Single-phase autotransformer

Abstract

The present application relates to a single-phase autotransformer, comprising: an iron core; a first winding, a first winding voltage regulating coil, a second winding, a third winding and a third winding voltage regulating coil wound on the iron core; and a first on-load tap changer and a second on-load tap changer. The first winding and the second winding are respectively a high-voltage winding and a low-voltage winding; the first on-load tap changer connects the first winding and the first winding voltage regulating coil; the second on-load tap changer connects the third winding and the third winding voltage regulating coil. In the above-mentioned single-phase autotransformer, both the first winding and the third winding have on-load voltage regulation, which can solve the problem of high-voltage or low-voltage overload caused by the third winding carrying different loads, and is conducive to improving the adaptability of the transformer to the grid voltage.

Description

Technical Field

[0001] The present application relates to the field of electric power technology, and in particular to a single-phase autotransformer. Background Art

[0002] With the increasing development of industry and economy, traditional transformers cannot meet the current demand for industrial electricity, and single-phase autotransformers with voltage regulation function came into being.

[0003] Traditional single-phase autotransformers use three voltage regulation methods: single high voltage regulation, single low voltage regulation, or high and low voltage regulation at the same time. They cannot adapt to the requirements of grid voltage changes when the third winding carries different loads, and cannot ensure the safe operation of the grid under different conditions. Therefore, traditional single-phase autotransformers have the disadvantage of poor adaptability to grid voltage. Summary of the invention

[0004] Based on this, it is necessary to provide a single-phase autotransformer with good adaptability to grid voltage.

[0005] A single-phase autotransformer comprises: an iron core, a first winding wound on the iron core, a first winding voltage regulating coil, a second winding, a third winding and a third winding voltage regulating coil, and a first on-load tap changer and a second on-load tap changer; the first winding and the second winding are respectively a high-voltage winding and a low-voltage winding;

[0006] The first on-load tap changer connects the first winding and the first winding voltage regulating coil;

[0007] The second on-load tap changer connects the third winding and the third winding voltage regulating coil.

[0008] In one embodiment, the first winding is a high voltage winding, the second winding is a low voltage winding, and the first winding voltage regulating coil is a high voltage voltage regulating coil.

[0009] In one embodiment, the single-phase autotransformer is a step-up transformer; the third winding voltage regulating coil, the third winding, the second winding, the first winding, and the first winding voltage regulating coil are wound on the iron core in sequence from the inside to the outside.

[0010] In one embodiment, the first on-load tap changer is a positive and negative voltage regulating on-load tap changer.

[0011] In one of the embodiments, the head end of the first winding is connected to the power grid; the end of the first winding is connected to the fixed contact of the polarity selector of the lead-in end of the first on-load tap changer; the two ends of the first winding voltage regulating coil are respectively connected to the positive and negative poles of the lead-in end polarity selector; the optional voltage regulating taps of the first on-load tap changer are respectively connected to different terminals of the first winding voltage regulating coil; the lead-out end of the first on-load tap changer and the head end of the second winding are connected to the power supply side; and the end of the second winding is connected to the power grid as a neutral point.

[0012] In one embodiment, the second on-load tap changer is a linear voltage regulating on-load tap changer.

[0013] In one embodiment, the head end of the third winding is connected to the power grid; the end of the third winding is connected to the head end of the third winding voltage regulating coil; different connection terminals of the third winding voltage regulating coil are respectively connected to the optional voltage regulating taps of the second on-load tap changer; and the lead-out terminal of the second on-load tap changer is connected to the power grid.

[0014] In one embodiment, the iron core is a single-phase three-column iron core structure; the third winding voltage regulating coil, the third winding, the second winding, the first winding and the first winding voltage regulating coil are all wound on the main column of the three-column iron core.

[0015] In one embodiment, the first winding is a fully continuous coil.

[0016] In one embodiment, the single-phase autotransformer further includes an oil conservator and an oil tank; the first on-load tap changer and its connecting wire, the second on-load tap changer and its connecting wire, the lead-out end of the first winding, the lead-out end of the second winding and the lead-out end of the third winding are arranged at different positions of the outer shell of the oil tank.

