A method of assembling a tap changer finished product

Abstract

The application discloses a tap changer finished product assembling method and relates to the technical field of tap changers, which comprises the following steps: tap changer assembling in tap changer component assembling, tap selector assembling, tap changer assembling in tap changer final assembling and inspection, tap changer debugging and the like for quality control. On the basis of the existing tap changer finished product assembling, the application proposes a kind of assembling method specially aiming at the manufacturing precision requirement and high reliability requirement of the super height of the converter transformer tap changer, formulates a tap changer prototype process control scheme for the converter transformer, and ensures the quality reliability of the tap changer manufacturing process.

Description

Technical Field

[0001] This invention relates to the field of tap changer technology, and in particular to a method for assembling a finished tap changer. Background Technology

[0002] Tap changers are key components for stabilizing the valve-side voltage in DC systems. Converter transformer tap changers switch frequently (6000 times / year) and have numerous components (over 400). A single switch, completed within 90ms, requires precise coordination of all components. Any malfunction in any component can lead to switching failure, inter-stage short circuits, and converter transformer failure. In recent years, several major electrical fires caused by tap changer failures have occurred in China, highlighting the critical importance of safe and reliable tap changer switching.

[0003] Long-term operational reliability is the most important performance indicator for tap changers. Currently, component assembly often involves placing all components at various workstations or on an assembly line. Because there are allowable dimensional tolerances in the assembly parts during component production, if the "convex" part of one component has an upper deviation (within the upper deviation limit), and the corresponding "concave" part of another component has a lower deviation (within the lower deviation limit), two qualified products that meet the dimensional tolerance standards will be unable to be assembled. If force is used to assemble them, the resistance in the assembly parts is too great when the two components move, causing jamming and unreliable product quality. In some cases, the product may even need to be scrapped as a defective product, affecting the product pass rate and wasting qualified components. Summary of the Invention

[0004] The technical problem solved by this invention is that, due to the allowable dimensional tolerance range of the assembly parts during the production of components, sometimes two qualified products that meet the dimensional tolerance standards cannot be assembled. If the assembly is done by force, the resistance of the assembly part is too great when the two parts move, which is quite jammed. The product quality is unreliable and may even need to be scrapped as defective products, affecting the product qualification rate and causing waste of qualified parts.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for assembling a finished tap changer, comprising: numbering each component and measuring its assembly parts to obtain measurement data; generating an Excel spreadsheet based on the numbering and the corresponding measurement data; classifying and rating the components according to the error size of the measurement data; assembling the components with mating relationships based on the classification and rating results to obtain a tap changer mating assembly; assembling the tap changer mating assembly to obtain an assembled tap changer and inspecting it; debugging the inspected assembled tap changer; and conducting a finished product test using the debugged assembled tap changer.

[0006] In a preferred embodiment of the tap changer assembly method of the present invention, the assembly of the tap changer components includes the assembly of a tap changer module and a tap selector module; the tap changer module includes a tap changer core and a tap changer assembly; the tap changer core further includes a switching mechanism, an arc plate assembly, a transition resistor, a tap changer body, and a tap changer oil chamber; the tap selector module includes a progressive drive mechanism, a contact system, and a tap selector assembly.

[0007] In a preferred embodiment of the tap changer assembly method of the present invention, the assembly of the tap changer components further includes numbering each component and measuring its assembly portion to obtain measurement data; comparing the measurement data of the components with the limit deviations of each component; if the measurement data of the component is greater than the corresponding limit deviation; treating the component as a defective product and deleting its corresponding number and measurement data from the Excel spreadsheet; if the measurement data of the component is less than the corresponding limit deviation; classifying the components with mating relationships.

[0008] As a preferred embodiment of the tap changer assembly method of the present invention, the assembly of the tap changer components further includes classifying the components with mating relationships; grouping the components into groups based on upper and lower deviations, including but not limited to setting the measurement data of the bracket inner groove and the support plate inner groove as group X and group Y; further grouping group X, for example, grouping the upper deviation of the bracket inner groove Φ18+0.1-Φ18+0.05 as group X1 and the upper deviation Φ18+0.05-Φ18 as group X2; further grouping group Y: grouping the upper deviation of the support plate inner groove Φ18+0.2-Φ18+0.15 as group Y1 and the upper deviation Φ18+0.15-Φ18+0.1 as group Y2.

[0009] As a preferred embodiment of the tap changer assembly method of the present invention, the assembly of tap changer components further includes: assembling X1, X2, Y1, and Y2 groups in groups X and Y respectively based on secondary grouping to obtain mating components; measuring the mating components and comparing the measured data with the limit deviation of the mating components; if the measured data of the mating components is greater than the corresponding limit deviation, the mating components are treated as defective products; if the measured data of the mating components is less than the corresponding limit deviation, the mating components are numbered and their measured data are recorded.

[0010] As a preferred embodiment of the tap changer assembly method of the present invention, the assembly of the tap changer and the tap changer assembly includes assembling the tap selector and the tap changer according to the set working position.

