Intelligent gas density relay

Abstract

The application discloses an intelligent gas density relay, which comprises a base assembly, a contact assembly and a display assembly fixed on the base assembly, one end of a joint is connected with the contact assembly and the display assembly through a pipeline, and the other end of the joint is communicated with a gas chamber of an electrical equipment to be measured; a first shell is sealingly fixed with the base assembly, the two ends of the first shell are sealingly connected with a front cover and a rear cover respectively, an intelligent remote transmission assembly is fixedly connected with the rear cover, the first shell is internally provided with a first closed gas chamber and a second closed gas chamber, the display assembly is arranged in the second closed gas chamber, and the contact assembly is arranged in the first closed gas chamber. The first pressure sensor, the second pressure sensor and the temperature sensor are used for monitoring whether the gas in the first closed gas chamber leaks in real time, so that when the standard gas in the first closed gas chamber changes, the change can be timely recognized, and necessary basic data for fault diagnosis is provided.

Description

Technical Field

[0001] This invention relates to the field of gas density relay technology, and more specifically to intelligent gas density relays. Background Technology

[0002] SF6, a gas with excellent insulating and arc-extinguishing properties, is widely used in high-voltage applications. Currently, the vast majority of high-voltage equipment on the market uses SF6 as its insulating gas. Since the SF6 content directly affects the insulation and arc-extinguishing performance of the equipment, a drop in SF6 gas density to a certain level will lead to the loss of insulation and arc-extinguishing properties, causing substantial direct losses and incalculable indirect losses. Therefore, gas-insulated electrical equipment in high-voltage applications is standardly equipped with SF6 density relays to monitor the SF6 gas content within the equipment. When the gas pressure is too low, an alarm or interlock signal is issued to notify maintenance personnel to address the problem.

[0003] However, gas density relays often suffer from low accuracy, with significant discrepancies between indicated and contact action values, leading to missed or false alarms. Maintenance personnel must then travel to the site to verify the information, identify the cause, and resolve the issue. According to statistics from the State Grid and China Southern Power Grid Research Institute in 2023, there are over 2 million gas density relays in operation in my country. This massive number of relays is widely distributed across the country, and the timing of fault reports is unpredictable, making maintenance extremely difficult. To address this problem, the power grid focuses on two main aspects: improving meter accuracy and enhancing the digitalization and intelligence capabilities of meters to provide more accurate fault diagnosis and prediction, ensuring maintenance personnel receive accurate and reliable performance data for precise maintenance. Therefore, providing a gas density relay with high accuracy, high reliability, and intelligent fault diagnosis and prediction capabilities has become a pressing issue for those skilled in the art. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an intelligent gas density relay, the purpose of which is to solve the problems in the background technology.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an intelligent gas density relay, comprising a base assembly, a contact assembly, a display assembly, a connector, a first housing, a front cover, a rear cover, and an intelligent remote transmission assembly; the contact assembly and the display assembly are respectively fixed on the base assembly, one end of the connector is connected to the contact assembly and the display assembly through a pipeline, and the other end of the connector is connected to the gas chamber of the electrical equipment under test; the first housing is sealed and fixed to the base assembly, and the two ends of the first housing are respectively sealed and connected by the front cover and the rear cover, the intelligent remote transmission assembly is fixedly connected to the rear cover, the first housing is provided with a first sealed gas chamber and a second sealed gas chamber, the display assembly is disposed in the second sealed gas chamber, and the contact assembly is disposed in the first sealed gas chamber.

[0006] Furthermore, the contact assembly includes a second base, an air passage, a low-stiffness Baden tube, a first end seat, and a first crossbeam; the second base is fixed on the base assembly, and one end of the low-stiffness Baden tube is welded to the second base; an air passage is provided on the second base; the inner cavity of the low-stiffness Baden tube is connected to the air passage inside the second base, and the other end of the low-stiffness Baden tube is provided with a first end seat for sealing and plugging, and the first end seat is provided with a first crossbeam.

[0007] Furthermore, the contact assembly also includes an adjusting rod, a micro switch, and a printed circuit board; the adjusting rod is provided on the first crossbeam, the printed circuit board is fixed on the second base, and the micro switch is provided on the printed circuit board;

[0008] The micro switch includes a first micro switch and a second micro switch; the adjusting rod includes a first adjusting rod and a second adjusting rod.

[0009] The micro switch is located below the adjusting rod; the wiring points of the micro switch are all connected to the terminal block mounted on the outside of the first housing via wires from the printed circuit board, and the terminal block is sealed and fixed to the first housing.

[0010] Furthermore, the display assembly includes a third base, a Baden tube welding interface, a movement, a dial, hands, a Baden tube, and a second end seat; the third base has a Baden tube welding interface inside; the third base is disposed inside the first housing and fixed on the base assembly, and the Baden tube welding interface of the third base is connected to the connector; one end of the Baden tube is welded to the Baden tube welding interface, and the other end of the Baden tube is provided with a second end seat for sealing.

[0011] Furthermore, one end of the temperature compensation element is fixed on the second end seat, and the other end of the temperature compensation element is connected to the second crossbeam; the second crossbeam is connected to one end of the connecting rod, and the other end of the connecting rod is connected to the movement; a dial is installed on the movement, a pointer is installed on the dial, a pointer lever is installed on the pointer, and the movement is fixed on the third base.

[0012] Furthermore, the stiffness of the Baden tubes used in the display components is >4 bar, while the stiffness of the low-stiffness Baden tubes used in the contact components is <2 bar.

