An assembly method for a tank-type capacitive voltage transformer

Abstract

The present invention relates to the technical field of the assembly of pot-type capacitive voltage transformers, and particularly to an assembly method for pot-type capacitive voltage transformers, comprising the following steps: S1, assembling a high-voltage capacitor module; S2, assembling an electromagnetic unit module; S3, assembling and encapsulating a low-voltage capacitor module; S4, docking the high-voltage capacitor module with the electromagnetic unit module and the low-voltage capacitor module; S5, evacuating and leak-checking; S6, conducting tests. It is possible to disassemble the whole machine into multiple cavities, install modules separately, shorten the production man-hours, improve the quality controllability, and keep the error precision characteristics of the pot-type capacitive voltage transformer product within the high-precision range of 0.2 level.

Description

Technical Field

[0001] The present invention relates to the technical field of the assembly of pot-type capacitive voltage transformers, and particularly to an assembly method for pot-type capacitive voltage transformers. Background Art

[0002] At present, the voltage transformers widely used in gas-insulated switchgear (GIS) are pot-type electromagnetic voltage transformers. With the increase of the voltage level, the manufacturing difficulty, process, cost, volume and weight of pot-type electromagnetic voltage transformers will increase exponentially, and their insulation characteristics are also very poor. In particular, pot-type electromagnetic voltage transformers are prone to ferroresonance with the power grid, and their ability to withstand lightning impulse overvoltage and switching impulse overvoltage is poor.

[0003] The capacitive voltage divider of traditional column-type capacitive voltage transformers has a complex structure and great manufacturing process difficulty. The capacitive voltage divider is composed of hundreds or hundreds of capacitor units connected in series. The column-type capacitive voltage transformer is greatly affected by high-voltage leads, adjacent objects and adjacent-phase power supplies. Environmental temperature, temperature gradient, surface pollution degree and relative humidity of porcelain bushings also affect the error characteristics. Various factors such as high-voltage leads and temperature changes (including the upper and lower temperature gradients of column-type capacitive voltage dividers) have an error influence of up to 0.3% on column-type capacitive voltage transformers of 765 kV voltage level, and the combined influence is even greater.

[0004] With the construction and development of UHV power grids, the existing conventional column-type capacitive voltage transformers of 1000 kV voltage level adopt an oil-paper composite voltage divider structure, which cannot be effectively connected with GIS stations, and has problems such as complex structure, great manufacturing process difficulty and poor error characteristic accuracy. The pot-type capacitive voltage transformer technology was proposed in the patent CN200610020003.7, but it does not involve the manufacturing process of capacitors and their pot-type capacitive voltage transformers. The cleanliness between coaxial electrodes and the assembly dimensions will directly affect the capacitance and error accuracy characteristics of pot-type capacitive voltage transformers. At present, pot-type capacitive voltage transformers only meet the requirements of voltage measurement level 0.5 and do not meet the requirements of metering level 0.2 error. Repeated disassembly and assembly of each component will also have a great impact on the cleanliness inside the encapsulated housing and electrode deformation. Summary of the Invention

[0005] Aiming at the problem that the error accuracy characteristics of current pot-type capacitive voltage transformers only meet the requirements of voltage measurement level 0.5 and cannot achieve high precision, the present invention provides an assembly method for pot-type capacitive voltage transformers.

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows.

[0007] An assembly method for a tank-type capacitive voltage transformer includes the following steps: S1, assembling the high-voltage capacitor module; S2, assembling the electromagnetic unit module; S3, assembling and encapsulating the low-voltage capacitor module; S4, docking the high-voltage capacitor module with the electromagnetic unit module and the low-voltage capacitor module; S5, evacuating and leak-checking; S6, conducting tests. It can disassemble the whole machine into multiple cavities and install them module by module, shortening the production man-hours and improving the quality controllability. It can keep the error precision characteristics of the tank-type capacitive voltage transformer product within the high-precision range of 0.2 level.

