A transformer on-load tap changer testing device

Abstract

The utility model belongs to transformer maintenance detection equipment technical field discloses a kind of transformer on-load switch testing device, including sampling assembly, sampling assembly includes sampling chamber;Sampling port, be located in the lateral wall of sampling chamber, and communicate with sampling chamber;Sampling tube, the both ends of sampling tube are communicated with sampling chamber and chromatographic analyzer;Suction tube, one end of suction tube communicates with sampling chamber, and the free end of suction tube is connected with vacuum pump. First impeller is rotationally arranged in sampling chamber: first impeller coaxially fixedly connected with cylinder body, cylinder body is the cylinder body with opening in top, piston is slidably connected in cylinder body, piston and cylinder body form sealed chamber, piston is connected with support rod, and the free end of support rod is rotationally connected with second impeller;The scheme is inhaled into sampling chamber in oil sample, and sampling chamber is negative pressure environment, so that bubble in oil sample is separated out and discharged under low pressure condition;The utility model solves the problem that there is bubble in transformer oil product.

Description

Technical Field

[0001] This solution belongs to the technical field of transformer maintenance and testing equipment, specifically involving a transformer on-load switch testing device. Background Technology

[0002] An on-load tap changer (OLTC) is a voltage regulating device used to change the tap position of a transformer winding. OLTC operates under transformer energization or load conditions. The basic principle of an OLTC is to switch between taps in the transformer windings without interrupting the transformer's load current, thereby changing the number of turns and ultimately achieving voltage regulation.

[0003] Referring to the existing public (announcement) technology with CN113702100A, transformer oil sample testing is a crucial part of transformer condition-based maintenance. Oil chromatography analysis plays a key role in determining the condition of operating transformers. Power companies are increasingly demanding higher standards for condition-based maintenance of substation equipment, leading to shorter oil sampling cycles for transformers. Transformer oil chromatography analysis remains critical for assessing the condition of operating transformers. With the significant increase in the scale of new energy grid connection, oil chromatography testing cycles are becoming shorter, oil sampling frequency is increasing, and the standards for oil sample acquisition are becoming more stringent.

[0004] A novel oil sampling device for on-load tap changers of transformers is disclosed in existing publication (announcement number CN113702100A), comprising a connecting plate, a connecting screw assembly, a tray, a connecting bolt assembly, an adjusting nut assembly, and an oil sampling valve. The connecting plate has a flat plate structure and is fixed to the lower end of the tap changer's oil sampling pipe by the connecting bolt assembly. The oil sampling valve is located in the oil sampling hole. The lower end of the connecting plate is provided with multiple screw holes. The connecting screw assembly includes multiple screws that are screwed into the screw holes, and both ends of the screws are provided with threaded sections. The tray is provided with holes corresponding to the connecting screw assembly so that it can be fitted onto the lower end of the connecting screw assembly. The screws in the connecting screw assembly pass through the tray and extend out.

[0005] The aforementioned device's oil valve is fixed to the connecting plate by welding or other methods, effectively protecting the valve body and preventing gas ingress or liquid leakage during the disassembly and assembly of the oil sampling valve. However, the oil in the transformer itself will release gas due to the dissociation of oil molecules under high voltage, resulting in air bubbles in the oil sample. These air bubbles cannot be eliminated by the aforementioned oil sampling device. For on-load switch oil sample testing, the presence of air bubbles will significantly interfere with the oil chromatographic analysis results. Utility Model Content

[0006] The purpose of this solution is to provide a transformer on-load switch testing device to address the problem of air bubbles in transformer oil.

[0007] To achieve the above objectives, this solution provides a pressure vessel on-load switch testing device, including a sampling component and a chromatographic analyzer, wherein the sampling component includes:

[0008] Sampling chamber;

[0009] The sampling port is located on the side wall of the sampling chamber and communicates with the sampling chamber;

[0010] A sampling tube, the two ends of which are respectively connected to a sampling chamber and a chromatographic analyzer;

[0011] A vacuum tube is provided, one end of which is connected to the sampling chamber, and the free end of which is connected to a vacuum pump.

[0012] The principle and effect of this scheme are as follows: The chromatographic analyzer is existing technology and will not be elaborated upon here. The sampling chamber is placed in the transformer oil. A vacuum pump creates a negative pressure environment within the sampling chamber, thereby drawing the oil sample from the sampling port into the chamber. The negative pressure environment within the sampling chamber accelerates the precipitation and expulsion of air bubbles in the oil sample under low pressure. The degassed oil sample is then sent into the chromatographic analyzer, avoiding interference from air bubbles in the analyzer's detection.