[0017] In the above-mentioned single-phase autotransformer, both the first winding and the third winding have on-load voltage regulation, which can solve the problem of high voltage or low voltage overload caused by the third winding carrying different loads, and is conducive to improving the adaptability of the transformer to the grid voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1A schematic diagram of the winding arrangement structure of a single-phase autotransformer in one embodiment;

[0020] Figure 2 A schematic diagram of winding connection of a single-phase autotransformer in one embodiment;

[0021] Figure 3 is a wiring schematic diagram of a first on-load tap changer in an embodiment;

[0022] Figure 4 is a wiring schematic diagram of a second on-load tap changer in one embodiment;

[0023] Figure 5 Schematic diagram of the overall layout of a single-phase autotransformer in one embodiment. DETAILED DESCRIPTION

[0024] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0026] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first winding may be referred to as a second winding, and similarly, a second winding may be referred to as a first winding. Both the first winding and the second winding are windings, but they are not the same winding.

[0027] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0028] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof.

[0029] At present, single-phase autotransformer products in domestic and foreign power equipment generally adopt three voltage regulation methods: separate high-voltage voltage regulation, separate low-voltage voltage regulation, or high-voltage and low-voltage simultaneous voltage regulation. These three forms of single-phase autotransformers cannot adapt to the requirements of grid voltage changes when the third winding carries different loads, and cannot ensure the safe operation of the grid under different conditions. After research, it was found that the reason for this problem is that the voltage output by the third winding of the transformer is fixed. Based on this, the present application proposes a double-switch single-phase autotransformer with load regulation on both the first winding and the third winding. It can adapt to the grid voltage requirements when the third winding carries compensation loads such as reactors and capacitors, or when the station load is connected at the same time, thereby truly realizing the automatic regulation of the grid current and solving the high-voltage or low-voltage overload problem caused by the third winding carrying different loads.

[0030] In one embodiment, Figure 1 As shown, a single-phase autotransformer is provided, including an iron core 100, a first winding 200, a first winding voltage regulating coil 300, a second winding 400, a third winding 500 and a third winding voltage regulating coil 600 wound on the iron core 100, and a first on-load tap changer (not shown) and a second on-load tap changer (not shown). The first winding 200 and the second winding 400 are respectively a high voltage winding and a low voltage winding, the first on-load tap changer connects the first winding 200 and the first winding voltage regulating coil 300; the second on-load tap changer connects the third winding 500 and the third winding voltage regulating coil 600.

[0031] Among them, the type of the iron core 100 is not unique, for example, it can be an E-type iron core, a C-type iron core or an O-type iron core. In one embodiment, the iron core 100 is a single-phase three-column iron core structure; the first winding 200, the first winding voltage regulating coil 300, the second winding 400, the third winding 500 and the third winding voltage regulating coil 600 are all wound on the main column of the three-column iron core, and the structure is more compact. The first winding 200 and the second winding 400 are high-voltage windings and low-voltage windings, respectively, which means that the first winding 200 is a low-voltage winding and the second winding 400 is a high-voltage winding; or the first winding 200 is a high-voltage winding and the second winding 400 is a low-voltage winding. Further, the types of the first on-load tap changer and the second on-load tap changer are not unique, for example, they can be positive and negative voltage regulating on-load tap changers, linear voltage regulating on-load tap changers or coarse and fine voltage regulating on-load tap changers. Each on-load tap changer includes at least two gears, which can change the number of connected coils of the corresponding voltage regulating coil. It can be understood that when the voltage regulating coil is not connected, one end of the on-load tap changer is connected to the end of the corresponding winding, and the other end is directly led out as a terminal. In addition, the winding method of each winding is not unique, for example, an inner screen continuous structure, a tangled continuous structure or a full continuous structure can be adopted. In one embodiment, the first winding 200 is a full continuous coil, which can reduce the complexity of design, process, and production, thereby reducing costs.

[0032] Specifically, the first on-load tap changer is used to change the number of chips of the first winding voltage regulating coil 300 put into the circuit, thereby adjusting the output voltage of the first winding 200; the second on-load tap changer is used to change the number of chips of the third winding voltage regulating coil 600 put into the circuit, thereby adjusting the output voltage of the third winding 500.

