Deflagration risk early warning device for mechanical sensing oil-immersed distribution transformer

Abstract

The utility model discloses a mechanical sensing deflagration risk early warning device for an oil-immersed distribution transformer, which comprises a control unit and a signal acquisition device, the signal acquisition device comprises a temperature sensing device, a liquid level sensing device and a pressure sensing device, the temperature sensing device comprises a temperature switch, and the liquid level sensing device comprises a pressure sensor. The liquid level sensing device comprises a liquid level switch, the pressure sensing device comprises a pressure switch, the control unit comprises a logic module, a power supply module, a sound module and a light emitting module, the logic module is connected with the temperature switch, the liquid level switch and the pressure switch through signal cables, and the logic module judges collected temperature, liquid level and pressure signals firstly and then sends the judged signals to the control unit; and the sound module and the light-emitting module are controlled to give an alarm after an early warning condition is met. The device is good in performance, long in service life, high in efficiency and capable of achieving early fault early warning of the distribution transformer and eradicating deflagration accidents.

Description

Technical Field

[0001] This utility model relates to the technical field of early warning devices for distribution transformers, specifically a mechanical sensing early warning device for the risk of explosion and combustion of oil-immersed distribution transformers. Background Technology

[0002] The structural characteristics of the distribution transformer (hereinafter referred to as the transformer) tank are as follows: the internal cavity of the transformer tank is completely sealed; the transformer tank contains electrical components that carry current; the electrical components inside the transformer tank are surrounded by an insulating medium (usually transformer oil) for insulation and heat dissipation protection; the operation of the electrical components inside the transformer tank causes heat to be generated inside the transformer tank, and the thermal expansion and contraction of the transformer oil causes the internal pressure of the transformer tank to change with temperature; for a transformer tank with a fixed structure, temperature, pressure and liquid level are the main physical quantities that need to be monitored.

[0003] The number of distribution transformers operating across the national power grid is in the hundreds of millions, with millions of new distribution transformers manufactured each year. Taking Shanghai as an example, the failure rate of distribution transformers is about 1‰, and about 85% of these failures are caused by moisture entering the distribution transformer tank due to oil tank leakage, which leads to insulation damage.

[0004] Traditional non-electrical quantity monitoring and protection devices for distribution transformers include pressure relief valves, oil level gauges, and thermometers. These devices monitor a single physical quantity within the transformer tank. For example, a pressure relief valve monitors the pressure inside the tank, releasing excessive pressure to prevent explosions when it reaches a threshold; an oil level gauge monitors the transformer oil level, issuing a low oil level indication when leakage causes a drop; and a thermometer monitors the oil temperature, issuing a high-temperature warning when the temperature is too high. However, these traditional non-electrical quantity monitoring devices only monitor a single physical quantity within the distribution transformer tank. By the time these devices issue warnings based on a single quantity, the fault within the tank has already progressed to a serious stage.

[0005] Traditional non-electrical quantity monitoring devices for distribution transformers cannot provide timely and effective early warnings of equipment anomalies, potentially leading to greater insulation damage or even transformer combustion and explosion accidents. This invention addresses this by enabling the coordinated monitoring of three variables—temperature, pressure, and liquid level—once the existing non-electrical quantity monitoring device, thereby achieving timely early warnings of distribution transformer faults. Utility Model Content

[0006] To address the shortcomings of existing technologies, the purpose of this utility model is to provide a mechanically sensing oil-immersed distribution transformer deflagration risk early warning device. By real-time monitoring of temperature, pressure, and liquid level signals, it achieves reliable early warning for distribution transformers and has the advantages of good performance, long service life, and high processing efficiency.

