A transformer voltage regulating lead structure based on vacuum switch

Abstract

The present invention provides a transformer voltage regulating lead structure based on a vacuum switch, comprising a column I, a column II, a vacuum switch, and a first voltage regulating coil and a second voltage regulating coil respectively arranged on the column I and the column II, wherein the upper and lower ends of the first voltage regulating coil and the second voltage regulating coil are respectively connected to the vacuum switch by connecting a voltage regulating lead. Compared with the prior art, the present invention can meet the switch carrying current, has a suitable insulation distance and a reasonable insulation margin, and has a small volume structure, thereby reducing production and transportation costs.

Description

Technical Field

[0001] The invention relates to the technical field of transformers, and in particular to a transformer voltage regulating lead structure based on a vacuum switch. Background Art

[0002] The voltage regulation mode of converter transformers in the currently operating and under-construction UHV DC transmission projects is on-load voltage regulation, the voltage regulation position is the grid-side neutral point, and the insulation level requirement of the voltage regulation lead is LI185AC95kV. The converter transformer is usually a two-column structure, and the conventional structure of its voltage regulation lead is to use two groups of oil-immersed on-load tap-changers, each group of on-load tap-changers is equipped with two potential resistors, and each column of voltage regulation lead is connected to a group of on-load tap-changers. Figure 1 and Figure 2 As shown in the figure, the voltage regulating leads of the two columns of the converter transformer are led out from the upper and lower parts of the voltage regulating coil respectively. The leads of the voltage regulating leads of the two columns are arranged in two layers, upper and lower, so as to ensure the insulation distance and heat dissipation between the leads. The voltage regulating leads of the two columns enter a group of oil-immersed on-load tap-changers to complete the connection. Under the on-load tap-changer, the lower side beam of the iron core extends out of the bracket for support, which is the potential resistance configured by the switch.

[0003] Each column of the conventional structure of the converter transformer voltage regulating lead is connected to a group of on-load tap changers, with clear wiring principle and simple structure. The insulation distance requirements between the voltage regulating leads and between the voltage regulating leads and the surrounding structural parts are fully met, and the electrical performance is highly reliable. However, there are the following problems:

[0004] (1) In the conventional converter transformer lead structure, each group of on-load tap changers is equipped with two potential resistors, which are large in size and require special bracket support;

[0005] (2) In the conventional converter transformer lead structure, the distance between the side yoke and the inner wall of the oil tank in the long axis direction is large, and the amount of transformer oil and steel is large;

[0006] (3) The insulation distance and insulation margin in the lead structure of conventional converter transformers are unreasonable. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to propose a transformer voltage regulating lead structure based on a vacuum switch. The invention can meet the switch carrying current, has a suitable insulation distance and a reasonable insulation margin, and has a small volume structure, thereby reducing production and transportation costs.

[0008] The purpose of the present invention can be achieved by the following technical solutions:

[0009] The present invention provides a transformer voltage regulating lead structure based on a vacuum switch, comprising an I column, a II column, a vacuum switch, and a first voltage regulating coil and a second voltage regulating coil respectively arranged on the I column and the II column, wherein the upper and lower ends of the first voltage regulating coil and the second voltage regulating coil are respectively connected to the vacuum switch by connecting a voltage regulating lead.

[0010] Preferably, the contacts at the upper and lower ends of the first voltage regulating coil and the second voltage regulating coil are respectively connected to a voltage regulating lead by cold pressing.

[0011] Preferably, the upper and lower ends of the first voltage regulating coil are connected to a first voltage regulating lead and a second voltage regulating lead respectively, and the first voltage regulating lead and the second voltage regulating lead are respectively routed along a column side close to the vacuum switch and connected to the vacuum switch.

[0012] Preferably, the protrusions at the upper and lower ends of the second voltage regulating coil are respectively connected to the third voltage regulating lead and the fourth voltage regulating lead, and the fourth voltage regulating lead is wound upward along a column side away from the vacuum switch to the upper end of the second voltage regulating coil and connected to the third voltage regulating lead, and is routed along the top of columns I and II to be connected to the vacuum switch.

[0013] Preferably, the vacuum switch is provided with an upper tap selector, a lower tap selector, an intermediate tap number terminal and a current outflow terminal terminal, the upper tap selector is connected to the first voltage regulating lead and the second voltage regulating lead, and the lower tap selector is connected to the third voltage regulating lead and the fourth voltage regulating lead.

