Rectifier and harmonic governing transformer

Abstract

The application discloses a rectification and harmonic treatment transformer, which comprises a core, a rectification winding for rectification wound on the core, and a harmonic treatment winding for harmonic treatment, wherein the rectification winding comprises a grid-side primary winding and a valve-side secondary winding corresponding to the grid-side primary winding, and the harmonic treatment winding comprises a harmonic treatment primary winding and a harmonic treatment secondary winding corresponding to the harmonic treatment primary winding. The rectification and harmonic treatment transformer integrates rectification and harmonic treatment functions, and can greatly reduce manufacturing cost and use cost. The rectification transformer can reduce harmonic content and improve power supply quality of a power grid system. Application of the scheme improves system efficiency and reliability and brings huge economic benefits.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of transformer, and particularly relates to a rectification and harmonic treatment transformer. BACKGROUND

[0002] The rectification transformer and rectification element transform the three-phase alternating current of the power grid into direct current with a certain number of phases required by the user. Since it is mainly used for power supply of nonlinear loads such as electric railways, electrolysis, chemical industry, calcium carbide furnace, etc., and in addition to the unidirectional blocking effect of the rectification element, the alternating magnetic field waveform of the rectification transformer is distorted. Even if the grid voltage is an ideal sine wave, the current taken from the alternating current grid by the rectification device is also non-sinusoidal. Non-sinusoidal alternating current not only enters the rectification device, but also is fed back to the alternating current grid by the rectification device, causing the voltage waveform at each point in the alternating current system to be distorted, which in turn affects the waveform of the current taken from the alternating current grid by the rectification device. The serious over-standard of harmonic content in the power system has the following hazards: increasing the additional loss of power supply equipment such as transformers, causing overheating of the equipment, and reducing the efficiency and utilization rate of the equipment; causing capacitors to malfunction due to overheating, overvoltage, etc., and cannot operate normally. Research and practice have proved that the size of the alternating current grid voltage waveform distortion has a direct relationship with the frequency of the harmonic current fed into the grid by the rectification device, i.e. the harmonic number. In order to effectively reduce the pollution of the harmonic of the rectification device to the grid, it is necessary to take measures to limit the frequency of the harmonic current injected into the grid by the rectification device.

[0003] The prior art is mostly to connect various types of filters on the valve side bus of the rectification transformer or to use two six-phase twelve-pulse rectification transformers in parallel output as twelve-phase twenty-four-pulse (i.e. increase the pulse number) and other methods. These methods not only have high cost but also are difficult to implement in engineering practice, so the above-mentioned problems need to be solved urgently. SUMMARY

[0004] The present application solves the technical problems in the prior art, and provides a rectification and harmonic treatment transformer, which combines the functions of rectification and harmonic treatment, and can greatly reduce the manufacturing cost and use cost.

[0005] The technical solution adopted by the present application to solve the technical problems is to provide a rectification and harmonic treatment transformer, which comprises: an iron core, a rectification winding for rectification wound on the iron core, and a harmonic treatment winding for harmonic treatment, the rectification winding comprises a grid side primary winding and a valve side secondary winding corresponding to the grid side primary winding, and the harmonic treatment winding comprises a harmonic treatment primary winding and a harmonic treatment secondary winding corresponding to the harmonic treatment primary winding.

[0006] Preferably, the rectifier winding and the core are concentrically arranged, the harmonic control winding and the core are concentrically arranged, the valve-side secondary winding and the network-side primary winding are radially arranged along the core from inside to outside, the harmonic control secondary winding and the harmonic control primary winding are radially arranged along the core from inside to outside.

[0007] Preferably, the rectifier winding and the harmonic control winding are arranged axially along the core, and the harmonic control winding is above the rectifier winding.

[0008] Preferably, the network-side primary winding is angularly connected.

[0009] Preferably, the network-side primary winding includes at least two network-side primary split windings, the valve-side secondary winding includes at least two valve-side secondary split windings, each valve-side secondary split winding corresponds to each network-side primary split winding, wherein each network-side primary split winding and the harmonic control primary winding are connected in parallel, and each valve-side secondary split winding and the harmonic control secondary winding are electrically independent.

[0010] Preferably, each valve-side secondary split winding is arranged axially along the core, and each network-side primary split winding is arranged axially along the core.