[0013] Furthermore, the base assembly includes a first base, an outer limiting device, and an inner limiting device; the first base is located in the middle part of the inner side of the first housing, and the second base and the third base are respectively located on the two end faces of the cylinder of the first base; wherein the outer limiting device and the inner limiting device are respectively fixed to one side of the upper part of the first base; the low-stiffness Baden tube of the contact assembly is located between the outer limiting device and the inner limiting device.

[0014] Furthermore, the outer surface of the inner limiting device is provided with a groove or hole.

[0015] Furthermore, the intelligent remote transmission component includes a second housing, an intelligent control unit, a housing cover, a first pressure sensor, a second pressure sensor, and a temperature sensor; the second housing is fixedly connected to the rear cover, the intelligent control unit is installed inside the second housing, and the first pressure sensor and the second pressure sensor are installed on the lower side wall of the second housing; the temperature sensor is located inside the first housing; the temperature sensor includes a first temperature sensor, a second temperature sensor, and a third temperature sensor;

[0016] The intelligent control unit is electrically connected to the first temperature sensor, the second temperature sensor, the third temperature sensor, the first pressure sensor, and the second pressure sensor.

[0017] The second housing has a cover on one side, and a sealing ring is provided between the second housing and the cover.

[0018] Furthermore, the first sealed gas chamber is pre-charged with SF6 gas at a pressure of P0; the low-stiffness Baden tube is disposed in the contact assembly, and one end of the low-stiffness Baden tube is connected to the SF6 gas passage of the electrical equipment.

[0019] In the initial state, the low-stiffness Baden tube is in contact with the inner limiting device, the pre-charge pressure P0 of the first sealed air chamber is greater than the internal air pressure of the low-stiffness Baden tube, and the inner limiting device restricts the low-stiffness Baden tube from moving inward.

[0020] When SF6 gas is introduced into the low-stiffness Baden pipe of the electrical equipment:

[0021] When the internal pressure of the low-rigidity Baden tube is less than the pre-filling pressure P0 of the first sealed air chamber, the low-rigidity Baden tube remains in contact with the inner limiting device.

[0022] When the internal pressure of the low-stiffness Baden tube is greater than or equal to the pre-charge pressure P0 of the first sealed air chamber, the low-stiffness Baden tube moves outward and disengages from the inner limiting device until the pressure of the low-stiffness Baden tube increases to the pre-charge pressure P0 + 0.1 MPa of the first sealed air chamber. At this point, the outer limiting device restricts the low-stiffness Baden tube from continuing to move outward, and the low-stiffness Baden tube does not continue to move outward as the air pressure increases; MPa is pressure.

[0023] When electrical equipment leaks SF6 gas:

[0024] When the internal pressure of the low-stiffness Baden tube is greater than the pre-charge pressure P0+0.1MPa of the first sealed air chamber, the low-stiffness Baden tube remains in contact with the external limiting device.

[0025] When the pre-charge pressure P0 of the first sealed air chamber is less than the internal pressure of the low-rigidity Baden tube and less than the pre-charge pressure P0 + 0.1 MPa of the first sealed air chamber, the low-rigidity Baden tube moves inward, causing the first crossbeam, the first adjusting rod, and the second adjusting rod to move inward synchronously.

[0026] When the internal pressure of the low-stiffness Baden tube drops to the warning threshold of the first micro switch, the first adjusting rod triggers the first micro switch to issue a low air pressure alarm signal.

[0027] When the internal pressure of the low-stiffness Baden tube drops to the second micro-switch locking threshold, the second adjusting rod triggers the second micro-switch to send a locking signal.

[0028] When the internal pressure of the low-stiffness Baden tube is less than the pre-charge pressure P0 of the first sealed air chamber, the inner limiting device restricts the low-stiffness Baden tube from continuing to move inward, and the low-stiffness Baden tube stops moving inward.

[0029] Compared with existing technologies, the present invention has the following advantages:

[0030] (1) The present invention improves the resolution of low stiffness Baden tube measurement by setting the stiffness of low stiffness Baden tube to <2 bar, and sets the low stiffness Baden tube corresponding to the micro switch in the first sealed air chamber. During the manufacturing process, the first sealed air chamber is pre-filled with compensation gas, so that the density relay has the ability to set different alarm / lock contacts.

[0031] (2) The present invention installs a first pressure sensor, a second pressure sensor, and a temperature sensor in the first sealed air chamber and the second housing to monitor in real time whether the gas in the first sealed air chamber leaks, so as to ensure that when the standard gas in the first sealed air chamber changes, it can be identified in time, providing the necessary basic data for fault diagnosis.

[0032] (3) By employing multiple temperature sensors, this invention can monitor the temperature inside the gas chamber of electrical equipment in a timely manner, thereby achieving accurate monitoring of the internal density of gas in electrical equipment, improving the detection rate of gas leakage in electrical equipment, enabling timely detection of gas leakage problems, thus giving maintenance personnel enough time to handle the problem, thereby achieving lean operation and maintenance management, reducing operation and maintenance costs, and ensuring the safe and reliable operation of power grid equipment. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the density relay of the present invention.

[0034] Figure 2 This is a schematic diagram of the contact component of the present invention.

[0035] Figure 3 This is a schematic diagram showing the motion and position relationship of the low-stiffness Baden tube after it is subjected to force according to the present invention.

[0036] Figure 4 This is a schematic diagram of the display component 3 of the present invention.