[0007] Therefore, the objective of this utility model is achieved through the following technical solution:

[0008] A mechanical sensing-based explosion risk warning device for oil-immersed distribution transformers includes a control unit and a signal acquisition device. The signal acquisition device includes a sealed housing, a temperature sensor, a liquid level sensor, and a pressure sensor installed on the oil-immersed distribution transformer. A pressure relief valve is installed on the top of the sealed housing. The temperature sensor includes a temperature switch, the liquid level sensor includes a liquid level switch, and the pressure sensor includes a pressure switch. The temperature switch, liquid level switch, and pressure switch are all installed inside the sealed housing, and each switch is connected to the control unit to collect temperature, liquid level, and pressure signals in real time. The control unit includes a logic module, a power module, a sound module, and a light-emitting module installed in a control box. The power module is connected to the logic module, sound module, and light-emitting module. The logic module is connected to the temperature switch, liquid level switch, and pressure switch via signal cables, and is also connected to the sound module and light-emitting module. The logic module judges the collected temperature, liquid level, and pressure signals, and controls the sound module and light-emitting module to sound an alarm when the warning conditions are met.

[0009] Preferably, the control unit further includes a network communication module installed in the control box, which is wirelessly connected to a user terminal with adapter software installed. The power module adopts an AC220V interface for connecting to an external power source, and the connection between the signal cable and the sealed housing adopts an airtight aviation plug.

[0010] Preferably, the pressure relief valve includes a valve cover installed on the top of the sealing housing, the valve cover having an exhaust hole, a compression spring and a pressure cover inside the valve cover, the pressure cover being movably mounted on the sealing housing, and the pressure cover having an exhaust channel that is not normally connected to the inner cavity of the valve cover.

[0011] Preferably, the temperature sensing device includes a temperature sensing component, a temperature bulb rod, a transmission rod, a shift fork, a driving component, and a temperature switch. The temperature sensing component is a bimetallic element, which is installed inside the temperature bulb rod below the sealed housing. A transmission rod is connected above the bimetallic element, and a shift fork is installed on the top of the transmission rod. The shift fork is connected to the temperature switch via the driving component. There are two temperature switches installed at a certain angle on the outside of the transmission rod. The transmission rod drives the shift fork to rotate, and the signal output of the temperature switch is realized through the driving component.

[0012] Preferably, the temperature switch includes a housing, electrical contacts, a reed, a button, and a lever. The electrical contacts and the reed are installed inside the housing. The button protruding from the top of the housing is provided on the reed. The lever is located on the top of the housing. One end of the lever is connected to the housing, the middle of the lever is fixedly connected to the button, and the other end of the lever is in contact with the driving component.

[0013] Preferably, the driving component is a cam, which is mounted on a rotating shaft outside the temperature switch. The cam has a lever, a limit lever, a first pressing surface, and a second pressing surface on its side, and the distance between the second pressing surface and the rotating shaft is greater than the distance between the first pressing surface and the rotating shaft.

[0014] Preferably, the temperature sensing component of the temperature sensing device is a temperature bulb assembly, which is installed inside the temperature bulb rod below the sealed housing. The temperature bulb assembly includes a temperature bulb, a capillary tube, and an elastic element. The temperature bulb is connected to the elastic element through the capillary tube, and the elastic element is connected to the transmission rod. The sealed system composed of the temperature bulb, capillary tube, and elastic element is filled with a temperature sensing medium.

[0015] Preferably, the liquid level sensing device includes a float, a transmission assembly, and a liquid level switch. The float is movably mounted on the outside of the temperature sensor rod and is connected to the liquid level switch via the transmission assembly. The liquid level switch is installed in the upper sealed housing and includes a housing, electrical contacts, a spring, a button, and a lever. The electrical contacts and the spring are installed inside the housing, and the button protruding from the top of the housing is provided on the spring. The lever is located on the top of the housing, with one end connected to the housing, the middle of the lever fixedly connected to the button, and the other end of the lever connected to the transmission assembly.

[0016] Preferably, the transmission component is a liquid level sensing guide rod, with an opening at one end of the lever, through which the liquid level sensing guide rod passes and has a protrusion at the top, allowing the liquid level sensing guide rod to move up and down within the opening of the lever.