[0011] Preferably, the valve-side secondary split windings are even in number, half of the valve-side secondary split windings are star-connected, the remaining valve-side secondary split windings are angularly connected, the line voltage effective value of the star-connected valve-side secondary split winding is equal to that of the angularly connected valve-side secondary split winding, and the harmonic control secondary winding is star-connected.

[0012] Preferably, the phase difference of the line voltage of the valve-side secondary split winding is 2π / 12.

[0013] Preferably, the number of split windings of the network-side primary split winding and the valve-side secondary split winding corresponds to the reactance height.

[0014] Preferably, the core uses high-permeability cold-rolled grain-oriented silicon steel, the core uses 45° full-inclination five-stage stepping lamination, the core is a non-perforated screw core, and the core is fixed by using a pull plate and binding structure.

[0015] Preferably, the capacity of the harmonic control winding is 25-30% of the total capacity of the transformer.

[0016] The rectification and harmonic treatment transformer of the present application has the following advantages: the harmonic treatment winding can eliminate about 10% of the non-characteristic harmonic currents of 5, 7, 17 and 19 times in the harmonic currents of the AC network side of the rectification device, so it is not necessary to connect various types of filters on the valve side bus of the transformer with rectification function or use two six-phase twelve-pulse rectification transformers in parallel output to form twelve-phase twenty-four-pulse (i.e. increase the pulse number) to reduce the floor area of the transformer with rectification function and the overall project cost. The present application combines the rectification and harmonic treatment functions into one transformer, which can greatly reduce the manufacturing cost and the use cost. The rectification transformer can reduce the harmonic content, improve the power supply quality of the power grid system, and the application of the scheme can improve the system efficiency and reliability and also bring huge economic benefits.

[0017] The rectification and harmonic treatment transformer of the present application is an environmentally friendly and energy-saving product, which has the characteristics of strong heat shock resistance, large overload capacity, non-combustible resin, difficult flammability, strong emergency overload capacity, convenient repair and maintenance, not sensitive to humidity and dust, no cracking, safe and reliable performance. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural diagram of the transformer in embodiment 2 of the present application;

[0019] Figure 2 is a front view of the transformer in embodiment 2 of the present application;

[0020] Figure 3 is a side view of the transformer in embodiment 2 of the present application;

[0021] Figure 4 is a primary winding connection diagram of the transformer in embodiment 2 of the present application;

[0022] Figure 5 is a secondary winding connection diagram of the transformer in embodiment 2 of the present application.

[0023] In the figure: 1-iron core; 2-harmonic treatment secondary winding; 3-harmonic treatment primary winding; 4-first network side primary split winding; 5-second valve side secondary split winding; 6-first valve side secondary split winding; 7-second network side primary split winding; 8-rectification winding; 9-harmonic treatment winding. DETAILED DESCRIPTION

[0024] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below in combination with the drawings and specific embodiments.

[0025] Embodiments of the present patent are described below in detail with reference to the accompanying drawings, wherein the same or similar components or components having the same or similar functions are denoted by the same or similar reference numerals throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are intended only for explanation of the present patent, and cannot be construed as limiting the present patent.

[0026] Embodiment 1

[0027] The embodiment provides a rectification and harmonic treatment transformer, comprising a core, a rectification winding for rectification wound on the core, a harmonic treatment winding for harmonic treatment, the rectification winding comprising a grid-side primary winding, a valve-side secondary winding corresponding to the grid-side primary winding, the harmonic treatment winding comprising a harmonic treatment primary winding, a harmonic treatment secondary winding corresponding to the harmonic treatment primary winding.

[0028] The rectification and harmonic treatment transformer of the embodiment has the beneficial effect that the harmonic treatment winding can eliminate about 10% of the 5th, 7th, 17th and 19th non-characteristic harmonic currents remaining in the harmonic currents of the AC grid side of the rectification device, so there is no need to connect various types of filters on the valve-side bus of the transformer with rectification function or use two six-phase twelve-pulse rectification transformers in parallel output as twelve-phase twenty-four-pulse (i.e. increase the pulse number) and other methods, thereby reducing the floor area of the transformer with rectification function and reducing the overall project cost.