[0037] Figure 5 This is a schematic diagram of the structure of a gas density relay with remote transmission and high precision functions in an embodiment of the present invention.

[0038] Figure 6 This is a schematic diagram of the circuit module of a gas density relay with remote transmission and high precision functions in an embodiment of the present invention.

[0039] Reference numerals: 1. Base assembly; 11. First base; 12. Outer limiting device; 13. Inner limiting device; 2. Contact assembly; 21. Second base; 211. Air passage; 22. Low-rigidity Baden tube; 23. First end seat; 24. First crossbeam; 25. Adjusting rod; 26. Micro switch; 27. Printed circuit board; 3. Display assembly; 31. Third base; 311. Baden tube welding interface; 32. Movement; 33. Dial; 34. Pointer; 35. Baden tube; 36. Second end seat; 37. Second crossbeam; 38. Connecting rod; 4. Connector; 5. First housing; 6. Front cover; 7. Rear cover; 801. Second housing; 802. Intelligent control unit; 803. Housing cover; 804. First pressure sensor; 805. Second pressure sensor; 806. Temperature sensor; V1 is the first sealed air chamber; V2 is the second sealed air chamber. Detailed Implementation

[0040] Example 1

[0041] like Figure 1As shown, the present invention provides a technical solution: an intelligent gas density relay, including a base assembly 1, a contact assembly 2, a display assembly 3, a connector 4, a first housing 5, a front cover 6, a rear cover 7, and an intelligent remote transmission assembly; the contact assembly 2 and the display assembly 3 are respectively fixed on the base assembly 1, one end of the connector 4 is connected to the contact assembly 2 and the display assembly 3 through a pipeline or directly to form an internal gas passage of the density relay, and the other end of the connector 4 is connected to the gas chamber of the electrical equipment under test; the first housing 5 is sealed and fixed to the base assembly 1, and the two ends of the first housing 5 are respectively sealed and connected by the front cover 6 and the rear cover 7, and the intelligent remote transmission assembly is fixedly connected to the rear cover 7; the first housing 5 is provided with a first sealed gas chamber V1 and a second sealed gas chamber V2, the display assembly 3 is disposed in the second sealed gas chamber V2, and the contact assembly 2 is disposed in the first sealed gas chamber V1.

[0042] like Figures 1-3 As shown, the contact assembly 2 includes a second base 21, an air passage 211, a low-stiffness Baden tube 22, a first end seat 23, a first crossbeam 24, an adjusting rod 25, a micro switch 26, and a printed circuit board 27. The second base 21 is fixed to the base assembly 1, and one end of the low-stiffness Baden tube 22 is welded to the second base 21. An air passage 211 is provided on the second base 21. The inner cavity of the low-stiffness Baden tube 22 communicates with the air passage 211 inside the second base 21, and the other end of the low-stiffness Baden tube 22 is sealed with a first end seat 23. The sealing mechanism includes a first crossbeam 24 on the first end seat 23, and an adjusting rod 25 (or multiple rods) on the first crossbeam 24; several microswitches 26 (or multiple microswitches) are respectively fixed on the printed circuit board 27, which is fixed on the second base 21, and the microswitches 26 are correspondingly positioned below the adjusting rods 25. The adjusting rods 25 can directly or indirectly trigger the microswitches 26 to operate; the contacts of the microswitches 26 are all connected to the terminal block mounted outside the first housing 5 via wires from the printed circuit board 27, and the housing of the terminal block is sealed.

[0043] Among them, the micro switch 26 includes a first micro switch and a second micro switch; the adjusting rod 25 includes a first adjusting rod and a second adjusting rod.

[0044] like Figure 1 and Figure 4 As shown, the display component 3 includes a third base 31, a Baden tube welding interface 311, a movement 32, a dial 33, a pointer 34, a Baden tube 35, a second end seat 36, a second crossbeam 37, and a connecting rod 38; the third base 31 has a Baden tube welding interface 311 inside; the third base 31 is disposed inside the first housing 5 and fixed on the base component 1, and the Baden tube welding interface 311 of the third base 31 is connected to the air passage in the connector 4; one end of the Baden tube 35 is welded to the Baden tube welding interface 311, and the other end of the Baden tube 35 is sealed by the second end seat 36;

[0045] One end of the temperature compensation element is fixed to the second end seat 36, and the other end of the temperature compensation element is connected to the second crossbeam 37. The second crossbeam 37 is connected to one end of the connecting rod 38, and the other end of the connecting rod 38 is connected to the movement 32. A dial 33 is mounted on the movement 32, and a pointer 34 is mounted on the dial 33. The pointer 34 can rotate with the moving parts of the movement 32. The movement 32 is fixed on the third base 31. Gas inside the electrical equipment enters the Baden tube 35 through the connector 4 and the Baden tube welding interface 311. The outside of the Baden tube 35 is fixed to maintain an atmospheric pressure environment of 1 atmosphere. When the gas pressure inside the Baden tube 35 forms a difference with the atmospheric pressure outside, the Baden tube 35 undergoes elastic deformation in the opposite direction of the curvature center. The displacement of the closed end of the Baden tube 35 drives the temperature compensation element, the second crossbeam 37, and the connecting rod 38 to drive the movement 32 and the pointer 34 to rotate, displaying the actual gas pressure value.