[0013] Furthermore, a first impeller is rotatably provided inside the sampling chamber.

[0014] The principle and effect of this scheme are as follows: when the oil flows into the sampling chamber under negative pressure through the sampling port, the oil impacts the first impeller and causes it to rotate. The shear force and turbulence effect generated by the blades of the first impeller cause the tiny bubbles in the oil (such as microbubbles with a diameter of <0.5mm) to accelerate collision and coalesce, forming larger bubbles (such as bubbles with a diameter of >2mm). Under the synergistic effect of negative pressure, they float to the top of the sampling chamber and are continuously discharged by the vacuum pump through the suction pipe.

[0015] Furthermore, the first impeller is coaxially fixedly connected to a cylinder body, the cylinder body having an opening at the top, a piston is slidably connected inside the cylinder body, the piston and the cylinder body enclose a sealed chamber, the piston is connected to a support rod, and the free end of the support rod is rotatably connected to a second impeller.

[0016] The principle and effect of this scheme are as follows: When the sampling chamber is under negative pressure, the pressure difference between the inside and outside of the cylinder drives the piston to slide towards the opening. This pushes the second impeller to rise vertically via the support rod. Simultaneously, the oil flows in and drives the first impeller to rotate. Through coaxial transmission, the cylinder and the second impeller rotate synchronously. During this process, the rotation of the first impeller creates a bottom vortex that breaks up the surface tension of the oil, causing deep bubbles to rise. Meanwhile, the second impeller rotates along a spiral trajectory as it rises, creating turbulence from top to bottom. This generates interlaced shear forces in the oil at different depths, accelerating the coalescence of microbubbles into larger bubbles, which are then discharged through the extraction pipe.

[0017] Furthermore, a groove for guiding the support rod is provided inside the cylinder.

[0018] The principle and effect of this solution are as follows: the slide groove is used to provide positioning and guidance for the up and down movement of the support rod.

[0019] Furthermore, there are multiple sampling ports, and these ports are spaced apart along the length of the sampling chamber; each sampling port is a conical structure; the suction pipe is located at the top of the sampling chamber, and the sampling chamber is connected to an extension rod.

[0020] The principle and effect of this scheme are as follows: when the extension rod drives the sampling chamber to move vertically in the transformer oil, multiple sampling ports distributed at intervals along the length of the chamber can correspond to oil products of different oil layers, avoiding sampling of oil products from only the same oil layer.

[0021] Furthermore, it also includes a filter assembly, which includes a filter screen and a sealing ball. The sealing ball is disposed inside the sampling port and is used to seal the sampling port. The sealing ball is connected to a compression spring, and the free end of the compression spring is fixedly connected to the sampling port. The filter screen is disposed outside the sealing ball, and the sealing ball and the filter screen are configured to cooperate with each other.

[0022] The principle and effect of this solution are as follows: A filter screen is used to filter large metal particles in the transformer oil, preventing them from entering the sampling chamber. A sealing ball seals the sampling chamber when no oil is being sampled, preventing external oil from entering. During oil sampling, a vacuum pump creates a negative pressure environment within the sampling chamber, causing the sealing ball to move and compress the spring, creating an oil passage gap between the sealing ball and the sampling port. External oil enters the sampling chamber through this gap. After the filter screen is installed, metal particles easily adhere to or clog the filter pores, reducing the oil intake at the sampling port; therefore, the filter screen needs to be cleaned. In this solution, after oil is sampled in the sampling chamber, the environment changes from negative pressure to normal pressure. The sealing ball returns to its original position under the preload of the spring. Because the spring is elastic, the sealing ball vibrates the filter screen when it comes into contact with it, shaking off any metal particles adhering to the screen.

[0023] Furthermore, one end of the sampling tube passes through the sampling chamber, a diaphragm pump is provided on the sampling tube, a support tube is fixedly connected to the sampling tube, the free end of the support tube is rotatably connected to the first impeller, a sampling port is provided on the support tube, a blocking ball is provided inside the sampling port, the blocking ball is used to seal the sampling port, a spring is connected to the blocking ball, and the free end of the spring is fixedly connected to the support tube.

