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

Abstract

The invention discloses a mechanical sensing deflagration risk early warning device and method for an oil-immersed distribution transformer, the device 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; after an early warning condition is met, the sound module and the light-emitting module are controlled to give an alarm; the method comprises the following steps: S1, starting a system; s2, monitoring a signal; and S3, performing judgment and early warning. 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] The present invention relates to the technical field of early warning devices for distribution transformers, and in particular to a mechanically sensing early warning device and method for the explosion risk of an oil-immersed distribution transformer. Background Art

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

[0003] The number of distribution transformers in operation across the national grid is in the billions, and millions of new distribution transformers are manufactured each year. Taking Shanghai as an example, the failure rate of distribution transformers is about 1‰, and about 85% of this is caused by oil tank leakage, which causes moisture to enter the distribution transformer tank and lead to insulation damage.

[0004] Traditional non-electrical monitoring and protection devices for distribution transformers include pressure relief valves, oil level gauges, and thermometers. These non-electrical monitoring and protection devices all monitor a single physical quantity within the distribution transformer tank. For example, a pressure relief valve monitors the pressure within the distribution transformer tank and, when the pressure reaches the threshold, opens to release excess pressure within the tank to prevent explosions. An oil level gauge monitors the transformer oil level within the distribution transformer tank and issues a low oil level indication when the tank leaks and the oil level drops. A thermometer monitors the oil temperature within the distribution transformer tank and issues a high temperature warning when the oil temperature is too high. However, these traditional non-electrical monitoring devices all monitor a single physical quantity within the distribution transformer tank. By the time these monitoring devices issue a warning based on a single physical quantity, the fault within the distribution transformer tank has already developed to a serious stage.

[0005] Because traditional non-electrical quantity monitoring devices for distribution transformers cannot effectively and promptly issue early warnings of equipment anomalies, this can lead to greater insulation damage or even explosions. This invention, based on existing non-electrical quantity monitoring devices, achieves coordinated monitoring of temperature, pressure, and liquid level, thereby providing timely early warnings of distribution transformer failures. Summary of the Invention

[0006] To address the shortcomings of the existing technology, the present invention aims to provide a mechanically sensing early warning device for oil-immersed distribution transformer explosion risk. This device, through real-time monitoring of temperature, pressure, and liquid level signals, provides reliable early warning of distribution transformer explosions. The device offers excellent performance, a long service life, and high processing efficiency. Furthermore, a control method based on this early warning device is provided that is convenient, fast, accurate, safe, and reliable.

[0007] Therefore, the purpose of the present invention is achieved through the following technical solutions:

[0008] A mechanically sensing oil-immersed distribution transformer explosion risk warning device includes a control unit and a signal acquisition device. The signal acquisition device includes a sealed housing, a temperature sensing device, a liquid level sensing device, and a pressure sensing device installed on the oil-immersed distribution transformer. A pressure relief valve is installed on the top of the sealed housing. The temperature sensing device includes a temperature switch, the liquid level sensing device includes a liquid level switch, and the pressure sensing device includes a pressure switch. The temperature switch, liquid level switch, and pressure switch are all installed in the sealed housing. Each switch is connected to the control unit and can 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 respectively connected to the logic module, the sound module, and the light-emitting module. The logic module is respectively connected to the temperature switch, the liquid level switch, and the pressure switch via signal cables. At the same time, the logic module is respectively connected to the sound module and the light-emitting module. The logic module judges the collected temperature, liquid level, and pressure signals, and controls the sound module and the light-emitting module to alarm when the warning conditions are met.

[0009] Preferably, the control unit also includes a network communication module installed in the control box, the network communication module is wirelessly connected to a user terminal installed with adaptation software, the power supply module adopts an AC220V interface connected to an external power supply, and the connection part between the signal cable and the sealed shell adopts an airtight aviation plug.

[0010] Preferably, the pressure relief valve includes a valve cover installed on the top of the sealed housing, the valve cover is provided with an exhaust hole, a compression spring and a pressure cover are provided inside the valve cover, the pressure cover is movably provided on the sealed housing, and the pressure cover is provided with an exhaust channel which is not connected to the inner cavity of the valve cover under normal circumstances.