[0033] In the above-mentioned single-phase autotransformer, both the first winding and the third winding have on-load voltage regulation. When the transformer is running, the grid voltage value can be detected according to the principle of mutual inductance, and the position of each on-load tap changer can be adjusted without disconnecting the load, so that the transformer can match the grid voltage value, which can solve the problem of high-voltage or low-voltage overload caused by different loads of the third winding, and is conducive to improving the adaptability of the transformer to the grid voltage.

[0034] In one embodiment, the first winding 200 is a high voltage winding, the second winding 400 is a low voltage winding, and the first winding voltage regulating coil 300 is a high voltage voltage regulating coil. Specifically, according to the transformer principle, the current on the high voltage side is much smaller than the current on the low voltage side. An on-load tap changer is connected to the high voltage side. The on-load tap changer has a small working current and a correspondingly small volume, which is easy to install.

[0035] Further, in one embodiment, the single-phase autotransformer is a step-up transformer; the third winding voltage regulating coil 600, the third winding 500, the second winding 400, the first winding 200, and the first winding voltage regulating coil 300 are sequentially wound on the iron core 100 from the inside to the outside. Specifically, the second winding 400 is a low-voltage winding, and the first winding 200 is a high-voltage winding. The single-phase autotransformer is a step-up transformer, which means that the low-voltage winding is used to connect the power supply side, and the high-voltage winding is used to connect the load, that is, the grid side. The high-voltage winding is placed in the outermost layer, and the low-voltage winding is placed between the high-voltage winding and the third winding, so that the leakage magnetic field is evenly distributed and the leakage reactance is reasonably distributed, so as not to increase the leakage magnetic flux and increase the additional loss due to the low-voltage and high-voltage windings being too far apart, thereby ensuring a better voltage regulation rate and operating performance.

[0036] It can be understood that in other embodiments, the second winding 400 can also be provided with a corresponding second winding voltage regulating coil and an on-load tap changer, that is, the first winding 200, the second winding 400 and the third winding 500 of the single-phase autotransformer all have a voltage regulation function, which is beneficial to further improve the adaptability of the transformer to the grid voltage.

[0037] In one embodiment, the first on-load tap changer is a positive and negative voltage regulating on-load tap changer. The positive and negative voltage regulating on-load tap changer refers to an on-load tap changer that regulates voltage based on the positive and negative voltage regulating principle. Using the positive and negative voltage regulating on-load tap changer is conducive to reducing the material cost of the single-phase autotransformer.

[0038] Furthermore, in one embodiment, the head end of the first winding 200 is connected to the power grid; the end of the first winding 200 is connected to the fixed contact of the polarity selector of the lead-in terminal of the first on-load tap changer; the two ends of the first winding voltage regulating coil 300 are respectively connected to the positive and negative poles of the lead-in terminal polarity selector. The optional voltage regulating taps of the first on-load tap changer are respectively connected to different terminals of the first winding voltage regulating coil 300; the lead-out terminal of the first on-load tap changer and the head end of the second winding 400 are connected to the power supply side; the end of the second winding 400 is connected to the power grid as a neutral point.

[0039] Specifically, Figure 2 and Figure 3 As shown, the first on-load tap changer Q1 is a positive and negative voltage regulating on-load tap changer including an input end polarity selector K, the first winding 200 is a high voltage winding H, the first winding voltage regulating coil 300 is a high voltage voltage regulating coil HT, and the second winding 400 is a low voltage winding L. The head end H1 of the high voltage winding H is connected to the power grid. The fixed contact K of the input end polarity selector is connected to the end H1' of the high voltage winding H; the positive pole (i.e. Figure 3 The variable contact "+" in the middle is connected to the head end 8' of the high-voltage voltage regulating coil HT, and the negative pole (i.e. Figure 3The variable contact "-" in the middle is connected to the end 1 of the high-voltage regulating coil HT. The optional voltage regulating taps (i.e. Figure 3 The variable contacts "1"-"9" in the circuit are connected to different terminals of the high voltage regulating coil HT respectively. The lead-out terminal O of the first on-load tap changer Q1 and the head end X1 of the low voltage winding L are connected to the power supply side; the end H0X0 of the low voltage winding L is connected to the grid as a neutral point.