[0024] The principle and effect of this scheme are as follows: When the diaphragm pump is working, it draws in the sampling tube. The plugging ball receives the negative pressure suction of the diaphragm pump, thereby compressing the spring and creating an oil sampling gap between itself and the sampling port. This allows the filtered oil in the sampling chamber to flow through the oil sampling gap into the support tube, and finally out of the sampling tube, completing the oil sampling. After the diaphragm pump stops working, the plugging ball loses the negative pressure suction of the diaphragm pump and, driven by the spring preload, returns to its original position, contacting the sampling port, thereby sealing the sampling port and preventing the oil in the sampling chamber from flowing into the support tube and the sampling tube.

[0025] Furthermore, the rotational axis of the first impeller coincides with the central axis of the sampling chamber; the central axes of the support tube and the sampling tube coincide with the central axis of the sampling chamber.

[0026] The principle and effect of this scheme are as follows: through the above settings, the oil sampled from the sampling port is located in the center of rotation area, where there are fewer metal impurities, making the sampled oil relatively clean.

[0027] Furthermore, a third impeller is provided inside the sampling tube, and a drive rod is coaxially and fixedly connected to the third impeller. The free end of the drive rod is coaxially and fixedly connected to the first impeller.

[0028] The principle and effect of this scheme are as follows: When the diaphragm pump is working, the sucked-in oil drives the third impeller to rotate. The third impeller drives the drive rod, the first impeller, and the second impeller to rotate synchronously, thereby causing the oil in the sampling chamber to rotate. During the rotation of the oil, due to centrifugal force, metal impurities are thrown outwards from the center of rotation, while the oil in the center of rotation is relatively cleaner. Thus, when sampling, the oil sample taken from the center of rotation contains fewer metal impurities, improving the purity of the oil sample. This helps reduce the risk of contamination and damage to the chromatograph by metal impurities, and improves the accuracy of detection.

[0029] Furthermore, the third impeller is coaxially fixedly connected to a support rod, which is rotatably connected to the inner wall of the sampling tube.

[0030] The principle and effect of this solution is that the support rod is used to support the third impeller, making its rotation more stable. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the internal structure of the sampling component of this utility model;

[0032] Figure 2 This is a schematic diagram of the sampling component of this utility model. Figure 1 ;

[0033] Figure 3 This is a schematic diagram of the sampling component of this utility model. Figure 2 ;

[0034] Figure 4 for Figure 1 Enlarged view of point A in the middle Figure 1 ;

[0035] Figure 5 for Figure 1 Enlarged view of point A in the middle Figure 2 ;

[0036] Figure 6 for Figure 2 Enlarged view of point B Figure 1 ;

[0037] Figure 7 for Figure 2 Enlarged view of point B Figure 2 .

[0038] The corresponding labels in the attached diagram are named as follows: Sampling assembly 1, Sampling chamber 11, Sampling port 111, Sampling tube 12, Air extraction tube 13, First impeller 14, Cylinder 15, Sealed chamber 151, Piston 16, Support rod 17, Second impeller 18, Extension rod 19, Filter assembly 2, Filter screen 21, Sealing ball 22, Compression spring 221, Support tube 23, Sampling port 231, Blocking ball 232, Spring 233, Third impeller 24, Drive rod 25, Support rod 26. Detailed Implementation

[0039] The following will describe the concept and technical effects of this utility model clearly and completely with reference to the embodiments, so as to fully understand the purpose, features and effects of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are all within the scope of protection of this utility model.

[0040] Example:

[0041] Please see Figures 1-3 This embodiment provides a transformer on-load switch testing device, including a sampling assembly 1 and a chromatograph (not shown). The chromatograph is existing equipment and will not be described in detail here. The sampling assembly 1 consists of a sampling chamber 11, a sampling port 111, a sampling tube 12, a suction tube 13, and auxiliary functional components. The specific structure and connection relationship are as follows:

[0042] The sampling chamber 11 is a cylindrical, sealed cavity with two conical sampling ports 111 spaced axially along its side wall, which are connected to the sampling chamber 11. Each sampling port 111 has an outer diameter of Φ5mm at the inlet and an inner diameter of Φ8mm at the outlet, used to guide the oil to flow into the chamber more rapidly. A vacuum pipe 13 is installed at the top of the sampling chamber 11, connected to a vacuum pump (not shown), to create a negative pressure environment of -0.08MPa within the chamber. An extension rod 19 is connected to the top of the sampling chamber 11, through which an external operating handle (not shown) is connected, allowing for vertical movement within the transformer oil to achieve layered sampling.