[0011] Preferably, the temperature sensing device includes a temperature sensing component, a temperature bulb rod, a transmission rod, a shift fork, a driving member and a temperature switch. The temperature sensing component adopts a bimetallic element, which is installed in 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 through the driving member. There are two temperature switches installed on the outside of the transmission rod at a certain angle. The transmission rod drives the shift fork to rotate and transmits the signal of the temperature switch through the driving member.

[0012] Preferably, the temperature switch includes a shell, an electrical contact, a reed, a button and a lever, the shell is equipped with an electrical contact and a reed, the reed is provided with a button protruding from the top of the shell, the lever is provided at the top of the shell, one end of the lever is connected to the shell, the middle part of the lever is fixedly connected to the button, and the other end of the lever is in contact with the driving member.

[0013] Preferably, the driving member is a cam, which is mounted on a rotating shaft outside the temperature switch. A lever, a limit rod, a first pressing surface, and a second pressing surface are provided on the side of the cam, 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 adopts a temperature bulb component, which is installed in the temperature bulb rod below the sealed shell. The temperature bulb component 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 closed system composed of the temperature bulb, the capillary tube and the 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 installed on the outside of the temperature bag rod. The float is connected to the liquid level switch through the transmission assembly. The liquid level switch is installed in a sealed shell above. The liquid level switch includes an outer shell, an electrical contact, a reed, a button and a lever. The outer shell is equipped with an electrical contact and a reed. The reed is provided with a button protruding from the top of the outer shell. The lever is provided at the top of the outer shell, one end of the lever is connected to the outer shell, the middle part of the lever is fixedly connected to the button, and the other end of the lever is connected to the transmission assembly.

[0016] Preferably, the transmission component is a liquid level sensing guide rod, an opening is provided at one end of the lever, the liquid level sensing guide rod passes through the opening and is provided with a protrusion on the top, and the liquid level sensing guide rod can move up and down in the opening of the lever.

[0017] Preferably, the pressure sensing device includes a breathable device and a pressure switch, there are two pressure switches and they are installed in a sealed shell, the breathable device is installed on the sealed shell, the pressure switch includes a shell, an air cavity is provided in the shell, a partition is installed in the air cavity and divides the air cavity into an upper air cavity and a lower air cavity, a piston is installed in the middle of the partition, a diaphragm is provided under the partition, the bottom surface of the piston is in contact with the diaphragm, the diaphragm is located in the lower air cavity and the lower air cavity is connected to the air inlet hole provided at the bottom of the shell, the piston is arranged through the partition and the top of the piston is connected to the reset spring and the movable contact, the top of the reset spring is connected to the pressure regulating knob, the pressure regulating knob is located on the shell and is threadedly connected to the shell, and the pre-tightening force of the reset spring on the piston is adjusted by screwing in and out of the pressure regulating knob, and fixed contacts are provided on both sides of the upper air cavity of the shell.

[0018] Preferably, the pressure switch includes a sensor housing, a pressure detector, and a wire. An air chamber is formed in the sensor housing and a pressure detector is installed. The air chamber is provided with a ventilation channel connected to the air in the outer shell. The pressure detector is connected to the wire. The wire is connected to the signal cable through a connector and transmits the detected pressure signal to the outside.

[0019] Based on the early warning device, the present invention provides a control method for a mechanically sensing oil-immersed distribution transformer explosion risk early warning device, the specific steps of which are as follows:

[0020] S1. System startup: Select the appropriate temperature switch, pressure switch, and liquid level switch, install the liquid level sensor, pressure sensor, and temperature sensor on the oil-immersed distribution transformer, start the control system, and establish real-time communication connections between the various units of the early warning device;

[0021] 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 sensing devices, and transmits the acquired signals to the logic control unit and the sound and light alarm unit;

[0022] S3. Judgment and warning: The logic control unit processes and judges the acquired signals in real time. When it detects that the values ​​of the liquid level, pressure and temperature signals reach the set warning conditions, it sends a command information to the sound and light alarm unit to implement the warning, and at the same time transmits the warning signal to the user terminal interface for display.

