A monitoring method for oil-immersed transformers

Abstract

This invention relates to a monitoring method for an oil-immersed transformer. The oil-immersed transformer has oil drain and injection ports along its diagonal. A booster pump and a filter press are sequentially connected to the oil drain port. Bypass pipelines are provided at the inlet and outlet of the filter press. A recovery tank is located at the outlet of the filter press, and a replenishment tank is located at the outlet of the recovery tank. The lower end caps of both the recovery and replenishment tanks are connected to the oil injection port. First and second monitoring mechanisms are provided on the outer walls of both tanks. A breathing pump is located at the lower end cap of the recovery and replenishment tanks. The monitoring method includes: real-time monitoring, filter press monitoring, and oil replacement monitoring. This invention's monitoring method for an oil-immersed transformer monitors various parameters of the transformer oil in real time and simultaneously replaces the old oil with new oil, thus protecting the transformer.

Description

Technical Field

[0001] This invention relates to the field of plant cultivation technology, and in particular to a monitoring method for an oil-immersed transformer. Background Technology

[0002] Transformers are crucial equipment in the power distribution system, playing a vital role in the power supply and distribution systems of industrial enterprises and civil buildings. Oil-immersed transformers, which utilize transformer oil as an insulation and cooling medium, were first introduced in the late 19th century. Transformer oil is widely used due to its abundant natural reserves, low price, excellent insulation properties (reducing insulation distance and lowering costs), low viscosity and good heat transfer properties, protection of the core and windings from moisture in the air, and protection of insulating paper and boards from oxygen, reducing aging of insulation materials and extending transformer life.

[0003] Currently, transformer oil testing is mostly conducted through sampling to indirectly ensure the normal operation of the transformer. However, conventional sampling testing methods still have the following shortcomings:

[0004] 1. Poor real-time performance, which delays the processing time of fault points and may even cause larger accidents;

[0005] 2. It can only detect, not control. Summary of the Invention

[0006] To address the technical problems existing in the background art, the present invention provides a monitoring method for oil-immersed transformers, which monitors various parameters of transformer oil in real time and simultaneously replaces old oil with new oil, thereby protecting the transformer.

[0007] The technical solution adopted by this invention is:

[0008] A monitoring method for an oil-immersed transformer includes an oil drain port at the lower corner of the oil tank and an oil filling port at the upper corner of the oil tank. The drain and filling ports are located on opposite sides of the oil tank. A booster pump and a filter press are sequentially connected to the oil drain port. The booster pump circulates the transformer oil. Bypass pipes are provided at the inlet and outlet of the filter press. A recovery tank is connected to the outlet of the filter press. A replenishment tank is connected to the outlet of the recovery tank. Pipes connecting the lower end caps of the recovery and replenishment tanks are connected to the oil filling port. A first monitoring mechanism and a second monitoring mechanism are fixedly installed on the outer wall of both tanks. A breathing pump is connected to the pipes connecting the lower end caps of the recovery and replenishment tanks.

[0009] The monitoring method includes:

[0010] A. Real-time monitoring:

[0011] The booster pump circulates the transformer oil in the order of oil-immersed transformer, bypass pipeline of filter press, and recovery tank. At this time, the first monitoring agency monitors various parameters of the transformer oil in the recovery tank.

[0012] The second monitoring agency monitors various parameters of the transformer oil in the replenishment tank;

[0013] B. Filtration pressure monitoring:

[0014] When the first monitoring agency detects abnormalities in various parameters of the transformer oil in the recovery tank, the booster pump circulates the transformer oil in the order of oil-immersed transformer, filter press, and recovery tank. At this time, the filter press filters the circulating transformer oil until the various parameters of the transformer oil in the recovery tank monitored by the first monitoring agency return to the set threshold.

[0015] C. Replacement monitoring:

[0016] When step B above, during the operation of the filter press monitoring, fails to restore the various parameters of the transformer oil in the recovery tank monitored by the first monitoring agency to the set threshold, and the various parameters of the transformer oil in the replenishment tank monitored by the second monitoring agency meet the set threshold;

[0017] The booster pump directs transformer oil along the bypass pipeline of the oil-immersed transformer and the filter press to the recovery tank. At the same time, the breathing pump draws gas from the top of the recovery tank into the replenishment tank and pressurizes the transformer oil in the replenishment tank into the oil-immersed transformer. In this way, the transformer oil in the oil-immersed transformer is replaced with new oil.

