Density monitoring device for direct-current wall bushing

Abstract

The invention relates to the technical field of switches operated by fluid pressure change, fluid pressure wave or flow change, in particular to a direct-current wall bushing density monitoring device. The direct-current wall bushing density monitoring device comprises a density relay, the density relay is connected with an air pipe, one end of the air pipe is provided with a valve used for being connected with a gas cavity of a direct-current wall bushing, a protection box is arranged outside the density relay, a mounting base is arranged in the protection box, the density relay is mounted on the mounting base, and the density relay is connected with the air pipe. And one end, far away from the valve, of the air pipe is connected with the mounting seat, so that the air path is connected with the density relay through the mounting seat, and the requirement that converter station operation and maintenance personnel conveniently, visually and safely obtain the internal air pressure value of the direct-current wall bushing can be met through the design.

Description

Technical Field

[0001] The invention relates to the technical field of switches operated by changes in fluid pressure, fluid pressure waves or flow rate changes, and in particular to a DC wall bushing density monitoring device. Background Art

[0002] In DC power transmission and transformation projects, the DC wall bushing is the only electrical component connecting the inside and outside of the valve hall, carrying the voltage and current of the entire line. Its performance reliability determines the safety and stability of the entire line. The DC wall bushing includes an insulating shell and a central conductive rod located inside the insulating shell. The inside of the insulating shell is filled with sulfur hexafluoride gas as an insulating gas. If the insulating gas is insufficient, it will cause breakdown, seriously endangering the safety of personnel and property.

[0003] A Chinese invention patent application with application publication number CN117727514A and application publication date March 19, 2024 discloses a high-voltage DC wall bushing, which includes a wall bushing for installation in a wall, and the two sides of the wall bushing are respectively connected to indoor and outdoor composite insulators, and end covers are arranged at the ends of the composite insulator away from the wall barrel to ensure internal sealing, and the interior is filled with insulating gas, and a central conductive rod is arranged inside the composite insulator and the wall barrel, and the two ends of the central conductive rod are connected to the indoor and outdoor conductive joints through the end covers for connection with the outside, and the internal insulating gas is often sulfur hexafluoride gas. If a gas leakage accident occurs, not only will the equipment be damaged due to breakdown discharge, but the sulfur hexafluoride gas discharged into the air will seriously pollute the environment.

[0004] At present, the pressure of sulfur hexafluoride gas in the DC wall bushing is usually monitored by installing at least three independent density relays on the wall barrel of the DC wall bushing. The installation height of the DC wall bushing is generally between 8.5 meters and 15 meters. On-site operation and maintenance personnel often need to use lifting equipment such as aerial platforms to check the pressure parameter value of the density relay on site. There are certain risks in high-altitude operations, and there are safety hazards under live working conditions. Summary of the invention

[0005] The purpose of the present invention is to provide a DC wall bushing density monitoring device to solve the problem that on-site inspection of the density relay requires high-altitude work and there are safety risks in inspection under live conditions.

[0006] The DC wall bushing density monitoring device of the present invention adopts the following technical solutions: A DC wall bushing density monitoring device comprises a density relay, wherein the density relay is connected to an air pipe, one end of the air pipe is provided with a valve for connecting to the gas cavity of the DC wall bushing, a protection box is arranged outside the density relay, a mounting seat is arranged inside the protection box, the density relay is mounted on the mounting seat, and one end of the air pipe away from the valve is connected to the mounting seat so that the gas path is connected to the density relay through the mounting seat.

[0007] Furthermore, a stop valve is provided in the air pipe between the density relay and the valve.

[0008] Furthermore, the mounting seat includes an integrated integrated valve, the integrated integrated valve includes a stop valve and a self-sealing valve, and the density relay is arranged on the gas path between the stop valve and the self-sealing valve.

[0009] Furthermore, one end of the air pipe away from the valve is fixedly connected to the one-piece integrated valve, the mounting seat includes the one-piece integrated valve and a supporting structure arranged between the one-piece integrated valve and the protective box, and the density relay is fixedly mounted on the one-piece integrated valve.

[0010] Furthermore, the air pipe is a composite pipe, the interior of which is a metal pipe body and the exterior of which is wrapped with a metal corrugated pipe for protection.

[0011] Furthermore, a thermal insulation sleeve is provided between the metal bellows and the metal pipe body.

[0012] Furthermore, at least one gas buffer is provided on the air pipe.

[0013] Furthermore, an observation window for observing the density relay instrument panel is provided on the protection box.