[0017] Preferably, the pressure sensing device includes a venting device and a pressure switch. Two pressure switches are installed within a sealed housing. The venting device is installed on the sealed housing. The pressure switch includes a housing with an air chamber inside. A partition is installed within the air chamber, dividing it into an upper air chamber and a lower air chamber. A piston is installed in the middle of the partition, and a diaphragm is located below the partition. The bottom surface of the piston contacts the diaphragm, which is located in the lower air chamber and communicates with an air inlet at the bottom of the housing. The piston passes through the partition, and its top is connected to a return spring and a movable contact. The top of the return spring is connected to a pressure adjusting knob, which is located on the housing and threadedly connected to it. By screwing the pressure adjusting knob in and out, the preload of the return spring on the piston is adjusted. Fixed contacts are located on both sides of the upper air chamber of the housing.

[0018] Preferably, the pressure switch includes a sensor housing, a pressure detector, and a wire. An air chamber is formed inside the sensor housing and a pressure detector is installed therein. The air chamber is provided with a ventilated channel that communicates with the air inside the housing. The pressure detector is connected to the wire, and the wire is connected to a signal cable through a connector to transmit the detected pressure signal outward.

[0019] The beneficial effects of this utility model are:

[0020] 1. The overall structure adopts a mechanical design, which can reliably eliminate electromagnetic interference. Each sensor is reliably installed above the oil-immersed distribution transformer, with good oil-gas isolation and sealing, long service life, and supports the long-term use requirements of LCC management of distribution transformers.

[0021] 2. Real-time acquisition and analysis of liquid level, pressure and temperature signals of oil-immersed distribution transformers are realized. Based on the set conditions, the logic module judges and gives different levels of risk warning signals, realizes user terminal display and audible and visual alarm, and has the advantages of being easy to use, fast and accurate, safe and reliable.

[0022] 3. This early warning device has good performance, long life and high efficiency. It can realize early fault warning of distribution transformers, prevent the occurrence of deflagration accidents, and has broad application prospects. Attached Figure Description

[0023] Figure 1 This is a first structural schematic diagram of the mechanical sensing oil-immersed distribution transformer deflagration risk early warning device of this utility model.

[0024] Figure 2 This is a schematic diagram of the second structure of the mechanical sensing oil-immersed distribution transformer deflagration risk early warning device of this utility model.

[0025] Figure 3 This is a schematic diagram illustrating the structure and operation of the temperature switch of this utility model. Figure 3 (a) shows the state where the reed is separated from the electrical contact. Figure 3 (b) represents the state where the reed and the electrical contact are closed;

[0026] Figure 4 This is a schematic diagram illustrating the structure and operation of the liquid level switch of this utility model. Figure 4 (a) shows the state where the reed is separated from the electrical contact. Figure 4 (b) represents the state where the reed and the electrical contact are closed;

[0027] Figure 5 This is a schematic diagram of the pressure switch of this utility model;

[0028] Figure 6 This is a status detection and early warning logic diagram of the mechanical sensing oil-immersed distribution transformer deflagration risk early warning device of this utility model.

[0029] In the diagram: 1-Pressure relief valve, 2-Shift fork, 3-Sealed housing, 4-Temperature switch, 5-Level switch, 6-Drive rod, 7-Temperature bulb rod, 8-Bimetallic element, 9-Float, 10-Pressure switch, 11-Oil-gas isolation block, 12-Airtight aviation connector, 13-Signal cable, 14-Logic module, 15-Power module, 16-Control unit, 17-Sound module, 18-Lighting module, 19-Level sensing guide rod, 20-Cam, 21-Lever, 22-Button, 23-Reed, 24-Electrical contact, 25-Air inlet, 26-Diaphragm, 27-Reset spring, 28-Piston, 29-Moving contact, 30-Fixed contact, 31-Pressure regulating knob. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0031] like Figure 1 , Figure 2 As shown in the figure, this utility model provides a mechanical sensing-based early warning device for the deflagration risk of an oil-immersed distribution transformer, including a control unit 16 and a signal acquisition device. The signal acquisition device includes a sealed housing 3, a temperature sensor, a liquid level sensor, and a pressure sensor installed on the oil-immersed distribution transformer. A pressure relief valve 1 is installed on the top of the sealed housing 3. The temperature sensor includes a temperature switch 4, the liquid level sensor includes a liquid level switch 5, and the pressure sensor includes a pressure switch 10. The temperature switch 4, liquid level switch 5, and pressure switch 10 are all installed inside the sealed housing 3. Each switch is connected to the external control unit 16 via a signal cable 13, enabling real-time acquisition of temperature, liquid level, and pressure signals. The temperature switch 4 can detect changes in the top oil temperature of the transformer, the liquid level switch 5 can detect changes in the transformer oil level, and the pressure switch 10 can monitor changes in the internal pressure of the transformer. In case of an abnormal situation, each switch transmits a signal to the control unit 16 for judgment to achieve early warning.