[0011] As a preferred embodiment of the tap changer assembly method of the present invention, the final assembly further includes: numbering the mating components; classifying the mating components with linkage relationship into groups based on upper and lower deviations, including but not limited to setting the movable clearance between the upper and lower sliding boxes of the bolt-action mechanism and the guide rail as group E and group F; further grouping group E, for example: setting the upper deviation Δ = 1.5-2mm of the movable clearance between the upper sliding box and the guide rail as group E1, the upper deviation Δ = 2-2.5mm as group E2, and the upper deviation Δ = 2.5-4mm as group E3; further grouping group F: setting the upper deviation Δ = 1-1.5mm of the movable clearance between the slide block of the lower sliding box and the cam plate as group F1, the upper deviation Δ = 1.5-2mm as group F2, and the upper deviation Δ = 2-3.5mm as group F3.

[0012] As a preferred embodiment of the tap changer assembly method of the present invention, the assembly of the tap changer components further includes: assembling groups E1, E2, E3, F1, F2, and F3 within groups E and F respectively based on secondary grouping to obtain a final assembly switch; measuring the final assembly switch and comparing the measured data with the limit deviation of the final assembly switch; if the measured data of the final assembly switch is greater than the corresponding limit deviation; processing the final assembly switch as a defective product; if the measured data of the final assembly switch is less than the corresponding limit deviation; and debugging the final assembly switch.

[0013] As a preferred embodiment of the tap changer assembly method of the present invention, the debugging includes mechanical operation test, measurement of the tap changer contact action sequence and tap changer withstand voltage test.

[0014] In a preferred embodiment of the tap changer assembly method of the present invention, the following steps are included: The debugging involves testing the final assembly switch and recording its measurement data; comparing the test data with the inspection record card; if the measurement data of the final assembly switch does not meet the technical requirements; treating the final assembly switch as a defective product; if the measurement data of the components meets the technical requirements; and conducting a final product experiment on the final assembly switch.

[0015] The beneficial effects of this invention are as follows: This invention discloses a method for assembling a finished tap changer, including tap changer assembly and tap selector assembly in the tap changer component assembly process; and tap changer final assembly and inspection in the tap changer final assembly and inspection process, as well as tap changer debugging, etc., for quality control. Based on existing tap changer final assembly methods, this invention proposes an assembly method specifically designed for the ultra-high manufacturing precision and high reliability requirements of converter transformer tap changers, and formulates a process control scheme for prototype tap changers for converter transformers to ensure the quality and reliability of the tap changer manufacturing process. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the classification, numbering, and assembly process of various components and the overall assembly of the tap changer in a tap changer assembly method according to an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of the basic process of quality control in a tap changer assembly method according to an embodiment of the present invention;

[0018] Figure 3 This is a schematic diagram of the SHZVII waveform standard in the assembly method of a tap changer product provided in an embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of the selector moving contact bridge assembly in a tap changer assembly method according to an embodiment of the present invention. Detailed Implementation

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] Example 1

[0022] Reference Figure 1-4 As an embodiment of the present invention, a method for assembling a finished tap changer is provided, comprising:

[0023] S1 assigns numbers to each component.

[0024] The components of the tap changer, including the bracket, support plate, turntable, shaft, shaft pin, sleeve, pull plate, bearing seat, square stationary contact, directional contact seat, stationary contact seat, contact bracket, spring, round stationary contact, round contact seat, and stationary contact seat, are numbered and measured to obtain measurement data of the key technical parameters of the components.

[0025] S2 generates an Excel spreadsheet based on the number and its corresponding measurement data.

[0026] Import the numbering and measurement data obtained from S1 into an Excel spreadsheet.

[0027] S3 classifies and rates the measurement data based on the error size.

[0028] The measurement data of the components are compared with the limit deviations of each component;

[0029] If the measured data of a component exceeds the corresponding limit deviation, the component will be treated as a non-conforming product, and its corresponding number and measurement data will be deleted from the Excel spreadsheet.

[0030] If the measured data of a component is less than the corresponding limit deviation, it is considered a qualified product.

[0031] The qualified parts with mating relationships are classified into groups X and Y, such as brackets and support plates, square stationary contacts and square contact seats, round stationary contacts and round contact seats, transition resistor connecting leads and connecting leads and resistor bracket fixing parts, selector or conversion selector moving contact bridge bracket and spring, etc.

[0032] The components described in S1 are classified and grouped once according to the upper and lower deviations, including but not limited to setting the measurement data of the bracket inner groove and the support plate inner groove as group X and group Y.

[0033] Group X is further subdivided, for example, the upper deviation of the inner groove of the support plate Φ18+0.1-Φ18+0.05 is grouped as X1, and the upper deviation Φ18+0.05-Φ18 is grouped as X2; Group Y is further subdivided: the upper deviation of the inner groove of the support plate Φ18+0.2-Φ18+0.15 is grouped as Y1, and the upper deviation Φ18+0.15-Φ18+0.1 is grouped as Y2.

[0034] S4 assembles the components with mating relationships based on the classification and rating results to obtain the tap changer mating assembly.