[0018] Furthermore, the pressure filter device is used to filter impurities from the old oil in the oil-immersed transformer tank, and includes a base mechanism, a filter mechanism, a top sealing mechanism, and an adjustment mechanism that are sequentially and sealed from bottom to top.

[0019] The base mechanism includes a base frame fixed to the ground, a base plate fixedly mounted on the base frame, an annular first sealing ring mounted on the upper surface of the base plate, an oil inlet communicating with the oil drain port through the base plate in the center of the inner ring of the first sealing ring, and multiple sliding rods arranged in an array fixedly mounted on the base plate of the outer ring of the first sealing ring.

[0020] The filtration mechanism includes multiple layers of filter plates stacked in the vertical direction. A first sliding hole and a through groove are provided through the filter plates. The first sliding hole is slidably sleeved on a sliding rod. An annular second sealing ring is provided on the upper end face of the filter plate. The through groove is located in the center of the filter plate. Cloth filter material is horizontally arranged in the through groove. A through hole is provided on one side of the through groove. The filter material and the through hole are both located on the filter plate inside the second sealing ring. A flow channel is provided at the lower part of the through hole to the side below the filter material.

[0021] The top sealing mechanism includes a sealing plate, on which a second sliding hole and a through hole are provided. The second sliding hole and the first sliding hole share the same central axis and are slidably sleeved on the sliding rod. The through hole and the through hole share the same central axis, and a limit bracket is fixedly provided on the upper surface of the sealing plate directly above the through hole. An oil outlet is provided through the center of the sealing plate.

[0022] The adjustment mechanism includes a sealing head that is sealed and slidably disposed in the perforation, a connecting rod that is fixedly disposed at the upper end of the sealing head, the connecting rod that is sealed and slidably disposed in the through hole, a counterweight that is fixedly disposed at the upper end of the connecting rod, and the counterweight that is mounted on the upper surface of the limiting bracket.

[0023] During the process of filtering oil in the oil tank of an oil-immersed transformer, when impurities and sludge adhere to the filter media on the lower filter plate, the oil-passing performance of the filter media decreases. The adjusting mechanism is then lifted upwards until the upper filter plate is perforated, and the filter media of that layer is used for filtration.

[0024] Furthermore, the bypass pipeline is connected between the oil inlet and the oil outlet of the filter press. At least one three-way valve A is provided at the three-way connection between the bypass pipeline and the oil inlet and outlet pipelines. The three-way valve A is a T-type valve.

[0025] A check valve A is installed on the connecting pipe between the bypass pipe and the oil inlet pipe and the oil outlet to prevent old oil from flowing back into the oil tank of the oil-immersed transformer.

[0026] Furthermore, the monitoring method also includes pressure filtration:

[0027] When the three-way valve A is opened to form an "I" shaped port, the bypass pipeline of the filter press is closed. The transformer oil in the oil-immersed transformer is drawn out by the booster pump to the filter press and filtered by the filter press. During the filtration process, when impurities and sludge adhere to the filter media on the lower filter plate, the oil-passing performance of the filter media decreases. The adjusting mechanism is then lifted upwards until the upper filter plate is perforated, and the filter media of that layer is then filtered.

[0028] Furthermore, the recycling tank includes a first tank body, with an inlet and a recycling outlet connected to the lower end cap of the first tank body. The inlet pipe extends upward to the upper part of the first tank body, and the recycling outlet is located in the center of the lower end cap. The upper end cap of the first tank body has two openings connected to it, and a breathing pump and a first air seal valve are respectively installed in the two openings. A first monitoring mechanism is fixedly installed on the side wall of the first tank body.

[0029] Furthermore, the replenishment tank includes a second tank body, with a drain port connected to the center of the lower end cap of the second tank body, and an oil replenishment port for filling the replenishment tank with transformer oil, a top port connected to a breathing pump, and a second air seal valve connected to a first air seal valve at the upper end cap of the second tank body. A second monitoring mechanism is fixedly installed on the side wall of the second tank body.