[0032] The control unit 16 includes a logic module 14, a power module 15, a sound module 17, and a light-emitting module 18 installed in the control box. The power module 15 is connected to the logic module 14, the sound module 17, and the light-emitting module 18. The logic module 14 is connected to the temperature switch 4, the liquid level switch 5, and the pressure switch 10 via signal cables 13. The logic module 14 is also connected to the sound module 17 and the light-emitting module 18. The logic module 14 is the core module of the control unit 16 and can judge the collected temperature, liquid level, and pressure signals. When the warning conditions are met, it controls the sound module 17 and the light-emitting module 18 to sound an alarm.

[0033] In this embodiment, the control unit 16 further includes a network communication module installed in the control box. The network communication module is wirelessly connected to a user terminal with adapter software installed. The power module 15 adopts an AC 220V interface connected to an external power source. The connection between the signal cable 13 and the sealed housing 3 adopts an airtight aviation plug 12, which is convenient to install and use, has high transmission efficiency, and good electrical performance.

[0034] In this embodiment, there is one pressure relief valve 1 with an exhaust pressure of 30-35 kPa. Two temperature switches 4 are used, with warning temperatures of T1 = 80 ± 2℃ and T2 = 100 ± 2℃. One level switch 5 is used, with a preset minimum level. Two pressure switches 10 are used, with warning pressures of P1 = 20 ± 1 kPa and P2 = 20 ± 1 kPa. It is understood that by setting one or more temperature / level / pressure switches 10, and adjusting the installation position of the temperature switch 4, the minimum level position of the level switch 5, and the warning pressure value of the pressure switch 10, the applicability and reliability of each switch are improved, better meeting practical application requirements.

[0035] In this embodiment, the pressure relief valve 1 includes a valve cover mounted on the top of the sealing housing 3. The valve cover has an exhaust port, and a compression spring and a pressure cap are disposed inside the valve cover. The pressure cap is movably disposed on the top plate inside the sealing housing 3. The pressure cap has an exhaust channel, and under normal conditions, the exhaust channel is not connected to the inner cavity of the valve cover, thus keeping the air inside the sealing housing 3 sealed. When the pressure exceeds a predetermined threshold, the air pressure pushes the pressure cap to overcome the preload of the compression spring and form an exhaust channel between the pressure cap and the valve cover. This exhaust channel can be provided by an exhaust port on the pressure cap, with the exhaust port exposed when the pressure cap rises, or by forming an exhaust channel between the outer side of the pressure cap and the outer shell after the pressure cap rises, thereby achieving the function of releasing pressure and protecting the switch.

[0036] In this embodiment, as Figure 1 , Figure 2 As shown, the temperature sensing device includes a temperature sensing component, a temperature bulb rod 7, a transmission rod 6, a shift fork 2, a driving component, and a temperature switch 4. The temperature sensing component uses a bimetallic element 8, which is installed inside the temperature bulb rod 7 below the sealed housing 3. The transmission rod 6 is connected above the bimetallic element 8, and the shift fork 2 is installed on the top of the transmission rod 6. The shift fork 2 is connected to the temperature switch 4 via the driving component. There are two temperature switches 4, which are installed at a certain angle on the outside of the transmission rod 6. The oil temperature inside the transformer is conducted to the bimetallic element 8. After being heated, the bimetallic element 8 deforms, causing the transmission rod 6 to rotate. The transmission rod 6 drives the shift fork 2 to rotate, and the signal output of the temperature switch 4 is achieved through the driving component.