[0014] Preferably, the I column and the II column are respectively provided with a first lightning arrester and a second lightning arrester, the first lightning arrester and the second lightning arrester are respectively led to the vacuum switch, the first lightning arrester and the first voltage regulating lead and the second voltage regulating lead are all connected to the upper tap selector, and the second lightning arrester and the third voltage regulating lead and the fourth voltage regulating lead are all connected to the lower tap selector.

[0015] Preferably, the upper tap selector and the lower tap selector are respectively provided with a group of plate potential resistors, the head end of each group of plate potential resistors is connected to the middle tap number terminal, and the end of each group of plate potential resistors is connected to the current outflow terminal terminal.

[0016] Preferably, all the voltage regulating leads are 185mm 2 , electrical density is 3.5A / mm 2 Lead cable.

[0017] Preferably, an insulating clamping plate for insulation and heat dissipation is provided between adjacent voltage regulating leads.

[0018] Preferably, when the voltage regulating leads are arranged in parallel, they are distributed in two layers, inner and outer.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The vacuum switch designed by the present invention has an upper tap selector and a lower tap selector respectively provided with a group of plate-type potential resistors, which are directly fixed on the vertical conductor clamps, and have a simpler structure and are easier to operate.

[0021] 2. The transformer voltage regulating lead structure based on the vacuum switch designed by the present invention has a side yoke that is relatively small in distance from the inner wall of the oil tank in the mid-long axis direction, which saves transformer oil and steel usage to a certain extent.

[0022] 3. A transformer voltage regulating lead structure based on a vacuum switch designed by the present invention adopts an inner and outer two-layer arrangement when the voltage regulating leads are parallel, thereby ensuring the insulation distance and heat dissipation between adjacent voltage regulating leads, and an insulating clamping plate for insulation and heat dissipation is provided between adjacent voltage regulating leads, so that the present invention meets the switch carrying current, has a suitable insulation distance and a reasonable insulation margin. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is the front view of the conventional structure schematic diagram of the voltage regulating lead wire of the converter transformer;

[0024] Figure 2 It is a top view of the conventional structure schematic diagram of the voltage regulating lead wire of the converter transformer;

[0025] Figure 3 A top view of a schematic diagram of a voltage regulating lead structure based on a vacuum switch in this embodiment;

[0026] Figure 4 This is a front view of a schematic diagram of a voltage regulating lead structure based on a vacuum switch in this embodiment;

[0027] Figure 5 This is a left view of a schematic diagram of a voltage regulating lead structure based on a vacuum switch in this embodiment;

[0028] Figure 6 This is a wiring schematic diagram of a vacuum switch based on a voltage regulating lead structure of a vacuum switch in this embodiment;

[0029] Figure 7 It is a schematic diagram of the conventional structure of the voltage regulating lead of the converter transformer - the distance from the side yoke to the box wall;

[0030] Figure 8 This is a schematic diagram of a voltage regulating lead structure based on a vacuum switch - the distance from the side yoke to the box wall in this embodiment;

[0031] Marked in the figure are: 11, I column, 12, II column, 21, first voltage regulating coil, 22, second voltage regulating coil, 3, vacuum switch, 41, first voltage regulating lead, 42, second voltage regulating lead, 43, third voltage regulating lead and 44, fourth voltage regulating lead. DETAILED DESCRIPTION

[0032] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0033] refer to Figure 3 and Figure 4 As shown, this embodiment provides a transformer voltage regulating lead structure based on a vacuum switch, including an I column 11, a II column 12, a first voltage regulating coil 21, a second voltage regulating coil 22, a vacuum switch 3, a first voltage regulating lead 41, a second voltage regulating lead 42, a third voltage regulating lead 43 and a fourth voltage regulating lead 44.