[0030] Furthermore, the recovery outlet of the recovery tank is connected to the outlet of the replenishment tank and connected to the oil filling port. A check valve C is connected to the connecting pipe of the oil filling port to prevent the oil in the oil tank of the oil-immersed transformer from flowing back.

[0031] The suction end of the breathing pump is connected to the pipeline on the recovery storage tank, and the exhaust end of the breathing pump is connected to the top opening of the replenishment storage tank.

[0032] The outlets of the first and second gas seal valves are connected to the recovery storage tank and the replenishment storage tank, respectively. The inlet ends of the first and second gas seal valves are connected through pipelines and then connected to the protective gas buffer container.

[0033] Furthermore, a shut-off valve is installed on the connecting pipeline between the recovery outlet of the recovery tank and the outlet of the replenishment tank;

[0034] A check valve B is installed on the connecting pipeline near the outlet of the replenishment tank to prevent oil from the recovery tank from flowing into the replenishment tank.

[0035] A three-way valve B is installed on the connecting pipeline between the breathing pump and the top port. The three-way valve B is an L-shaped valve, and its outlet end is connected to the protective gas recovery container through a pipeline.

[0036] Furthermore, the first and second monitoring mechanisms include electrical control boxes respectively fixedly installed on the side walls of the recovery tank and the replenishment tank. The electrical control boxes are equipped with a real-time integrated precision oil dielectric loss tester, a power module, a communication module, and an automatic control device.

[0037] The real-time integrated precision oil dielectric loss tester includes a dielectric loss oil cup, a temperature controller, a temperature sensor, a dielectric loss test bridge, an AC test power supply, and a standard capacitor, used to monitor the acid value, water-soluble acid content, oxidation stability, breakdown voltage, dielectric loss factor, interfacial tension, flash point / pour point, gas component content, and volume resistivity of transformer oil in real time.

[0038] The power module and communication module are used to provide power to the real-time integrated precision oil dielectric loss tester and to transmit real-time data of transformer oil remotely.

[0039] The breathing pump, three-way valve A, shut-off valve, three-way valve B, and booster pump are electrically connected to the control module of the automatic control device.

[0040] Furthermore, the monitoring method also includes oil storage protection:

[0041] When the booster pump and the breathing pump are running, the level of transformer oil in the recovery and replenishment tanks changes. The inert gas in the protective gas buffer container is connected to the inlet of the first and second gas seal valves through pipelines, and then enters the recovery and replenishment tanks respectively by the regulation of the first and second gas seal valves.

[0042] This ensures that the transformer oil in the recovery and replenishment tank only comes into contact with inert gas, preventing the transformer oil from oxidizing and deteriorating, while maintaining the gas-liquid balance in the recovery and replenishment tank.

[0043] The advantages of the monitoring method for oil-immersed transformers of the present invention are as follows:

[0044] 1. Real-time monitoring of the transformer oil in the recovery storage tank through transformer oil circulation;

[0045] 2. Impurities and water in transformer oil are filtered out using a pressure filtration device;

[0046] 3. The first and second air-sealing valves prevent the transformer in the recovery and replenishment tank from oxidizing due to contact with air;

[0047] 4. The gas from the recovery tank is pumped into the replenishment tank using a breathing pump to replace the transformer oil. Attached Figure Description

[0048] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings required for the specific embodiments will be briefly introduced below. The accompanying drawings in the following description are embodiments of the present invention.

[0049] Figure 1 is a general perspective view of a monitoring method for an oil-immersed transformer provided by an example of the present invention;

[0050] Figure 2 is an exploded schematic diagram of the filter press device in a monitoring method for an oil-immersed transformer provided by an example of the present invention;

[0051] Figure 3 is a schematic diagram of the recovery and replenishment tank of the monitoring method for an oil-immersed transformer provided in an example of the present invention;

[0052] Figure 4 is a partially enlarged schematic diagram of the adjustment mechanism of a monitoring method for an oil-immersed transformer provided in an example of the present invention.