[0023] Preferably, in step S3, under different warning conditions, different warning signals will be displayed on the interface of the user terminal. The warning signal expresses the degree of risk by combining color and number. Yellow represents risk, and red represents greater 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 will be uniformly displayed in green on the user terminal interface.

[0024] The beneficial effects of the present invention are:

[0025] 1. The overall mechanical structure can reliably eliminate electromagnetic interference. Each sensor device is reliably installed above the oil-immersed distribution transformer, with good oil and gas isolation and sealing, long service life, and support the long-term use requirements of LCC management of distribution transformers;

[0026] 2. It realizes the real-time acquisition and analysis of the liquid level, pressure and temperature signals of the oil-immersed distribution transformer. It gives different levels of risk warning signals based on the set conditions after judgment by the logic module, and realizes user-side display and sound and light alarm. It has the advantages of being easy to use, fast, accurate, safe and reliable.

[0027] 3. The early warning device has good performance, long service life and high efficiency. It can realize early fault warning of distribution transformers and prevent explosion accidents. It has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a first structural schematic diagram of the mechanical sensing oil-immersed distribution transformer explosion risk warning device of the present invention;

[0029] Figure 2 This is a second structural schematic diagram of the mechanical sensing oil-immersed distribution transformer explosion risk warning device of the present invention;

[0030] Figure 3 The structure and operation diagram of the temperature switch of the present invention is shown in FIG. Figure 3 (a) is the state where the reed and the electrical contact are separated. Figure 3 (b) is the state where the reed and the electrical contact are closed;

[0031] Figure 4 The structure and operation diagram of the liquid level switch of the present invention is shown in FIG. Figure 4 (a) is the state where the reed and the electrical contact are separated. Figure 4 (b) is the state where the reed and the electrical contact are closed;

[0032] Figure 5 It is a structural schematic diagram of the pressure switch of the present invention;

[0033] Figure 6 This is a state detection and warning logic diagram of the mechanical sensing oil-immersed distribution transformer explosion risk warning device of the present invention;

[0034] In the figure: 1-pressure relief valve, 2-shift fork, 3-sealed housing, 4-temperature switch, 5-liquid level switch, 6-transmission rod, 7-temperature bulb rod, 8-bimetallic element, 9-float, 10-pressure switch, 11-oil and gas isolation block, 12-airtight aviation plug, 13-signal cable, 14-logic module, 15-power module, 16-control unit, 17-sound module, 18-light module, 19-liquid level sensor guide rod, 20-cam, 21-lever, 22-button, 23-reed, 24-electrical contact, 25-air inlet, 26-diaphragm, 27-return spring, 28-piston, 29-movable contact, 30-fixed contact, 31-pressure regulating knob. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0036] like Figure 1 、 Figure 2 As shown, an embodiment of the present invention provides a mechanical sensing oil-immersed distribution transformer explosion risk warning device, including a control unit 16 and a signal acquisition device, wherein the signal acquisition device includes a sealed housing 3, a temperature sensing device, a liquid level sensing device and a pressure sensing device installed on the oil-immersed distribution transformer, a pressure relief valve 1 is installed on the top of the sealed housing 3, the temperature sensing device includes a temperature switch 4, the liquid level sensing device includes a liquid level switch 5, and the pressure sensing device includes a pressure switch 10. The temperature switch 4, the liquid level switch 5 and the pressure switch 10 are all installed in the sealed housing 3, and each switch is connected to the external control unit 16 through a signal cable 13, and can collect temperature, liquid level and pressure signals in real time. Among them, the temperature switch 4 can detect changes in the oil temperature of the top layer of the transformer, the liquid level switch 5 can detect changes in the oil level height of the transformer, and the pressure switch 10 can monitor changes in the internal pressure of the transformer. When an abnormal situation occurs, each switch transmits a signal to the control unit 16 for judgment to achieve an early warning.