[0037] In this embodiment, as Figure 3As shown, the temperature switch 4 includes a housing, electrical contacts 24, a reed 23, a button 22, and a lever 21. The electrical contacts 24 and the reed 23 are installed inside the housing. The button 22 protrudes from the top of the housing on the reed 23. The lever 21 is located on the top of the housing. One end of the lever 21 is connected to the housing, and the middle of the lever 21 is fixedly connected to the button 22. The other end of the lever 21 is in contact with the pressing surface of the cam 20. Under normal conditions, the lever 21 of the temperature switch 4 is in contact with the first pressing surface. At this time, the reed 23 and the electrical contacts 24 are in a separated state. When the fork 2 pushes the lever to rotate the cam 20 by a certain angle, the second pressing surface contacts the lever 21 of the temperature switch 4 and presses down the button 22 through the lever 21. This pushes the reed 23 down so that the reed 23 and the electrical contacts 24 are in a contact state, thus realizing the closure of the temperature switch 4 and giving a corresponding temperature signal.

[0038] In this embodiment, the driving component is a cam 20, which is mounted on a rotating shaft outside the temperature switch 4. The cam 20 has a lever, a first pressing surface, and a second pressing surface on its side. The distance between the second pressing surface and the rotating shaft is greater than the distance between the first pressing surface and the rotating shaft. Figure 3 As shown in (a), when the first pressing surface contacts the lever 21 of the temperature switch 4, the temperature switch 4 is in the open state, while as Figure 3 As shown in (b), after the shift fork 2 pushes the cam 20 to rotate a certain angle via the shift lever, the second pressing surface of the cam 20 fully contacts the lever 21 of the temperature switch 4, realizing the closed state of the temperature switch 4 and providing a temperature indication signal. In this embodiment, a limit rod is also provided on the cam 20 on one side of the shift lever. When the second pressing surface contacts the lever 21 of the temperature switch 4, one end of the limit rod makes active contact with the column on the side of the shift fork 2, providing stable support for the contact between the second pressing surface of the cam 20 and the lever 21 of the temperature switch 4, thereby maintaining the closed state of the temperature switch 4.

[0039] In other embodiments, the temperature sensing component of the temperature sensing device can be a temperature bulb assembly. The temperature bulb assembly is installed inside the temperature bulb rod 7 below the sealed housing 3. The temperature bulb assembly includes a temperature bulb, a capillary tube, and an elastic element. The temperature bulb is connected to the elastic element through the capillary tube. The elastic element is connected to the transmission rod 6. The elastic element can be a multi-turn spring tube arranged in a spiral. The sealed system composed of the temperature bulb, capillary tube, and elastic element is filled with a temperature-sensing medium. The temperature-sensing medium in the temperature bulb senses the temperature change, causing a change in the pressure (volume) of the working substance in the temperature bulb. This change causes the elastic element to deform, which drives the transmission rod 6 to rotate. The transmission rod 6 drives the shift fork 2 to rotate and, through the drive component, realizes the signal output of the temperature switch 4, thereby realizing the temperature indication of the transformer.

[0040] In this embodiment, as Figure 1 , Figure 2 As shown, the liquid level sensing device includes a float 9, a transmission assembly, and a liquid level switch 5. The float 9 is movably mounted on the outside of the temperature sensor rod 7. The transmission assembly uses a liquid level sensing guide rod 19. The float 9 is connected to the liquid level switch 5 through the liquid level sensing guide rod 19. The liquid level switch 5 is installed in the upper sealed housing 3. When the level of transformer oil in the oil-immersed distribution transformer drops, the float 9 and the liquid level sensing guide rod 19 drop accordingly. The liquid level sensing guide rod 19 activates the liquid level switch 5 through a lever 21. The main structure of the liquid level switch 5 is the same as that of the temperature switch 4. Figure 4 As shown, the liquid level switch 5 includes a housing, electrical contacts 24, a reed 23, a button 22, and a lever 21. The electrical contacts 24 and the reed 23 are installed inside the housing. A button 22 protruding from the top of the housing is provided on the reed 23. The lever 21 is located on the top of the housing, with one end connected to the housing, the middle of the lever 21 fixedly connected to the button 22, and the other end connected to a liquid level sensing rod 19. An opening is provided at one end of the lever 21, through which the liquid level sensing rod 19 passes and has a protrusion at its top. The liquid level sensing rod 19 can move up and down within the opening of the lever 21. When the liquid level drops, a float pulls the liquid level sensing rod. When the float reaches the lowest liquid level, the protrusion at the top of the liquid level sensing rod contacts the lever and presses down, thus connecting the electrical contacts and the reed inside the liquid level switch. By adjusting the length of the liquid level sensing rod, different minimum liquid levels can be indicated. Figure 4 As shown in (a), under normal conditions, the top of the liquid level sensing rod 19 is higher, at which time the reed 23 and the electrical contact 24 are in the separated state, as shown in (a). Figure 4 As shown in (b), when the liquid level sensing guide rod 19 moves downward to the min position, the protrusion at the top of the liquid level sensing guide rod 19 drives the lever 21 to press down the button 22, which in turn pushes the spring 23 to move down so that the spring 23 and the electrical contact 24 are in contact, thus realizing the closure of the liquid level switch 5 and giving the corresponding liquid level signal.