[0046] The contact assembly 2 and display assembly 3 use Baden tubes with different stiffnesses. The Baden tube 35 used in display assembly 3 has a stiffness greater than 4 bar, while the low-stiffness Baden tube 22 used in contact assembly 2 has a stiffness less than 2 bar. Both contact assembly 2 and display assembly 3 withstand the same gas pressure. The displacement at the end of the low-stiffness Baden tube 22 in contact assembly 2 is greater than the displacement at the end of the Baden tube 35 in display assembly 3. This means that contact assembly 2 has higher pressure measurement resolution and higher pressure measurement accuracy. (bar is a unit of pressure.)

[0047] like Figure 1 As shown, the base assembly 1 includes a first base 11, an outer limiting device 12, and an inner limiting device 13; the first base 11 is located in the middle part of the inner side of the first housing 5, and the second base 21 and the third base 31 are respectively located at both ends of the cylindrical plane of the first base 11; wherein the outer limiting device 12 and the inner limiting device 13 are respectively fixed to one side of the upper part of the first base 11.

[0048] The low-stiffness Baden tube 22 of the contact assembly 2 is disposed between the outer limiting device 12 and the inner limiting device 13, so that the movement of the low-stiffness Baden tube 22 is restricted within the pressure range of 0.1MPa.

[0049] The inner limiting device 13 has a groove or hole on its outer surface. When the low-rigidity Baden tube 22 is in close contact with the outer surface of the inner limiting device 13, the gas in the first sealed air chamber V1 can still transmit pressure through the groove or hole and act on the low-rigidity Baden tube 22, so that the low-rigidity Baden tube 22 will not fail to work after being inflated.

[0050] The first sealed gas chamber V1 is pre-charged with SF6 gas at a pressure of P0; the low-stiffness Baden tube 22 is disposed in the contact assembly 2, and one end of the low-stiffness Baden tube 22 is connected to the SF6 gas passage of the electrical equipment.

[0051] In the initial state, the low-stiffness Baden tube 22 is in contact with the inner limiting device 13, the pre-charge pressure P0 of the first sealed air chamber V1 is greater than the internal air pressure of the low-stiffness Baden tube 22, and the inner limiting device 13 restricts the low-stiffness Baden tube 22 from moving inward.

[0052] When SF6 gas is introduced into the low-stiffness Baden pipe 22 of the electrical equipment:

[0053] When the internal pressure of the low-rigidity Baden tube 22 is less than the pre-charge pressure P0 of the first sealed air chamber V1, the low-rigidity Baden tube 22 remains in contact with the inner limiting device 13.

[0054] When the internal pressure of the low-stiffness Baden tube 22 is greater than or equal to the pre-charge pressure P0 of the first sealed air chamber V1, the low-stiffness Baden tube 22 moves outward and disengages from the inner limiting device 13 until the pressure of the low-stiffness Baden tube 22 increases to the pre-charge pressure P0 + 0.1 MPa of the first sealed air chamber V1. At this point, the outer limiting device 12 restricts the low-stiffness Baden tube 22 from continuing to move outward, and the low-stiffness Baden tube 22 does not continue to move outward as the air pressure increases; MPa is pressure.

[0055] When electrical equipment leaks SF6 gas:

[0056] When the internal pressure of the low-rigidity Baden tube 22 is greater than the pre-charge pressure P0 + 0.1 MPa of the first sealed air chamber V1, the low-rigidity Baden tube 22 remains in contact with the external limiting device 12.

[0057] When the pre-charge pressure P0 of the first sealed air chamber V1 is less than the internal pressure of the low-rigidity Baden tube 22 and less than the pre-charge pressure P0 + 0.1 MPa of the first sealed air chamber V1, the low-rigidity Baden tube 22 moves inward, causing the first crossbeam 24 and the first and second adjusting rods to move inward synchronously.

[0058] When the internal pressure of the low-stiffness Baden tube 22 drops to the first micro switch warning threshold, the first adjusting rod triggers the first micro switch to issue a low air pressure alarm signal.

[0059] When the internal pressure of the low-stiffness Baden tube 22 further drops to the second micro switch locking threshold, the second adjusting rod triggers the second micro switch to send a locking signal.

[0060] When the internal pressure of the low-stiffness Baden tube 22 is less than the pre-charge pressure P0 of the first sealed air chamber V1, the inner limiting device 13 restricts the low-stiffness Baden tube 22 from continuing to move inward, and the low-stiffness Baden tube 22 stops moving inward.

[0061] Working principle of intelligent gas density relay:

[0062] The internal air passage of the density relay is connected to the air chamber of the electrical equipment, and the air pressure inside the density relay is equal to the air pressure inside the air chamber of the electrical equipment.

[0063] When the air pressure inside the electrical equipment changes, the pressure monitored by the density relay can change in real time along with the pressure of the electrical equipment;

[0064] In the initial state, the low-stiffness Baden tube 22 is in contact with the inner limit device 13, and the gas in the electrical equipment is not introduced into the density relay. During the manufacturing process, the first sealed gas chamber V1 is pre-charged with SF6 gas at a pressure of P0.

[0065] When the pre-charge pressure P0 of the first sealed air chamber V1 is greater than the internal pressure of the low-stiffness Baden tube 22 in the initial state, the low-stiffness Baden tube 22 tends to move inward (the reference direction is its own curvature center). The inner limiting device 13 of the base assembly 1 prevents the low-stiffness Baden tube 22 from moving inward, and the position of the low-stiffness Baden tube 22 remains unchanged in the initial position.