[0037] 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 a control box. The power module 15 is connected to the logic module 14, the sound module 17 and the light-emitting module 18 respectively. The logic module 14 is connected to the temperature switch 4, the liquid level switch 5 and the pressure switch 10 respectively through a signal cable 13. At the same time, the logic module 14 is connected to the sound module 17 and the light-emitting module 18 respectively. The logic module 14 is the core module of the control unit 16, which can judge the collected temperature, liquid level and pressure signals, and control the sound module 17 and the light-emitting module 18 to alarm when the warning conditions are met.

[0038] In this embodiment, the control unit 16 also includes a network communication module installed in the control box, which is wirelessly connected to a user terminal installed with adaptation software. The power supply module 15 adopts an AC 220V interface connected to an external power supply, and the connection between the signal cable 13 and the sealed shell 3 adopts an airtight aviation plug 12, which is easy to install and use, has high transmission efficiency, and good electrical performance.

[0039] In this embodiment, there is one pressure relief valve 1, the exhaust pressure is selected to be 30-35 kPa, two temperature switches 4 are provided, the warning temperatures are T1 = 80 ± 2°C and T2 = 100 ± 2°C, one liquid level switch 5 is provided, and the minimum liquid level is preset, and two pressure switches 10 are provided, with the warning pressures P1 = 20 ± 1 kPa and P2 = 20 ± 1 kPa. It will be understood that by providing one or more temperature / liquid level / pressure switches 10, and adjusting the installation position of the temperature switch 4, the minimum liquid level position corresponding to the liquid level switch 5, and the warning pressure value of the pressure switch 10, the applicability and reliability of each switch can be improved to better meet actual application requirements.

[0040] In this embodiment, the pressure relief valve 1 includes a valve cover mounted on top of a sealed housing 3. The valve cover is provided with an exhaust hole. A compression spring and a gland are disposed within the valve cover. The gland is movably mounted on the top plate of the sealed housing 3. The gland is provided with an exhaust passage, and under normal conditions, the exhaust passage is disconnected from the inner cavity of the valve cover, thereby maintaining a sealed state within the sealed housing 3. When the pressure exceeds a predetermined threshold, the gas pressure pushes the gland to overcome the preload force of the compression spring and form an exhaust passage between the gland and the valve cover. This exhaust passage can be provided by an exhaust hole disposed on the gland and exposed when the gland is raised, or by forming an exhaust passage between the outer side of the gland and the outer shell after the gland is raised, thereby achieving the purpose of releasing pressure and protecting the switch.

[0041] In this embodiment, if 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 drive element, and a temperature switch 4. The temperature sensing component uses a bimetallic element 8, which is mounted within the temperature bulb rod 7 below the sealed housing 3. The transmission rod 6 is connected to the top of the bimetallic element 8, and the shift fork 2 is mounted on the top of the transmission rod 6. The shift fork 2 is connected to the temperature switch 4 through the drive element. Two temperature switches 4 are installed on the outside of the transmission rod 6 at a certain angle. The oil temperature in the transformer is transferred to the bimetallic element 8 through heat conduction. When heated, the bimetallic element 8 deforms and drives the transmission rod 6 to rotate. The transmission rod 6 drives the shift fork 2 to rotate, and the transmission is transmitted through the drive element to realize the signal output of the temperature switch 4.

[0042] In this embodiment, if Figure 3As shown, the temperature switch 4 includes a shell, an electrical contact 24, a reed 23, a button 22 and a lever 21. The electrical contact 24 and the reed 23 are installed in the shell. The reed 23 is provided with a button 22 protruding from the top of the shell. The lever 21 is set at the top of the shell, one end of the lever 21 is connected to the shell, the middle part of the lever 21 is fixedly connected to the button 22, and the other end of the lever 21 is in contact with the pressing surface of the cam 20. Under normal circumstances, 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 contact 24 are in a separated state. When the fork 2 pushes the shift rod to rotate the cam 20 to a certain angle, the second pressing surface contacts the lever 21 of the temperature switch 4 and presses the button 22 through the lever 21, thereby pushing the reed 23 downward so that the reed 23 and the electrical contact 24 are in a contact state, thereby realizing the closure of the temperature switch 4 and giving a corresponding temperature signal.