[0008] Preferably, the high-voltage capacitor module includes a housing; a core column, a high-voltage electrode and a low-voltage electrode are coaxially arranged in the housing; a four-way connector is connected to the outer wall of the housing; step S1 includes the following steps: S11, coaxially assembling the low-voltage electrode into the housing; the high-voltage electrode is fixed on the core column inside the housing; S12, with one end of the high-voltage electrode as the stationary end and the low-voltage electrode as the moving end, sleeving the low-voltage electrode outside the high-voltage electrode; then using bolts to encapsulate the housing; S13, connecting the four-way connector to the outer wall of the housing.

[0009] Preferably, after step S13, it further includes step S14: evacuating and inflating the installed high-voltage capacitor module for leak-checking; evacuating to below 10 Pa and maintaining for at least 8 hours; filling insulating gas to the rated pressure and sealing for leak-checking; S15, conducting semi-finished product tests; including capacitance, withstand voltage, partial discharge quantity, and dielectric loss tests.

[0010] Preferably, in step S13, the four-way connector includes an outer shell one; a conductive rod is arranged inside the outer shell one; the conductive rod is integrally arranged in a T shape or a cross shape.

[0011] Preferably, in step S4, one end of the conductive rod is connected to the housing, one end is connected to the electromagnetic unit module, and the other end is connected to the low-voltage capacitor module.

[0012] Preferably, the electromagnetic unit module includes an iron core; a coil is wound around the iron core; a shielding cover is sleeved outside the coil; an insulating layer is arranged outside the shielding cover; the iron core is arranged on a clamping piece; the clamping piece is arranged on an outer shell two; a fixing piece is arranged at the lower end of the clamping piece; a compensating reactor is arranged on the fixing piece.

[0013] Preferably, in step S2, it includes the following steps: S21, fixing the iron core on the clamping piece; S22, sleeving the coil on the iron core; then assembling the shielding cover outside the coil; then assembling the insulating layer outside the shielding cover; S23, assembling the compensating reactor on the fixing piece.

[0014] Preferably, after step S23, it further includes step S24: evacuating and inflating the electromagnetic unit module for leak-checking; evacuating to below 10 Pa and maintaining for at least 4 hours, filling insulating gas to the rated pressure and sealing for leak-checking; the sealing time is 24 h; then conducting semi-finished product tests on the electromagnetic unit module.

[0015] Preferably, the low-voltage capacitor module includes a third housing; the third housing is provided with capacitor elements; in step S3, the following steps are included: S31, assembling the capacitor elements in the third housing; S32, measuring the temperature coefficient of the low-voltage capacitor module; the temperature coefficient parameter is within the range of ±1×10-4 / K; S33, evacuating, inflating, and leak-checking the low-voltage capacitor module; evacuating to below 10 Pa and maintaining for at least 4 hours, filling with insulating gas to the rated pressure, and sealing and leak-checking; the sealing duration is 24 h; S34, conducting semi-finished product tests, including capacitance, withstand voltage, partial discharge quantity, and dielectric loss tests.

[0016] It can be seen from the above technical solutions that the advantages of the present invention are as follows:

[0017] 1. Provide an assembly method for the tank-type capacitive voltage transformer, which simplifies the process of repeated disassembly and assembly to the greatest extent, and avoids the intrusion of metal impurities and dust into the UHV cavity caused by repeated disassembly and assembly.

[0018] 2. Split the whole machine into multiple cavities, install and test semi-finished products in modules, shorten the production man-hours, improve the quality controllability, and the module installation and detection can increase the probability of discovering and solving potential problems. Ensure that each component is qualified and reliable before the whole machine is assembled.

[0019] 3. Adopt the arrangement and installation method with the high-voltage inner side and the low-voltage outer side of the coaxial electrode, the axial electric field distribution is uniform, which is beneficial to improving the UHV voltage insulation ability, the overall volume is small, the structure is compact, and it is very suitable for enclosed power stations or places with limited space.

