RU2137237C1 - Three-phase high-voltage transformer with voltage control for supply of 12-phase rectifier-inverter aggregate - Google Patents

Abstract

FIELD: rectifier-inverter aggregates. SUBSTANCE: network and valve windings are put on concentration centers. Each of them occupies two concentration centers located side by side. Half of parts of valve winding are Y-connected and each part of second half includes delta-connected section. EFFECT: increased efficiency, improved mass and size characteristics and reduced coefficient of nonsinusoidality of voltage of supply network. 5 dwg

Description

 The invention relates to the field of electrical engineering, namely to transformers operating on rectifier-inverter units.

 Known three-phase transformer with voltage regulation for supplying a 12-phase rectifier-inverter unit, containing a magnetic rod system, three-phase network and valve windings located on three concentrates on the rods of the magnetic system, while the network winding having adjustment sections is located on one concentrator, and the valve winding is divided into four electrically unconnected parts, two of which are connected according to the "star" scheme, and the other two - according to the "triangle" scheme, one part, connections in the "star" do "and one part connected in a" triangle "are intertwined on an inner concentrator and are designed to power a 12-phase rectifier; one part connected to a "star" and one part connected to a "triangle" are located on the third concentrator floor and are designed to power a 12-phase inverter, while the number of turns of the parts intended to power the inverter>: 15% higher than the number of turns similar parts designed to power the rectifier [1].

 The described technical solution is characterized by a double number of parts of the valve coil, since half of these parts are used for rectifier operation, and the other half for inverter operation. The double power of the parts of the valve winding leads to a large consumption of materials in the transformer.

 Closest to the claimed is a three-phase transformer with voltage regulation, designed to power the rectifier-inverter unit, containing a rod magnetic system, three-phase network and valve windings located on four concentrates on the rods of the magnetic system, while the network winding consists of two sections connected in series and each of the sections of the network winding is located on a separate concentrate, and the valve winding is divided into electrically unconnected parts, each of the cat ryh is made of sections, while on one of the concentrates of the valve winding there are one section of each part of it, and on the other, the remaining sections of each of the parts of the valve coil and sections of the parts located on one concentrate are connected in series with sections of the parts located on the other a concentrate, the concentrates being arranged in such a way that between the concentrates on which the sections of one winding are located, at least one section of the other winding is located [2].

 Based on the described technical solution, a transformer for an inverter-rectifier unit can be created in which each part of the valve winding operates in both the rectifier and inverter modes.

 The disadvantages of the solution are as follows.

 The alternation of the concentrates of the network and valve windings at high voltage levels of the supply network leads to a significant decrease in the fill factor of the window of the magnetic system with conductive material, which is why the transformer is characterized by insufficiently high mass and dimensional indicators and a reduced efficiency.

 Connecting the rectifier to the ends of the sections located on one concentrate, and the inverter to the ends of the sections located on another concentrator, allows you to have a voltage increased by 10-20% in comparison with the rectifier (which is necessary for operation).

 However, with the known schemes for connecting parts and sections of valve windings, it is not possible to provide a phase shift of 30 electrical degrees between the parts on the inverter and rectifier inputs of the transformer. Therefore, the 12-phase conversion mode in the inverter and in the rectifier is unattainable. Thus, the coefficient of non-sinusoidality of the supply voltage will be large.

 The aim of this invention is to remedy these disadvantages, namely: increasing efficiency, improving overall dimensions and reducing the coefficient of non-sinusoidality of the voltage of the supply network.

 This goal is achieved by the fact that in a three-phase high-voltage transformer with voltage regulation for supplying a 12-phase rectifier-inverter unit containing a rod magnetic system, three-phase network and valve windings located on four concentrates on the rods of the magnetic system, while the network winding consists of two sections connected in series, and each of the sections of the network winding is located on a separate concentrate, and the valve winding is divided into electrically unconnected parts, each of which it is made of sections, with one section of each valve part being located on one of the concentrates of the valve coil, and the other sections of each of the parts of the valve coil and the sections of parts located on one concentrator are connected in series with the sections of the parts located on the other on another concentrator, it is SUGGESTED that the concentrators belonging to one winding be placed next to each other, half of the parts of the valve winding should be connected according to the "star" scheme, the other half of the parts should be connected with such a connection scheme, in which nd its section situated at one concentration, is connected in a "delta" so that beginning of its phase section with the number n is coupled with the end section with the phase number m; the beginning of the same phase section with number n is connected to an electric circuit formed by two equally rotationally opposed phase sections with numbers n and m located on the other concentrate, each of the parts being made with two three-phase groups of inputs, each of the parts connected according to the "star" scheme, connect the beginning of one of its sections to one three-phase group of inputs, and the beginning of its other section to the other, and connect a section to each three-phase group of inputs to one three-phase group of inputs ju, connected in a "triangle", and to another three-phase group of inputs - another section, moreover, one of the sections of the network winding should be executed with adjusting tap, where n and m - phase numbers can take the values 1, 2, 3, and n ≠ m.