[0034] The I column 11 and the II column 12 are respectively provided with a first voltage regulating coil 21 and a second voltage regulating coil 22 in a spiral shape. The upper end and the lower end of the first voltage regulating coil 21 are respectively connected to the first voltage regulating lead 41 and the second voltage regulating lead 42. The first voltage regulating lead 41 and the second voltage regulating lead 42 are respectively routed and connected to the vacuum switch 3 through a three-way handle; the upper end and the lower end of the second voltage regulating coil 22 are respectively connected to the third voltage regulating lead 43 and the fourth voltage regulating lead 44. The fourth voltage regulating lead 44 is wound upward along a column side away from the vacuum switch 3 to the upper end of the second voltage regulating coil 22, connected to the third voltage regulating lead 43, and routed along the top of the I column 11 and the II column 12 through a three-way handle to connect to the vacuum switch 3. When adjacent voltage regulating leads are parallel, an inner and outer two-layer arrangement is adopted to ensure the insulation distance and heat dissipation between adjacent voltage regulating leads. All voltage regulating leads are 185mm 2 Lead cable, electrical density is about 3.5A / mm 2 An insulating clamping plate for insulation and heat dissipation is provided between adjacent voltage regulating leads.

[0035] The neutral point lead wire is a combination of copper rod and copper stranded wire. The rigid copper rod is used for clamping to ensure mechanical properties, and the tough copper stranded wire is convenient for adjustment during lead assembly and to prevent the switch from being stressed when lifting the switch. It has sufficient rigidity to ensure good stress, and has sufficient toughness to facilitate adjustment during assembly.

[0036] All voltage regulating leads are arranged vertically to save space.

[0037] refer to Figure 6As shown, the vacuum switch 3 adopts the VRGⅡ type of the German MR company. The vacuum switch 3 is provided with an upper tap selector and a lower tap selector. The upper tap selector is connected to the first voltage regulating lead 41 and the second voltage regulating lead 42, and the lower tap selector is connected to the third voltage regulating lead 43 and the fourth voltage regulating lead 44. All the voltage regulating leads enter the first layer of the vacuum switch 3 to complete the connection. The first lightning arrester and the second lightning arrester are respectively provided with the I column 11 and the II column 12. The first lightning arrester and the second lightning arrester are respectively connected through 50mm 2 The lead cable is led to the vacuum switch 3, the first lightning arrester is connected to the upper tap selector together with the first voltage regulating lead 41 and the second voltage regulating lead 42, and the second lightning arrester is connected to the lower tap selector together with the third voltage regulating lead 43 and the fourth voltage regulating lead 44. Figure 5 As shown, the upper tap selector and the lower tap selector are respectively provided with a group of plate-type potential resistors, which are directly fixed on the vertical conductor clamps. The head end of each group of plate-type potential resistors is connected to the middle tap number terminal of the vacuum switch 3, and the end of each group of potential resistors is connected to the current outflow terminal terminal of the vacuum switch 3 to complete the potential resistor function.

[0038] Since the arc of the vacuum switch is extinguished in the sealed vacuum bubble during the switching process, it is different from the oil-immersed switch which uses insulating oil as the arc extinguishing medium. Compared with the oil-immersed switch, the obvious advantages of the vacuum switch are as follows:

[0039] ① Long contact life. Compared with insulating oil, vacuum has better insulation performance, so vacuum interrupters only need a small contact gap, so the arc length is short, the arc extinguishing time is short, the contact wear is less, and the contact life is greatly extended.

[0040] ② No oil carbonization. Since the arc is extinguished in the fully enclosed vacuum interrupter during the vacuum switching process, and the insulating oil in the switch is not needed to directly extinguish the arc, the oil in the tap changer oil chamber will not carbonize, which increases the reliability of arc extinguishing.

[0041] ③ Long maintenance interval. Due to the above two advantages of the vacuum switch, the number of maintenance-free operations is greatly increased compared with the oil-immersed switch, reaching 300,000 times, which greatly reduces the transformer power outage time and its maintenance and maintenance costs, reduces the safety hazards in the maintenance process, and extends the maintenance cycle. It can even achieve maintenance-free vacuum switches within the full life cycle of the transformer.

[0042] The assembly and wiring process of a transformer voltage regulating lead structure based on a vacuum switch provided in this embodiment is as follows:

[0043] The voltage regulating lead wires are assembled according to the designed voltage regulating lead wire structure. First, all the voltage regulating lead wire clamps are assembled to the device body according to the designed structure. Most of the wire clamps adopt standardized design, and 20mm thick laminated paperboard is selected and 22mm diameter through holes are punched every 100mm. The wire clamps are fastened with M20 laminated wood insulating screws and insulating nuts. Then all the voltage regulating lead cables are assembled to the wire clamps according to the designed structure for clamping, and the connection with the voltage regulating coil outlet is completed, and the connection is all cold-pressed. Then the vacuum switch 3 is assembled to the designed position, and the voltage regulating lead cable is connected to the vacuum switch 3. The specific wiring process is as follows:

[0044] (1) Lead preparation

[0045] During the acceptance inspection of the previous process before starting work, focus on checking whether the markings of each branch line are complete.