[0035] Based on the secondary grouping, the X1 group, X2 group, Y1 group and Y2 group in each of the X and Y groups are assembled to obtain the mating components, reducing the data problems caused by small deviations between the mating components.

[0036] The mating components are measured, and the measurement data is compared with the limit deviations of the mating components.

[0037] If the measured data of the component is greater than the corresponding limit deviation;

[0038] The mating component is treated as a defective product if the measured data of the mating component is less than the corresponding limit deviation;

[0039] Number the mating components and record their measurement data; for example, by grouping and assembling in S4, the limit deviation between the inner groove of the bracket and the inner groove of the support plate is less than 0.1mm, ensuring the accuracy of the tap changer components;

[0040] The above steps S1-S4 complete the assembly of the tap changer components into two parts: the tap changer module and the tap selector module. The tap changer module includes the tap changer core and the tap changer assembly. The tap changer core also includes a switching mechanism, an arc plate assembly, a transition resistor, the tap changer body, and the tap changer oil chamber. The tap selector module also includes a step-through mechanism, a contact system, and the tap selector assembly. The corresponding tap changer mating components are obtained.

[0041] S5 assembles the tap changer and related components to obtain the final tap changer, which is then inspected.

[0042] Based on the upper and lower deviations, the mating components with linkage relationships are classified and grouped, such as the contact system and the tap changer core system; including but not limited to setting the movable clearance between the upper and lower slide boxes of the bolt-action mechanism and the guide rail as group E and group F.

[0043] Group E is further subdivided, for example: the upper deviation of the movable clearance between the upper sliding box and the guide rail Δ = 1.5-2mm is designated as Group E1, the upper deviation Δ = 2-2.5mm as Group E2, and the upper deviation Δ = 2.5-4mm as Group E3; Group F is further subdivided, for example: the upper deviation of the movable clearance between the sliding block of the lower sliding box and the cam plate Δ = 1-1.5mm is designated as Group F1, the upper deviation Δ = 1.5-2mm as Group F2, and the upper deviation Δ = 2-3.5mm as Group F3;

[0044] Based on E1, E2, E3, F1, F2 and F3 groups in groups E and F respectively, the final assembly switch is obtained;

[0045] The final assembly switch is measured, and the measured data is compared with the limit deviation of the final assembly switch.

[0046] If the measured data of the final assembly switch is greater than the corresponding limit deviation;

[0047] The assembled switch is treated as a defective product if the measured data of the assembled switch is less than the corresponding limit deviation;

[0048] For example, the deviation △1 between the sliding block and the cam plate of the slide box and the sliding block and the guide rail should be greater than 0.5mm to ensure the accuracy of the assembled load switch.

[0049] S6 performs debugging on the assembled tap changer after inspection.

[0050] Mechanical operation test, tap changer contact action sequence measurement and tap changer withstand voltage test were performed on the S5 assembly switch, and the measurement data were recorded.

[0051] The test data is compared with the inspection record card. If the measurement data of the final assembly switch does not meet the technical requirements, the final assembly switch is treated as a defective product.

[0052] If the measurement data of the component meets the technical requirements, then the assembled switch is a qualified product.

[0053] S7 conducts final product testing by debugging the assembly tap changer.

[0054] The finished product tests include mechanical tests, insulation tests, and switching tests. The mechanical tests include simulating a transformer drying process and performing drying treatment according to the transformer vapor phase drying temperature rise process. The mechanical life test includes 10 operations under alternating hot and cold oil conditions. The operation test under the maximum allowable static pressure includes 10 operations at room temperature under the maximum allowable static pressure (80 kPa). The tests include pressure and vacuum tests, including a pressure test with a pressure difference of 1.0 bar and a vacuum test with a pressure difference of 1.0 bar.

[0055] Insulation tests measure insulation performance by applying an external voltage.

[0056] The switching test involves performing multiple switching operations on the tap changer. Once the test is passed, the product is put into storage.

[0057] Example 2

[0058] Reference Figure 2 This is another embodiment of the present invention. Unlike the first embodiment, this embodiment provides a specific assembly process for assembling a finished tap changer. To verify and illustrate the technical effects of this method, this embodiment uses a traditional technical solution and the method of the present invention for comparative testing. The test results are compared using scientific demonstration methods to verify the real effect of this method.

[0059] Tap changer assembly and inspection includes five parts: switching mechanism, arc plate assembly, transition resistor, tap changer body and tap changer oil chamber. The key points of switching mechanism assembly include quick mechanism, vacuum bubble lever mechanism, contact assembly and overall assembly of switching mechanism. Contact assembly also includes mechanical contacts and main contacts.

[0060] The rapid assembly process for mechanical components includes:

[0061] ① Check the main items and main dimensions of the main parts (you can refer to the existing quality characteristic importance classification table).

[0062] ②Inspect whether the moving components such as guide rails, guide sleeves, sliders, claws, cam discs, upper and lower sliding boxes, and support plates have been nitrided for wear resistance.

[0063] ③ When the energy storage spring is not installed, the upper and lower sliding boxes slide flexibly on the guide rail without jamming (upper and lower sliding box movement clearance △=2±0.5), the claw clamp reset action is flexible, and the slide block of the lower part of the sliding box and the slider of the cam plate move freely (assembly movement clearance △>1).