[0029] Embodiment 2

[0030] As shown in Figures 1 to 3 The embodiment provides a rectification and harmonic treatment transformer, comprising a core 1, a rectification winding 8 for rectification wound on the core 1, a harmonic treatment winding 9 for harmonic treatment, the rectification winding 8 comprising a grid-side primary winding, a valve-side secondary winding corresponding to the grid-side primary winding, the harmonic treatment winding 9 comprising a harmonic treatment primary winding 3, a harmonic treatment secondary winding 2 corresponding to the harmonic treatment primary winding 3. The transformer in the embodiment is a three-phase transformer, and has a multi-split winding structure.

[0031] Preferably, the rectification winding 8 and the core 1 are arranged in a concentric manner, the harmonic treatment winding 9 and the core 1 are arranged in a concentric manner, the valve-side secondary winding and the grid-side primary winding are arranged radially along the core 1 from the inside to the outside, and the harmonic treatment secondary winding 2 and the harmonic treatment primary winding 3 are arranged radially along the core 1 from the inside to the outside.

[0032] Preferably, the rectification winding 8 and the harmonic treatment winding 9 are arranged axially along the core 1, and the harmonic treatment winding 9 is located above the rectification winding 8.

[0033] Preferably, the network side primary winding is connected in a delta (D) connection. High harmonic currents in the field current, dominated by 3nth harmonic, can form a loop current in the network side primary winding when the network side primary winding is connected in a delta (D) connection, and will not be injected into the common high voltage network. If the network side power grid contains 3nth harmonic, the 3nth harmonic will still form a loop current in the triangle, making the magnetic flux a sine wave, and the valve side electromotive force and current are also sine waves. The 3nth harmonic current will not appear in the load, realizing the circulation of 3nth harmonic. Therefore, compared with the prior art network side primary winding connected in a star (Y) connection, it is beneficial to suppress high harmonic currents, reduce power loss of the transformer, and ensure the quality of the power supply waveform.

[0034] Preferably, the network side primary winding includes at least two network side primary split windings, and the valve side secondary winding includes at least two valve side secondary split windings, each valve side secondary split winding corresponding to each network side primary split winding, wherein each network side primary split winding, harmonic control primary winding 3 is connected in parallel, and each valve side secondary split winding, harmonic control secondary winding 2 is electrically independent.

[0035] Specifically, the network side primary split winding in the embodiment includes a first network side primary split winding 4 and a second network side primary split winding 7, and the valve side secondary split winding includes a first valve side secondary split winding 6 corresponding to the first network side primary split winding 4 and a second valve side secondary split winding 5 corresponding to the second network side primary split winding 7, as shown in Figure 4 , wherein the primary winding has three branches, the first network side primary split winding 4, the second network side primary split winding 7, and the harmonic control primary winding 3 are connected in parallel, as shown in Figure 5 , the secondary winding has three outputs, the first valve side secondary split winding 6, the second valve side secondary split winding 5, and the harmonic control secondary winding 2 are electrically independent. The first valve side secondary split winding 6, the second valve side secondary split winding 5, and the harmonic control secondary winding 2 are not connected electrically. Specifically, the transformer in the embodiment is a 12-pulse 6-phase rectifier transformer. Of course, the transformer can be provided with four network side primary split windings to realize a 24-pulse 12-phase rectifier transformer.

[0036] The two groups of valve side secondary split windings for rectification are not adjusted simultaneously, but are independently adjusted. That is, the two groups of valve side secondary split windings for rectification can work independently or simultaneously without interfering with each other.

[0037] Preferably, each valve side secondary split winding is arranged axially along the core 1, and each network side primary split winding is arranged axially along the core 1.

[0038] Specifically, the first valve-side secondary split winding 6 and the first network-side primary split winding 4 are radially arranged along the core 1 from inside to outside, and the second valve-side secondary split winding 5 and the second network-side primary split winding 7 are radially arranged along the core 1 from inside to outside; the first valve-side secondary split winding 6 and the second valve-side secondary split winding 5 are axially arranged along the core 1, and the first network-side primary split winding 4 and the second network-side primary split winding 7 are axially arranged along the core 1; the first valve-side secondary split winding 6 is located above the second valve-side secondary split winding 5, and the first network-side primary split winding 4 is located above the second network-side primary split winding 7.

