Self-checking density relay and mounting structure and use method thereof

Abstract

The invention discloses a self-checking density relay and an installation structure and a use method thereof, the density relay comprises a dial plate and an alarm circuit, the center of the dial plate is provided with a rotating pointer, the dial plate is provided with an alarm pressure area and an air pressure normal area, and the alarm circuit comprises an alarm normally open node and an alarm indicating lamp which are connected in series. The alarm normally-open node is interlocked with the alarm pressure range of the internal pressure monitoring module. The installation structure comprises closed combination equipment and the density relay. According to the application method, the density relay is adopted, the internal pressure monitoring module monitors that the internal pressure of the relay reaches or leaves the alarm pressure range by pressurizing or depressurizing the interior of the density relay, so that the alarm normally-open node is closed or opened, and the alarm indicating lamp is turned on or turned off; observing whether the pointer points to the alarm pressure area and recording the pressure value. The method has the beneficial effects that the operation and maintenance process is fundamentally simplified; the verification safety and accuracy are improved; and system reliability is enhanced.

Description

Technical Field

[0001] This application belongs to the field of density relay technology, specifically relating to a self-calibrating density relay and its installation structure and usage method. Background Technology

[0002] Gas-insulated switchgear (GIS) is a critical high-voltage power distribution device in power systems. It integrates circuit breakers, disconnectors, grounding switches, instrument transformers, surge arresters, busbars, and other components into a metal grounded casing filled with SF6 insulating gas at a certain pressure. This provides reliable insulation and arc extinguishing for high-voltage energized parts, offering advantages such as compact structure, high reliability, and strong environmental adaptability. In GIS equipment, SF6 gas is typically divided into several independent chambers according to functional units. Each chamber is equipped with an SF6 density relay for real-time monitoring of gas pressure changes. This device not only reflects pressure fluctuations caused by temperature changes but also promptly issues alarm or lockout signals when gas leakage causes the density to drop to a set threshold, thereby ensuring safe equipment operation and preventing faults caused by decreased insulation capacity. Therefore, as a critical condition monitoring device, the accuracy of the SF6 density relay directly affects the safety and reliability of the GIS and must be regularly calibrated.

[0003] Currently, on-site calibration of SF6 density relays is typically conducted during equipment shutdowns for maintenance. To minimize the complex procedures involved in gas recovery, treatment, and refilling due to disassembly of equipment seals, and to reduce potential sealing risks, a "non-removal of the density relay" calibration method is generally adopted. This method directly utilizes the SF6 gas within the gas chamber as the medium, connecting the calibration instrument to the density relay's monitoring port or dedicated test port via a connecting pipeline. While this method avoids completely removing the density relay from the gas chamber, its practical operation still presents several significant inconveniences and technical drawbacks. First, the calibration process relies on an external dedicated calibration instrument, which is usually bulky and requires transport to the site and finding suitable installation and operating space, particularly difficult in the compact layout of substations. Second, to achieve signal monitoring and simulation, personnel must manually disconnect the electrical connection between the density relay and the secondary control circuit. This process not only increases workload but also carries the risk of damaged terminals, mislabeling, or incorrect rewiring, potentially affecting the normal transmission of subsequent monitoring signals. Furthermore, the entire calibration process involves multiple steps, including pipeline connection, seal inspection, slow charging and discharging to balance pressure, recording of signal trigger points, and equipment restoration. The process is cumbersome and time-consuming, requiring a high level of professional skill and adherence to operational procedures from maintenance personnel. In cases of uneven skill levels among personnel or limited on-site working conditions, inaccurate calibration data, low work efficiency, and even the potential for minor SF6 gas leaks or secondary circuit malfunctions due to improper operation can easily occur.

[0004] More specifically, existing verification methods, due to their inherently invasive and manual nature, are ill-suited to the demands of online and intelligent equipment status monitoring in the context of smart grid development. Frequent power outage verification also affects power supply continuity and increases operation and maintenance costs. Therefore, there is an urgent need for a more efficient, convenient, reliable SF6 density relay verification method and device that reduces interference to the secondary circuits of equipment, in order to improve the inherent safety and operational efficiency of verification work and ensure the long-term stable operation of GIS equipment. This is precisely the core technical problem that this patent application aims to solve. Summary of the Invention

[0005] The purpose of this application is to provide a self-calibrating density relay, its installation structure, and its usage method, thereby solving the problem of inconvenient testing of density relays.