[0014] Furthermore, a pipe clamp for fixing to a wall is provided on the air pipe.

[0015] Further, at least three density relays are provided and installed in parallel.

[0016] Beneficial effect: The present invention is an improved invention. The DC wall bushing density monitoring device of the present invention includes a density relay, which can monitor the air pressure inside the DC wall bushing in real time, and judge whether the internal sulfur hexafluoride gas has leaked by the change of air pressure. In the process of continuous leakage, the instrument panel value of the density relay decreases, and an alarm will be issued to a certain extent. If the leakage continues, a locking operation will be performed. The density relay is connected to an air pipe, and a valve for connecting to the gas cavity of the DC wall bushing is installed at one end of the air pipe. The gas cavity in the DC wall bushing is connected through the valve, the air pipe and the interface of the density relay, which can be automatically By setting the position of the density relay, the difficulty of on-site operation and maintenance is reduced. At the same time, under live working conditions, it is not easy to have potential safety hazards for personnel. A protective box is set outside the density relay, and a mounting seat is set inside the protective box. The density relay is installed on the mounting seat, and the end of the air pipe away from the valve is connected to the mounting seat so that the air path is connected to the density relay through the mounting seat. This can prevent environmental factors such as rain, snow, and dust from damaging the density relay, which is beneficial to improving the monitoring accuracy and service life. This design can meet the needs of the converter station operation and maintenance personnel to obtain the internal air pressure value of the DC wall bushing conveniently, intuitively and safely. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of an embodiment of a DC wall bushing density monitoring device of the present invention; Figure 2 for Figure 1 A partial enlarged view of the middle valve and trachea; Figure 3 for Figure 1 The front view of the middle protective box; Figure 4 for Figure 3 Schematic diagram of the structure with the door removed; Figure 5 for Figure 3 Side view of Figure 6 This is the schematic diagram for non-disassembly verification of the density relay.

[0018] In the figure: 1. DC wall bushing; 2. Density relay; 3. Valve; 4. Air pipe; 5. Protective box; 6. Box door; 7. Stop valve; 8. Self-sealing valve; 9. Gas buffer; 10. Observation window; 11. Pipe clamp; 12. Installation door; 13. Integrated integrated valve; 14. Support structure. DETAILED DESCRIPTION

[0019] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0020] The process of the converter station operation and maintenance personnel checking the density relay on site is relatively complicated and there are safety hazards. The idea of ​​the present invention is to connect the interface of the density relay with the gas cavity of the DC wall bushing through a valve and an air pipe, move the position of the density relay downward, and obtain the internal air pressure value of the DC wall bushing conveniently, intuitively and safely.

[0021] Based on the above ideas, Figure 1 , 2 , 4, and 5, in a basic embodiment, the DC wall bushing density monitoring device of the present invention includes a density relay 2, which can monitor the air pressure inside the DC wall bushing 1 in real time, and judge whether the internal sulfur hexafluoride gas has leaked by the change of the air pressure. In the process of continuous leakage, the instrument panel value of the density relay 2 decreases, and an alarm will be issued to a certain extent. If the leakage continues, a locking operation will be performed. The density relay 2 is connected to an air pipe 4, and a valve 3 for connecting to the gas cavity of the DC wall bushing 1 is installed at one end of the air pipe 4. The gas cavity in the DC wall bushing 1 is connected to the air pipe 4 through the valve 3, the air pipe 4 and the density relay. 2 interface connection, the position of the density relay 2 can be freely set, reducing the difficulty of on-site operation and maintenance. At the same time, under live working conditions, it is not easy to have personnel safety hazards. A protective box 5 is arranged on the outside of the density relay 2, and a mounting seat is arranged inside the protective box 5. The density relay 2 is installed on the mounting seat, and the end of the air pipe 4 away from the valve 3 is connected to the mounting seat so that the air path is connected to the density relay 2 through the mounting seat. It can prevent environmental factors such as rain, snow and dust from damaging the density relay 2, which is beneficial to improving the monitoring accuracy and service life. Through this design, the needs of the converter station operation and maintenance personnel to obtain the internal air pressure value of the DC wall bushing 1 conveniently, intuitively and safely can be met.

[0022] In a preferred embodiment, a stop valve 7 is provided in the air pipe between the density relay 2 and the valve 3. The stop valve 7 is integrated in the protective box 5, which can conveniently and quickly realize the opening and closing of the air circuit of the density relay 2, facilitate adjustment and maintenance, reduce operational risks, and ensure personnel safety.