[0020] 4. The assembly method of the tank-type capacitive voltage transformer can effectively avoid the introduction of impurities between electrodes, confirm the assembly dimensions, avoid problems such as the introduction of metal impurities and electrode deformation caused by secondary disassembly and assembly, ensure the accuracy of the capacitance of the voltage-dividing capacitor, and keep the product error precision characteristics of the tank-type capacitive voltage transformer within the high-precision range of 0.2 level. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions of the present invention, the drawings required to be used in the description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 It is a schematic structural diagram of the present invention.

[0023] Figure 2 It is a schematic assembly diagram of the high-voltage capacitor module of the present invention.

[0024] Figure 3 It is a schematic structural diagram of the low-voltage capacitor module of the present invention.

[0025] Figure 4 This is a schematic structural diagram of the electromagnetic unit module of the present invention.

[0026] Description of main reference numerals

[0027] 1 - housing, 2 - low - voltage electrode, 3 - high - voltage electrode, 4 - core column, 5 - four - way connector, 6 - low - voltage capacitor module, 7 - electromagnetic unit module;

[0028] 501 - outer shell one, 502 - conductive rod; 601 - outer shell three, 602 - capacitor element; 701 - coil, 702 - compensating reactor, 703 - iron core, 704 - shielding cover, 705 - fixing member, 706 - clamping member, 707 - outer shell two. Specific embodiments

[0029] To make the objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the present invention will be clearly and completely described below in conjunction with the drawings in the specific embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in this patent, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of this patent.

[0030] As Figure 1 、 2 shown, an assembly method of a tank - type capacitive voltage transformer first assembles the high - voltage capacitor module; the high - voltage capacitor module includes a housing 1; a core column 4, a high - voltage electrode 3, and a low - voltage electrode 2 are coaxially arranged inside the housing 1; a four - way connector 5 is connected to the outer wall of the housing 1; the following steps are included: coaxially assemble the low - voltage electrode 2 into the housing 1; fix the high - voltage electrode 3 on the core column 4 inside the housing 1; with one end of the high - voltage electrode 3 as the stationary end and the low - voltage electrode 2 as the moving end, sleeve the low - voltage electrode 2 outside the high - voltage electrode 3; then seal the housing 1 with bolts. The four - way connector 5 includes an outer shell one 501; a conductive rod 502 is arranged inside the outer shell one 501; the conductive rod 502 is integrally arranged in a T - shape or cross - shape; the four - way connector 5 is connected to the outer wall of the housing 1; the electromagnetic unit module 7 and the low - voltage capacitor module 6 are connected to the four - way connector 5 to form a closed cavity. The assembled high - voltage capacitor module is evacuated, filled with gas, and leak - tested; evacuated to below 10 Pa and maintained for at least 8 hours; filled with insulating gas to the rated pressure and sealed for leak - testing; semi - finished product tests are carried out; including capacitance, withstand voltage, partial discharge quantity, and dielectric loss tests. The gap between the high - voltage electrode 3 and the low - voltage electrode 2 is tested circumferentially at four points with a tool gauge block. The installation deviation between the electrodes is controlled within ±5 mm.