[0066] When SF6 gas from the electrical equipment is introduced into the density relay, the gas inside the electrical equipment flows through connector 4 into the low-stiffness Baden tube 22 of the contact assembly 2. Before the pressure inside the low-stiffness Baden tube 22 is lower than the pre-charge pressure P0 of the first sealed chamber V1, and before the pre-charge pressure P0 of the first sealed chamber V1 is greater than the pressure inside the low-stiffness Baden tube 22, the low-stiffness Baden tube 22 remains stationary in contact with the inner limiting device 13.

[0067] When the pressure inside the low-stiffness Baden tube 22 is equal to or greater than the pre-charge pressure P0 of the first sealed air chamber V1, the pressure inside the low-stiffness Baden tube 22 is greater than the pre-charge pressure P0 of the first sealed air chamber V1. The low-stiffness Baden tube 22 begins to move outward, and the inner wall of the low-stiffness Baden tube 22 disengages from the inner limiting device 13. As the internal pressure of the low-stiffness Baden tube 22 increases, the distance it moves outward increases until the internal pressure of the low-stiffness Baden tube 22 increases to the pre-charge pressure P0 + 0.1 MPa of the first sealed air chamber V1. At this point, the path of the low-stiffness Baden tube 22 moving outward is blocked by the outer limiting device 12. After that, the low-stiffness Baden tube 22 does not move outward with the increase of the internal pressure, and the low-stiffness Baden tube 22 remains stationary. MPa is the pressure.

[0068] When gas leaks inside the electrical equipment, the gas pressure inside the electrical equipment decreases, and the gas pressure inside the low-rigidity Baden tube 22 decreases accordingly. Before the pressure inside the low-rigidity Baden tube 22 exceeds the pre-charge pressure P0+0.1MPa of the first sealed air chamber V1, the outer wall of the low-rigidity Baden tube 22 contacts the outer limiting device 12, and the low-rigidity Baden tube 22 does not move inward as the internal pressure decreases, and the low-rigidity Baden tube 22 remains stationary.

[0069] When the internal pressure of the low-stiffness Baden tube 22 is less than or equal to the pre-charge pressure P0 + 0.1 MPa of the first sealed air chamber V1, and greater than the pre-charge pressure P0 of the first sealed air chamber V1, there is a difference between the internal pressure of the low-stiffness Baden tube 22 and the pre-charge pressure P0 of the first sealed air chamber V1 (the internal pressure of the low-stiffness Baden tube 22 is slightly greater than the pre-charge pressure P0 of the first sealed air chamber V1 but is in the process of decreasing). As the internal gas pressure of the low-stiffness Baden tube 22 decreases, it moves inward, and the first crossbeam 24 fixed on the first end seat 23 also moves inward. The adjusting rod 25 installed on the first crossbeam 24 moves inward together with the first crossbeam 24. As the air pressure decreases, the distance between the adjusting rod 25 and the contact of the micro switch 26 gets closer and closer.

[0070] When the air pressure of the electrical equipment drops to the alarm threshold preset by the first micro switch, the first adjusting rod triggers the signal switching of the first micro switch (from disconnected to connected or from connected to disconnected), sending an alarm signal of low air pressure to the background monitoring system and notifying the maintenance personnel to perform maintenance.

[0071] When the air pressure drops further and reaches the lockout threshold preset by the second micro switch, the second adjusting rod triggers the signal switching of the second micro switch (from disconnected to connected or from connected to disconnected), sending a lockout signal to the background monitoring system that the air pressure of the electrical equipment does not meet the safety requirements for operation. The electrical equipment then stops working.

[0072] When the electrical equipment continues to leak, after the gas leaks from the electrical equipment, when the internal pressure of the low-rigidity Baden tube 22 is less than the pre-charge pressure P0 of the first sealed air chamber V1, the path of the low-rigidity Baden tube 22 moving inward is blocked by the inner limit device 13, and the low-rigidity Baden tube 22 cannot continue to move inward. The low-rigidity Baden tube 22 does not move inward as the pressure decreases, so that the low-rigidity Baden tube 22 will not be damaged due to excessive internal and external pressure difference.

[0073] For example, a density relay with parameters of 0.60 / 0.55 / 0.50 / 0.50 has a rated value of 0.6MPa, an alarm value of 0.55MPa, and a lockout value of 0.50MPa. The first sealed air chamber V1 is filled with gas at 0.49MPa, the inner limit pressure is set to 0.49MPa, and the outer limit device 12 restricts the position of the low-rigidity Baden tube 22 to 0.59MPa.

[0074] Before the density relay is installed, the air pressure in the first sealed air chamber V1 is 0.49 MPa. The air pressure inside the low-rigidity Baden tube 22 is equal to the local atmospheric pressure. The air pressure in the first sealed air chamber V1 is greater than the pressure inside the low-rigidity Baden tube 22. The low-rigidity Baden tube 22 tends to move inward. The inner limit device 13 blocks the low-rigidity Baden tube 22 from moving inward and keeps it in the initial position. The low-rigidity Baden tube 22 remains in contact with the inner limit device 13, protecting the low-rigidity Baden tube 22 from being damaged due to excessive external pressure.

[0075] When the density relay is installed and in normal operation, the electrical equipment is filled with SF6 gas at 0.6 MPa. The pressure inside the low-rigidity Baden tube 22 is equal to the pressure inside the electrical equipment. The gas pressure inside the low-rigidity Baden tube 22 is greater than the gas pressure inside the first sealed air chamber V1, generating an outward force. The installation position of the outer limit device 12 corresponds to the state of the low-rigidity Baden tube 22 at 0.59 MPa. When the low-rigidity Baden tube 22 moves to 0.59 MPa, it is blocked by the outer limit device 12 and will not move outward as the internal pressure of the low-rigidity Baden tube 22 increases. The outer wall of the low-rigidity Baden tube 22 is kept pressed against the outer limit device 12, and the low-rigidity Baden tube 22 will not be damaged due to excessive increase in internal pressure.