[0053] In the diagram: 100, oil-immersed transformer; 101, oil drain port; 102, oil inlet port; 1, filter press device; 11, base mechanism; 111, base frame; 112, base plate; 113, first sealing ring; 114, oil inlet; 115, slide rod; 12, filter mechanism; 121, filter plate; 122, first sliding hole; 123, second sealing ring; 124, filter media; 125, perforation; 13, top sealing mechanism; 131, sealing plate; 132, second sliding hole; 133, through hole; 134, oil outlet; 135, limiting bracket; 14 1. Adjustment mechanism; 141. End cap; 142. Connecting rod; 143. Counterweight head; 2. Recovery storage tank; 20. First tank body; 21. Inlet; 22. Recovery outlet; 23. Breathing pump; 24. First air seal valve; 25. First monitoring mechanism; 3. Refilling storage tank; 30. Second tank body; 31. Oil replenishment port; 32. Outlet; 33. Top port; 34. Second air seal valve; 35. Second monitoring mechanism; 41. Check valve A; 42. Three-way valve A; 43. Shut-off valve; 44. Check valve B; 45. Three-way valve B; 46. Check valve C. Detailed Implementation

[0054] To more clearly and explicitly illustrate the specific objectives and implementation methods of this invention, a complete description of the technical solution of this invention will be provided below. The described embodiments are only a part of the embodiments of this invention, not all of them. Without creative effort, all other embodiments based on the embodiments described in this invention are within the protection scope of this invention.

[0055] The present invention discloses a monitoring method for an oil-immersed transformer, as shown in Figure 1. The transformer is configured as an oil-immersed transformer 100. An oil drain port 101 communicating with the lower corner of the oil tank of the oil-immersed transformer 100 is provided, and an oil filling port 102 communicating with the upper corner of the oil tank of the oil-immersed transformer 100 is provided. The drain and filling ports 101 and 102 are located on both sides of the diagonal of the oil tank.

[0056] The monitoring device includes a filter press 1 connected to the oil drain port 101. The filter press 1 is used to filter impurities from the old oil in the oil tank of the oil-immersed transformer 100. The outlet end of the filter press 1 is connected in sequence to a recovery and replenishment storage tank 2 and a replenishment storage tank 3. The recovery storage tank 2 is used to store and monitor the old oil in the oil tank of the oil-immersed transformer 100, and the replenishment storage tank 3 is used to store and monitor the new oil injected into the oil tank of the oil-immersed transformer 100.

[0057] As shown in Figure 2, the filter press 1 includes a base mechanism 11, a filter mechanism 12, a top sealing mechanism 13, and an adjusting mechanism 14, which are sequentially and sealed together from bottom to top.

[0058] As shown in Figure 2, the base mechanism 11 includes a base frame 111 fixed to the ground. A base plate 112 is fixedly installed on the base frame 111. An annular first sealing ring 113 is provided on the upper surface of the base plate 112. An oil inlet 114 communicating with the oil drain port 101 is provided through the base plate 112 at the center of the inner ring of the first sealing ring 113. A check valve A 41 is provided on the connecting pipeline between the bypass pipeline and the oil inlet 114 pipeline and the oil drain port 101 to prevent old oil from flowing back into the oil tank of the oil-immersed transformer 100. At the same time, a booster pump is provided on the connecting pipeline between the check valve A 41 and the bypass pipeline. The booster pump is used to extract the transformer oil in the oil tank of the oil-immersed transformer 100. Multiple sliding rods 115 are fixedly arranged in an array on the base plate 112 of the outer ring of the first sealing ring 113.

[0059] As shown in Figure 2, the filtration mechanism 12 includes multiple layers of filter plates 121 stacked in the vertical direction. A first sliding hole 122 and a through groove are provided through the filter plate 121. The first sliding hole 122 is slidably sleeved on the slide rod 115. An annular second sealing ring 123 is provided on the upper end surface of the filter plate 121. The through groove is located in the center of the filter plate 121. A cloth filter material 124 is horizontally arranged in the through groove. A through hole 125 is provided on one side of the through groove, penetrating the filter plate 121. The filter material 124 and the through hole 125 are both located on the filter plate 121 inside the ring of the second sealing ring 123. A flow channel is provided at the lower part of the through hole 125 to the side below the filter material 124.