[0031] Secondly, assemble the electromagnetic unit module 7, as Figure 4As shown in the figure; the electromagnetic unit module 7 includes an iron core 703; a coil 701 is wound around the iron core 703; a shielding cover 704 is sleeved outside the coil 701; an insulating layer is arranged outside the shielding cover 704; the iron core 703 is arranged on the clamping piece 706; the clamping piece 706 is arranged on the outer shell two 707; a fixing piece 705 is arranged at the lower end of the clamping piece 706; a compensating reactor 702 is arranged on the fixing piece 705; the following steps are included: fixing the iron core 703 on the clamping piece 706; sleeving the coil 701 on the iron core 703; then assembling the shielding cover 704 outside the coil 701; then assembling the insulating layer outside the shielding cover 704; assembling the compensating reactor 702 on the fixing piece 705. Evacuate and fill the electromagnetic unit module 7 with gas for leak detection; evacuate to below 10 Pa and maintain for at least 4 hours, fill with insulating gas to the rated pressure, and perform sealing leak detection; the sealing duration is 24 h; then perform a semi-finished product test on the electromagnetic unit module 7. Among them, the coil 701 is assembled by coaxial winding. From the inside to the outside in sequence are: low-voltage coil, regulating winding, high-voltage coil. The low-voltage coil is provided with multiple groups of turns adjustment taps, and the coil 701 is assembled by coaxial winding. This arrangement method can realize the full-automatic equipment winding of the high-voltage coil, improve the winding efficiency and the precise control of the winding outer diameter.

[0032] Assemble and package the low-voltage capacitor module 6 again; as Figure 3 shown, the low-voltage capacitor module 6 includes an outer shell three 601; a capacitor element 602 is arranged in the outer shell three 601; the following steps are included: assembling the capacitor element 602 in the outer shell three 601; measuring the temperature coefficient of the low-voltage capacitor module 6; the temperature coefficient parameter is within the range of ±1×10 -4 / K; evacuate and fill the low-voltage capacitor module 6 with gas for leak detection; evacuate to below 10 Pa and maintain for at least 4 hours, fill with insulating gas to the rated pressure, and perform sealing leak detection; the sealing duration is 24 h; perform a semi-finished product test, including capacitance, withstand voltage, partial discharge amount, and dielectric loss test. The capacitor element 602 is a ceramic capacitor or a film capacitor element, arranged in a cylindrical layout, and is integrally docked with the outer shell three 601 and fixed by coaxial assembly in a plug-and-play manner.

[0033] Then dock the high-voltage capacitor module with the electromagnetic unit module 7 and the low-voltage capacitor module 6; use the conductive rod 502 to make three-way connections by means of static and dynamic contact plugging, one direction of the conductive rod 502 is connected to the housing 1, one direction is connected to the electromagnetic unit module 7, and the other direction is connected to the low-voltage capacitor module 6. After docking is completed, perform leak detection on the whole machine, especially perform local bandaging leak detection on the sealing surfaces between the modules for testing. Perform routine tests and gas component tests on the whole machine.

[0034] The above insulating gas is SF6 gas.

[0035] By using the assembly method of this pot-type capacitive voltage transformer, the process of repeated disassembly and assembly is simplified to the greatest extent, and the intrusion of metal impurities and dust into the UHV cavity caused by repeated disassembly and assembly is avoided. The whole machine can be disassembled into multiple cavities, installed in modules and semi-finished products can be tested, which shortens the production man-hours and improves the quality controllability. The modular installation and detection can increase the probability of discovering and solving potential problems. Ensure that each component is qualified and reliable before the whole machine is assembled. The coaxial electrode is arranged with the high voltage on the inner side and the low voltage on the outer side. The axial electric field distribution is uniform, which is beneficial to improving the UHV voltage insulation ability. The overall volume is small and the structure is compact, which is very suitable for enclosed power stations or places with limited space. It can effectively avoid the introduction of impurities between electrodes, confirm the assembly dimensions, avoid problems such as the introduction of metal impurities and electrode deformation caused by secondary disassembly and assembly, ensure the accuracy of the capacitance of the voltage dividing capacitor, and keep the error precision characteristics of the pot-type capacitive voltage transformer product within the high-precision range of 0.2 level.