[0006] The objective of this application is achieved through the following technical solution: A self-calibrating density relay includes a dial and an alarm circuit. The dial has a rotating pointer at its center and is divided into an alarm pressure zone and a normal pressure zone. The alarm circuit includes a normally open alarm contact and an alarm indicator light connected in series. The normally open alarm contact is interlocked with the alarm pressure range of the internal pressure monitoring module.

[0007] Furthermore, a detachable indicator light shielding cap is connected in parallel to the alarm indicator light.

[0008] Furthermore, the alarm circuit includes a primary alarm circuit and a secondary alarm circuit, and the alarm pressure area includes a primary alarm pressure area and a secondary alarm pressure area. The secondary alarm pressure area, the primary alarm pressure area, and the normal pressure area are arranged from low pressure to high pressure. The primary alarm circuit includes a primary alarm normally open node and a primary alarm indicator light connected in series. The secondary alarm circuit includes a secondary alarm normally open node and a secondary alarm indicator light connected in series. The primary alarm pressure range of the internal pressure monitoring module is interlocked with the primary alarm normally open node, and the primary alarm pressure range of the internal pressure monitoring module is interlocked with the secondary alarm normally open node.

[0009] Furthermore, a detachable primary indicator light shielding cap is connected in parallel to the primary alarm indicator light, and a detachable secondary indicator light shielding cap is connected in parallel to the secondary alarm indicator light.

[0010] Furthermore, the dial is also divided into a primary indicator light change area and a secondary indicator light change area. The primary indicator light change area is located between the primary alarm pressure area and the normal air pressure area, and the secondary indicator light change area is located between the secondary alarm pressure area and the primary alarm pressure area.

[0011] Furthermore, the density relay is an SF6 density relay.

[0012] An installation structure for a self-calibrating density relay includes a closed assembly device and the aforementioned self-calibrating density relay. The closed assembly device is connected to a valve before the relay, the valve before the relay is connected to the density relay, and the density relay is connected to a self-sealing valve interface.

[0013] A method for using a self-calibrating density relay: By applying or depressurizing the density relay, the internal pressure monitoring module detects whether the internal pressure of the relay reaches or leaves the alarm pressure range, causing the normally open alarm node to close or open, the alarm indicator light to light up or turn off, and the pointer to point to the alarm pressure area to be observed and the pressure value to be recorded.

[0014] Furthermore, the density relay is installed between the relay inlet valve and the self-sealing valve interface of the enclosed combination equipment; the relay inlet valve is closed and the self-sealing valve interface is opened to gradually reduce the pressure inside the density relay; the relay inlet valve is opened and the self-sealing valve interface is closed to gradually increase the pressure inside the density relay.

[0015] Furthermore, by connecting an indicator light shielding cap in parallel to the alarm indicator light, the density relay can function normally.

[0016] The beneficial effects of this application are: (1) Fundamentally simplify the operation and maintenance process: No need for equipment power outages, no reliance on external calibration instruments, no need to disassemble secondary circuits, the calibration process is completed automatically, greatly reducing manpower, time costs and operational complexity.

[0017] (2) Improve the safety and accuracy of calibration: avoid the risk of gas leakage and wiring errors that may be caused by manual operation and pipeline connection in the traditional method.

[0018] (3) Enhanced system reliability: Reduced the potential impact of frequent intervention operations on equipment sealing and electrical connections, and improved the long-term operational stability and power supply continuity of the GIS body.

[0019] The aforementioned main solution and its various further alternatives can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed in this application; furthermore, the (non-conflicting alternatives) can also be freely combined with each other and with other alternatives. Those skilled in the art, after understanding the solution of this application, will realize from the prior art and common general knowledge that there are many combinations, all of which are technical solutions to be protected by this application, and will not be exhaustively listed here. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the relay structure of this application.