[0040] When the negative pole of the introduction end polarity selector is connected to the circuit, the put-in coils of the high-voltage voltage regulating coil HT and the high-voltage coil H produce a canceling effect, which is equivalent to reducing the number of put-in coils of the high-voltage winding H; when the positive pole of the introduction end polarity selector is connected to the circuit, the put-in coils of the high-voltage voltage regulating coil HT and the high-voltage coil H produce a superimposed effect, which is equivalent to increasing the number of put-in coils of the high-voltage winding H. By changing the number of put-in coils of the high-voltage winding H, the output voltage of the high-voltage winding H can be changed to achieve high-voltage voltage regulation. Taking the positive pole of the polarity selector K as an example, when the lead-out terminal 0 of the first on-load tap changer Q1 is connected to the optional voltage regulating tap 9, the high-voltage voltage regulating coil HT is not connected to the circuit at all; when the lead-out terminal 0 of the first on-load tap changer Q1 is connected to the optional voltage regulating tap 1, the high-voltage voltage regulating coil HT is fully connected to the circuit. Figure 3 As shown, by using the first on-load tap changer Q1 with 9 optional voltage regulating taps, ±8 levels of high-voltage on-load voltage regulation can be achieved, and the voltage regulation range is wide, which is conducive to further improving the adaptability of the transformer to the power grid.

[0041] In one embodiment, the second on-load tap changer is a linear voltage regulating on-load tap changer, which can reduce the number of coil turns and is conducive to reducing the material cost of the single-phase autotransformer.

[0042] In one embodiment, the head end of the third winding 500 is connected to the power grid; the end of the third winding 500 is connected to the head end of the third winding voltage regulating coil 600; different connection terminals of the third winding voltage regulating coil 600 are respectively connected to the optional voltage regulating taps of the second on-load tap changer; and the lead-out terminal of the second on-load tap changer is connected to the power grid.

[0043] Specifically, Figure 2 and Figure 4 As shown, the second on-load tap changer Q2 is a linear voltage-regulating on-load tap changer, the third winding 500 is a winding T, and the third winding voltage-regulating coil 600 is a voltage-regulating coil TT. The head end Y1 of the winding T is connected to the power grid, the end Y1' of the winding T is connected to the head end T6' of the voltage-regulating coil TT, and the end Y1' of the winding T is also connected to the optional voltage-regulating tap 7 of the second on-load tap changer Q2. Different connection terminals of the voltage-regulating coil TT are respectively connected to the optional voltage-regulating taps (i.e., Figure 4The output terminal 0 of the second on-load tap changer Q2 is connected to the grid via the terminal Y2.

[0044] like Figure 4 As shown, by connecting the optional voltage-regulating taps of the second on-load tap changer Q2 to different terminals of the voltage-regulating coil TT, the number of connected coils of the voltage-regulating coil TT can be changed, thereby changing the output voltage of the winding T, and realizing the voltage regulation of the third winding. When the lead-out terminal 0 of the second on-load tap changer Q2 is connected to the optional voltage-regulating tap 7, the voltage-regulating coil TT is completely disconnected from the circuit; when the lead-out terminal 0 of the second on-load tap changer Q2 is connected to the optional voltage-regulating tap 1, the voltage-regulating coil TT is completely connected to the circuit. Figure 4 As shown, by using the first on-load tap changer Q2 with 7 optional voltage regulating taps, ±3 levels of on-load voltage regulation of the third winding can be achieved, and the voltage regulation range is wide, which is conducive to further improving the adaptability of the transformer to the power grid.

[0045] In one embodiment, the single-phase autotransformer further includes an oil conservator and an oil tank. The first on-load tap changer Q1 and its connecting wire, the second on-load tap changer Q2 and its connecting wire, the lead-out end of the first winding 200, the lead-out end of the second winding 400 and the lead-out end of the third winding 500 are arranged at different positions of the outer shell of the oil tank.

