An equal potential connection system and method for valve side dc bushing test of a converter transformer

Abstract

This invention relates to an equipotential bonding system and method for testing DC bushings on the valve side of a converter transformer. The DC testing device includes a test equalizing ball with a metal support plate inside. A bushing tail metal component is located at the lower end of the test bushing, and an equipotential bonding assembly is located below this component. The equipotential bonding assembly includes a metal connecting plate and a floating pressure plate. The metal connecting plate is connected to the upper bushing tail metal component via a connecting rod assembly. An insulating protective plate is located along the outer edge of the metal connecting plate. The metal connecting plate is connected to the lower floating pressure plate via a floating connecting rod assembly. The floating connecting rod assembly includes a floating connecting rod and a spring sleeved on the floating connecting rod. The upper end of the spring abuts against the metal connecting plate, and the lower end abuts against the floating pressure plate. This invention offers simple and convenient installation and connection, ensures reliable equipotential bonding, and allows for flexible adjustment according to different product requirements, making it widely applicable.

Description

Technical Field

[0001] This invention relates to the field of DC bushing testing technology for the valve side of converter transformers, specifically to an equipotential bonding system and method for testing DC bushings on the valve side of converter transformers. Background Technology

[0002] Currently, ultra-high voltage direct current (UHVDC) transmission has become an important way to alleviate the contradiction between energy resources and economic layout. The DC bushing on the valve side of the converter transformer is the core component of the converter transformer. One side of the bushing needs to be installed on the outdoor converter transformer and lead the output terminal of the transformer winding out of the oil tank. The other side needs to pass through the wall and extend into the valve hall to form an electrical connection with the converter valve. Therefore, the detection of the performance and condition of the DC bushing is particularly important.

[0003] According to relevant standards, when DC test items are carried out on the DC bushing of the converter transformer valve side for factory testing or type testing, the external insulation (shielding cover) around the shorter end of the bushing and the grounding plate need to be tested together, and the position should be as similar as possible to the expected operating conditions. In the past, DC test equipment had a complex structure, was difficult to manufacture, had high process requirements, was complicated to use, and had high manufacturing costs. However, with the advancement of localization and the development and progress of domestic bushing manufacturers, the test equipment required for DC testing of bushings can now be independently designed, processed and assembled as needed to improve test efficiency.

[0004] Based on actual requirements such as test conditions and space dimensions, the tail end of the bushing needs to be shielded within a well-shaped equipotential bonding sphere. For ease of bushing installation, some DC test wiring devices have the equipotential bonding sphere fixed inside the test tank. However, this requires a soft copper stranded wire or other similar metal wire connected inside the equipotential bonding sphere to the high-potential portion of the bushing to achieve equipotential bonding. The disadvantages of this method are: connecting the connecting wire to the live part of the bushing tail end with screws is risky if the equipotential bonding wire is too short to be installed outside the tank, requiring an operator to reach into the tank for connection, which significantly impacts efficiency; if the equipotential bonding wire is too long, it may snag on the insulating cardboard inside the test device during the bushing's descent, causing insulation damage. Furthermore, because the test device is enclosed, the condition of the bushing and equipotential bonding wire cannot be detected, making it impossible to determine whether the live part of the bushing tail end and the equipotential bonding wire are fully inside the equipotential bonding sphere. A loose connection between the bushing tail end and the equipotential bonding wire, or failure to fully enter the equipotential bonding sphere, will cause discharge. If the equipotential bonding wire and the insulating component come into contact and rub against each other for a long time, the equipotential bonding wire may be damaged, or the screws connecting the equipotential bonding wire and the bushing may become loose, which will lead to the failure of equipotential bonding.