[0021] Figure 2 This is the circuit diagram of the alarm circuit in this application.

[0022] Figure 3 This is a schematic diagram of the installation structure of this application.

[0023] In the diagram: 1. Primary alarm indicator light; 2. Secondary alarm indicator light; 3. Primary indicator light shielding cap; 4. Secondary indicator light shielding cap; 5. Secondary indicator light change area; 6. Primary indicator light change area; 7. Normal gas pressure area; 8. Primary alarm pressure area; 9. Secondary alarm pressure area; 10. Pointer; 11. Secondary wiring terminal; 12. Primary alarm normally open contact; 13. Secondary alarm normally open contact; 14. Relay valve before meter; 15. Self-sealing valve interface; 16. Enclosed combination equipment. Detailed Implementation

[0024] The following non-limiting embodiments are used to illustrate this application.

[0025] Example 1 refer to Figure 1 and Figure 2As shown, a self-calibrating density relay is achieved by modifying the wiring of the internal nodes of the existing density relay and adding node alarm indicator lights. At the same time, corresponding alarm pressure areas are drawn on the density relay dial. When the pointer rotates to the alarm range, observe whether the corresponding alarm indicator light is lit, or when the pointer leaves the alarm range, observe whether the corresponding alarm indicator light is extinguished.

[0026] The density relay includes a dial and an alarm circuit. A rotating pointer 10 is located at the center of the dial. The pointer 10 senses the internal pressure of the relay through a transmission module in the prior art and provides feedback through its own rotation angle. The pointer 10 points to the pressure value on the dial to determine the internal pressure of the relay.

[0027] The dial is divided into an alarm pressure zone and a normal pressure zone 7. This zoned pressure reading allows for easy identification of the pressure range. The alarm circuit includes a normally open alarm contact and an alarm indicator light connected in series. The normally open alarm contact is interlocked with the alarm pressure range of the internal pressure monitoring module. The internal pressure monitoring module is also an existing module of the current density relay.

[0028] When the pointer reaches (leaves) the alarm pressure area of ​​the density relay, under normal circumstances, the internal pressure monitoring module will close (open) the corresponding normally open node, and the alarm light will turn on (off). The density relay is verified to be qualified by judging whether the pointer rotates to the corresponding alarm pressure area when the alarm light turns on (off).

[0029] The alarm indicator light is connected in parallel with a removable indicator light shielding cap. When the indicator light shielding cap is installed, the alarm indicator light is short-circuited and can be used as a general density relay to be compatible with existing density relays.

[0030] Example 2 refer to Figure 1 and Figure 2 As shown, a self-calibrating density relay is an extended implementation based on Example 1.

[0031] The alarm circuit includes a primary alarm circuit and a secondary alarm circuit. The alarm pressure area includes a primary alarm pressure area 8 and a secondary alarm pressure area 9. The secondary alarm pressure area 9, the primary alarm pressure area 8, and the normal pressure area 7 are arranged from low pressure to high pressure. By setting two levels of alarms, the full pressure range from low pressure to high pressure is covered, ensuring the reliability of the calibration.

[0032] The first-level alarm circuit includes a first-level alarm normally open node 12 connected in series and a first-level alarm indicator light 1. The second-level alarm circuit includes a second-level alarm normally open node 13 connected in series and a second-level alarm indicator light 2. The first-level alarm pressure range of the internal pressure monitoring module is interlocked with the first-level alarm normally open node 12, and the second-level alarm pressure range of the internal pressure monitoring module is interlocked with the second-level alarm normally open node 13.

[0033] When the pointer reaches (leaves) the first-level alarm pressure area of ​​the density relay, under normal circumstances, the internal pressure monitoring module will close (open) the normally open first-level alarm terminal, and the first-level alarm light will turn on (off). When the pointer reaches (leaves) the second-level alarm pressure area of ​​the density relay, under normal circumstances, the internal pressure monitoring module will close (open) the normally open second-level alarm terminal, and the second-level alarm light will turn on (off). The density relay is verified to be qualified by judging whether the pointer rotates to the corresponding alarm pressure area when the alarm light turns on (off).