[0043] In this embodiment, the driving member is a cam 20, which is mounted on the rotating shaft outside the temperature switch 4. A lever, a first pressing surface, and a second pressing surface are provided on the side of the cam 20, 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. 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 off state, and as shown in 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, achieving 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 movably contacts 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.

[0044] In other embodiments, the temperature sensing component of the temperature sensing device may adopt a temperature bulb assembly, which is installed in the temperature bulb rod 7 below the sealed shell 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, and the elastic element is connected to the transmission rod 6. The elastic element may adopt a multi-turn spring tube arranged in a spiral. The closed system composed of the temperature bulb, the capillary tube and the elastic element is filled with a temperature sensing medium. The temperature sensing medium in the temperature bulb senses the temperature change and causes the pressure (volume) of the working substance in the temperature bulb to change. This change causes the elastic element to deform and then drive the transmission rod 6 to rotate. The transmission rod 6 drives the fork 2 to rotate and realizes the signal output of the temperature switch 4 through the drive member, thereby realizing the temperature indication of the transformer.

[0045] In this embodiment, if 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 package rod 7. The transmission assembly adopts 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 liquid level of the 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 realizes the operation of the liquid level switch 5 through the 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, an electrical contact 24, a reed 23, a button 22 and a lever 21. The housing is provided with an electrical contact 24 and a reed 23. The reed 23 is provided with a button 22 protruding from the top of the housing. The lever 21 is provided at the top of the housing. One end of the lever 21 is connected to the housing. The middle of the lever 21 is fixedly connected to the button 22. The other end of the lever 21 is connected to the liquid level sensing guide rod 19. An opening is provided at one end of the lever 21. The liquid level sensing guide rod 19 passes through the opening and is provided with a protrusion on the top. The liquid level sensing guide rod 19 can move up and down in the opening of the lever 21. When the liquid level drops, the float pulls the liquid level sensing guide rod. When the float reaches the lowest liquid level, the protrusion on the top of the liquid level sensing guide rod contacts the lever and presses down the lever to connect the electrical contacts and reed in the liquid level switch. By adjusting the length of the liquid level conduction rod, the indication of different minimum liquid levels can be achieved. Figure 4 As shown in (a), the top of the liquid level sensor guide rod 19 is higher under normal conditions, and the reed 23 and the electrical contact 24 are in a separated state. Figure 4 As shown in (b), when the liquid level sensing rod 19 moves downward to the min position, the protrusion on the top of the liquid level sensing rod 19 drives the lever 21 to press the button 22, thereby pushing the reed 23 downward so that the reed 23 and the electrical contact 24 are in contact, thereby realizing the closure of the liquid level switch 5 and giving the corresponding liquid level signal.

[0046] In this embodiment, if Figure 1 、 Figure 2 As shown, the pressure sensing device includes a breathable device and a pressure switch 10. There are two pressure switches 10 and they are installed in the sealed housing 3. The breathable device is installed on the sealed housing 3. The gas in the transformer is sent into the sealed housing 3 by the breathable device. The breathable 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 breathable steel that can pass gas but block liquid. The gas in the flange can flow upward into the pressure switch 10 through the microporous structure of the breathable steel, and finally achieve the consistency of air pressure in the sealed housing 3 and above the transformer oil and isolate the oil and gas, so as to prevent oil and gas from entering the sealed housing 3 and corroding the switch and causing damage.