[0005] Patent CN112098785B discloses a test device for DC bushings on the converter valve side and its assembly and usage method. The insulating paper tube, equalizing ball, and its external insulating component in the device are located in the test oil tank. The equalizing ball has an open structure at both the top and bottom. This device solves the inconvenience caused by the traditional structure where the equalizing ball is fixed inside the device and requires the connection of an equipotential line during bushing installation. The structure where the equalizing ball is directly connected to the bushing is convenient to install and has a reliable connection. The equalizing ball and its external insulating component are first placed on the equalizing ball mounting frame. The metal connector is installed on the conductive rod at the tail of the bushing under test. Then, the bushing under test is connected and fixed to the equalizing ball and its external insulating component placed on the mounting frame through the metal connector. However, the above structure of the device is all fixed and is designed for the special structure of the equalizing ball with an open structure at both the top and bottom. Summary of the Invention

[0006] The purpose of this invention is to provide an equipotential bonding system and method for testing the DC bushing on the valve side of a converter transformer. The system is simple and convenient to install and connect, and can ensure reliable equipotential bonding. It can also be flexibly adjusted according to different product conditions and has a wide range of applications.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] An equipotential bonding system for testing DC bushings on the valve side of a converter transformer includes a test bushing, a DC test device, and an equipotential bonding assembly. The DC test device contains a test equalizing ball, which in turn contains a metal support plate. The lower end of the test bushing has a bushing tail metal component, and the equipotential bonding assembly is located below this tail metal component. The equipotential bonding assembly includes a metal component connecting plate and a floating pressure plate. The metal component connecting plate is adjustablely connected to the upper bushing tail metal component via a connecting rod assembly. An insulating protective plate is provided along the outer edge of the metal component connecting plate. The metal component connecting plate is adjustablely connected to the lower floating pressure plate via a floating connecting rod assembly. The floating connecting rod assembly includes a floating connecting rod and a spring sleeved on the floating connecting rod. The upper end of the spring abuts against the metal component connecting plate, and the lower end abuts against the floating pressure plate. During the test, the floating pressure plate contacts the metal support plate.

[0009] The connecting rod assembly includes a metal connecting rod, an upper nut, and a lower nut, wherein the upper end of the metal connecting rod is fixedly connected to the metal part at the tail of the sleeve, and the lower end is clamped and fixed to the metal connecting plate by the upper nut and the lower nut.

[0010] The floating link assembly includes a floating link and a limiting nut, wherein the lower end of the floating link is fixedly connected to the floating pressure plate, and the upper end passes through the metal connecting plate and is threadedly connected to the limiting nut.

[0011] The floating pressure plate is provided with a positioning sleeve, and the lower end of the spring is sleeved on the positioning sleeve, while the lower end of the floating connecting rod passes through the positioning sleeve.

[0012] The metal support plate is provided with positioning holes, and the lower end of the floating connecting rod protrudes from the floating pressure plate and is embedded in the corresponding positioning hole.

[0013] The outer wall of the metal connecting plate is provided with insulating mounting holes, and the insulating protection plate is fixed to a corresponding set of insulating mounting holes by insulating screws.

[0014] The test equalization sphere is open at the top, and the upper part of the test equalization sphere is cylindrical and the lower part is hemispherical.

[0015] The DC test device includes an oil tank and an insulating part located inside the oil tank. The lower end of the test sleeve passes through an opening in the insulating part and is inserted into the test equalizing ball.

[0016] The test sleeve is equipped with a sleeve flange, and when the test sleeve enters the DC test device, the sleeve flange is fixed to the upper end of the oil tank of the DC test device.

[0017] A method for using an equipotential bonding system for testing the DC bushing on the valve side of a converter transformer, comprising the following steps:

[0018] Step 1: Assemble the equipotential bonding assembly and adjust the distance between the metal connecting plate and the floating pressure plate as needed;

[0019] Step 2: Connect the metal connecting plate to the metal part at the lower end of the test sleeve via the connecting rod assembly, and adjust the distance between the metal connecting plate and the metal part at the lower end of the sleeve as needed;

[0020] Step 3: Lower the lower end of the test sleeve together with the installed equipotential bonding assembly into the DC test device until the floating pressure plate is in complete contact with the metal support plate;

[0021] Step 4: After the test bushing falls into the DC test device, fix the bushing flange on the test bushing to the upper end of the oil tank of the DC test device.