[0041] In this embodiment, as Figure 1 , Figure 2 As shown, the pressure sensing device includes a venting device and a pressure switch 10. There are two pressure switches 10 installed inside the sealed housing 3. The venting device is installed on the sealed housing 3. Gas inside the transformer is sent into the sealed housing 3 through the venting device. The venting device includes an oil-gas isolation block 11 and a flange. The flange is installed below the sealed housing 3. The oil-gas isolation block 11 is installed on the sealed housing 3 inside the flange. The oil-gas isolation block 11 can be made of ventilated steel that allows gas to pass through but blocks liquid. Gas inside the flange can flow upward into the pressure switch 10 through the microporous structure of the ventilated steel. Ultimately, the gas pressure inside the sealed housing 3 and above the transformer oil are consistent, and the oil and gas are isolated, preventing oil and gas from entering the sealed housing 3 and corroding the switch, causing damage.

[0042] In this embodiment, as Figure 5 As shown, the pressure switch 10 includes a housing with an air chamber inside. A partition is installed within the air chamber, dividing it into an upper air chamber and a lower air chamber. A piston 28 is installed in the middle of the partition, and a diaphragm 26 is located below the partition. The bottom surface of the piston 28 contacts the diaphragm 26. The diaphragm 26 is located in the lower air chamber, which communicates with an air inlet 25 located at the bottom of the housing. The piston 28 penetrates the partition, and its top is connected to a return spring 27 and a movable contact 29. The top of the return spring 27 is connected to a pressure regulating knob 31, which is located on the housing. The piston 28 is threadedly connected to the housing. The preload of the return spring 27 on the piston 28 is adjusted by screwing in and releasing the pressure adjustment knob 31. Fixed contacts 30 are located on both sides of the upper air chamber of the housing. When the air pressure in the lower air chamber is greater than that in the upper air chamber and sufficient to overcome the force of the return spring 27, the piston 28 moves upward, causing the movable contact 29 to contact the fixed contacts 30, providing a circuit connection signal. When the pressure is insufficient to overcome the force of the return spring 27, the piston 28 moves downward, causing the movable contact 29 to separate from the fixed contacts 30, providing a circuit disconnection signal. In practice, the operating pressure is set by the pressure adjustment knob 31. When the pressure through the air inlet 25 increases, the diaphragm 26 pushes the piston 28 upward. When the pressure change reaches the set value, the movable contact 29 closes with the fixed contact 30, sending a signal.

[0043] In other embodiments, the pressure switch 10 may be a pressure detector, including a sensor housing, a pressure detector, and a wire. An air chamber is formed inside the sensor housing and the pressure detector is installed therein. The air chamber is provided with a ventilated channel communicating with the air inside the housing. The pressure detector is connected to the wire, and the wire is connected to the signal cable 13 through a connector and transmits the detected pressure signal outward.