[0034] The dial is also divided into a primary indicator light change area 6 and a secondary indicator light change area 5. The primary indicator light change area 6 is located between the primary alarm pressure area 8 and the normal air pressure area 7, while the secondary indicator light change area 5 is located between the secondary alarm pressure area 9 and the primary alarm pressure area 8. The pressure areas are transitioned through these change areas, and the illumination or extinguishing of the alarm indicator light within these areas can be considered relative errors and treated as normal conditions.

[0035] A removable primary indicator light shield 3 is connected in parallel to the primary alarm indicator light 1, and a removable secondary indicator light shield 4 is connected in parallel to the secondary alarm indicator light 2. The first end of the primary alarm line is connected to potential V1, the first end of the secondary alarm line is connected to potential V2, and the ends of both the primary and secondary alarm lines are connected to potential V0.

[0036] The density relay is an SF6 density relay, suitable for gas-insulated switchgear—SF6 fully enclosed switchgear.

[0037] Example 3 refer to Figure 3 As shown, a mounting structure for a self-calibrating density relay includes a closed assembly device 16, and also includes the self-calibrating density relay of embodiment 1 or 2.

[0038] The enclosed combination device 16 is connected to the relay pre-valve 14, which is connected to the density relay. The density relay is connected to the self-sealing valve interface 15. The pressure or pressure inside the density relay is increased or decreased by opening and closing the relay pre-valve 14 and the self-sealing valve interface 15.

[0039] Example 4 refer to Figures 1-3As shown, a method for using a self-calibrating density relay is described, employing the self-calibrating density relay of Example 1.

[0040] By applying or reducing pressure inside the density relay, the internal pressure monitoring module detects whether the internal pressure of the relay reaches or leaves the alarm pressure range, causing the normally open alarm node to close or open, the alarm indicator light to light up or turn off, and the pointer 10 to be observed to point to the alarm pressure area and the pressure value to be recorded.

[0041] Install the density relay between the relay inlet valve 14 and the self-sealing valve port 15 of the enclosed combination equipment 16. Close the relay inlet valve 14 and open the self-sealing valve port 15 to gradually depressurize the density relay and observe the illumination time of the alarm indicator light. Open the relay inlet valve 14 and close the self-sealing valve port 15 to gradually pressurize the density relay and observe the extinguishing time of the alarm indicator light.

[0042] Connecting an indicator light shielding cap in parallel to the alarm indicator light ensures the density relay functions normally.

[0043] Example 5 refer to Figures 1-3 As shown, a method for using a self-calibrating density relay is described, employing the self-calibrating density relay of Example 2.

[0044] Forward verification: Close the valve 14 before the relay gauge and slowly release the internal SF6 gas through the self-sealing valve interface 15. When the internal pressure of the SF6 density relay drops to the first-level alarm pressure range (set value), the normally open first-level alarm node 12 closes, and the first-level alarm indicator light 1 illuminates. At this time, observe whether the pointer 10 points to the first-level indicator light change area 6, and record the scale value pointed to by the pointer 10 at this moment. Continue to slowly release the internal SF6 gas before the gauge valve. When the internal pressure of the SF6 density relay drops to the second-level alarm pressure range (set value), the normally open second-level alarm node 13 closes, and the second-level alarm indicator light 2 illuminates. At this time, observe whether the pointer 10 points to the second-level indicator light change area 5, and record the scale value pointed to by the pointer at this moment.

[0045] Reverse verification: With the self-sealing valve interface 15 closed, slowly open the valve 14 before the relay gauge. When the internal pressure of the SF6 density relay rises to the secondary alarm pressure range (set value), the normally open secondary alarm node 13 opens, and the secondary alarm indicator light 2 goes out. At this time, observe whether the pointer 10 points to the secondary indicator light change area 5, and record the scale value pointed to by the pointer at this moment. When the internal pressure of the SF6 density relay rises to the primary alarm pressure range (set value), the normally open primary alarm node 12 opens, and the primary alarm indicator light 1 goes out. At this time, observe whether the pointer 10 points to the primary indicator light change area 6, and record the scale value pointed to by the pointer 10 at this moment.

