] In combination with the sixth possible implementation of the first aspect, the embodiment of the present invention provides an eighth possible implementation of the first aspect, wherein the supporting wooden bracket includes 8 threaded holes.

[0013] In a second aspect, an embodiment of the present invention further provides a three-phase transformer system, which includes the above-mentioned three-phase transformer on-load switch and transformer.

[0014] The embodiments of the present invention bring the following beneficial effects:

[0015] The embodiment of the present invention provides a three-phase transformer on-load switch and a three-phase transformer system, which converts the current of the transformer into a transition voltage through a transition circuit; changes the impedance of the voltage regulating circuit connected to the sub-circuit through a selection circuit to change the impedance of the voltage regulating circuit and the transformed voltage corresponding to the transition voltage; and reduces the voltage oscillation generated by the sub-circuit when the impedance of the voltage regulating circuit connected to the sub-circuit is changed through the selection circuit through a protection module. This method reduces the voltage regulation oscillation of the transformer during the voltage regulation process and improves safety.

[0016] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0017] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 A schematic diagram of the structure of a three-phase transformer on-load switch provided in an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of the structure of the installation of a lightning arrester and a supporting wooden bracket provided by an embodiment of the present invention;

[0021] Figure 3 An electrical schematic diagram of a three-phase transformer on-load switch provided in an embodiment of the present invention;

[0022] Figure 4 A schematic structural diagram of a three-phase transformer system provided in an embodiment of the present invention.

[0023] Icons: 10-first sub-circuit; 20-second sub-circuit and 30-third sub-circuit; 101-first transition circuit; 102-first selection circuit; 103-first voltage regulation circuit; 104-first protection module; 201-second transition circuit; 202-second selection circuit; 203-second voltage regulation circuit; 204-second protection module; 301-third transition circuit; 302-third selection circuit; 303-third voltage regulation circuit; 304-third protection module; 1-positive (+) polarity tap lead; 2-negative (-) polarity tap lead; 3-lightning arrester; 4-supporting wooden bracket; 5-M16 nylon bolts and nuts; 111-three-phase transformer on-load switch; 222-transformer. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0025] At present, with the development of social economy, people's demand for electricity is growing, and various countries are investing more and more in large generator transformers. In order to improve the power generation efficiency more efficiently, the low-voltage side generally uses a star connection and the high-voltage side uses a triangle connection. At the same time, the voltage on the high-voltage side is constantly increasing, which objectively places higher requirements on the insulation reliability level of the transformer.

[0026] However, when the high-voltage delta-connected voltage regulating coil adopts the axial splitting method, it is naturally split into two coils, and the middle voltage regulation method that can avoid risks cannot be adopted. Therefore, the end voltage regulation method must be adopted for voltage regulation. When conducting high-voltage impact tests, huge shocks are usually caused at the ends of the voltage regulating coil. The existing method is to connect three single-phase switches in the circuit to solve the insulation problem, which is costly.

[0027] Based on this, a three-phase transformer on-load switch and a three-phase transformer system provided in an embodiment of the present invention can be applied to various transformer scenarios.

[0028] To facilitate understanding of this embodiment, a three-phase transformer on-load switch disclosed in an embodiment of the present invention is first introduced in detail.

[0029] The embodiment of the present invention provides a three-phase transformer on-load switch, such as Figure 1 As shown, the system includes three sub-circuits, which can be respectively referred to as a first sub-circuit 10, a second sub-circuit 20 and a third sub-circuit 30, each of which has the same structure; the first sub-circuit is connected to the first phase circuit of the transformer; the second sub-circuit is connected to the second phase circuit; and the third sub-circuit is connected to the third phase circuit.

[0030] The above-mentioned sub-circuits specifically include a transition circuit, a selection circuit, a voltage regulating circuit and a protection module; specifically, each sub-circuit can be expressed as: the first sub-circuit 10 includes a first transition circuit 101, a first selection circuit 102, a first voltage regulating circuit 103 and a first protection module 104; the second sub-circuit 20 includes a second transition circuit 201, a second selection circuit 202, a second voltage regulating circuit 203 and a second protection module 204; the third sub-circuit 30 includes a third transition circuit 301, a third selection circuit 302, a third voltage regulating circuit 303 and a third protection module 304.

[0031] Taking the first subcircuit as an example, the connection relationship and function between the transition circuit, the selection circuit, the voltage regulating circuit and the protection module are introduced. The second and third subcircuits are the same and will not be described here. The first transition circuit, the first selection circuit and the first voltage regulating circuit are connected in sequence; the first transition circuit is connected to the first transformer; the first protection module is arranged at both ends of the first voltage regulating circuit; the first transition circuit is used to convert the current transmitted by the first phase circuit of the transformer into a transition voltage; the first selection circuit is used to change the impedance of the first voltage regulating circuit connected to the first subcircuit to change the impedance of the first voltage regulating circuit and the transformed voltage corresponding to the transition voltage; the first protection module is used to reduce the voltage oscillation when the impedance of the first voltage regulating circuit connected to the subcircuit is changed by the first selection circuit and the first subcircuit generates voltage oscillation.