[0036] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for assembling a tank-type capacitor voltage transformer, characterized in that: The following steps are involved: S1, assembling a high-voltage capacitor module; the high-voltage capacitor module comprises a housing (1); a core column (4), a high-voltage electrode (3) and a low-voltage electrode (2) are coaxially arranged in the housing (1); a four-way connector (5) is connected to the outer wall of the housing (1); step S1 comprises the following steps: S11, coaxially assembling the low-voltage electrode (2) in the housing (1); the high-voltage electrode (3) is fixed on the core column (4) inside the housing (1); S12, with one end of the high-voltage electrode (3) as the stationary end and the low-voltage electrode (2) as the moving end, the low-voltage electrode (2) is covered outside the high-voltage electrode (3); The housing (1) is then sealed with bolts; S13, a four-way connector (5) is connected to the outer wall of the housing (1); the four-way connector (5) comprises a conductive rod (502), one direction of the conductive rod (502) is connected to the housing (1), one direction is connected to the electromagnetic unit module (7), and the other direction is connected to the low-voltage capacitor module (6); S14: the installed high-voltage capacitor module is evacuated and filled with gas for leak detection; evacuated to below 10 Pa and maintained for at least 8 hours; filled with insulating gas to the rated pressure, and sealed for leak detection; S15, semi-finished product tests are carried out; including capacitance, withstand voltage, partial discharge, and dielectric loss tests; S2, assembling the electromagnetic unit module (7); S3, assembling and packaging the low voltage capacitor module (6); S4, docking the high-voltage capacitor module with the electromagnetic unit module (7) and the low-voltage capacitor module (6); S5, vacuum leak detection; S6. Conduct the test.

2. The method for assembling a tank-type capacitor voltage transformer according to claim 1, characterized in that: In step S13, the four-way connector (5) comprises a housing 1 (501); a conductive rod (502) is arranged inside the housing 1 (501); and the conductive rod (502) is arranged in a T-shape or a cross shape as a whole.

3. The method for assembling a tank-type capacitor voltage transformer according to claim 1, characterized in that: The electromagnetic unit module (7) comprises an iron core (703); a coil (701) is wound around the iron core (703); a shielding cover (704) is provided on the outer shell of the coil (701); an insulating layer is provided on the outer shell (704); the iron core (703) is arranged on a clamp (706); the clamp (706) is arranged on a second housing (707); a fixing part (705) is arranged at the lower end of the clamp (706); and a compensating reactor (702) is arranged on the fixing part (705).

4. The method for assembling a tank-type capacitor voltage transformer according to claim 3, characterized in that: Step S2 includes the following steps: S21, fixing the iron core (703) on the clamp (706); S22, sleeve the coil (701) onto the iron core (703); then assemble a shielding cover (704) outside the coil (701); and then assemble an insulating layer outside the shielding cover (704); S23. Assemble the compensating reactor (702) on the fixing member (705).

5. The method for assembling a tank-type capacitor voltage transformer according to claim 4, characterized in that: After step S23, the method further comprises step S24: evacuating the electromagnetic unit module (7) and inflating it for leak detection; evacuating it to below 10 Pa and maintaining it for at least 4 hours, inflating it with insulating gas to the rated pressure, and sealing it for leak detection; the sealing time is 24 hours; and then conducting a semi-finished product test of the electromagnetic unit module (7).

6. The method for assembling a tank-type capacitor voltage transformer according to claim 1, characterized in that: The low-voltage capacitor module (6) comprises a housing three (601); the housing three (601) is provided with a capacitor element (602); step S3 comprises the following steps: S31, assembling a capacitor element (602) in the housing three (601); S32, measure the temperature coefficient of the low voltage capacitor module (6); the temperature coefficient parameter is within ±1×10 -4 / K range; S33, the low-voltage capacitor module (6) is evacuated and filled with gas for leak detection; the evacuation is maintained below 10 Pa for at least 4 hours, and then filled with insulating gas to the rated pressure, and then sealed for leak detection; the sealing time is 24 hours; S34. Conduct semi-finished product tests, including capacitance, withstand voltage, partial discharge, and dielectric loss tests.

Images