[0046] When the output voltage of the field node is mismatched or the load of the SF6 density relay is large, in order to be compatible with the existing SF6 density relay, install the primary indicator light shield 3 and the secondary indicator light shield 4. At this time, the primary alarm indicator light 1 and the secondary alarm indicator light 2 are short-circuited. When the internal alarm node of the SF6 density relay is closed, neither the primary alarm indicator light 1 nor the secondary alarm indicator light 2 will light up.

[0047] The foregoing basic examples and their further alternative examples can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed in this application. In the scheme of this application, each alternative example can be arbitrarily combined with any other basic example and alternative example.

[0048] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A self-calibrating density relay, comprising a dial, characterized in that: It also includes an alarm circuit, a rotating pointer (10) in the center of the dial, and an alarm pressure area and a normal air pressure area (7) on the dial. The alarm circuit includes a series-connected normally open alarm node and an alarm indicator light. The normally open alarm node is interlocked with the alarm pressure range of the internal pressure monitoring module.

2. The self-calibrating density relay according to claim 1, characterized in that: The alarm indicator light is connected in parallel with a detachable indicator light shielding cap.

3. The self-calibrating density relay according to claim 1, characterized in that: The alarm circuit includes a primary alarm circuit and a secondary alarm circuit. The alarm pressure area includes a primary alarm pressure area (8) and a secondary alarm pressure area (9). The secondary alarm pressure area (9), the primary alarm pressure area (8), and the normal pressure area (7) are arranged from low pressure to high pressure. The primary alarm circuit includes a primary alarm normally open node (12) and a primary alarm indicator (1) connected in series. The secondary alarm circuit includes a secondary alarm normally open node (13) and a secondary alarm indicator (2) connected in series. The primary alarm pressure range of the internal pressure monitoring module is interlocked with the primary alarm normally open node (12). The primary alarm pressure range of the internal pressure monitoring module is interlocked with the secondary alarm normally open node (13).

4. The self-calibrating density relay according to claim 3, characterized in that: The first-level alarm indicator (1) is connected in parallel with a detachable first-level indicator shielding cap (3), and the second-level alarm indicator (2) is connected in parallel with a detachable second-level indicator shielding cap (4).

5. The self-calibrating density relay according to claim 3 or 4, characterized in that: The dial is further divided into a primary indicator light change area (6) and a secondary indicator light change area (5). The primary indicator light change area (6) is located between the primary alarm pressure area (8) and the normal air pressure area (7). The secondary indicator light change area (5) is located between the secondary alarm pressure area (9) and the primary alarm pressure area (8).

6. The self-calibrating density relay according to claim 1, characterized in that: The density relay mentioned is an SF6 density relay.

7. A mounting structure for a self-calibrating density relay, comprising a closed assembly (16), characterized in that: It also includes a self-calibrating density relay as described in any one of claims 1 to 6, wherein the closed combination device (16) is connected to the relay front valve (14), the relay front valve (14) is connected to the density relay, and the density relay is connected to the self-sealing valve interface (15).

8. A method for using a self-calibrating density relay, characterized in that, Using any of the self-calibrating density relays described in claims 1 to 6, by applying or reducing pressure inside the density relay, the internal pressure monitoring module detects that the internal pressure of the relay has reached or left the alarm pressure range, causing the normally open alarm node to close or open, the alarm indicator light to light up or turn off, and observes whether the pointer (10) points to the alarm pressure area and records the pressure value.

9. The method of using the self-calibrating density relay according to claim 8, characterized in that: Install the density relay between the relay inlet valve (14) and the self-sealing valve interface (15) of the closed combination equipment (16); close the relay inlet valve (14) and open the self-sealing valve interface (15) to gradually reduce the pressure inside the density relay; open the relay inlet valve (14) and close the self-sealing valve interface (15) to gradually increase the pressure inside the density relay.

10. The method of using the self-calibrating density relay according to claim 8 or 9, characterized in that: Connecting an indicator light shielding cap in parallel to the alarm indicator light ensures the density relay functions normally.

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