[0076] When the electrical equipment leaks gas, the gas pressure inside the low-rigidity Baden tube 22 gradually decreases. When the gas pressure inside the low-rigidity Baden tube 22 is greater than 0.59 MPa, the outer wall of the low-rigidity Baden tube 22 remains in contact with the outer limiting device 12, and its position remains unchanged.

[0077] When the internal pressure of the low-stiffness Baden tube 22 decreases to 0.59MPa, the low-stiffness Baden tube 22 moves inward as the leakage increases, and the gas pressure inside the low-stiffness Baden tube 22 decreases to 0.55MPa. The first adjusting rod triggers the first micro switch to act and sends an alarm signal.

[0078] When the SF6 gas in the electrical equipment leaks further and the SF6 pressure inside the equipment drops to 0.50 MPa, the second regulating rod triggers the second micro switch, sending a lockout signal to the background monitoring system and notifying maintenance personnel to perform maintenance. If the gas leak in the electrical equipment continues unresolved and the pressure inside the equipment drops to 0.49 MPa, the inward movement path of the low-stiffness Baden tube 22 is blocked by the inner limit device 13, preventing it from continuing to move inward due to the gas leak. The inner limit device 13 protects the low-stiffness Baden tube 22 from damage due to excessive pressure difference during operation.

[0079] Example 2

[0080] like Figure 5 As shown, the intelligent remote transmission component includes a second housing 801, an intelligent control unit 802, a housing cover 803, a first pressure sensor 804, a second pressure sensor 805, and a temperature sensor 806.

[0081] The second housing 801 is fixedly connected to the rear cover 7 described in Embodiment 1. The connection method is not limited to the direct contact connection shown in the attached drawings. The intelligent control unit 802 is installed inside the second housing 801. The first pressure sensor 804 and the second pressure sensor 805 are respectively installed on the lower side wall of the second housing 801. The first pressure sensor 804 measures the pressure of the first sealed air chamber V1, and the second pressure sensor 805 is in gas communication with the electrical equipment body and measures the gas pressure inside the electrical equipment. Three temperature sensors 806 with different thermal conductivity are set inside the first housing 5 of the density relay. In actual use, the intelligent control unit 802 will automatically select a temperature sensor 806 with the thermal conductivity closest to the temperature of the electrical equipment body from the three temperature sensors 806 with different thermal conductivity based on the thermal conductivity of the electrical equipment being tested, so as to obtain accurate remote transmission data. The temperature sensor 806 includes a first temperature sensor, a second temperature sensor, and a third temperature sensor.

[0082] The second housing 801 has a cover 803 on one side, and a sealing ring is provided between the second housing 801 and the cover 803.

[0083] like Figure 6 As shown, the intelligent control unit 802 is equipped with a contact one control switch, a contact two control switch, a contact three control switch, a power supply module, and a signal transceiver module; the intelligent control unit 802 is electrically connected to the first temperature sensor, the second temperature sensor, the third temperature sensor, the first pressure sensor 804, the second pressure sensor 805, the contact one control switch, the contact two control switch, the contact three control switch, the power supply module, and the signal transceiver module as contact control switches for an electronic trigger device.

[0084] The electronic trigger device contact control switch is equipped with three monitoring circuits, namely K1, K2, and K3: K1 is the first monitoring circuit; K2 is the second monitoring circuit; and K3 is the third monitoring circuit.

[0085] K1: Connect the contact one control switch to the background monitoring system to realize the status monitoring of the contact one control switch;

[0086] K2: Connect the contact two control switch to the background monitoring system to realize the status monitoring of the contact two control switch;

[0087] K3: Connect the three-contact control switch to the background monitoring system to realize the status monitoring of the three-contact control switch.

[0088] The working principle of the electronic trigger device contact control switch is as follows: the electronic trigger device contact control switch does not participate in the control of the contact signal when the density relay is working normally; in the scenario where the micro switch 26 fails to conduct, when the first sealed air chamber V1 leaks and the gas pressure in the first sealed air chamber V1 drops to the preset drop threshold △P, the electrical equipment body also leaks. When the leak reaches the set alarm value P1, the background monitoring system should send an alarm signal to the system when the body leaks to the alarm value P1. However, because the gas pressure drops to △P after the first sealed air chamber V1 leaks, the pressure of the density relay to send the alarm signal also needs to be reduced to P1-△P accordingly, which leads to the problem that the normal contact cannot be triggered at the alarm signal value. At this time, the first pressure sensor 804 and temperature sensor 806, which are connected to the first sealed air chamber V1, monitor in real time whether gas leakage occurs in the first sealed air chamber V1. When a leak is detected, the intelligent control unit 802 will activate. After the gas leakage in the electrical equipment reaches the alarm / lockout threshold, the intelligent control unit 802 will activate the corresponding electronic trigger device contact control switch to send an alarm signal to the background monitoring system, ensuring the safe and reliable operation of the electrical equipment. It will also send a gas leakage fault alarm to the background monitoring system via remote transmission; △P is a preset drop threshold.