[0039] Preferably, the valve-side secondary split windings are even in number, and half of the valve-side secondary split windings are connected in star (y) and the remaining valve-side secondary split windings are connected in delta (d) so that the line voltage effective values of the valve-side secondary split windings connected in star are equal to those of the valve-side secondary split windings connected in delta, and the harmonic control secondary windings 2 are connected in star (y). Therefore, when the number of turns of the valve-side secondary split winding coils is selected, the ratio of the number of turns of the two groups of coils should be close to to meet the requirements of the industry standard for valve-side voltage and to reduce the circulating current between the two groups of valve-side secondary split windings as much as possible.

[0040] Specifically, in the embodiment, the first valve-side secondary split winding 6 is connected in star (y), the second valve-side secondary split winding 5 is connected in delta (d), and the outputs of the two groups are rectified so that the line voltage effective values of the first valve-side secondary split winding 6 and the second valve-side secondary split winding 5 are equal, and the harmonic control secondary windings 2 are connected in star (y) for harmonic control. Therefore, when the number of turns of the valve-side secondary split winding coils is selected, the ratio of the number of turns of the first valve-side secondary split winding 6 and the second valve-side secondary split winding 5 should be close to to meet the requirements of the industry standard for valve-side voltage and to reduce the circulating current between the two groups of valve-side secondary split windings as much as possible.

[0041] Preferably, the phase difference of the line voltage of the valve-side secondary split winding is 2π / 12 (30° in electrical angle), which realizes input multiplexing, forming a 6-phase rectification system containing 12 pulses per cycle.

[0042] The line voltage of the valve-side secondary split winding refers to the voltage between two phases with the same name on different sides of the valve-side secondary split winding, such as: the output line voltage Ua2b2 of the second valve-side secondary split winding 5 corresponds to the output line voltage Ua3b3 of the first valve-side secondary split winding 6, which is the line voltage of the same name; the output line voltage Ua2c2 of the second valve-side secondary split winding 5 corresponds to the output line voltage Ua3c3 of the first valve-side secondary split winding 6; and the output line voltage Ub2c2 of the second valve-side secondary split winding 5 corresponds to the output line voltage Ub3c3 of the first valve-side secondary split winding 6.

[0043] The harmonic management winding 9 can be calculated by the impedance between the conventional transformer windings through the relevant arrangement, and the short-circuit reactance X is calculated according to the following formula:

[0044]

[0045] In the formula, IW is the ampere-turns of the harmonic management winding, ΣDr is the equivalent area of the leakage magnetic flux of the harmonic management winding (cm2), ρ is the Lo's coefficient, Kx is the reactance correction coefficient, Et is the turn potential (V / turn), and Hk is the average reactance height of the two windings of the harmonic management winding (cm).

[0046] Wherein, ΣDr is proportional to the distance between the windings, which has a much greater impact on the short-circuit reactance X than ρ and Kx. When designing the rectifier and harmonic management transformer, the formula can be realized by adjusting the distance between the windings and other parameters (IW, Et, Hk, etc.) (see the Design Manual of Power Transformer for details).

[0047] Preferably, the number of splits of the network side primary split winding and the valve side secondary split winding corresponds to the reactance height.

[0048] The capacity and height of the harmonic management primary winding 3 and the harmonic management secondary winding 2 are designed to be approximately zero in terms of equivalent impedance, so as to balance the local ampere-turns and effectively reduce the problem of impedance mismatch caused by the difference in leakage reactance due to the structure of the windings, i.e., the position difference of the windings, which leads to circulating current heating and the like. That is, the first valve side secondary split winding 6 and the second valve side secondary split winding 5 can carry different amounts of loads, and the load adjustment is not simultaneous and synchronized, but independent. That is, the rectifier loads of the first valve side secondary split winding 6 and the second valve side secondary split winding 5 can work independently or simultaneously, without interference and influence.

[0049] Preferably, the core 1 is made of high-permeability cold-rolled grain-oriented silicon steel, the lamination mode of the core 1 is 45° full-inclined five-level stepping lamination, the core 1 is a non-perforated screw core, and the core 1 is fixed by using a pull plate and binding structure, which effectively reduces the no-load current, excitation current, hysteresis loss and noise.

[0050] Preferably, the capacity of the harmonic management winding 9 is 25-30% of the total capacity of the transformer. The equivalent impedance of the harmonic management winding 9 is designed to be approximately zero. Therefore, the equivalent impedance of any harmonic is also zero, which can be realized by reasonably adjusting the structure and layout of each winding of the transformer, so as to ensure that the impedance of each harmonic is substantially zero, and thus good filtering effect can be achieved.