[0022] The advantages and positive effects of this invention are as follows:

[0023] 1. This invention utilizes an equipotential bonding assembly to achieve equipotential bonding between the lower end of the test sleeve and the metal support plate inside the test equalizing ball. The metal connecting plate in the equipotential bonding assembly is connected to the upper metal part at the tail of the sleeve via a connecting rod assembly. At the same time, the lower side of the metal connecting plate is connected to the lower floating pressure plate via a floating connecting rod assembly. This not only makes installation and connection simpler and more convenient, but also ensures that the floating pressure plate, under spring pressure, can fully contact the metal support plate, thereby guaranteeing the reliability of the equipotential bonding between the lower end of the test sleeve and the equalizing ball.

[0024] 2. This invention allows for the adjustment of the distance between the metal connecting plate and the metal part at the tail of the sleeve, as well as the distance between the floating pressure plate and the metal connecting plate, by tightening the upper and lower nuts in the connecting rod assembly and the limiting nut in the floating connecting rod assembly. This also allows for the adjustment of the spring's preload pressure. This not only simplifies and facilitates adjustment but also greatly expands the applicability of the invention and improves its flexibility. Furthermore, it ensures that the pressure on the floating pressure plate is appropriate, guaranteeing sufficient contact between the floating pressure plate and the metal support plate while preventing excessive pressure on the metal support plate.

[0025] 3. After the test sleeve is lowered into the DC test device, the sleeve flange is fixed to the upper end of the oil tank of the DC test device to achieve a pressure holding effect. This ensures that the floating pressure plate and the metal support plate of the equalizing ball are always in full contact during the entire test, thereby further ensuring the reliability of the equipotential connection. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating the usage state of the present invention.

[0027] Figure 2 for Figure 1 Top view of the evenly pressure ball.

[0028] Figure 3 for Figure 1 A schematic diagram of the structure of the intermediate potential connection component.

[0029] Figure 4 for Figure 3 Enlarged view of point A in the image.

[0030] Figure 5 for Figure 3 Top view of the intermediate potential connection component.

[0031] Figure 6 for Figure 3 Top view of the metal connecting plate.

[0032] Among them, 1 is the test bushing, 101 is the metal part at the tail of the bushing, 102 is the tail guide post, 103 is the bushing flange, 2 is the DC test device, 201 is the oil tank, 202 is the insulation part, 203 is the test equalizing ball, 2031 is the metal support plate, 20311 is the positioning hole, 20312 is the guide post hole of the support plate, 3 is the equipotential bonding assembly, 301 is the metal part connecting plate, 3011 is the metal part connecting hole, 3012 is the floating plate connecting hole, 30 13 is an insulating mounting hole, 3014 is a first guide post hole, 302 is a connecting rod assembly, 3021 is a metal connecting rod, 3022 is a lower nut, 3023 is an upper nut, 303 is a floating pressure plate, 3031 is a second guide post hole, 304 is a floating connecting rod assembly, 3041 is a floating connecting rod, 3042 is a limit nut, 3043 is a pressure plate connection end, 305 is a spring, 306 is a positioning sleeve, 307 is an insulating protection plate, and 308 is an insulating screw. Detailed Implementation

[0033] The invention will now be described in further detail with reference to the accompanying drawings.

[0034] like Figures 1-6 As shown, the present invention includes a test sleeve 1, a DC test device 2, and an equipotential bonding assembly 3. The DC test device 2 contains a test equalizing ball 203, which contains a metal support plate 2031. The lower end of the test sleeve 1 has a sleeve tail metal part 101, and the equipotential bonding assembly 3 is located below the sleeve tail metal part 101. Figures 3-5 As shown, the equipotential bonding assembly 3 includes a metal connecting plate 301 and a floating pressure plate 303. The metal connecting plate 301 is connected to the upper sleeve tail metal part 101 via a connecting rod assembly 302. An insulating protective plate 307 is provided on the outer edge of the metal connecting plate 301. The metal connecting plate 301 is connected to the lower floating pressure plate 303 via a floating connecting rod assembly 304. The floating connecting rod assembly 304 includes a floating connecting rod 3041 and a spring 305 sleeved on the floating connecting rod 3041. The upper end of the spring 305 abuts against the metal connecting plate 301, and the lower end abuts against the floating pressure plate 303.