[0060] As shown in Figure 2, the top sealing mechanism 13 includes a sealing plate 131. A second sliding hole 132 and a through hole 133 are provided through the sealing plate 131. The second sliding hole 132 and the first sliding hole 122 share the same central axis and are slidably sleeved on the sliding rod 115. The through hole 133 and the through hole 125 share the same central axis. A limit bracket 135 is fixedly provided on the upper plate surface of the sealing plate 131 directly above the through hole 133. An oil outlet 134 is provided through the center of the sealing plate 131.

[0061] As shown in Figure 2, the adjusting mechanism 14 includes a sealed head 141 that is sealed and slidably disposed within a through hole 125. A connecting rod 142 is fixedly disposed at the upper end of the sealed head 141. The connecting rod 142 is sealed and slidably disposed within a through hole 133. A counterweight head 143 is fixedly disposed at the upper end of the connecting rod 142. The counterweight head 143 is mounted on the upper end surface of the limiting bracket 135. The lifting and lowering of the adjusting mechanism 14 is achieved by the pressure between the mutually sealed filter plates 121 and the self-weight of the counterweight head 143. To improve the accuracy of the adjusting mechanism 14, as shown in Figure 4, a hydraulic cylinder or electric cylinder fixed to the base frame 111 is disposed on the upper part of the counterweight head 143. The stroke end of the hydraulic cylinder or electric cylinder is arranged in the vertical direction and is fixedly connected to the counterweight head 143.

[0062] As shown in Figure 2, a bypass pipeline is provided between the oil inlet 114 and the oil outlet 134 of the filter press 1. At least one three-way valve A42 is provided at the three-way connection between the bypass pipeline and the oil inlet and outlet pipelines 114 and 134. The three-way valve A42 is a T-type valve.

[0063] As shown in Figure 3, the recycling tank 2 includes a first tank body 20. The lower end cap of the first tank body 20 is connected to an inlet 21 and a recycling outlet 22. The pipeline of the inlet 21 extends upward to the upper part of the first tank body 20. The recycling outlet 22 is located in the center of the lower end cap. The upper end cap of the first tank body 20 is connected to two openings, and a breathing pump 23 and a first air seal valve 24 are respectively installed at the two openings. A first monitoring mechanism 25 is fixedly installed on the side wall of the first tank body 20.

[0064] As shown in Figure 3, the replenishment tank 3 includes a second tank body 30. The lower end cap of the second tank body 30 is connected to a drain port 32. The upper end cap of the second tank body 30 is connected to an oil filling port 31 for filling the replenishment tank 3 with transformer oil, a top port 33 connected to a breathing pump 23, and a second air seal valve 34 connected to a first air seal valve 24. A second monitoring mechanism 35 is fixedly installed on the side wall of the second tank body 30.

[0065] As shown in Figure 3, the recovery outlet 22 of the recovery storage tank 2 is connected to the outlet 32 ​​of the replenishment storage tank 3, and is connected to the oil inlet 102. A check valve C46 is connected to the connecting pipe of the oil inlet 102 to prevent backflow of oil in the oil tank of the oil-immersed transformer 100. The suction end of the breathing pump 23 is connected to the pipeline on the recovery storage tank 2, and the exhaust end of the breathing pump 23 is connected to the top opening 33 of the replenishment storage tank 3. The outlet ends of the first and second gas sealing valves 24 and 34 are connected to the recovery storage tank 2 and the replenishment storage tank 3, respectively. The inlet ends of the first and second gas sealing valves 24 and 34 are connected to the protective gas buffer container through pipelines. A shut-off valve 43 is installed on the connecting pipeline between the recovery outlet 22 of the recovery storage tank 2 and the outlet 32 ​​of the replenishment storage tank 3; a check valve B44 is installed on the connecting pipeline near the outlet 32 ​​of the replenishment storage tank 3 to prevent oil in the recovery storage tank 2 from flowing into the replenishment storage tank 3; a three-way valve B45 is installed on the connecting pipeline between the breathing pump 23 and the top port 33. The three-way valve B45 is an L-shaped valve, and its outlet end is connected to the protective gas recovery container through a pipeline.