[0047] In this embodiment, if Figure 5 As shown, the pressure switch 10 includes a housing, an air cavity is provided in the housing, a partition is installed in the air cavity and the air cavity is divided into an upper air cavity and a lower air cavity, a piston 28 is installed in the middle of the partition, a diaphragm 26 is provided below the partition, the bottom surface of the piston 28 contacts the diaphragm 26, the diaphragm 26 is located in the lower air cavity and the lower air cavity is connected to the air inlet 25 provided at the bottom of the housing, the piston 28 is provided through the partition and the top of the piston 28 is connected to the reset spring 27 and the movable contact 29, the top of the reset spring 27 is connected to the pressure regulating knob 31, and the pressure regulating knob 31 is located on the housing and Threadedly connected to the housing, the preload force exerted by the return spring 27 on the piston 28 is adjusted by screwing in and out of a pressure-adjusting knob 31. Fixed contacts 30 are located on either side of the upper air chamber of the housing. When the air pressure in the lower air chamber exceeds that in the upper air chamber and is sufficient to overcome the force of the return spring 27, the piston 28 moves upward, causing both ends of the movable contact 29 to contact the fixed contacts 30, signaling a circuit connection. When the pressure is insufficient to overcome the force of the return spring 27, the piston 28 moves downward, separating the ends of the movable contact 29 from the fixed contacts 30, signaling a circuit disconnection. In practice, the operating pressure is set by the pressure-adjusting 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 contacts 30, signaling a circuit disconnection.

[0048] In other embodiments, the pressure switch 10 may adopt a pressure detector, including a sensor housing, a pressure detector, and a wire. An air chamber is formed in the sensor housing and a pressure detector is installed. The air chamber is provided with a ventilation channel connected to the air in the outer shell. 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 to the outside.

[0049] Based on the above-mentioned early warning device, the present invention also provides a control method for a mechanically sensing oil-immersed distribution transformer explosion risk early warning device, the specific steps of which are as follows:

[0050] S1. System startup: Select the appropriate temperature switch 4, pressure switch 10, and liquid level switch 5, install the liquid level sensor, pressure sensor, and temperature sensor on the oil-immersed distribution transformer, start the control system, and establish real-time communication connections between the various units of the early warning device;

[0051] 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 sensing devices, and transmits the acquired signals to the logic control unit 16 and the sound and light alarm unit;

[0052] S3. Judgment and warning: The logic control unit 16 processes and judges the acquired signals in real time. When it detects that the values ​​of the liquid level, pressure and temperature signals reach the set warning conditions, it sends a command information to the sound and light alarm unit to implement a warning, and at the same time transmits the warning signal to the user terminal interface for display.

[0053] In the method of the present invention, in step S3, under different warning conditions, warning signals of different colors and levels will be displayed on the interface of the user terminal, such as Figure 6 As shown, different colors and levels correspond to different warning conditions, which are:

[0054] (1) Yellow 1: t<80℃, 20kPa≤P<30kPa, L=“Normal”;

[0055] (2) Yellow 2: 80℃≤t<100℃, P<20kPa, L=“Normal”;

[0056] (3) Yellow 3: 80℃≤t<100℃, 20kPa≤P<30kPa, L=“Normal”;

[0057] (4) Red Level 1: t ≥ 100°C, P < 20 kPa, L = "Normal";

[0058] (5) Red Level 2: t ≥ 100°C, 20 kPa ≤ P < 30 kPa, L = "Normal";

[0059] (6) Red 3: 80℃≤t<100℃, P<20kPa, L=“min”;

[0060] (7) Red 4: 80℃≤t<100℃, 20kPa≤P<30kPa, L=“min”;

[0061] (8) Red 5: t<80℃, P≥30kPa, L=“Normal”;

[0062] (9) Red 6: t<80℃, P≥30kPa, L=“min”;

[0063] In the above conditions, t is temperature, P is pressure, and L is liquid level. When the transformer oil is higher than the set value, it is "Normal"; when it is lower than the set value, it is "min".

[0064] In the method of the present invention, the degree of risk is expressed by combining colors and numbers. Yellow represents risk, and red represents greater 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 in green on the user terminal interface.

[0065] It should be noted that the above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Equivalent modifications made based on the above embodiments fall within the scope of protection of the present invention.