[0064] ④ The energy storage springs should be paired and assembled (with matching marking colors), and the energy storage springs should be lined with plastic conduits to prevent compression bending.

[0065] ⑤ When assembling the pressure plates at both ends of the guide rail, the guide rail should not be locked in place, and the guide rail should be able to rotate.

[0066] ⑥ The eccentric wheel marked with "△" is installed facing down and rotates flexibly within the two blocks of the upper sliding box.

[0067] ⑦ The assembly of the disc spring oil buffer composite device should meet the technical requirements of the drawing, and special attention should be paid to the combination and assembly of the disc springs.

[0068] ⑧ Check the maximum torque Mmax of the fast-acting mechanism for energy storage, which is 30 Nm ± 10%.

[0069] ⑨ Check the release angle α1 of the quick-release mechanism in both directions, which is 150° to 155° (equivalent to 27.5 to 28.5 rotations of the SHM-D electric mechanism handle).

[0070] b. The assembly process for the vacuum tube lever mechanism components includes:

[0071] ① Before installing components, each part should be inspected, deburred, and cleaned.

[0072] ② Ensure the lever rotates freely;

[0073] ③ Threadlocker should be used to connect the shaft pin and the insulating bead;

[0074] ④ The insulating column moves freely up and down without any jamming.

[0075] ⑤ Check the main items and main dimensions of the main parts (see HM 0036II.3902 Quality Characteristic Importance Classification Table).

[0076] c. The mechanical contact assembly process includes:

[0077] ① Before installing components, each part should be inspected, deburred, and cleaned.

[0078] ② Ensure that there is no jamming when the contacts open and close;

[0079] ③ After the waveform of the isolating contact meets the requirements, the connecting parts are connected with thread-locking adhesive;

[0080] ④ The strips must be insulated after processing;

[0081] ⑥ Inspect the main items and main dimensions of the main parts (see HM 0036.3912 Quality Characteristic Importance Classification Table).

[0082] d. The main contact assembly process includes:

[0083] ① Before installing components, each part should be inspected, deburred, and cleaned.

[0084] ②The moving contact group should move without any obstruction;

[0085] ③ The connection must be reliable and there must be no looseness.

[0086] ④ The contact pressure is compressed by 3mm, F=260±20N;

[0087] ⑤ The slotted parts rotate freely without any jamming.

[0088] ⑥ Ensure that the thickness of each flexible connector is 2mm;

[0089] e. The overall assembly process for the switching mechanism includes:

[0090] ① Clean all components and parts before installation;

[0091] ② The vacuum bubble opening distance is 3.5-4mm. After adjusting the opening distance, tighten the nut.

[0092] ③ The high-speed mechanism should operate flexibly without any jamming.

[0093] ④ Finally, tighten all threaded connections until they are secure.

[0094] (2) The assembly points of the arc plate assembly switching mechanism are as follows:

[0095] ① There must be no jamming at the contact point of the arc-shaped plate;

[0096] ② The contact pressure compression is 3mm, F=260±20N;

[0097] ③ The molded arc plate should be marked with the manufacturing batch number and date. The molded surface should be smooth, flat, and have a uniform gloss, without burrs, scrap edges, missing materials, cracks, or deformation.

[0098] (3) The key points of transition resistor assembly include two parts: frame-type resistor element and transition resistor.

[0099] a. The inspection and assembly of frame-type resistor elements includes:

[0100] ① Whether the resistance wire is wound flat and whether the spacing between the two parallel resistance flat wires is uniform;

[0101] ② The welding between the resistance wire and the connecting piece must be firm, and there must be no welding quality defects such as incomplete welding;

[0102] ③ Whether the clay interlayer has broken or other quality issues;

[0103] ④ Measure the resistance value of the resistive element and mark the thickness and resistance value of the resistive flat wire.

[0104] b. Inspection, connection method and assembly of transition resistors:

[0105] ①After installation, the connection method between the transition resistor and the fixed arc contact of the contact switching mechanism meets the design requirements for whether current is shunted;

[0106] ② The insulation distance between the connecting leads of the transition resistor and between the connecting leads and the fixing parts of the resistor support should meet the requirement of >2mm;

[0107] ③ Check whether the connection between the transition resistor and the spark gap is correct and reliable.

[0108] (4) The specific steps for assembling and inspecting the tap changer body include:

[0109] a. The assembly of the tap changer core includes:

[0110] No quality issues were found during the inspection of the above components, and the tap changer body assembly can proceed.

[0111] ① As per design requirements, a transition resistor should be installed after the switch has undergone a power-on test;

[0112] ② Install the intermediate cylinder according to the design voltage level requirements.

[0113] b. Inspection of the tap changer body includes:

[0114] ①After the tap changer is assembled, it is hoisted into the oil chamber for 2000 mechanical operation tests;

[0115] ② After the machine has finished operating, use a special wrench to reciprocate the tap changer core to check whether the movement of each moving part is flexible, whether the tap change of the contacts is normal, and whether there is any looseness.