[0043] A first impeller 14 is coaxially mounted inside the sampling chamber 11, with six curved blades at a 30° angle. The rotating shaft of the first impeller 14 is connected to the inner wall of the sampling chamber 11 via bearings, allowing the impeller to rotate freely under the impact of oil flow. A cylinder 15 is coaxially fixedly connected to the upper end of the rotating shaft of the first impeller 14. The cylinder 15 is a cylindrical structure with an open top, and its inner wall is machined with two symmetrical axial grooves (not shown). A piston 16 is installed inside the cylinder 15, and the piston 16 slides against the inner wall of the cylinder 15 via a polytetrafluoroethylene sealing ring. A support rod 17 is welded to the top of the piston 16, and the support rod 17 is slidably connected to the groove. The top end of the support rod 17 is connected to a second impeller 18 via a ball bearing. When the vacuum pump is started, the pressure difference inside and outside the cylinder 15 drives the piston 16 to move upward along the groove, causing the second impeller 18 to rise synchronously and rotate with the first impeller 14 at 120 rpm, forming a turbulent flow field from top to bottom.

[0044] During operation, oil flows into the sampling chamber 11 under negative pressure through the sampling port 111. The oil impacts the first impeller 14, causing it to rotate. The shear force and turbulence generated by the blades of the first impeller 14 accelerate the collision and coalescence of tiny bubbles in the oil (such as microbubbles with a diameter <0.5mm), forming larger bubbles (such as bubbles with a diameter >2mm). Under the synergistic effect of negative pressure, these bubbles rise to the top of the sampling chamber 11. When the sampling chamber 11 is under negative pressure, the pressure difference inside and outside the cylinder 15 drives the piston 16 to slide towards the top opening. This, along with the support rod 17, pushes the second impeller 18 to rise vertically. Simultaneously, the oil flows in, driving the first impeller 14 to rotate. Through coaxial transmission, this drives the cylinder 15 and the second impeller 18 to rotate synchronously. During this process, the rotation of the first impeller 14 creates a bottom vortex that breaks up the surface tension of the oil, causing deep bubbles to rise. Meanwhile, the second impeller 18 rotates along a spiral trajectory as it is lifted, creating a downward turbulence that causes oil at different depths to generate interlaced shear forces, accelerating the coalescence of microbubbles into large bubbles, which are then discharged through the suction pipe 13.

[0045] Please see Figures 3-7Each sampling port 111 is equipped with a filter assembly 2, including a stainless steel filter screen 21 with a pore size of 0.1 mm and a nitrile rubber sealing ball 22. The sealing ball 22 is used to seal the sampling port 111. The sealing ball 22 is connected to a compression spring 221. The free end of the compression spring 221 is fixedly connected to the sampling port 111, and the filter screen 21 is located outside the sealing ball 22. The sealing ball 22 and the filter screen 21 are configured to cooperate with each other. Under normal conditions, the preload of the compression spring 221 causes the sealing ball 22 to press tightly against the filter screen 21 to achieve a seal (e.g., ...). Figure 4 (As shown). When the vacuum pump is pumping air, the pressure difference inside and outside the sampling chamber 11 overcomes the spring force of the compression spring 221, causing the sealing ball 22 to move inward, forming an annular oil inlet channel (as shown). Figure 5 (As shown); when the pumping stops, the sealing ball 22 resets and strikes the filter screen 21, generating high-frequency vibration to remove surface impurities.

[0046] Please see Figure 2 and Figure 3 One end of the sampling tube 12 passes through the top of the sampling chamber 11 and extends to the center of its bottom; the other end is connected to the chromatograph. A diaphragm pump (not shown) is connected in series in the middle of the sampling tube 12, and a support tube 23 is welded to the section of the tube near the bottom of the sampling chamber 11. The end of the support tube 23 is connected to the rotating shaft of the first impeller 14 via a bearing and a rotary joint. A Φ3mm sampling port 231 is opened on the side wall of the support tube 23. A polyurethane blocking ball 232 is installed inside the sampling port 231 to seal the sampling port 231, and is connected to the inner wall of the support tube 23 via a spring 233. When the diaphragm pump is started, the blocking ball 232 disengages from the sampling port 231 under negative pressure to form an oil sampling passage (e.g., ...). Figure 7 (As shown); when the pump stops, spring 233 pushes the plugging ball 232 to reset the seal (as shown). Figure 6 (As shown).