[0023] In other embodiments, the stop valve 7 may not be provided, and the gas circuit of the density relay 2 may be opened and closed by the valve 3 fixed on the DC wall bushing 1. Although the operation is more complicated and personnel still need to climb high to operate, it can work normally.

[0024] In a preferred embodiment, the mounting seat includes an integrated integrated valve 13, which includes a stop valve 7 and a self-sealing valve 8, and the density relay 2 is arranged on the gas path between the stop valve 7 and the self-sealing valve 8. During the calibration operation, the gas path between the DC wall bushing 1 and the density relay 2 is first blocked by the stop valve 7 or the valve 3, and then the self-sealing valve 8 is controlled to open, and the density relay 2 in the protective box 5 is calibrated by inputting standard gas to ensure that its reading is accurate, the output signal is normal, and the error is guaranteed to be within a reasonable range.

[0025] In other embodiments, the self-sealing valve 8 can also be replaced by a sealing end cover. During the verification operation, the air path between the DC wall bushing 1 and the density relay 2 is first blocked, and then the sealing end cover is opened for calibration operation. After the calibration operation is completed, the sealing end cover is sealed tightly. The currently commonly used sealing form is to set a sealing ring between the end cover and the air pipe. After frequent operation or long-term pressure, it may cause aging damage or deformation, and may cause leakage. Although it will make the operation process complicated and there is a certain risk of leakage, it can also work normally.

[0026] In a preferred embodiment, one end of the air pipe 4 away from the valve 3 is fixedly connected to the integrated integrated valve 13, the mounting seat includes the integrated integrated valve 13 and a support structure 14 arranged between the integrated integrated valve 13 and the protection box 5, the density relay 2 is fixedly mounted on the integrated integrated valve 13, and the interior of the protection box 5 is tightly and orderly arranged, which is convenient for operation under the premise of ensuring the sealing of the air path. In other embodiments, the integrated integrated valve 13 is fixed to the box body of the protection box 5 by bolts, which can also achieve similar effects and can work normally.

[0027] In a preferred embodiment, the air pipe 4 is a composite pipe, with a metal air pipe inside and a metal bellows wrapped outside for protection. The metal air pipe is made of copper, which has a certain hardness compared to stainless steel pipes or bare copper air pipes, and still maintains plasticity. The installer can bend and wire according to the specific working conditions on site, and there is no need to dock in sections, which reduces the docking and sealing links and reduces the risk of product leakage. The metal bellows is used to protect the internal air pipe 4 and prevent the influence of the external environment on the air pipe 4. The metal pipe body has good toughness and high strength, which can reduce the occurrence of leakage. In other embodiments, stainless steel pipes or bare copper air pipes can also be directly used, which can significantly reduce costs, but the airtightness is poor, which may lead to leakage accidents, and requires on-site docking and sealing, which has safety hazards of leakage, but it can also work normally.

[0028] In a preferred embodiment, an insulating sleeve is arranged between the metal bellows and the metal pipe body, which can reduce the temperature difference between the density relay 2 and the DC wall bushing 1, avoid the reading of the sealed relay 2 being unreferenced due to the temperature difference, and make the detection air pressure of the density relay 2 more reflective of the actual insulating gas density of the DC wall bushing 1, thereby ensuring real-time and accurate detection.

[0029] In other embodiments, the insulation sleeve is not provided, and there will be a temperature difference between the density relay 2 and the DC wall bushing 1. The detection result will be somewhat different from the actual situation. However, the difference between the two can be reduced by adding a temperature sensor or shortening the gas path length of the density relay 2. Although the accuracy is still somewhat different from the actual situation, it can also work normally.

[0030] In a preferred embodiment, at least one gas buffer 9 is provided on the air pipe to prevent the excessive air flow velocity from causing impact and damage to the equipment, thereby extending the service life of the equipment, protecting the safe operation of the DC wall bushing 1, and avoiding loss of life and property.

[0031] In other embodiments, the gas buffer portion 9 may not be provided. By increasing the cross-sectional area of ​​the gas path, the gas flow rate can be reduced while keeping the gas flow rate unchanged, thereby ensuring the safe operation of the equipment and reducing the risk of damage to the instrument. Although this will increase production costs and installation difficulty, it can still operate normally.