[0089] The intelligent control unit 802 includes a processor (MCU); the processor can be: a general-purpose computer, an industrial computer, a central processing unit (CPU), a microcontroller, an ARM chip, an AI chip, a microcontroller unit (MCU), a field-programmable gate array (FPGA), a programmable logic controller (PLC), an industrial control motherboard, an embedded main control board, etc.

[0090] The power supply module can be: switching power supply, AC 220V, DC power supply, low dropout linear regulator (LDO), programmable power supply, solar power, storage battery, rechargeable battery, battery, etc.

[0091] The first pressure sensor 804 and the second pressure sensor 805 can be various pressure-sensing elements such as pressure sensors and pressure transmitters.

[0092] Among them, the temperature sensor 806 can be: thermocouple, thermistor, semiconductor type; the temperature sensor 806 can be contact type and non-contact type; the temperature sensor 806 can be thermistor and thermocouple. In short, temperature acquisition can use various temperature sensing elements such as temperature sensor and temperature transmitter.

[0093] The communication method of the signal transceiver module can be wired or wireless. The wired communication method can be RS232 serial interface, RS485 serial bus, industrial bus such as CAN-BUS, fiber optic Ethernet, 4-20 mA current signal, HART protocol, IIC bus, SPI interface, 1-Wire bus, coaxial cable, PLC power line carrier, etc.

[0094] Wireless communication methods can include 2G / 3G / 4G / 5G, WIFI, Bluetooth, Lora, Lorawan, Zigbee, infrared, ultrasound, sound waves, satellite, light waves, quantum communication, sonar, and sensors with built-in 5G / NB-IoT communication modules (such as narrowband IoT NB-IoT).

[0095] The first pressure sensor 804 and the second pressure sensor 805 can be absolute pressure sensors, relative pressure sensors, or a combination of both, and there can be several of them. The first pressure sensor 804 and the second pressure sensor 805 can be in the form of diffused silicon pressure sensors, MEMS pressure sensors, chip-type pressure sensors, coil-inductive pressure sensors (such as pressure measurement sensors with a Baden tube and an induction coil), or resistive pressure sensors (such as pressure measurement sensors with a Baden tube and a slide wire resistor). They can be analog or digital pressure sensors. Pressure acquisition uses various pressure-sensing elements such as pressure sensors and pressure transmitters, including diffused silicon, sapphire, piezoelectric, and strain gauge types (resistive strain gauge type, ceramic strain gauge type).

[0096] In the case that there is no gas leakage in the electrical equipment, the gas mass in the gas chamber of the electrical equipment will not change, but the gas chamber density will change with temperature. And it is highly probable that the electrical equipment will not leak.

[0097] Based on the premise that the electrical equipment is leak-proof, the gas in the first sealed air chamber V1 is monitored in real time by the first pressure sensor 804 and the temperature sensor 806. The real-time pressure P0 and real-time temperature T of the gas in the first sealed air chamber V1 are obtained and converted into the standard pressure value corresponding to 20℃. Finally, by combining 20℃ and pressure value, the gas density value of the electrical equipment air chamber under the corresponding working condition is calculated by the Bridgman equation of state.

[0098] By monitoring the gas in the first sealed air chamber V1 using the first pressure sensor 804 and temperature sensor 806, the detection rate of gas leakage in electrical equipment is improved, and gas leakage problems can be detected in a timely manner. This gives maintenance personnel enough time to handle the problem, thereby achieving lean operation and maintenance management, reducing operation and maintenance costs, and ensuring the safe and reliable operation of power grid equipment.

[0099] The density relay can be a density relay with an indicator (a density relay with a pointer display, a density relay with a digital display, or a density relay with an LCD display) or a density relay without an indicator (i.e., a density switch).

[0100] The benefits of density relays are mainly threefold: First, the use of low-stiffness Baden tube 22 greatly improves the measurement accuracy of the density relay's operating contacts, making the measured contacts more accurate and reducing false alarms caused by insufficient accuracy of the contact measurement device, thus improving the precision, quality, and efficiency of operation and maintenance. Second, the low-stiffness Baden tube 22 uses gas compensation, which greatly improves the environmental adaptability of the density relay. Third, it can monitor the temperature and pressure inside the first sealed air chamber and electrical equipment in real time, providing more accurate basic data for equipment fault diagnosis and prediction, further improving measurement accuracy, accurately diagnosing faults, and providing accurate information and decision support for operation and maintenance.