[0035] In this invention, the lower end of the test sleeve 1 is first connected to the equipotential bonding assembly 3. Then, the test sleeve 1 and the equipotential bonding assembly 3 are lowered into the DC test device 2. When the lower end of the test sleeve 1 enters the test equalizing ball 203 and the floating pressure plate 303 on the lower side of the equipotential bonding assembly 3 is in full contact with the metal support plate 2031, an equipotential connection is achieved between the test sleeve 1 and the test equalizing ball 203. After the floating pressure plate 303 contacts the metal support plate 2031, the lower end of the test sleeve 1 can continue to move down a set distance. This causes the metal connecting plate 301 to move down and compress the spring 305, giving the floating pressure plate 303 sufficient clamping force, thereby ensuring that the floating pressure plate 303 is in full contact with the metal support plate 2031.

[0036] like Figures 3-5 As shown, in this embodiment, the connecting rod assembly 302 includes a metal connecting rod 3021, an upper nut 3023, and a lower nut 3022. The upper end of the metal connecting rod 3021 is fixedly connected to the metal part 101 at the tail of the sleeve, and the lower end is clamped and fixed on the metal connecting plate 301 by the upper nut 3023 and the lower nut 3022. By screwing the upper nut 3023 and the lower nut 3022, the connection position between the metal connecting rod 3021 and the metal connecting plate 301 can be changed, thereby adjusting the distance between the metal connecting plate 301 and the metal part 101 at the tail of the sleeve according to actual needs.

[0037] like Figures 3-5 As shown, in this embodiment, the floating link assembly 304 includes a floating link 3041 and a limiting nut 3042. The lower end of the floating link 3041 is fixedly connected to the floating pressure plate 303, and the upper end passes through the metal connecting plate 301 and is threadedly connected to the limiting nut 3042. Tightening the limiting nut 3042 can adjust the limiting height of the metal connecting plate 301 and the spring 305, thereby adjusting the preload pressure of the spring 305 on the floating pressure plate 303.

[0038] like Figure 4 As shown, in this embodiment, the floating pressure plate 303 is provided with a positioning sleeve 306, and the lower end of the spring 305 is sleeved on the positioning sleeve 306, while the lower end of the floating connecting rod 3041 passes through the positioning sleeve 306.

[0039] like Figure 2 As shown in this embodiment, the metal support plate 2031 can be provided with positioning holes 20311 as needed. The pressure plate connection end 3043 on the lower side of the floating connecting rod 3041 can expose the floating pressure plate 303 and be embedded in the corresponding positioning hole 20311 to assist in positioning, thereby ensuring that the pressing position of the floating pressure plate 303 and the metal support plate 2031 is accurate.

[0040] like Figure 6 As shown, in this embodiment, the metal connecting plate 301 has four metal connecting holes 3011 evenly distributed along the circumferential direction for the metal connecting rod 3021 to pass through, and two floating plate connecting holes 3012 are symmetrically provided on both sides of the metal connecting plate 301 for the floating connecting rod 3041 to pass through.

[0041] like Figure 6 As shown, in this embodiment, the outer wall of the metal connecting plate 301 is provided with an insulating mounting hole 3013, such as... Figure 3 and Figure 5 As shown, the insulating protection plate 307 is fixed to a corresponding set of insulating mounting holes 3013 by insulating screws 308.

[0042] like Figure 1 As shown, in this embodiment, the tail metal part 101 of the sleeve is provided with a tail guide post 102 in the middle, as... Figure 2 As shown, the metal support plate 2031 has a support plate guide post hole 20312 in the middle for the tail guide post 102 to pass through, as... Figure 6 As shown, the metal connecting plate 301 has a first guide post hole 3014 in the middle for the tail guide post 102 to pass through, as... Figure 3 As shown, the floating pressure plate 303 has a second guide post hole 3031 in the middle for the tail guide post 102 to pass through.

[0043] like Figure 1 As shown, in this embodiment, the upper end of the test equalizing ball 203 is open, and the upper part of the test equalizing ball 203 is cylindrical and the lower part is hemispherical. The metal support plate 2031 is provided at the connection between the cylinder and the hemisphere.