[0116] ③ Switch to core waveform adjustment, and follow the waveform standard (see below). Figure 3 .

[0117] ( Figure 3 The specific waveform standards for the oil-immersed vacuum tap changer are as follows: The vacuum bulb is allowed to bounce during the process, but each bounce must not exceed 2 milliseconds; no bounces are allowed in the middle of the composite waveform; sharp zero-crossings are allowed for other bounces; there must be no break before the vacuum bulb breaks; the three-phase synchronization of the composite waveform is less than 3ms; the composite waveform time is 75–90ms; t(double single) = 70–90ms; t1 ≥ 3ms; t2 ≥ 14ms; t3 = 3–5ms; t4 ≥ 10ms; t5 > 2ms; mechanical break ≥ 24mm.

[0118] c. Inspect the main items and main dimensions of the main parts.

[0119] (5) The specific steps for assembling and inspecting the tap changer oil chamber include:

[0120] a. Inspect the main items and main dimensions of the main parts, including...

[0121] b. Requirements for head flange assembly and inspection include:

[0122] ① All mating dimensions of the head flange, support flange and head cover with the sealing elements shall conform to the dimensions required by the drawing, and there shall be no defects on the sealing surface such as sand holes, shrinkage cavities, scratches or bumps that affect the sealing performance;

[0123] ② After processing, the head flange and intermediate flange should undergo a semi-finished product sealing test (75℃±10℃ hot oil 200kPa pressure 30min or 200kPa air and water filling 20min for leak testing) to assess the casting quality of aluminum castings (for companies with advanced casting equipment and forming processes and stable casting quality, the test can be waived after quality certification).

[0124] ③ Bursting cover processing and burst pressure test: For different batches of materials, two are processed for each batch and a burst pressure test is conducted under water pressure. The burst pressure should meet 300kPa±20%. If there is a difference in burst pressure, the final correction dimension of the processing should be determined.

[0125] ④ Check whether the oil suction bend has an overflow vent screw to avoid mixing with other bends;

[0126] ⑤ Check whether there is an overflow groove on the contact surface of the fixed equalizing ring (cylinder-side O-ring seal pressure ring) at the bottom of the head flange, so as to avoid residual gas between the equalizing ring and the cylinder during oil filling, which may affect the insulation performance to ground.

[0127] c. Requirements for inspecting and testing the assembly of insulating cylinders include:

[0128] ①Inspect the batch number of the insulating cylinder, the cutting sequence number, and the surface roughness of the contact hole.

[0129] ② Use a special fixture to assemble the O-ring on the contact, and allow a small amount of grease to be applied to the surface to prevent accidental damage to the seal during assembly;

[0130] ③ The insulating cylinder should be marked with contact symbols, and all markings should be clear and legible.

[0131] d. Requirements for cylinder bottom assembly and inspection include:

[0132] ① All mating dimensions of the bottom of the cylinder and the sealing elements shall conform to the dimensions required in the drawing, and there shall be no defects on the sealing surface such as sand holes, shrinkage cavities, scratches or bumps that affect the sealing performance;

[0133] ② After the bottom of the cylinder is machined, a semi-finished product sealing test should be carried out (75℃±10℃ hot oil 200kPa pressure 30min or 200kPa air and water filling 20min for leak test) to assess the casting quality of aluminum castings (for enterprises with advanced casting equipment and forming process and stable casting quality, the test can be waived after quality certification).

[0134] ③ Check whether the transmission of the connector on the bottom shaft is flexible and there should be no jamming.

[0135] e. Requirements for oil chamber assembly and inspection include:

[0136] ① The head flange, insulating cylinder and cylinder bottom are aligned and riveted together without misalignment, and the rivets have no traces of hammering.

[0137] ② All sealing parts must use fluororubber seals, and nitrile rubber seals must not be used without authorization;

[0138] ③ The equipotential bonding between the neutral point lead-out contact and the bottom pressure ring should be reliable, and the connecting piece should be tightly attached to the inner wall of the oil chamber.

[0139] ④ Oil chamber leak test: withstand 0.1MPa, 24h air pressure without leakage.

[0140] II. The overall assembly and inspection of the tap changer includes:

[0141] (1) The assembly process of the tap changer includes:

[0142] a. Lift the assembled tap changer body, and gently insert the tap changer body into the tap changer oil chamber according to the position of the oil suction pipe. Be careful not to damage the fasteners that secure the tap changer body to the oil chamber.

[0143] b. Install the location indicator signs correctly according to the drawing requirements, paying attention to the indication of the "△" mark;

[0144] c. Cover the head cover, tighten the bolts on the head cover, use a special swivel tool to rotate the head worm gear transmission device, and visually check through the observation window whether the position indication of each tap is correct.

[0145] (2) Tap changer inspection includes:

[0146] a. Check that the contact resistance of the main contacts, transition contacts, and neutral point lead-out contacts of the tap changer is ≤500μΩ;

[0147] b. Check the markings and factory serial number on the tap changer nameplate. The error between the transition resistance value on the nameplate and the measured value should be ≤ ±10%.