[0032] like Figure 3 As shown, in a preferred embodiment, the protective box 5 is provided with an observation window 10 for observing the instrument panel of the density relay 2, so that the air pressure value measured by the density relay 2 can be obtained intuitively and quickly without touching the protective box 5, thereby preventing the potential safety hazard caused by the box being electrified due to leakage. In other embodiments, the observation window 10 may not be provided, and the box door 6 may be opened on site to observe and record the measured value of the density relay 2, and normal operation can be achieved.

[0033] In a preferred embodiment, the air pipe 4 is provided with a pipe clamp 11 for fixing to the wall, and the pipe clamp 11 is fixed to the wall to facilitate free wiring and reduce the difficulty of installation. In other embodiments, it can also be fixed with a strap, which can also work normally.

[0034] In a preferred embodiment, at least three density relays 2 are provided and installed in parallel. Multiple sealed relays cooperate with each other to reduce errors, prevent damage to the power system due to damage to a certain density relay 2 and abnormal reported data, which cannot be handled in time, thereby ensuring safe and stable operation of the power system.

[0035] A box door 6 is installed on the protection box 5, and an installation door 12 for installing the density relay 2 is provided on the side of the box, which reduces the difficulty of installation. A mounting plate for fixing to the wall is installed on the side of the protection box, which can be fixed to the wall with screws.

[0036] First, reserve the installation position of the protection box 5 in advance during civil construction. During installation, first fix the valve 3 on the wall-penetrating cylinder of the DC wall bushing 1, fix the air pipe 4 to the valve 3, fix the protection box 5, fix the air pipe 4 along the wall until it enters the reserved line inlet of the protection box 5, install the stop valve 7 and the self-sealing valve 8 in the protection box 5, connect the air pipe 4, and connect the density relay 2 to the box in order. Check the density relay 2 and the above-mentioned control valve before powering on.

[0037] like Figure 6 As shown, during operation, the stop valve 7 is opened, the self-sealing valve 8 is closed, the DC wall bushing 1, the air pipe 4, the stop valve 7, and the density relay 2 form a stable airway, and the instrument panel displays the current air pressure value. When the DC wall bushing 1 leaks, the display value of the density relay 2 will decrease with the change of air pressure. When it drops to the alarm value, an alarm signal will be sent to the control end. When the gas in the DC wall bushing 1 continues to leak until the display value of the density relay 2 reaches the locking value, the control end will receive a locking signal, and the circuit will no longer be connected. After on-site inspection and maintenance, the power supply will continue to operate.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A DC wall bushing density monitoring device, comprising a density relay, characterized in that: The density relay is connected to an air pipe, one end of which is equipped with a valve for connecting to the gas cavity of the DC wall bushing. A protective box is provided outside the density relay, a mounting seat is provided inside the protective box, the density relay is installed on the mounting seat, and one end of the air pipe away from the valve is connected to the mounting seat so that the air path is connected to the density relay through the mounting seat.

2. The DC wall bushing density monitoring device according to claim 1, characterized in that: The air pipe between the density relay and the valve is provided with a stop valve.

3. The DC wall bushing density monitoring device according to claim 2, characterized in that: The mounting seat comprises an integrated integrated valve, which comprises a stop valve and a self-sealing valve, and a density relay is arranged on the gas path between the stop valve and the self-sealing valve.

4. The DC wall bushing density monitoring device according to claim 3, characterized in that: One end of the air pipe away from the valve is fixedly connected to the one-piece integrated valve, the mounting seat includes the one-piece integrated valve and a supporting structure arranged between the one-piece integrated valve and the protective box, and the density relay is fixedly installed on the one-piece integrated valve.

5. The DC wall bushing density monitoring device according to any one of claims 1 to 4, characterized in that: The air pipe is a composite pipe, the interior of which is a metal pipe body and the exterior of which is wrapped with a metal corrugated pipe for protection.

6. The DC wall bushing density monitoring device according to claim 5, characterized in that: A heat-insulating sleeve is arranged between the metal corrugated pipe and the metal pipe body.

7. The DC wall bushing density monitoring device according to any one of claims 1 to 4, characterized in that: At least one gas buffer portion is arranged on the gas pipe.

8. The DC wall bushing density monitoring device according to any one of claims 1 to 4, characterized in that: The protection box is provided with an observation window for observing the instrument panel of the density relay.

9. The DC wall bushing density monitoring device according to any one of claims 1 to 4, characterized in that: The air pipe is provided with a pipe clamp for fixing on the wall.

10. The DC wall bushing density monitoring device according to any one of claims 1 to 4, characterized in that: At least three density relays are provided and installed in parallel.

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