[0047] Please continue reading. Figure 2 and Figure 3The rotation axis of the first impeller 14 coincides with the central axis of the sampling chamber 11; the central axes of the support tube 23 and the sampling tube 12 coincide with the central axis of the sampling chamber 11; a third impeller 24 is coaxially mounted inside the sampling tube 12, and one end of its rotating shaft is welded and fixed to the drive rod 25. The upper end of the drive rod 25 is connected to the rotating shaft of the first impeller 14 through a coupling, and the lower end is rotatably connected to the inner wall of the sampling tube 12 through a support rod 26. When the diaphragm pump works, the sucked-in oil drives the third impeller 24 to rotate, and the third impeller 24 drives the drive rod 25, the first impeller 14 and the second impeller 18 to rotate synchronously, thereby causing the oil in the sampling chamber 11 to rotate. During the rotation of the oil, due to centrifugal force, metal impurities accumulate to the outer periphery, while the oil in the center of the rotation is relatively cleaner and flows to the sampling tube 12 through the sampling port 231. This method ensures that the oil sample taken from the center of rotation contains fewer metal impurities, improving the purity of the oil sample. This helps reduce the risk of contamination and damage to the chromatograph by metal impurities, thereby improving the accuracy of the detection.

[0048] The above descriptions are merely embodiments of this utility model, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of this utility model, and these should also be considered within the scope of protection of this utility model. These modifications will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application shall be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A transformer on-load tap changer test device comprising a sampling assembly (1) and a chromatograph, characterized in that, The sampling component (1) includes: Sampling chamber (11); Sampling port (111), the sampling port (111) is located on the side wall of the sampling chamber (11) and is connected to the sampling chamber (11); The sampling tube (12) is connected at both ends to the sampling chamber (11) and the chromatograph, respectively. A vacuum pipe (13) is provided, one end of which is connected to a sampling chamber (11), and a vacuum pump is connected to the free end of the vacuum pipe (13); a first impeller (14) is rotatably provided in the sampling chamber (11); a cylinder (15) is coaxially fixedly connected to the first impeller (14), the cylinder (15) is a cylinder (15) with an opening at the top, a piston (16) is slidably connected in the cylinder (15), the piston (16) and the cylinder (15) enclose a sealed chamber (151), the piston (16) is connected to a support rod (17), and a second impeller (18) is rotatably connected to the free end of the support rod (17).

2. The transformer on-load tap changer test apparatus of claim 1, wherein: The cylinder (15) has a groove for guiding the support rod (17).

3. The transformer on-load tap changer test apparatus of claim 1, wherein: The number of sampling ports (111) is multiple, and the multiple sampling ports (111) are spaced apart along the length direction of the sampling chamber (11); the sampling ports (111) are conical sampling ports (111); the air extraction pipe (13) is located at the top of the sampling chamber (11), and the sampling chamber (11) is connected to an extension rod (19).

4. The transformer on-load switch testing device according to claim 3, characterized in that: It also includes a filter assembly (2), which includes a filter screen (21) and a sealing ball (22). The sealing ball (22) is located inside the sampling port (111) and is used to seal the sampling port (111). The sealing ball (22) is connected to a compression spring (221). The free end of the compression spring (221) is fixedly connected to the sampling port (111). The filter screen (21) is located outside the sealing ball (22). The sealing ball (22) and the filter screen (21) are configured to cooperate with each other.

5. A transformer on-load tap changer test apparatus as claimed in claim 4, characterised in that: One end of the sampling tube (12) passes through the sampling chamber (11). A diaphragm pump is provided on the sampling tube (12). A support tube (23) is fixedly connected to the sampling tube (12). The free end of the support tube (23) is rotatably connected to the first impeller (14). A sampling port (231) is provided on the support tube (23). A blocking ball (232) is provided inside the sampling port (231). The blocking ball (232) is used to seal the sampling port (231). A spring (233) is connected to the blocking ball (232). The free end of the spring (233) is fixedly connected to the support tube (23).

6. A transformer on-load tap changer test apparatus as claimed in claim 5, characterised in that: The rotation axis of the first impeller (14) coincides with the central axis of the sampling chamber (11); the central axes of the support tube (23) and the sampling tube (12) coincide with the central axis of the sampling chamber (11).

7. A transformer on-load tap changer test apparatus as claimed in claim 6, characterised in that: The sampling tube (12) is provided with a third impeller (24), and the third impeller (24) is coaxially fixedly connected to a drive rod (25). The free end of the drive rod (25) is coaxially fixedly connected to the first impeller (14).

8. A transformer on-load tap changer test apparatus according to claim 7, characterised in that: The third impeller (24) is coaxially fixedly connected with a supporting rod (26), and the supporting rod (26) is rotationally connected with the inner wall of the sampling pipe (12).

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