[0051] The rectifying and harmonic governing transformer of the embodiment has the following advantages: the harmonic governing winding 9 can eliminate about 10% of the non-characteristic harmonic currents of 5th, 7th, 17th and 19th orders in the AC network side of the rectifying device, so there is no need to connect various types of filters on the valve side bus of the transformer with rectifying function or use two six-phase twelve-pulse rectifying transformers in parallel output to be twelve-phase twenty-four-pulse (i.e. increase the pulse number) and other methods, thereby reducing the floor area of the transformer with rectifying function and the overall project cost. The embodiment combines the rectifying and harmonic eliminating functions into one transformer, which greatly reduces the manufacturing and using costs, especially the multiple split windings are distributed on the same core 1, which improves the utilization rate of the core 1, reduces the loss of the transformer and has significant economic benefits; at the same time, the construction amount of civil engineering is greatly reduced, the construction period is accelerated and the cost is reduced; the rectifying transformer can reduce the harmonic content, improve the power supply quality of the power grid system, and the application of the scheme improves the system efficiency and reliability and also brings huge economic benefits.

[0052] The rectifying and harmonic governing transformer of the embodiment is an environmentally friendly and energy-saving product, which has the characteristics of strong heat shock resistance, large overload capacity, non-combustible resin, difficult to burn, strong emergency overload capacity, convenient repair and maintenance, not sensitive to humidity and dust, no cracking, safe and reliable performance, and is especially suitable for use in harsh environments with large load fluctuation range and dirty and humid conditions.

[0053] It can be understood that the above embodiments are only exemplary embodiments for illustrating the principles of the present application, and the present application is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and essence of the present application, and these modifications and improvements are also considered to be within the protection scope of the present application.

Claims

1. A rectifier and harmonic management transformer, characterized by, The application relates to a transformer, which comprises an iron core, a rectification winding for rectification wound on the iron core, a harmonic management winding for harmonic management, the rectification winding and the harmonic management winding are arranged axially along the iron core, the rectification winding is concentrically arranged with the iron core, the harmonic management winding is concentrically arranged with the iron core, the harmonic management winding is located above the rectification winding, the rectification winding comprises a grid-side primary winding and a valve-side secondary winding corresponding to the grid-side primary winding, the grid-side primary winding is connected in an angle shape to form a triangle, the harmonic management winding comprises a harmonic management primary winding and a harmonic management secondary winding corresponding to the harmonic management primary winding, the grid-side primary winding comprises at least two grid-side primary split windings, the valve-side secondary winding comprises at least two valve-side secondary split windings, each valve-side secondary split winding corresponds to each grid-side primary split winding, wherein each grid-side primary split winding and the harmonic management primary winding are connected in parallel, each valve-side secondary split winding and the harmonic management secondary winding are independent of each other in electricity, the valve-side secondary split windings are even in number, half of the valve-side secondary split windings are connected in a star shape, the other valve-side secondary split windings are connected in an angle shape, the line voltage effective value of the valve-side secondary split windings connected in the star shape is equal to that of the valve-side secondary split windings connected in the angle shape, the harmonic management secondary winding is connected in a star shape, and the phase difference of the line voltage of the same name end of the valve-side secondary split winding is 2pi / 12. The valve-side secondary winding and the grid-side primary winding are arranged radially from inside to outside along the iron core, and the harmonic management secondary winding and the harmonic management primary winding are arranged radially from inside to outside along the iron core.

2. The rectification and harmonic management transformer of claim 1, wherein, Each valve-side secondary split winding is arranged axially along the iron core, and each grid-side primary split winding is arranged axially along the iron core.

3. The rectification and harmonic management transformer of claim 1, wherein, The number and reactance height of the grid-side primary split winding and the valve-side secondary split winding correspond to each other.

4. The rectification and harmonic management transformer of claim 1, wherein, The iron core is made of high-permeability cold-rolled grain-oriented silicon steel, the lamination mode of the iron core is 45-degree full-inclined five-stage stepping lamination, the iron core is a non-perforated screw iron core, and the iron core is fixed by means of a pull plate and binding structure.

5. The rectifier and harmonic management transformer of any one of claims 1-4, wherein, The capacity of the harmonic management winding is 25-30% of the total capacity of the transformer.

6. The rectifier and harmonic management transformer of any one of claims 1-4, wherein, ​

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