Claims

1. A mechanical sensing oil-immersed distribution transformer explosion risk warning device, characterized by: It includes a control unit and a signal acquisition device. The signal acquisition device includes a sealed shell, 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 shell. 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 in the sealed shell, 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 the control box. The power module is respectively connected to the logic module, the sound module and the light-emitting module. The logic module is respectively connected to the temperature switch, the liquid level switch and the pressure switch through signal cables.

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

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

4. The mechanical sensing oil-immersed distribution transformer explosion risk 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 member and a temperature switch. The temperature sensing component adopts a bimetallic element, which is installed in 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 through the driving member. There are two temperature switches installed on the outside of the transmission rod at a certain angle. The transmission rod drives the shift fork to rotate and realizes the signal output of the temperature switch through the transmission of the driving member.

5. The mechanical sensing oil-immersed distribution transformer explosion risk warning device according to claim 4, characterized in that: The temperature switch includes a shell, an electrical contact, a reed, a button and a lever. The electrical contact and the reed are installed in the shell. The reed is provided with a button protruding from the top of the shell. The lever is provided at the top of the shell. One end of the lever is connected to the shell, the middle part of the lever is fixedly connected to the button, and the other end of the lever is in contact with the driving member.

6. The mechanical sensing oil-immersed distribution transformer explosion risk warning device according to claim 4, characterized in that: The driving member is a cam, which is installed on the rotating shaft outside the temperature switch. A shift rod, a limit rod, a first pressing surface, and a second pressing surface are set on the side of the cam, 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 oil-immersed distribution transformer explosion risk warning device according to claim 4, characterized in that: The temperature sensing component of the temperature sensing device adopts a temperature bulb assembly, which is installed in a 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 closed system composed of the temperature bulb, the capillary tube and the elastic element is filled with a temperature sensing medium.

8. The mechanical sensing oil-immersed distribution transformer explosion risk warning device 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 installed on the outside of the temperature bulb rod. The float is connected to the liquid level switch through the transmission assembly. The liquid level switch is installed in a sealed shell above. The liquid level switch includes an outer shell, an electrical contact, a reed, a button and a lever. The outer shell is equipped with an electrical contact and a reed. The reed is provided with a button protruding from the top of the outer shell. The lever is provided at the top of the outer shell. One end of the lever is connected to the outer shell, the middle part of the lever is fixedly connected to the button, and the other end of the lever is connected to the transmission assembly.

9. The mechanical sensing oil-immersed distribution transformer explosion risk warning device according to claim 1, characterized in that: The pressure sensing device includes a breathable device and a pressure switch. There are two pressure switches and they are installed in a sealed shell. The breathable device is installed on the sealed shell. The pressure switch includes a shell. There is an air cavity in the shell. A partition is installed in the air cavity and divides the air cavity into an upper air cavity and a lower air cavity. 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 cavity and the lower air cavity is connected to the air inlet hole provided at the bottom of the shell. The piston is arranged through the partition and the top of the piston is connected to the reset spring and the movable contact. The top of the reset spring is connected to the pressure regulating knob. The pressure regulating knob is located on the shell and is threadedly connected to the shell. The pre-tightening force of the reset spring on the piston is adjusted by screwing in and out of the pressure regulating knob. Fixed contacts are provided on both sides of the upper air cavity of the shell.

10. A control method for the mechanical sensing oil-immersed distribution transformer explosion risk warning device according to any one of claims 1 to 9, characterized in that: The steps include: S1. System startup: Select the appropriate temperature switch, pressure switch, and liquid level switch, install the liquid level sensor, pressure sensor, and temperature sensor on the oil-immersed distribution transformer, start the control system, and establish real-time communication connections between the various units of the early warning device; 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 sensing devices, and transmits the acquired signals to the logic control unit and the sound and light alarm unit; S3. Judgment and warning: The logic control unit processes and judges the acquired signals in real time. When it detects that the values ​​of the liquid level, pressure and temperature signals reach the set warning conditions, it sends a command information to the sound and light alarm unit to implement the warning, and at the same time transmits the warning signal to the user terminal interface for display.

Images