 The need and sufficiency of these distinctive features to achieve the goal is confirmed by the following.

 The location of the concentrators belonging to one winding next to each other minimizes the number of channels between the concentrators, designed for the full voltage of the supply network. Thus, the fill factor of the magnetic system window with a conductor material is increased, the efficiency is increased, and the overall dimensions of the transformer are improved.

 The connection diagrams of the valve coil parts and phase sections stipulated above, together with the specification of connecting the groups of transformer inputs, provided that the number of turns in the sections is equal, the phase voltage angles between the input groups of each part can be reached at 30 electrical degrees and the required voltage difference for the inverter and a rectifier component of 10-20%.

 The implementation of one of the sections of the network winding with adjusting tap allows you to provide the necessary regulation of the output voltage of the transformer.

 In the future, the essence of the invention is illustrated by an example implementation.

 In FIG. 1 shows a three-phase transformer 1 containing a magnetic system 2 with rods 3, 4, 5, a three-phase network winding 6, and a three-phase valve winding 7. The network winding 6 consists of two sections 8 and 9 connected in series. The valve winding 7 is divided into two electrically unconnected parts 10 and 11. Part 10 is made of sections 12 and 13, and part 11 is made of sections 14, 15, 16. Section 14 consists of three sections of phases 17, 18, 19 located respectively on the rods 3, 4, 5 of the magnetic system 2. Section 15 consists of three sections of phases 20, 21, 22, located respectively on rods 3, 4, 5. Section 16 consists of three sections of phases 23, 24, 25 located respectively on rods 3, 4, 5. Sections 12 and 13 of part 10 are connected in series with each other. Sections 14, 15, 16 of part 11 are interconnected in series. Part 10 has a star connection diagram. Section 14 of part 11 is connected in a triangle pattern. At the same time, the beginning of its phase 19 section (in Fig. 1 the beginning of each phase section above, the end below) located on the third rod (n = 3), is connected to the end of the phase 17 section located on the first rod (m = 1). At the same time, the beginning of the phase 19 section is connected to an electric circuit formed by phase sections 22 and 23 located on the third and first rods (n = 3, m = 1), respectively. These sections of the phases 22 and 23 have equal numbers of turns and are interconnected in series in the opposite direction.

 Part 10 is connected to two three-phase groups of inputs 26 and 27, and part 11 is connected to two three-phase groups of inputs 28 and 29. Section 9 of the network winding is equipped with adjustment tap.

 In FIG. 2 shows the location of the phase sections located on the rod 5 of the magnetic system. As seen in FIG. 2, winding sections and parts are located on four concentrates. On the first concentrator from the rod 5, sections of the phases 22 and 25 of the sections 15 and 16 of the valve winding part 7, respectively, are wound into each other (the phase sections 22 and 25 have equal numbers of turns), and the phase section of the section 13 of the part 10 of the valve coil 7 .

 On the second concentrate from the rod 5, there is a section of the phase 19 of the section 14 of part 11 of the valve coil 7 and a phase section of the section 12 of part 10 of the valve coil 7. Thus, in the second from the rod concentrate, there is one section of each part of the valve coil 7, namely: 14 of part 11 and section 12 of part 10. And on the first concentrator from the rod, the remaining sections of each part of the valve winding 7 are located, namely: sections 15, 16 of part 11 and section 13 of part 10.

 Structurally, the phase sections located on the second concentrate are designed so that the magnetic coupling between them is strong.

 On the third from the rod 5 concentrator is a phase section of section 8 of the network winding 6.

 On the fourth from the rod 5 concentrate is a phase section of section 9 of the network winding 6.

 Similarly located sections of the phases of the windings on the rods 3 and 4 of the magnetic system 2.

 Thus, section 8 of the network winding 6 is located on the third concentrate, and section 9 of the network winding 6 is located on the fourth concentrate.

 Thus, it follows from the above arrangement of sections that sections of the valve coil are located on the first and second concentrates, and sections of the network coil are located on the third and fourth concentrates. It follows that the concentrates 1, 2, located next to each other, belong to the valve winding, and the concentrates 3, 4 located next to each other belong to the network winding. The group of inputs 26, 27, 28, 29 are connected with parts 10 and 11 of the valve coil 7 as follows.

 The group of inputs 26 of the part 10 of the valve coil 7 is connected to the beginnings of the section 12 located on the second from the rod concentrate, and the group of inputs 27 of the same part is connected to the beginnings of the section 13 located on the first from the rod concentrate.

 The group of inputs 28 of the part 11 of the valve coil 7 is connected to the beginning of the section 14 located on the second from the rod concentrate, and the group of inputs 29 of the same part of the valve coil is connected to the ends of the sections of the phases 23, 24, 25 of the section 16 located on the first from the rod of the concentrate.