[0044] Based on the aforementioned early warning device, this utility model also provides a control method for a mechanically sensing oil-immersed distribution transformer deflagration risk early warning device, the specific steps of which are as follows:

[0045] S1. System Start-up: Select the appropriate temperature switch 4, pressure switch 10 and level switch 5, install the level sensor, pressure sensor and temperature sensor on the oil-immersed distribution transformer, start the control system, and establish real-time communication connection between each unit of the early warning device.

[0046] S2, Signal Monitoring: The signal acquisition unit monitors the liquid level, pressure and temperature of the oil-immersed distribution transformer in real time through various sensors, and transmits the acquired signals to the logic control unit 16 and the audible and visual alarm unit.

[0047] S3. Judgment and Warning: The logic control unit 16 processes and judges the acquired signals in real time. When the values ​​of liquid level, pressure and temperature signals reach the set warning conditions, it sends an instruction to the audible and visual alarm unit to realize the warning, and at the same time transmits the warning signal to the user terminal interface for display.

[0048] In the method of this utility model, in step S3, under different warning conditions, different colors and levels of warning signals will be displayed on the user terminal interface, such as... Figure 6 As shown, different colors and levels correspond to different warning conditions, namely:

[0049] (1) Yellow Level 1: t < 80℃, 20kPa ≤ P < 30kPa, L = "Normal";

[0050] (2) Yellow Level 2: 80℃≤t<100℃, P<20kPa, L=“Normal”;

[0051] (3) Yellow Level 3: 80℃≤t<100℃, 20kPa≤P<30kPa, L=“Normal”;

[0052] (4) Red Level 1: t≥100℃, P<20kPa, L=“Normal”;

[0053] (5) Red Level 2: t≥100℃, 20kPa≤P<30kPa, L=“Normal”;

[0054] (6) Red Level 3: 80℃≤t<100℃, P<20kPa, L=“min”;

[0055] (7) Red Level 4: 80℃≤t<100℃, 20kPa≤P<30kPa, L=“min”;

[0056] (8) Red Level 5: t < 80℃, P ≥ 30kPa, L = "Normal";

[0057] (9) Red Level 6: t < 80℃, P ≥ 30kPa, L = “min”;

[0058] In the above conditions, t is temperature, P is pressure, L is liquid level, and "Normal" is used when the transformer oil is above the set value and "min" is used when it is below the set value.

[0059] In this invention, the degree of risk is expressed by a combination of color and number. Yellow represents risk, and red represents high risk. Yellow is divided into 3 levels, and red is divided into 6 levels. The higher the level, the higher the risk. When there is no risk, it is uniformly displayed as green on the user terminal interface.

[0060] It should be noted that the above embodiments are merely preferred embodiments of the present utility model and are not intended to limit the scope of protection of the present utility model. Equivalent modifications made based on the above embodiments are all within the scope of protection of the present utility model.

Claims

1. A mechanical sensing oil-immersed distribution transformer explosion risk early warning device, characterized in that: The system includes a control unit and a signal acquisition device. The signal acquisition device comprises a sealed housing mounted on an oil-immersed distribution transformer, a temperature sensor, a liquid level sensor, and a pressure sensor. A pressure relief valve is installed on the top of the sealed housing. The temperature sensor includes a temperature switch, the liquid level sensor includes a liquid level switch, and the pressure sensor includes a pressure switch. The temperature switch, liquid level switch, and pressure switch are all installed inside the sealed housing, and each switch is connected to the control unit. The control unit includes a logic module, a power module, a sound module, and a light-emitting module installed in a control box. The power module is connected to the logic module, the sound module, and the light-emitting module, respectively. The logic module is connected to the temperature switch, the liquid level switch, and the pressure switch via signal cables, respectively.

2. The mechanical sensing oil-immersed distribution transformer explosion risk early warning device according to claim 1, characterized in that: The control unit also includes a network communication module installed in the control box. The network communication module is wirelessly connected to the user terminal. The power module adopts an AC 220V interface for connecting to an external power source. The connection between the signal cable and the sealed housing adopts an airtight aviation plug.

3. The mechanical sensing oil-immersed distribution transformer explosion risk early warning device according to claim 1, characterized in that: The pressure relief valve includes a valve cover installed on the top of the sealing housing. The valve cover has an exhaust hole. A compression spring and a pressure cover are provided inside the valve cover. The pressure cover is movably mounted on the sealing housing and has an exhaust channel.