[0044] like Figure 1 As shown, in this embodiment, the DC test device 2 includes an oil tank 201 and an insulating part 202 disposed in the oil tank 201. The lower end of the test sleeve 1 passes through the opening in the insulating part 202 and is inserted into the test equalizing ball 203.

[0045] like Figure 1 As shown, in this embodiment, the test sleeve 1 is provided with a sleeve flange 103. When the test sleeve 1 enters the DC test device 2, the sleeve flange 103 is fixed to the upper end of the oil tank 201 of the DC test device 2, thereby playing a pressure-holding role. That is, the metal connecting plate 301 in the equipotential bonding assembly 3 continuously applies pressure to the floating pressure plate 303 through the spring 305, thereby ensuring that the floating pressure plate 303 and the metal support plate 2031 are always in full contact and in an equipotential bonding state throughout the entire test process.

[0046] The working principle of this invention is as follows:

[0047] Step 1: Assemble the equipotential bonding assembly 3, and adjust the distance between the metal connecting plate 301 and the floating pressure plate 303 according to the specifications of the test product, thereby adjusting the preload pressure of the spring 305. In addition, the metal connecting plate 301 and the floating pressure plate 303 must be kept parallel. The distance between the metal connecting plate 301 and the floating pressure plate 303 can be adjusted by turning the limiting nut 3042.

[0048] Step 2: Connect the metal connecting plate 301 to the metal part 101 at the lower end of the test sleeve 1 via the connecting rod assembly 302. Adjust the positions of the upper nut 3023 and the lower nut 3022 according to the test requirements, thereby adjusting the distance between the metal connecting plate 301 and the metal part 101 at the lower end of the sleeve. It is necessary to ensure that after the floating pressure plate 303 on the lower side contacts the metal support plate 2031, the metal part 101 at the lower end of the sleeve can drive the metal connecting plate 301 to continue to descend a sufficient distance so that the spring 305 has sufficient clamping force on the floating pressure plate 303, thereby ensuring that the floating pressure plate 303 and the metal support plate 2031 are in full contact, while the metal support plate 2031 is not subjected to excessive force.

[0049] Step 3: Lower the lower end of the test sleeve 1 together with the installed equipotential bonding assembly 3 into the DC test device 2. The lowering process should be carried out slowly, and the fit between the test sleeve 1 and the insulation part 202 inside the DC test device 2 should be observed while it is lowering.

[0050] Step 4: After the test sleeve 1 falls into the DC test device 2, the sleeve flange 103 on the test sleeve 1 is fixedly connected to the upper end of the oil tank 201 of the DC test device 2 to achieve pressure maintenance, so that the floating pressure plate 303 and the metal support plate 2031 can be kept in full contact throughout the test.

[0051] In step one above, the distance adjustment between the metal connecting plate 301 and the floating pressure plate 303, and in step two above, the distance adjustment between the metal connecting plate 301 and the metal part 101 at the tail of the sleeve, need to take into account the specific product specifications and the position of the sleeve flange 103 on the test sleeve 1, so as to ensure that after the sleeve flange 103 is fixed to the upper end of the oil tank 201, the pressure on the floating pressure plate 303 is appropriate, that is, it can ensure that the floating pressure plate 303 and the metal support plate 2031 are in full contact, while the metal support plate 2031 is not subjected to excessive pressure.

[0052] In addition, the present invention can be adjusted according to the actual product conditions by screwing on the upper nut 3023, the lower nut 3022 and the limiting nut 3042. This not only makes the adjustment simple and convenient, but also greatly expands the scope of application of the present invention and improves the flexibility of its use.