[0046] Before wiring, the drawing designer, process manager, quality specialist, assembly workshop technicians, team leaders and key personnel will discuss and formulate the wiring method based on the drawings and process-related requirements. Subsequent products will be routed strictly in accordance with the unified method.

[0047] (2) Use a spirit level to measure the levelness of the switch support plate, and use a laser ruler to measure the height from the switch support plate to the bottom surface of the clamp to see if it meets the requirements of the drawing.

[0048] (3) Hoist the vacuum switch 3 onto the switch support plate according to the drawing requirements, make a special tooling pad according to the size of the switch support plate, and temporarily pad the vacuum switch 3 by 15 mm to the height consistent with the drawing size. Position the vacuum switch 3 according to the size from the center of the vacuum switch 3 to the center line of the I column 11, and fix the vacuum switch 3 with bolts to prevent the switch from tipping over.

[0049] (4) Fix the wire clamp on the corresponding limb of the clamp, install the insulating screw and nut to fix it without tightening it, and check against the drawing to confirm that everything is correct.

[0050] (5) The length of the voltage regulating lead should be cut according to the length required by the drawing. When cutting, turn on the vacuum cleaner and use the material box to receive the lower part.

[0051] (6) When measuring the lead length of the voltage regulating lead, a certain arc should be maintained so that the voltage regulating lead has sufficient expansion margin to avoid damage to the vacuum switch 3 due to force. Each lead must have a certain arc transition when turning and cannot be bent into a right angle. The bending radius must be greater than or equal to 30mm.

[0052] (7) Arrange the leads on the side of the vacuum switch 3, ensuring that each voltage regulating lead has a certain arc transition with the insulating column of the vacuum switch 3 and cannot be bent into a right angle; arrange the leads on the side of the I column 11 and the II column 12, and the connection part is at the bottom of the lightning arrester.

[0053] (8) At the bend of the voltage regulating lead, remove the insulation and re-wrap it in a single layer and half fold it to ensure there are no gaps and the wrapping is tight and smooth.

[0054] (9) Direct hand contact is not allowed during the assembly of the arrester. Gloves must be worn during installation and inspection. The arrester must be installed between the voltage regulating lead poles, and the minimum insulation distance from the tap lead is 150mm. The arrester number corresponds to the voltage regulating lead number one by one, and the connection method is cold pressing.

[0055] (10) The transition resistor lead of the vacuum switch 3 is connected to the switch terminal position.

[0056] (11) If the tap difference between the same phase of the voltage regulating lead wire is greater than 8 taps, the insulation distance shall be greater than 25mm; the insulation distance between the different phase tap wires shall be greater than 40mm.

[0057] (12) After the voltage regulating lead is connected, use a special pen for ultra-high voltage to mark the tapping number on the surface of the voltage regulating lead. Each voltage regulating lead should be marked at least twice.

[0058] (13) The neutral point lead is formed by cold-pressing a copper rod and a copper stranded wire, and the position is determined according to the size of the center of the lead to the center line of the I column 11.

[0059] (14) The 15mm support pad on the switch bracket must not be removed before the device is put into the tank.

[0060] (15) The terminal crimping area is made of two layers of semi-conductive crepe paper (46# carbon black paper), and the beginning and end of the semi-conductive paper should be at least 10 mm away from the insulating layer.

[0061] The insulation distance of a transformer voltage regulating lead structure based on a vacuum switch provided in this embodiment is shown in Table 1:

[0062] Lead wire and corresponding electrode name Minimum insulation distance (mm) Branch line - box wall, fuel tank aluminum shield, side column shield 70 Branch line-sharp angle (R ≥ 5mm) 55 Different column branch wire: same number / different number 0 / 25 Same column branch wire: No. difference ≤8 / >8 0 / 25 Branch wire - switch contacts on the same column: No. difference ≤8 / >8 20 / 35 Branch line-different column switch contact 35 Branch line - lightning arrester 150 Network side tail-other branch lines 60 Lightning arrester-box wall 150 Switch contact-box wall, side column shielding 100

[0063] refer to Figure 7 and Figure 8 As shown, in the conventional converter transformer lead structure, the distance between the side yoke and the inner wall of the oil tank in the medium and long axis direction is 1790 mm. In this embodiment, a transformer voltage regulating lead structure based on a vacuum switch is provided, in which the distance between the side yoke and the inner wall of the oil tank in the medium and long axis direction is 1260 mm. Under the same conditions, the length dimension of the converter transformer is reduced by 520 mm, which saves the transformer oil and steel consumption to a certain extent.