[0148] III. Assembly and inspection of the progressive transmission mechanism are as follows:

[0149] ① Check that the main items and main dimensions of the main parts meet the requirements of the drawings (see HM0036.3912 Quality Characteristic Importance Classification Table);

[0150] ② The assembly of the upper and lower grooved wheels with their respective crank arms should conform to the requirements of the drawings;

[0151] ③ All moving parts of ferrous metals should undergo surface hardening treatments such as tempering, surface hardening, carbonitriding, and nitriding to reduce wear debris;

[0152] ④ Adjusting washers should be used to adjust the clearance between all moving parts of the progressive transmission mechanism. Except for the non-tangential entry of the groove roller into the groove of the groove wheel (grooving wheel retraction), all movements should be flexible and without jamming.

[0153] IV. The assembly and inspection of the contact system are as follows;

[0154] ① Check that the main items and main dimensions of the main parts meet the requirements of the drawings.

[0155] ②Selector stationary contact assembly and inspection include

[0156] a. The performance indicators of epoxy glass fiber extruded girders should meet the requirements of the company's internal control standards and be free of insulation defects such as cracks;

[0157] b. Assemble the fixed contact on the insulating rod according to the diagram. Note that the connection surfaces of all tap leads should be parallel and not skewed.

[0158] c. After the fixed contacts on the insulating rod are assembled, the semi-finished product shall undergo a power frequency withstand voltage test according to the insulation class (DE class) performance requirements of the selector;

[0159] ③ The assembly and inspection of the selector moving contact bridge includes:

[0160] a. Selector moving contact bridge assembly as follows Figure 4 As shown.

[0161] b. The contact pressure of the selector moving contact is between 60N and 80N.

[0162] ④ The assembly and inspection of the selector center post includes:

[0163] The insulating sleeve of the selector's center column and the internal support should be tightly fitted and not loose.

[0164] ⑤ Assembly and inspection of the moving contact of the selector includes:

[0165] a. Assemble the selector moving contact bridge within the moving contact bracket according to the drawing requirements;

[0166] b. The contact pressure of the moving contact of the selector is 70N~90N;

[0167] c. The equipotential bonding between the moving contact and the contact support must be reliable.

[0168] V. The overall assembly and inspection of the tap selector are as follows:

[0169] (1) Tap selector assembly process

[0170] a. Assembly of the tap selector base;

[0171] b. Connection between the tap selector contact system (including the selector) and the progressive drive mechanism.

[0172] c. Selector moving contact system drive tube and bottom assembly;

[0173] d. The wire and the conductive ring should be clamped firmly and should not be loose.

[0174] (2) The tap selector inspection process includes:

[0175] ① Selector rigidity check includes:

[0176] a. Does the glass fiber reinforcement content (30%) of the nylon support for the moving contact bridge meet the requirements of the drawing?

[0177] b. When the selector moving contact bridge is closed or closed from the fixed contact, the central column must not be twisted, deformed or twisted;

[0178] c. Add a support ring to the middle of the selector cage for fixation.

[0179] ② The wear resistance test of the selector contacts includes:

[0180] a. Whether the ag content (2%) and surface hardness of the silver-copper alloy material of the moving contact bridge meet the requirements of the drawing; whether the surface hardness of the fixed contact and conductive ring before plating and after plating (hard silver) meets the requirements of the drawing;

[0181] b. Whether the progressive transmission components undergo surface hardening treatment includes:

[0182] ③ The conductivity check of the contact system includes:

[0183] a. The contact resistance of the single and double contacts of the selector at each tap position should be <150μΩ or the conductive loop resistance between the fixed contact and the connecting lead at each tap position should be <400μΩ.

[0184] b. The contact resistance of the selector contacts should be <300μΩ or the conductive circuit resistance of each phase (K+, K- or O+, O-) of the selector should be <400μΩ; the switching time of the selector should be ≤600ms.

[0185] c. The shortest distance between the cylindrical part of the moving contact and the stationary contact must be greater than 2mm, and there must be no engagement on the spherical surface of the stationary contact.

[0186] ④ The floating performance check and adjustment of the moving contact bridge includes:

[0187] a. The clearance between the moving contact bridge bracket and the spring cap of the selector or changeover selector should be ≥1.5mm, and there should be no jamming;

[0188] b. The distance between the spring support of the Geneva mechanism and the pressing part (mounting spring) at the top of the selector center column should be 6±1mm;

[0189] c. If items a and b fail the inspection, it is permissible to adjust the deviation between the center plane layer of the selector stationary contact and the center plane layer of the conductive ring (adjust with an adjusting washer at the bottom of the selector center post);

[0190] The top contact layer of the selector is allowed to be 0.5 to 1 mm higher than the conductive ring; the middle contact layer of the selector is allowed to deviate from the conductive ring by ±0.25 mm; the bottom contact layer of the selector is allowed to be 0.5 to 1 mm lower than the conductive ring.