[0046] Among them, the oil storage cabinet 700 is used to store the cooling oil required for the transformer to work, and the oil tank 800 includes an outer shell and an internal space for arranging the cooling oil pipeline. The outer shell of the oil tank 800 is also provided with a terminal of a single-phase autotransformer, which is convenient for wiring and removal of the connecting wire. Take the case where the first winding 200 is a high-voltage winding and the second winding 400 is a low-voltage winding as an example. The lead-out end of the first winding 200 is a high-voltage head end H1, the lead-out end of the second winding 400 includes a low-voltage head end X1 and a low-voltage end H0X0, and the lead-out end of the third winding 500 is a third winding head end Y1. Further, the terminal Y2 is also provided on the outer shell of the oil tank 800. By arranging each terminal at different positions of the oil tank outer shell, interference caused by too short a distance between the wiring can be avoided.

[0047] Further, such as Figure 5As shown, the oil tank 800 is a rectangular oil tank. The first on-load tap changer Q1 and its connecting wires, the second on-load tap changer Q2 and its connecting wires, the high-voltage head end H1 and its connecting wires, and the low-voltage terminal H0X0 and its connecting wires are respectively arranged at the four corners of the oil tank 800, making full and reasonable use of the space at the four corners of the rectangular oil tank. The smaller space above the oil tank is used to place the third winding head end Y1 and the terminal Y2 and their lead wires, which have a lower voltage and require a smaller insulation distance. The space below the oil tank is used to place the relatively simple low-voltage head end X1 and its lead wires, and the lead wires of the low-voltage head end X1 are directly connected to the low-voltage bushing lead. In addition, the oil storage cabinet 700 is placed on the side farthest from the lead end of the high-voltage winding (i.e., the high-voltage head end H1), which can ensure the insulation distance requirement of the lead end of the high-voltage winding. The above arrangement can not only improve the occupancy rate of the oil tank 800, but also make full use of every inch of the space of the oil tank 800, making the product structure more compact. That is, the weight of transformer oil can be saved, the volume of the oil tank and the weight of the insulating steel plate can be reduced, while the insulation distance inside the transformer is ensured, the transformer footprint can be reduced while ensuring the transformer performance, which is conducive to saving design costs.

[0048] Combine the following Figures 1 to 5 The single-phase autotransformer in the present application is described in detail.

[0049] In one embodiment, a single-phase autotransformer includes an iron core 100, a first winding 200 wound on the iron core 100, a first winding voltage regulating coil 300, a second winding 400, a third winding 500, a third winding voltage regulating coil 600, and a first on-load tap changer Q1 and a second on-load tap changer Q2. Figure 2 As shown, the first winding 200 is a high voltage winding H, the second winding 400 is a low voltage winding L, and the third winding 500 is a winding T. Correspondingly, the first winding voltage regulating coil 300 is a high voltage voltage regulating coil HT, and the third winding voltage regulating coil 600 is a voltage regulating coil TT. The iron core 100 is a single-phase three-column iron core structure, and the voltage regulating coil TT, winding T, low voltage winding L, high voltage winding H, and high voltage voltage regulating coil HT are sequentially wound on the middle column of the iron core 100 from the inside to the outside.

[0050] like Figure 2 and Figure 3As shown, the first on-load tap changer Q1 is a positive and negative voltage regulating on-load tap changer including an input-end polarity selector. Specifically, the constant contact K of the input-end polarity selector is connected to the end H1' of the high-voltage winding H; the positive and negative poles of the input-end polarity selector are respectively connected to the head end 8' and the end 1 of the high-voltage voltage regulating coil HT. The optional voltage regulating taps of the first on-load tap changer Q1 are respectively connected to different terminals of the high-voltage voltage regulating coil HT. The lead-out terminal 0 of the first on-load tap changer Q1 and the head end X1 of the low-voltage winding L are connected to the power supply side; the end H0X0 of the low-voltage winding L is connected to the power grid as a neutral point. The head end H1 of the high-voltage winding H is connected to the power grid. When the negative pole of the polarity selector at the introduction end is connected to the circuit, the input coil of the high-voltage voltage regulating coil HT and the high-voltage coil H produce a canceling effect, which is equivalent to reducing the number of input coils of the high-voltage winding H; when the positive pole of the polarity selector K at the introduction end is connected to the circuit, the input coil of the high-voltage voltage regulating coil HT and the high-voltage coil H produce a superimposed effect, which is equivalent to increasing the number of input coils of the high-voltage winding H. By changing the number of input coils of the high-voltage winding H, the output voltage of the high-voltage winding H can be changed to achieve high-voltage voltage regulation. Taking the positive pole of the polarity selector K as an example, when the lead-out terminal 0 of the first on-load tap changer Q1 is connected to the optional voltage regulating tap 9, the high-voltage voltage regulating coil HT is not connected to the circuit at all; when the lead-out terminal 0 of the first on-load tap changer Q1 is connected to the optional voltage regulating tap 1, the high-voltage voltage regulating coil HT is fully connected to the circuit.