[0064] In the conventional converter transformer lead structure, each group of on-load tap changers is configured with two potential resistors, and the potential resistors are relatively large and require special brackets for support. The switch potential resistor in the transformer voltage regulating lead structure based on a vacuum switch provided in this embodiment is a plate-type structure with a relatively small volume. It only needs to be fixed on a vertical conductor clamp, and has a relatively simple structure and is easier to operate.

[0065] In the conventional converter transformer lead structure, a bracket for supporting two sets of on-load tap changers needs to be specially installed. The switch bracket is heavy and difficult to assemble on site. In the transformer voltage regulating lead structure based on a vacuum switch provided in this embodiment, the switch bracket is directly welded to the upper side beam of the core, and the structure is simple and easy to operate.

[0066] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A transformer voltage regulating lead structure based on a vacuum switch, characterized in that: It comprises an I column (11), a II column (12), a vacuum switch (3), and a first voltage regulating coil (21) and a second voltage regulating coil (22) respectively arranged on the I column (11) and the II column (12), wherein the upper and lower ends of the first voltage regulating coil (21) and the second voltage regulating coil (22) are respectively connected to the vacuum switch (3) by connecting a voltage regulating lead wire; The contacts at the upper and lower ends of the first voltage regulating coil (21) and the second voltage regulating coil (22) are respectively connected to a voltage regulating lead wire by cold pressing; The outlet ends of the upper and lower ends of the first voltage regulating coil (21) are respectively connected to a first voltage regulating lead (41) and a second voltage regulating lead (42); the first voltage regulating lead (41) and the second voltage regulating lead (42) are respectively routed along a column side close to the vacuum switch (3) and connected to the vacuum switch (3); The upper and lower ends of the second voltage regulating coil (22) are connected to a third voltage regulating lead (43) and a fourth voltage regulating lead (44) respectively; the fourth voltage regulating lead (44) is wound upward along a column side away from the vacuum switch (3) to the upper end of the second voltage regulating coil (22) and connected to the third voltage regulating lead (43); and is routed along the top of the I column (11) and the II column (12) and connected to the vacuum switch (3); The vacuum switch (3) is provided with an upper tap selector, a lower tap selector, an intermediate tap number terminal and a current outflow terminal terminal, the upper tap selector is connected to a first voltage regulating lead (41) and a second voltage regulating lead (42), and the lower tap selector is connected to a third voltage regulating lead (43) and a fourth voltage regulating lead (44); The upper tap selector and the lower tap selector are respectively provided with a group of plate-type potential resistors, the head end of each group of plate-type potential resistors is connected to the middle tap number terminal, and the end of each group of plate-type potential resistors is connected to the current outflow terminal terminal; An insulating clamping plate for insulation and heat dissipation is arranged between adjacent voltage regulating leads.

2. A transformer voltage regulating lead structure based on a vacuum switch according to claim 1, characterized in that: The I column (11) and the II column (12) are respectively provided with a first lightning arrester and a second lightning arrester, the first lightning arrester and the second lightning arrester are respectively led to the vacuum switch (3), the first lightning arrester and the first voltage regulating lead (41) and the second voltage regulating lead (42) are all connected to the upper tap selector, and the second lightning arrester and the third voltage regulating lead (43) and the fourth voltage regulating lead (44) are all connected to the lower tap selector.

3. The transformer voltage regulating lead structure based on a vacuum switch according to claim 1, characterized in that: All the voltage regulating leads are 185mm 2 , electrical density is 3.5A / mm 2 Lead cable.

4. The transformer voltage regulating lead structure based on a vacuum switch according to claim 1, characterized in that: When the voltage regulating leads are connected in parallel, two layers of distribution are adopted, inner and outer layers.

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