[0066] As shown in Figure 3, the first and second monitoring mechanisms 25 and 35 include electrical control boxes fixedly installed on the side walls of the recovery tank and the replenishment tank 2 and 3, respectively. The electrical control boxes are equipped with a real-time integrated precision oil dielectric loss tester, a power supply module, a communication module, and an automatic control device.

[0067] The real-time integrated precision oil dielectric loss tester includes a dielectric loss oil cup, a temperature controller, a temperature sensor, a dielectric loss test bridge, an AC test power supply, and a standard capacitor. It is used to monitor the acid value, water-soluble acid content, oxidation stability, breakdown voltage, dielectric loss factor, interfacial tension, flash point / pour point, gas component content, and volume resistivity of the transformer oil in real time. The power supply module and communication module are used to provide power to the real-time integrated precision oil dielectric loss tester and to transmit real-time data of the transformer oil remotely. Three-way valve A42, shut-off valve 43, three-way valve B45, and the first and second air-sealing valves 24 and 34 are all configured as self-controlled valves. These self-controlled valves, the breathing pump 23, and the booster pump are electrically connected to the control module of the self-control device.

[0068] Based on the specific structure of the monitoring method for an oil-immersed transformer described in the above embodiments, the working method of the monitoring method for an oil-immersed transformer will be further explained below.

[0069] Real-time monitoring phase:

[0070] A. The automatic control device opens the three-way valves A42 and B45 to an "L"-shaped port, starts the booster pump, opens the shut-off valve 43, and closes the breathing pump 23. At this time, the bypass pipeline is opened.

[0071] B. In the oil-immersed transformer 100, the oil in the oil tank passes sequentially through check valve A41, bypass pipeline, and inlet 21 until it enters the first tank 20. The transformer oil in the first tank 20 is monitored by the first monitoring mechanism 25.

[0072] C. The transformer oil in the first tank 20 passes through the recovery outlet 22, the shut-off valve 43, and the check valve C46 in sequence until it returns to the oil tank of the oil-immersed transformer 100.

[0073] D. When all parameters of the transformer oil in the first tank 20 monitored by the first monitoring agency 25 meet the requirements, this state shall be maintained;

[0074] During the real-time monitoring phase, if the transformer oil parameters in the first tank 20 monitored by the first monitoring agency 25 do not meet the requirements, the system will switch to the pressure filtration monitoring phase.

[0075] E. The automatic control device opens the three-way valve A42 to a straight "I" shape, opens the three-way valve B45 to an L shape, starts the booster pump, opens the shut-off valve 43, and closes the breathing pump 23. At this time, the bypass pipeline is closed.

[0076] F. In the oil-immersed transformer 100, the oil in the oil tank passes sequentially through check valve A41, oil inlet 114, and oil outlet 134 until it reaches the first tank 20. The transformer oil in the first tank 20 is monitored by the first monitoring mechanism 25.

[0077] G. During the process of filtering the oil in the oil tank of the oil-immersed transformer 100, when impurities and sludge adhere to the filter material 124 on the lower filter plate 121, the oil passing performance of the filter material 124 decreases, and the adjusting mechanism 14 is pushed upward until the perforation 125 of the upper filter plate 121 is reached, and the oil is filtered by the filter material 124 of the filter plate 121 of that layer.

[0078] H. When all parameters of the transformer oil in the first tank 20 monitored by the first monitoring agency 25 are restored and meet the requirements, this state shall be maintained;

[0079] During the pressure filtration monitoring phase, if the transformer oil parameters in the first tank 20 monitored by the first monitoring agency 25 do not meet the requirements, while the transformer oil parameters in the second tank 30 monitored by the second monitoring agency 35 meet the requirements, the system will switch to the replacement monitoring state.

[0080] I. The automatic control device opens the three-way valve A42 to an "L" shape, opens the three-way valve B45 to an "I" shape, starts the booster pump, starts the breathing pump 23, and closes the shut-off valve 43. At this time, the bypass pipeline is opened.