[0191] ⑤ The inspection of the moving contact clearance includes:

[0192] a. The minimum clearance between the selector's moving contact bridge and the fixed contact shield is >2mm;

[0193] b. The minimum clearance between the top of the nylon bracket of the selector's moving contact bridge and the top of the fixed contact is >2mm;

[0194] c. The minimum clearance between the moving contact bridge fixing bolt of the selector and the "+" and "-" fixed contacts is >2mm;

[0195] d. The minimum movable gap between the polarity conversion moving contact bridge bracket and the + connection lead is >10mm.

[0196] ⑥ The check of the selector equipotential bonding area includes:

[0197] Check that the upper and lower flanges of the selector are at the same potential. If there is a lack of equipotential, check and eliminate the equipotentiality of components such as the Geneva mechanism, transmission pipe and the crank arm at the bottom of the selector one by one.

[0198] ⑦ The manufacturing quality inspection of components for selectors with electric field performance requirements includes:

[0199] a. The surface roughness (polishing) of the shielding cover and the ER of the fixed contact, and the conductive ring should meet the technical requirements of the drawing;

[0200] b. The insulation layer of the selector connecting wires should be tightly and securely wrapped, and should not be loose;

[0201] c. The bolts connecting the wires and the conductive rings must not protrude more than 2mm above the plane of the clamping parts;

[0202] d. The surfaces of components requiring electric field performance shall not have any damage from manufacturing, transportation, or storage.

[0203] VI. The tap changer assembly is as follows:

[0204] The assembly of a tap changer includes the following two aspects:

[0205] (1) The tap selector and tap switch are assembled according to the set working position.

[0206] (2) The connection and adjustment of the tap changer and the electric mechanism include:

[0207] a. The tap changer and the electric mechanism are connected at the same set working position;

[0208] b. Verifying the balance of the rotation difference between the two directions of rotation includes:

[0209] When the tap changer is connected to the electric mechanism, the number of handle rotations must be the same from the moment the tap changer switches in both directions until the electric mechanism completes its operation. See the table below for specific adjustments.

[0210] Table 1: Record of the rotation difference between the two directions of the tap changer.

[0211]

[0212] During the assembly of the tap changer, an "Inspection Record Sheet" is created for key control points. Each key parameter is inspected, and corresponding records are generated and archived. The inspection record card is created in tabular form, as shown in the table below.

[0213] Table 2: Inspection Record Sheet.

[0214]

[0215]

[0216]

[0217] VII. The tap changer debugging steps are as follows:

[0218] The commissioning of the tap changer mainly includes the following:

[0219] Mechanical operation test;

[0220] Test a is conducted on a special test stand. During the test, the oil chamber is filled with transformer oil, and the moving parts and contacts of the selector are lubricated with transformer oil.

[0221] b. Before operating the tap changer electrically, manually check the correctness of the connection between the tap changer and the electric mechanism, as well as the reliability of the mechanical limit switches at both ends;

[0222] c. A properly assembled tap changer should be able to perform 10 operating cycles without failure when the contacts are not energized;

[0223] d. The electric mechanism shall be able to perform 10 operating cycles without failure under operating conditions or with an equivalent load.

[0224] e. Check the synchronization of the tap changer position indicator, the electric mechanism position indicator, and the remote position indicator;

[0225] (Note: a. The tap changer and the electric mechanism can be mechanically tested separately.)

[0226] b. (The process of going from 1 to N, and then from N to 1, is considered one operation loop.)

[0227] Measurement of the contact sequence of the tap changer

[0228] After the mechanical operation test of the tap changer, the sequence of operation of the tap selector, the transfer selector and the tap changer is measured, as well as the contact change procedure of the tap changer is measured.

[0229] If the tap changer has a potentiometer switch, the sequence of actions of the potentiometer switch and the selector should also be measured.

[0230] The sequence of action of the tap changer contacts includes:

[0231] ① The sequence of contact actions is represented by the number of rotations of the electric mechanism handle. The sequence of contact actions at each tap position conforms to the requirements of the table below.

[0232] Table 3: Contact action sequence table.

[0233]

[0234]

[0235] It should be noted that the moving contact of the tap selector leaves after the moving contact of the tap selector leaves the fixed contact, and closes before the moving contact of the tap selector closes the fixed contact.

[0236] ② The sequence of tap changer contact action is checked by the sound of each contact action;

[0237] b. The procedure for measuring tap changer contact changes includes:

[0238] ① The oscilloscope detection method is used, and in routine tests, it is usually represented by a composite waveform diagram (one channel is used for each phase);

[0239] ② Measuring instruments typically use optical oscilloscopes or digital recorders. It is recommended to use digital recorders with waveform amplification and storage functions, and their sampling frequency should not be lower than 5000Hz.

[0240] ③ Apply a DC signal voltage of 3-6V to the tap changer contacts without changing the transition resistance value; the test wiring is relatively simple.

[0241] ④ The switching time of each contact of the tap changer should meet the requirements.

[0242] The withstand voltage test for tap changers includes:

[0243] The switch must undergo the corresponding insulation test according to the requirements in Table 5-4, and the test values ​​shall be in accordance with the product's technical requirements. The insulation test items include: rated external withstand voltage (50Hz, 1min), and rated lightning impulse withstand voltage (1.2 / 50μs).