[0051] like Figure 2 and Figure 4 As shown, the second on-load tap changer Q2 is a linear voltage-regulating on-load tap changer. Specifically, the head end Y1 of the winding T is connected to the power grid, the end Y1' of the winding T is connected to the head end T6' of the voltage-regulating coil TT, and the end Y1' of the winding T is also connected to the tap 7 of the second on-load tap changer Q2. Different terminals of the voltage-regulating coil TT are respectively connected to the taps of the second on-load tap changer Q2; the lead-out terminal 0 of the second on-load tap changer Q2 is connected to the power grid through the terminal Y2. By connecting the optional voltage-regulating taps of the second on-load tap changer Q2 to different terminals of the voltage-regulating coil TT, the number of input cakes of the voltage-regulating coil TT can be changed, thereby changing the output voltage of the winding T, and realizing the third winding voltage regulation. When the lead-out terminal 0 of the second on-load tap changer Q2 is connected to the optional voltage-regulating tap 7, the voltage-regulating coil TT is completely disconnected from the circuit; when the lead-out terminal 0 of the second on-load tap changer Q2 is connected to the optional voltage-regulating tap 1, the voltage-regulating coil TT is completely connected to the circuit.

[0052] The above-mentioned double-on-load high-overload single-phase autotransformer uses a first on-load tap changer Q1 with 9 optional voltage regulating taps and a second on-load tap changer Q2 with 7 optional voltage regulating taps, which can achieve ±8 levels of high-voltage on-load voltage regulation and ±3 levels of third winding on-load voltage regulation. The maximum voltage regulation range can reach 17*7=119 levels. The transformer has many working positions and a wide voltage regulation range during operation, which is conducive to further improving the adaptability of the transformer to the power grid.

[0053] like Figure 5 As shown, the single-phase autotransformer also includes an oil storage cabinet 700 and an oil tank 800. Among them, the oil tank 800 is a rectangular oil tank. The first on-load tap changer Q1 and its connecting wires, the second on-load tap changer Q2 and its connecting wires, the high-voltage head end H1 and its connecting wires, and the low-voltage terminal H0X0 and its connecting wires are respectively arranged at the four corners of the oil tank 800, making full and reasonable use of the four corners of the rectangular oil tank. The smaller space above the oil tank is used to place the third winding head end Y1 and the terminal Y2 and their lead wires with lower voltage and smaller insulation distance requirements. The space below the oil tank is used to place the relatively simple low-voltage head end X1 and its lead wires, and the low-voltage head end X1 lead wire is directly connected to the low-voltage bushing lead. In addition, the oil storage cabinet 700 is placed on the side farthest from the lead end of the high-voltage winding (i.e., the high-voltage head end H1), which can ensure the insulation distance requirement of the high-voltage winding lead end. The above arrangement can not only improve the occupancy rate of the oil tank 800, but also make full use of every inch of the space of the oil tank 800, making the product structure more compact. In other words, it can save the weight of transformer oil, reduce the volume of the oil tank and the weight of the insulating steel plate, and at the same time ensure the insulation distance inside the transformer, while ensuring the performance of the transformer and reducing the area occupied by the transformer, which is conducive to saving design costs.