[0081] J. In the oil-immersed transformer 100, the old oil in the oil tank passes through the check valve A41, the bypass pipeline, and the inlet 21 in sequence, until it enters the first tank 20.

[0082] K. The breathing pump 23 draws the gas in the first tank 20 into the second tank 30. At this time, the new transformer oil in the second tank 30 passes through the drain port 32, check valve B44, and check valve C46 in sequence until it enters the oil tank of the oil-immersed transformer 100.

[0083] During the replacement of old and new oil in the oil tank of L, oil-immersed transformer 100, when the various parameters of the transformer oil in the first tank 20 monitored by the first monitoring agency 25 are restored and meet the requirements, this state is stopped and switched to the real-time monitoring stage.

[0084] Based on the above, and guided by an embodiment of the monitoring method for an oil-immersed transformer of the present invention, those skilled in the art can make various changes and modifications without departing from the technical concept of the invention. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A monitoring method for an oil-immersed transformer, characterized in that: The oil-immersed transformer (100) has an oil drain port (101) connected to the lower corner of its oil tank and an oil filling port (102) connected to the upper corner of its oil tank. The oil drain and filling ports (101 and 102) are located on opposite sides of the oil tank. A booster pump and a filter press (1) are connected in sequence to the oil drain port (101). The booster pump is used to circulate the transformer oil. The filter press (1) has bypass pipes at its inlet and outlet. The filter press (1) is connected to a recovery tank (2) at its outlet, and a replenishment tank (3) is connected to its outlet. The lower end caps of the recovery and replenishment tanks (2 and 3) are connected to an oil inlet (102). A first monitoring mechanism (25) and a second monitoring mechanism (35) are fixedly installed on the outer wall of both tanks. A breathing pump (23) is connected to the lower end caps of the recovery and replenishment tanks (2 and 3). The monitoring method includes: A. Real-time monitoring: The booster pump circulates the transformer oil along the bypass pipeline of the oil-immersed transformer (100), the filter press (1), and the recovery tank (2) in sequence. At this time, the first monitoring unit (25) monitors various parameters of the transformer oil in the recovery tank (2). The second monitoring agency (35) monitors various parameters of the transformer oil in the replenishment tank (3); B. Filtration pressure monitoring: When the first monitoring agency (25) detects abnormal parameters of the transformer oil in the recovery tank (2), the booster pump circulates the transformer oil in the order of oil-immersed transformer (100), filter press (1), and recovery tank (2). At this time, the filter press (1) filters the circulating transformer oil until the parameters of the transformer oil in the recovery tank (2) monitored by the first monitoring agency (25) return to the set threshold. C. Replacement monitoring: When the above step B, filter press monitoring, fails to restore the various parameters of the transformer oil in the recovery tank (2) monitored by the first monitoring agency (25) to the set threshold during operation, and the various parameters of the transformer oil in the replenishment tank (3) monitored by the second monitoring agency (35) meet the set threshold; The booster pump drives the transformer oil through the bypass pipeline of the oil-immersed transformer (100) and the filter press (1) to the recovery tank (2). At the same time, the breathing pump (23) drives the gas above the recovery tank (2) into the replenishment tank (3) and pressurizes the transformer oil in the replenishment tank (3) into the oil-immersed transformer (100). In this way, the transformer oil in the oil-immersed transformer (100) is replaced with new and old.