[0244] Table 4: Insulation Test Requirements.

[0245]

[0246] Assemble the tap changer according to the above procedure, and control other parameters to the same qualified value within the specified conditions. Some data controlling the assembly of the switching mechanism are shown below.

[0247] Table 5: Experimental data (Table 1).

[0248]

[0249]

[0250] Assemble the tap changer according to the above procedure, and keep other parameters within the same value range that meet the conditions. Some data controlling the assembly of the tap selector are shown below.

[0251] Table 6: Experimental data from Table 2.

[0252]

[0253] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for assembling a finished tap changer, characterized in that, include: Each component is numbered, and its assembly parts are measured to obtain measurement data; An Excel spreadsheet is generated based on the number and its corresponding measurement data; Classify and rate the measurement data according to the error size; Based on the classification and rating results, the components with mating relationships are assembled to obtain a tap changer mating assembly; The tap changer and its components are assembled to obtain the final tap changer, which is then inspected. The final assembly tap changer, after inspection, was tested and adjusted. The final product was tested by adjusting the assembly tap changer; The assembly of the tap changer components includes the assembly of two parts: the tap changer module and the tap selector module. The tap changer module includes a tap changer core and a tap changer assembly; The tap changer core also includes a switching mechanism, an arc plate assembly, a transition resistor, a tap changer body, and a tap changer oil chamber; The tap selector module includes a progressive drive mechanism, a contact system, and an overall tap selector. The process involves numbering each component and measuring its assembly parts to obtain measurement data. The measurement data of the components are compared with the limit deviations of each component; If the measured data of the component is greater than the corresponding limit deviation; The components were treated as defective products, and their corresponding numbers and measurement data were deleted from the Excel spreadsheet. If the measured data of the component is less than the corresponding limit deviation; The components that have a mating relationship are classified; The assembly of the tap changer components also includes, The components that have a mating relationship are classified; The components are classified and grouped according to the upper and lower deviations, including but not limited to setting the measurement data of the bracket inner groove and the support plate inner groove as group X and group Y. Subgroup X into two subgroups, such as: The upper deviation of the inner groove of the support Φ18+0.1-Φ18+0.05 is taken as group X1, and the upper deviation Φ18+0.05-Φ18 is taken as group X2. Group Y is further subdivided: The upper deviation Φ18+0.2-Φ18+0.15 of the inner groove of the support plate is taken as group Y1, and the upper deviation 18+0.15-Φ18+0.1 is taken as group Y2. Based on the secondary grouping, the X1 group, X2 group, Y1 group and Y2 group in each of the X and Y groups are assembled to obtain the mating components; The mating components are measured, and the measurement data is compared with the limit deviations of the mating components. If the measured data of the component is greater than the corresponding limit deviation; The mating component is treated as a defective product if the measured data of the mating component is less than the corresponding limit deviation; Number the mating components and record their measurement data.

2. The assembly method for the finished tap changer as described in claim 1, characterized in that: The assembly of the tap changer assembly includes assembling the tap selector and the tap changer in their set working positions.

3. The assembly method for the finished tap changer as described in claim 2, characterized in that: The final assembly also includes, Number the mating components; Based on the upper and lower deviations, the mating components with linkage relationships are classified and grouped, including but not limited to setting the movable clearance between the upper and lower slide boxes of the bolt-action mechanism and the guide rail as group E and group F. Group E is further subdivided, as follows: The upper deviation Δ=1.5-2mm of the movable clearance between the upper sliding box and the guide rail is designated as group E1, the upper deviation Δ=2-2.5mm as group E2, and the upper deviation Δ=2.5-4mm as group E3. Group F was regrouped: The upper deviation Δ=1-1.5mm of the movable clearance between the slide block and the cam plate of the sliding box is designated as group F1, the upper deviation Δ=1.5-2mm as group F2, and the upper deviation Δ=2-3.5mm as group F3.

4. The assembly method for the finished tap changer as described in claim 3, characterized in that: The assembly of the tap changer components also includes assembling E1, E2, E3, F1, F2 and F3 groups in each of E and F groups based on secondary grouping to obtain the final assembly switch. The final assembly switch is measured, and the measured data is compared with the limit deviation of the final assembly switch. If the measured data of the final assembly switch is greater than the corresponding limit deviation; The assembled switch is treated as a defective product. If the measured data of the assembled switch is less than the corresponding limit deviation, the assembled switch is adjusted.

5. The assembly method for the finished tap changer as described in claim 4, characterized in that: The commissioning includes mechanical operation tests, measurement of the tap changer contact action sequence, and tap changer withstand voltage tests.

6. The assembly method for the finished tap changer as described in claim 5, characterized in that: The debugging process involves testing the final assembly switch and recording its measurement data. Compare the test data with the inspection record card. If the measurement data of the final assembly switch does not meet the technical requirements; The assembled switch was treated as a defective product; If the measurement data of the component meets the technical requirements; The assembled switch will undergo a finished product test.

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