 The described design has only one between the high and low voltage windings (in the prototype 3 channels). The presence of only one channel with a large potential difference leads to good transformer mass and dimensions, a low level of energy loss in it and a high efficiency.

_BA,

_CB,

_AC сетевой обмотки 6;
б)

_B3a3,

_c3b3,

_a3c3,

_b4a4,

_c4b4,

_a4c4 на группах вводов 26, 27 части 10 вентильной обмотки 7;
в)

_b1c₁,

_c1b1,

_a1c1,

_b2c2,

_c2b2,

_a2c2 на группах вводов 28, 29 части 11 вентильной обмотки 7;
Как видно из диаграмм 3а и 3б, с учетом равенства витков в секциях 15, 16 части 11 на каждой из групп вводов 28, 29 части 11 линейные напряжения сдвинуты по фазе относительно линейных напряжений на группах вводов 26, 27 части 10 равно на 30 эл. градусов.In FIG. 3 shows vector diagrams of linear stresses:
a)

_BA ,

_CB

_AC network winding 6;
b)

_B3a3 ,

_c3b3 ,

_a3c3 ,

_b4a4 ,

_c4b4 ,

_a4c4 on input groups 26, 27 of part 10 of the valve coil 7;
in)

_b1 c ₁ ,

_c1b1 ,

_a1c1 ,

_b2c2 ,

_c2b2 ,

_a2c2 on the input groups 28, 29 of part 11 of the valve coil 7;
As can be seen from diagrams 3a and 3b, taking into account the equality of turns in sections 15, 16 of part 11 on each of the groups of inputs 28, 29 of part 11, the linear voltages are out-of-phase with respect to the linear voltages on the groups of inputs 26, 27 of part 10 and are equal to 30 e. degrees.

 Thus, when powered from the groups of inputs 26 and 28 of the rectifier, it will have a 12-phase rectification mode taking into account the phase shift of the voltages.

 Similarly, when powered from input groups 27 and 29 of the inverter (for the inverter, a slightly higher voltage of the transformer windings is required than for the rectifier), the inverter will also operate in 12-phase mode.

 Providing a 12-phase mode both during operation of the inverter and during operation of the rectifier, it is possible to provide a low level of output of higher harmonious currents to the supply network and thereby have a reduced value of the coefficient of non-sinusoidality of the supply voltage.

 The effect of using this invention will consist in the fact that when performing transformers on Russian railways with direct current in accordance with the stated solution, a transition will be made from a two-stage transformation to a single-stage.

 Currently, DC substations of railways have step-down transformers with a voltage of 110 kV for a voltage of 35 or 10 kV, and converter transformers with separate windings for the rectifier and separate windings for the inverter are connected to these transformers. With such solutions, it is impossible to achieve a one-step transformation, i.e. converter transformer power directly from the high voltage network. The impossibility is due to the fact that a large number of parts of the valve winding at high voltage levels of the supply network, taking into account the need to provide the necessary short-circuit voltages windings, requires even greater costs than the provision of two-stage transformation.

 Thus, the claimed technical solution will allow 2 times to reduce the number of transformers and to reduce due to this capital costs at the converter substations of the railways.

 1. Transformer TRDTP-20000 / 35I. Dimensional installation drawing of the UPS. 672434.041-01GH.

 2. A.S. USSR N 1020872, H 01 F 27/28, 1983

Claims (1)

 A three-phase high-voltage transformer with voltage regulation for supplying a 12-phase rectifier-inverter unit, containing a rod magnetic system, three-phase network and valve windings located on four concentrates on the rods of the magnetic system, while the network winding consists of two sections connected in series, and each of sections of the network winding is located on a separate concentrate, and the valve winding is divided into electrically non-connected parts, each of which is made of sections, while m on one of the concentrates of the valve coil are located one section of each of its parts, and on the other - the remaining sections of each of the parts of the valve coil, and sections of the parts located on one concentrate are connected in series with sections of the parts located on the other concentrate, characterized in that the concentrators belonging to one winding are located next to each other, half of the parts of the valve winding are connected according to the star pattern, and each of the other half of the parts has a section located on one concentrate and connected by about the "triangle" circuit so that the beginning of its phase section with number n is connected to the end of the phase section with number m, the beginning of the same phase section with number n is connected to an electric circuit formed by two equally rotational in series counter-connected phase sections with numbers n and m, located on another concentrate, each of the parts is made with two three-phase groups of inputs, with each of the parts connected according to the "star" scheme, to one three-phase group of inputs connected to the beginning of one of its sections, and to the other - the beginning of its other with sections, and in each of the parts with a different connection scheme, a section connected to a “triangle” is connected to one three-phase group of inputs, and another section is connected to another three-phase group of inputs, and one of the sections of the network winding is made with adjusting tapes, where m and n - phase numbers can take the values 1, 2, 3, moreover, m ≠ n.

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