[0032] In the specific implementation process, in the same subcircuit, the selection circuit and the voltage regulating circuit are connected in a triangle axial split manner. The selection circuit includes a first selection switch and a second selection switch connected in series. The voltage regulating circuit includes a first coil and a second coil. Corresponding to the triangle axial split manner, the voltage cannot be adjusted by the middle voltage regulation method at this time, resulting in higher requirements for the insulation level. The first selection switch is connected to the negative pole of the tap of the first coil; the second selection switch is connected to the negative pole of the tap of the second coil; the positive pole of the tap of the first coil is connected to the positive pole of the tap of the second coil.

[0033] The transition circuit comprises a first transition resistor and a second transition resistor connected in series; the first transition resistor is connected to the first selection switch; and the second transition resistor is connected to the second selection switch.

[0034] The above-mentioned protection module can be a damping device. In a specific implementation, the protection device can be a three-phase lightning arrester and an insulating bracket; the three-phase lightning arrester is respectively connected to the positive and negative poles of the tapping tap of the first coil, and the positive and negative poles of the tapping tap of the second coil. In a specific implementation, the three-phase lightning arrester can be respectively connected to the positive and negative poles of the tapping tap of the first coil, and the positive and negative poles of the tapping tap of the second coil through three-phase connecting leads. Since the positive pole of the tapping tap of the first coil is connected to the positive pole of the tapping tap of the second coil, the three terminals of the three-phase lightning arrester are respectively connected to the negative pole of the tapping tap of the first coil, the negative pole of the tapping tap of the second coil, and the positive pole of the tapping tap of the first coil (that is, the positive pole of the tapping tap of the second coil).

[0035] In a specific implementation, the insulating bracket can be a supporting wooden bracket, which is used to release the oscillating voltage. The insulating bracket can also be made of other insulating materials, but the creepage distance of the material is required to be longer.

[0036] The above-mentioned supporting wooden bracket usually includes multiple wooden boards, which can also be called wooden strips, etc.; multiple wooden boards are connected by riveting to form a supporting wooden bracket; the supporting wooden bracket can be in the shape of a rectangular parallelepiped, with a hollow middle for placing a lightning arrester.

[0037] During the installation process, the three-phase lightning arrester can be fixed to the supporting wooden bracket by bolts corresponding to the threaded holes; at this time, the supporting wooden bracket includes a set number of threaded holes, which can be specifically 8 threaded holes.

[0038] The embodiment of the present invention provides a three-phase transformer on-load switch, in which the current of the transformer is converted into a transition voltage through a transition circuit; the impedance of the voltage regulating circuit connected to the sub-circuit is changed through a selection circuit to change the impedance of the voltage regulating circuit and the transformed voltage corresponding to the transition voltage; the voltage oscillation generated by the sub-circuit when the impedance of the voltage regulating circuit connected to the sub-circuit is changed through the selection circuit is reduced through a protection module. This method reduces the voltage regulation oscillation of the transformer during the voltage regulation process and improves safety.

[0039] The present invention also provides another three-phase transformer on-load switch. Figure 1 The switch is realized on the basis of the switch shown in FIG. The switch is a high-voltage delta-connected axial split transformer on-load switch, in which the arrester structure design is also adopted. The switch consists of a three-phase integrated on-load switch, a three-phase arrester, a supporting wooden bracket, and a three-phase connecting lead. In the switch, the three-phase arrester is installed on the supporting wooden bracket, and the arrester is connected to the positive and negative poles of the tapping tap with a lead, so that the arrester is used to reduce the voltage regulation oscillation of the on-load switch in the full range. At the same time, the use of the arrester on the axial split transformer can reduce the insulation level requirements of the on-load switch.

[0040] The above switch is also called a high-voltage delta-connected axial split on-load switch. This switch uses an axial split transformer with a high-voltage delta connection. Because its own coil has been split into two coils, the conventional delta-connected middle voltage regulation method cannot be used. After using the delta-connected end voltage regulation structure, the voltage regulating coil will cause great oscillations inside during the impact test, causing damage to the transformer switch. Therefore, a lightning arrester is introduced into the switch. Specifically, lightning arresters are set on both sides of the voltage regulating coil (equivalent to the above-mentioned "voltage regulating circuit") to limit the oscillating voltage at both ends of the voltage regulating coil during the impact test, thereby protecting the insulation between the internal contacts of the on-load voltage regulating switch (i.e. the above-mentioned "three-phase transformer on-load switch").

[0041] Specifically, if Figure 2 As shown, three lightning arresters are fixed to the bracket of the transformer using four M16 nylon bolts. The terminals at both ends of the lightning arrester are connected to the positive and negative poles of the voltage regulating coil using cold-pressed terminals, and the outside is wrapped with insulating crepe paper.