[0054] In addition, for conventional 220kV and above transformer products, the high-voltage winding generally adopts an inner-screen continuous coil or a tangled continuous coil, which has a complex structure and high process cost. The inner-screen continuous coil has a low duty cycle, resulting in a very high electrical density at the shielding end, which increases the hot spot temperature rise of the winding and increases the cost. In addition, the longitudinal insulation distribution gradient of the inner-screen continuous coil is large, so the coil shielding section needs to enlarge the coil oil channel to adjust the longitudinal insulation distribution. The tangled continuous coil can solve the above two problems, but on the one hand, the tangled continuous coil process is complex, the winding is difficult and can easily lead to tangled short circuits; on the other hand, the tangled coil has many restrictions and can only be wound with paper-wrapped copper flat wire or combined wire. Under the premise of ensuring all product performance, the high-voltage winding H of this application adopts a fully continuous structure, which can not only reduce the complexity of design, process, and production, but also solve the problem of excessive temperature rise caused by high overload operation. Through reasonable design of high-voltage, low-voltage and tertiary winding structures, the coordination between the radial oil channel and the axial oil channel in the oil tank can be optimized, the coil oil channel at the hot spot can be enlarged, and the size of the oil channel can be reasonably distributed and arranged. This can solve the problem of excessive hot spot temperature rise of the high-voltage winding or the low-voltage winding caused by the third winding being connected to compensation loads such as reactors or capacitors or to different loads such as station loads at the same time.

[0055] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0056] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0057] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A single-phase autotransformer, characterized in that: include: Iron core; A first winding, a first winding voltage regulating coil, a second winding, a third winding and a third winding voltage regulating coil wound on the iron core; and a first on-load tap changer and a second on-load tap changer; The iron core is an E-type iron core, a C-type iron core or an O-type iron core; The first on-load tap changer connects the first winding and the first winding voltage regulating coil; The second on-load tap changer connects the third winding and the third winding voltage regulating coil; The first winding is a high voltage winding, the second winding is a low voltage winding, and the first winding voltage regulating coil is a high voltage voltage regulating coil; The first on-load tap changer is a positive and negative voltage regulating on-load tap changer; The head end of the first winding is connected to the power grid; the end of the first winding is connected to the fixed contact of the polarity selector of the lead-in end of the first on-load tap changer; the two ends of the first winding voltage regulating coil are respectively connected to the positive and negative poles of the lead-in end polarity selector; the optional voltage regulating taps of the first on-load tap changer are respectively connected to different terminals of the first winding voltage regulating coil; the lead-out end of the first on-load tap changer and the head end of the second winding are connected to the power supply side; the end of the second winding is connected to the power grid as a neutral point.

2. The single-phase autotransformer according to claim 1, characterized in that: The single-phase autotransformer is a step-up transformer; the third winding voltage regulating coil, the third winding, the second winding, the first winding, and the first winding voltage regulating coil are sequentially wound on the iron core from the inside to the outside.

3. The single-phase autotransformer according to claim 1, characterized in that: The first winding is an inner-screen continuous structure or a tangled continuous structure.

4. The single-phase autotransformer according to claim 1, characterized in that: The second winding is provided with a corresponding second winding voltage regulating coil and an on-load tap changer.

5. The single-phase autotransformer according to claim 1, characterized in that: The second on-load tap changer is a linear voltage regulating on-load tap changer.

6. The single-phase autotransformer according to claim 5, characterized in that: The head end of the third winding is connected to the power grid; the end of the third winding is connected to the head end of the third winding voltage regulating coil; different connection terminals of the third winding voltage regulating coil are respectively connected to the optional voltage regulating taps of the second on-load tap changer; the lead-out end of the second on-load tap changer is connected to the power grid.

7. The single-phase autotransformer according to claim 1, characterized in that: The iron core is a single-phase three-column iron core structure; the third winding voltage regulating coil, the third winding, the second winding, the first winding and the first winding voltage regulating coil are all wound on the main column of the three-column iron core.

8. The single-phase autotransformer according to claim 1, characterized in that: The first winding is a fully continuous coil.

9. The single-phase autotransformer according to any one of claims 1 to 8, characterized in that: The single-phase autotransformer also includes an oil conservator and an oil tank; the first on-load tap changer and its connecting wire, the second on-load tap changer and its connecting wire, the lead-out end of the first winding, the lead-out end of the second winding and the lead-out end of the third winding are arranged at different positions of the outer shell of the oil tank.

10. The single-phase autotransformer according to claim 9, characterized in that: The oil tank is a rectangular oil tank.

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