[0101] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An intelligent gas density relay, characterized in that, The device includes a base assembly, a contact assembly, a display assembly, a connector, a first housing, a front cover, a rear cover, and an intelligent remote transmission assembly. The contact assembly and the display assembly are respectively fixed on the base assembly. One end of the connector is connected to the contact assembly and the display assembly through a pipeline, and the other end of the connector is connected to the air chamber of the electrical equipment under test. The first housing is sealed and fixed to the base assembly. The two ends of the first housing are sealed and connected by the front cover and the rear cover, respectively. The intelligent remote transmission assembly is fixedly connected to the rear cover. The first housing has a first sealed air chamber and a second sealed air chamber. The display assembly is located in the second sealed air chamber, and the contact assembly is located in the first sealed air chamber. The base assembly includes a first base, an outer limiting device, and an inner limiting device; the first base is located in the middle of the inner side of the first housing; the outer limiting device and the inner limiting device are respectively fixed to one side of the upper part of the first base; a low-rigidity Baden tube is arranged between the outer limiting device and the inner limiting device; The other end of the low-stiffness Baden tube is provided with a first end seat for sealing and plugging, and the first end seat is provided with a first crossbeam; The contact assembly also includes an adjusting rod, a micro switch, and a printed circuit board; the first crossbeam is provided with an adjusting rod, the printed circuit board is fixed on the second base, the second base is fixed on the base assembly, and the printed circuit board is provided with a micro switch; The micro switch includes a first micro switch and a second micro switch; the adjusting rod includes a first adjusting rod and a second adjusting rod. The first sealed gas chamber is pre-charged with SF6 gas at a pressure of P0; a low-stiffness Baden tube is installed inside the contact assembly, and one end of the low-stiffness Baden tube is connected to the SF6 gas passage of the electrical equipment. In the initial state, the low-stiffness Baden tube is in contact with the inner limiting device, the pre-charge pressure P0 of the first sealed air chamber is greater than the internal air pressure of the low-stiffness Baden tube, and the inner limiting device restricts the low-stiffness Baden tube from moving inward. When SF6 gas is introduced into the low-stiffness Baden pipe of the electrical equipment: When the internal pressure of the low-rigidity Baden tube is less than the pre-filling pressure P0 of the first sealed air chamber, the low-rigidity Baden tube remains in contact with the inner limiting device. When the internal pressure of the low-stiffness Baden tube is greater than or equal to the pre-charge pressure P0 of the first sealed air chamber, the low-stiffness Baden tube moves outward and disengages from the inner limiting device until the pressure of the low-stiffness Baden tube increases to the pre-charge pressure P0 + 0.1 MPa of the first sealed air chamber. At this point, the outer limiting device restricts the low-stiffness Baden tube from continuing to move outward, and the low-stiffness Baden tube does not continue to move outward as the air pressure increases; MPa is pressure. When electrical equipment leaks SF6 gas: When the internal pressure of the low-stiffness Baden tube is greater than the pre-charge pressure P0+0.1MPa of the first sealed air chamber, the low-stiffness Baden tube remains in contact with the external limiting device. When the pre-charge pressure P0 of the first sealed air chamber is less than the internal pressure of the low-rigidity Baden tube and less than the pre-charge pressure P0 + 0.1 MPa of the first sealed air chamber, the low-rigidity Baden tube moves inward, causing the first crossbeam, the first adjusting rod, and the second adjusting rod to move inward synchronously. When the internal pressure of the low-stiffness Baden tube drops to the warning threshold of the first micro switch, the first adjusting rod triggers the first micro switch to issue a low air pressure alarm signal. When the internal pressure of the low-stiffness Baden tube drops to the second micro-switch locking threshold, the second adjusting rod triggers the second micro-switch to send a locking signal. When the internal pressure of the low-stiffness Baden tube is less than the pre-charge pressure P0 of the first sealed air chamber, the inner limiting device restricts the low-stiffness Baden tube from continuing to move inward, and the low-stiffness Baden tube stops moving inward.

2. The intelligent gas density relay according to claim 1, characterized in that: The contact assembly includes an air passage and a low-stiffness Baden tube; one end of the low-stiffness Baden tube is welded to a second base; an air passage is provided on the second base; the inner cavity of the low-stiffness Baden tube is connected to the air passage inside the second base.

3. The intelligent gas density relay according to claim 2, characterized in that: The micro switch is positioned below the adjusting rod; the wiring points of the micro switch are all connected from the printed circuit board to the terminal block mounted on the outside of the first housing via wires, and the terminal block is sealed and fixed to the first housing.

4. The intelligent gas density relay according to claim 3, characterized in that: The display assembly includes a third base, a Baden tube welding interface, a movement, a dial, hands, a Baden tube, and a second end seat; the third base has a Baden tube welding interface inside; the third base is disposed inside the first housing and fixed on the base assembly, and the Baden tube welding interface of the third base is connected to the connector; one end of the Baden tube is welded to the Baden tube welding interface, and the other end of the Baden tube is provided with a second end seat for sealing.

5. The intelligent gas density relay according to claim 4, characterized in that: One end of the temperature compensation element is fixed on the second end seat, and the other end of the temperature compensation element is connected to the second crossbeam; the second crossbeam is connected to one end of the connecting rod, and the other end of the connecting rod is connected to the movement; a dial is installed on the movement, a pointer is installed on the dial, a pointer lever is installed on the pointer, and the movement is fixed on the third base.

6. The intelligent gas density relay according to claim 5, characterized in that: The display components use Baden tubes with a stiffness >4 bar, while the contact components use low-stiffness Baden tubes with a stiffness <2 bar.

7. The intelligent gas density relay according to claim 6, characterized in that: The second and third bases are respectively located on the two end faces of the cylinder of the first base.

8. The intelligent gas density relay according to claim 7, characterized in that: The outer surface of the inner limiting device has a groove or hole.

9. The intelligent gas density relay according to claim 8, characterized in that: The intelligent remote transmission component includes a second housing, an intelligent control unit, a housing cover, a first pressure sensor, a second pressure sensor, and a temperature sensor; the second housing is fixedly connected to the rear cover, the intelligent control unit is installed inside the second housing, and the first pressure sensor and the second pressure sensor are installed on the lower side wall of the second housing; the temperature sensor is located inside the first housing; the temperature sensor includes a first temperature sensor, a second temperature sensor, and a third temperature sensor; The intelligent control unit is electrically connected to the first temperature sensor, the second temperature sensor, the third temperature sensor, the first pressure sensor, and the second pressure sensor. The second housing has a cover on one side, and a sealing ring is provided between the second housing and the cover.

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