[0042] Figure 2 Among them, 1 is the positive (+) polarity tap lead; 2 is the negative (-) polarity tap lead; 3 is the lightning arrester; 4 is the supporting wooden bracket; 5 is the M16 nylon bolt and nut.

[0043] In the specific implementation process; first install the lightning arrester on the supporting wooden bracket and fix it with M16 nylon bolts and nuts. Then, lead the lead wires to both ends of the lightning arrester and crimp them with cold crimping to complete the assembly. Then, connect the lead wires to the positive and negative poles of the tapping terminals of the two voltage regulating coils.

[0044] Figure 3 The electrical schematic diagram of the above three-phase transformer load switch, A, B, C are the connection terminals of the three sub-circuits and the transformer, and the position of the lightning arrester is as follows: Figure 3 As shown, the nine terminals 1, 2, 3, 4, 5, 6, 7, 8, and 9 on the voltage regulating coil represent the nine gears of the voltage regulating coil. Ak, Bk, and Ck are the contact points of the transition circuit and the selection circuit respectively.

[0045] The above three-phase transformer load switch only needs a small investment of built-in lightning arrester, which can reduce costs and obtain greater benefits. Using this switch in a high-voltage split transformer can effectively reduce the insulation level required by the switch. Originally, three single-phase switches were used, but now one three-phase switch can solve the problem, greatly reducing the procurement cost of transformer accessories.

[0046] The embodiment of the present invention also provides a three-phase transformer system, such as Figure 4 As shown, the system includes the above-mentioned three-phase transformer on-load switch 111 and transformer 222.

[0047] The three-phase transformer system provided in the embodiment of the present invention has the same technical features as the three-phase transformer on-load switch provided in the above embodiment, so it can also solve the same technical problems and achieve the same technical effects.

[0048] The computer program product of the three-phase transformer on-load switch and the three-phase transformer system provided in the embodiments of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the switch described in the previous switch embodiment. The specific implementation can be found in the switch embodiment and will not be repeated here.

[0049] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described system and device can refer to the corresponding process in the aforementioned switch embodiment, and will not be repeated here.

[0050] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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, and it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the switch described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0052] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0053] Finally, it should be noted that the above embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that any person skilled in the art can still modify the technical solutions recorded in the above embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; 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 be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A three-phase transformer on-load switch, characterized in that: It comprises three sub-circuits; the three sub-circuits are respectively connected to the first phase circuit, the second phase circuit and the third phase circuit of the transformer; the sub-circuit comprises a transition circuit, a selection circuit, a voltage regulation circuit and a protection module; the transition circuit, the selection circuit and the voltage regulation circuit are connected in sequence; the transition circuit is connected to the transformer; the protection module is arranged at both ends of the voltage regulation circuit; The transition circuit is used to convert the current of the transformer into a transition voltage; The selection circuit is used to change the impedance of the voltage regulating circuit connected to the sub-circuit, so as to change the impedance of the voltage regulating circuit and the transformed voltage corresponding to the transition voltage; The protection module is used to reduce the voltage oscillation when the impedance of the voltage regulating circuit connected to the sub-circuit is changed by the selection circuit and the sub-circuit generates voltage oscillation; The selection circuit is connected to the voltage regulating circuit in a delta connection axial splitting manner; the selection circuit comprises a first selection switch and a second selection switch connected in series; the voltage regulating circuit comprises a first coil and a second coil; the first selection switch is connected to the negative pole of the tap of the first coil; the second selection switch is connected to the negative pole of the tap of the second coil; the positive pole of the tap of the first coil is connected to the positive pole of the tap of the second coil; The transition circuit comprises a first transition resistor and a second transition resistor connected in series; the first transition resistor is connected to the first selection switch; the second transition resistor is connected to the second selection switch; The protection module includes a three-phase lightning arrester and an insulating bracket; the three-phase lightning arrester is respectively connected to the positive electrode and the negative electrode of the tapping terminal of the first coil, and the positive electrode and the negative electrode of the tapping terminal of the second coil; The three-phase lightning arrester is connected to the positive pole and negative pole of the tapping terminal of the first coil and the positive pole and negative pole of the tapping terminal of the second coil respectively through three-phase connecting leads.

2. The switch according to claim 1, characterized in that: The insulating support comprises a supporting wood support; the supporting wood support is used for releasing the oscillating voltage.

3. The switch according to claim 2, characterized in that: The supporting wood bracket includes a set number of threaded holes; the three-phase lightning arrester is fixed to the supporting wood bracket by bolts corresponding to the threaded holes.

4. The switch according to claim 3, characterized in that: The supporting wood bracket includes a plurality of wooden boards; the plurality of wooden boards are connected by riveting to form the supporting wood bracket.

5. The switch according to claim 3, characterized in that: The supporting wood bracket includes 8 threaded holes.

6. A three-phase transformer system, characterized in that: The system comprises a three-phase transformer on-load switch and a transformer as described in any one of claims 1 to 5.

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