4. The mechanical sensing oil-immersed distribution transformer explosion risk early warning device according to claim 1, characterized in that: The temperature sensing device includes a temperature sensing component, a temperature bulb rod, a transmission rod, a shift fork, a driving component, and a temperature switch. The temperature sensing component uses a bimetallic element, which is installed inside the temperature bulb rod below the sealed housing. A transmission rod is connected above the bimetallic element, and a shift fork is installed on the top of the transmission rod. The shift fork is connected to the temperature switch via the driving component. There are two temperature switches installed at a certain angle on the outside of the transmission rod. The transmission rod drives the shift fork to rotate, and the signal output of the temperature switch is realized through the driving component.

5. The mechanical sensing oil-immersed distribution transformer explosion risk early warning device according to claim 4, characterized in that: The temperature switch includes a housing, electrical contacts, a spring, a button, and a lever. The electrical contacts and the spring are installed inside the housing. The button protruding from the top of the housing is provided on the spring. The lever is located on the top of the housing. One end of the lever is connected to the housing, the middle of the lever is fixedly connected to the button, and the other end of the lever is in contact with the driving component.

6. The mechanical sensing-based explosion risk warning device for oil-immersed distribution transformers according to claim 4, characterized in that: The driving component is a cam, which is mounted on a rotating shaft outside the temperature switch. The side of the cam is provided with a lever, a limit lever, a first pressing surface, and a second pressing surface, and the distance between the second pressing surface and the rotating shaft is greater than the distance between the first pressing surface and the rotating shaft.

7. The mechanical sensing-based explosion risk warning device for oil-immersed distribution transformers according to claim 4, characterized in that: The temperature sensing component of the temperature sensing device is a temperature bulb assembly, which is installed inside the temperature bulb rod below the sealed housing. The temperature bulb assembly includes a temperature bulb, a capillary tube, and an elastic element. The temperature bulb is connected to the elastic element through the capillary tube, and the elastic element is connected to the transmission rod. The sealed system composed of the temperature bulb, capillary tube, and elastic element is filled with a temperature sensing medium.

8. The mechanical sensing-based explosion risk warning device for oil-immersed distribution transformers according to claim 1, characterized in that: The liquid level sensing device includes a float, a transmission assembly, and a liquid level switch. The float is movably mounted on the outside of the temperature sensor rod and is connected to the liquid level switch via the transmission assembly. The liquid level switch is installed in the upper sealed housing and includes a housing, electrical contacts, a spring, a button, and a lever. The electrical contacts and the spring are installed inside the housing, and the button protruding from the top of the housing is provided on the spring. The lever is located on the top of the housing, with one end connected to the housing, the middle of the lever fixedly connected to the button, and the other end of the lever connected to the transmission assembly.

9. A mechanically sensing explosion risk warning device for oil-immersed distribution transformers according to claim 8, characterized in that: The transmission component is a liquid level sensing guide rod. One end of the lever is provided with an opening, the liquid level sensing guide rod passes through the opening, and a protrusion is provided on the top of the liquid level sensing guide rod.

10. A mechanically sensing oil-immersed distribution transformer deflagration risk early warning device according to claim 1, characterized in that: The pressure sensing device includes a venting device and a pressure switch. There are two pressure switches installed inside a sealed housing. The venting device is installed on the sealed housing. The pressure switch includes a housing with an air chamber inside. A partition is installed inside the air chamber, dividing it into an upper air chamber and a lower air chamber. A piston is installed in the middle of the partition. A diaphragm is provided below the partition. The bottom surface of the piston contacts the diaphragm. The diaphragm is located in the lower air chamber, which is connected to an air inlet at the bottom of the housing. The piston passes through the partition, and its top is connected to a return spring and a movable contact. The top of the return spring is connected to a pressure adjusting knob, which is located on the housing and threadedly connected to it. By screwing the pressure adjusting knob in and out, the preload of the return spring on the piston is adjusted. Fixed contacts are provided on both sides of the upper air chamber inside the housing.

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