Claims

1. A system for equal potential bonding for valve side DC bushing test of a converter transformer, characterized by: The test sleeve (1), DC test device (2), and equipotential bonding assembly (3) are included. The DC test device (2) is equipped with a test equalizing ball (203) inside, and a metal support plate (2031) is provided inside the test equalizing ball (203). The lower end of the test sleeve (1) is equipped with a sleeve tail metal part (101), and the lower side of the sleeve tail metal part (101) is equipped with an equipotential bonding assembly (3). The equipotential bonding assembly (3) includes a metal part connecting plate (301) and a floating pressure plate (303). The metal part connecting plate (301) is adjustablely connected to the upper sleeve tail part through a connecting rod assembly (302). Metal parts (101) are connected, and an insulating protective plate (307) is provided on the outer edge of the metal parts connecting plate (301). The metal parts connecting plate (301) is adjustablely connected to the lower floating pressure plate (303) through a floating link assembly (304). The floating link assembly (304) includes a floating link (3041) and a spring (305) sleeved on the floating link (3041). The upper end of the spring (305) abuts against the metal parts connecting plate (301) and the lower end abuts against the floating pressure plate (303). During the test, the floating pressure plate (303) contacts the metal support plate (2031).

2. The commutation transformer valve-side DC bushing test equal potential bonding system according to claim 1, characterized in that: The connecting rod assembly (302) includes a metal connecting rod (3021), an upper nut (3023), and a lower nut (3022), wherein the upper end of the metal connecting rod (3021) is fixedly connected to the metal part (101) at the tail of the sleeve, and the lower end is clamped and fixed on the metal connecting plate (301) by the upper nut (3023) and the lower nut (3022).

3. The commutation transformer valve side DC bushing test equal potential bonding system of claim 1, wherein: The floating link assembly (304) includes a floating link (3041) and a limiting nut (3042), wherein the lower end of the floating link (3041) is fixedly connected to the floating pressure plate (303), and the upper end passes through the metal connecting plate (301) and is threadedly connected to the limiting nut (3042).

4. The commutation transformer valve side DC bushing test equal potential bonding system of claim 1, wherein: The floating pressure plate (303) is provided with a positioning sleeve (306), and the lower end of the spring (305) is sleeved on the positioning sleeve (306), while the lower end of the floating connecting rod (3041) passes through the positioning sleeve (306).

5. The commutation transformer valve side DC bushing test equal potential bonding system of claim 1, wherein: The metal support plate (2031) is provided with positioning holes (20311), and the lower end of the floating connecting rod (3041) protrudes from the floating pressure plate (303) and is embedded in the corresponding positioning hole (20311).

6. The commutation transformer valve side DC bushing test equal potential bonding system of claim 1, wherein: The outer wall of the metal connecting plate (301) is provided with insulating mounting holes (3013), and the insulating protection plate (307) is fixed to a corresponding set of insulating mounting holes (3013) by insulating screws (308).

7. The commutation transformer valve side DC bushing test equal potential bonding system of claim 1, wherein: The test equalization ball (203) has an open top, and the upper part of the test equalization ball (203) is cylindrical and the lower part is hemispherical.

8. The commutation transformer valve side DC bushing test equal potential bonding system of claim 1, wherein: The DC test device (2) includes an oil tank (201) and an insulating part (202) provided in the oil tank (201). The lower end of the test sleeve (1) passes through the opening in the insulating part (202) and is inserted into the test equalizing ball (203).

9. The commutation transformer valve-side DC bushing test equal potential bonding system of claim 8, wherein: The test sleeve (1) is provided with a sleeve flange (103), and when the test sleeve (1) enters the DC test device (2), the sleeve flange (103) is fixed to the upper end of the oil tank (201) of the DC test device (2).

10. A method of testing the equal potential bonding system of a converter transformer valve side DC bushing according to claim 9, characterized in that: Includes the following steps: Step 1: Assemble the equipotential bonding assembly (3) and adjust the distance between the metal connecting plate (301) and the floating pressure plate (303) as needed; Step 2: Connect the metal connecting plate (301) to the metal part (101) at the lower end of the test sleeve (1) via the connecting rod assembly (302), and adjust the distance between the metal connecting plate (301) and the metal part (101) at the lower end of the sleeve as needed; Step 3: Lower the lower end of the test sleeve (1) together with the installed equipotential bonding assembly (3) into the DC test device (2) until the floating pressure plate (303) is in complete contact with the metal support plate (2031); Step 4: After the test sleeve (1) falls into the DC test device (2), fix the sleeve flange (103) on the test sleeve (1) to the upper end of the oil tank (201) of the DC test device (2).

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