2. The monitoring method for an oil-immersed transformer according to claim 1, characterized in that: The filter press (1) is used to filter impurities in the old oil in the oil tank of the oil-immersed transformer (100), and includes a base mechanism (11), a filter mechanism (12), a top sealing mechanism (13), and an adjustment mechanism (14) that are sequentially sealed and connected from bottom to top: The base mechanism (11) includes a base frame (111) fixed on the ground, a base plate (112) fixedly installed on the base frame (111), an annular first sealing ring (113) is provided on the upper plate surface of the base plate (112), an oil inlet (114) communicating with the oil drain port (101) is provided through the base plate (112) in the center of the inner ring of the first sealing ring (113), and multiple slide rods (115) arranged in an array are fixedly installed on the base plate (112) of the outer ring of the first sealing ring (113). The filtration mechanism (12) includes multiple layers of filter plates (121) stacked in the vertical direction. A first sliding hole (122) and a through groove are provided through the filter plates (121). The first sliding hole (122) is slidably sleeved on the slide rod (115). An annular second sealing ring (123) is provided on the upper end surface of the filter plate (121). The through groove is located in the center of the filter plate (121). A cloth filter material (124) is horizontally arranged in the through groove. A through hole (125) is provided on one side of the through groove, penetrating the filter plate (121). The filter material (124) and the through hole (125) are both located on the filter plate (121) within the ring of the second sealing ring (123), and the lower part of the through hole (125) faces the filter material. (124) A flow channel is provided on one side below; The top sealing mechanism (13) includes a sealing plate (131), on which a second sliding hole (132) and a through hole (133) are provided. The second sliding hole (132) and the first sliding hole (122) share the same central axis and are slidably sleeved on the sliding rod (115). The through hole (133) and the through hole (125) share the same central axis. A limit bracket (135) is fixedly provided on the upper plate surface of the sealing plate (131) directly above the through hole (133). An oil outlet (134) is provided through the center of the sealing plate (131). The adjustment mechanism (14) includes a sealing head (141) that is sealed and slidably disposed in the perforation (125). A connecting rod (142) is fixedly disposed at the upper end of the sealing head (141). The connecting rod (142) is sealed and slidably disposed in the through hole (133). A counterweight head (143) is fixedly disposed at the upper end of the connecting rod (142). The counterweight head (143) is mounted on the upper surface of the limiting bracket (135). During the process of filtering the oil in the oil tank of the oil-immersed transformer (100), when impurities and sludge adhere to the filter material (124) on the lower filter plate (121), the oil passing performance of the filter material (124) decreases, the adjusting mechanism (14) is lifted upward until the perforation (125) of the upper filter plate (121) is reached, and the oil is filtered by the filter material (124) of the filter plate (121) of that layer.

3. The monitoring method for an oil-immersed transformer according to claim 2, characterized in that: The bypass pipeline is connected between the oil inlet (114) and the oil outlet (134) of the filter press (1). At least one three-way valve A (42) is provided at the three-way connection between the bypass pipeline and the oil inlet and outlet (114, 134) pipelines. The three-way valve A (42) is a T-type valve. A check valve A (41) is installed on the connecting pipeline between the bypass pipeline and the oil inlet (114) pipeline and the oil outlet (101) to prevent old oil from flowing back into the oil tank of the oil-immersed transformer (100).

4. The monitoring method for an oil-immersed transformer according to claim 3, characterized in that: The monitoring method further includes pressure filtration: When the three-way valve A (42) is opened into a straight-line port, the bypass pipeline of the filter press (1) is closed. The transformer oil in the oil-immersed transformer (100) is drawn out by the booster pump to the filter press (1) and filtered by the filter press (1). During the filtration process, when impurities and sludge adhere to the filter material (124) on the lower filter plate (121), the oil passage performance of the filter material (124) decreases. The adjusting mechanism (14) is lifted up until the perforation (125) of the upper filter plate (121) is reached, and the filter material (124) of the filter plate (121) of that layer is filtered.

5. The monitoring method for an oil-immersed transformer according to claim 1, characterized in that: The recycling tank (2) includes a first tank body (20). The lower end cap of the first tank body (20) is connected to an inlet (21) and a recycling outlet (22). The pipeline of the inlet (21) extends upward to the upper part of the first tank body (20). The recycling outlet (22) is located in the center of the lower end cap. The upper end cap of the first tank body (20) is connected to two openings. The two openings are respectively equipped with a breathing pump (23) and a first air seal valve (24). A first monitoring mechanism (25) is fixedly installed on the side wall of the first tank body (20).

6. The monitoring method for an oil-immersed transformer according to claim 5, characterized in that: The replenishment tank (3) includes a second tank body (30). The lower end cap of the second tank body (30) is connected to a drain port (32). The upper end cap of the second tank body (30) is connected to an oil filling port (31) for filling the replenishment tank (3) with transformer oil, a top port (33) connected to a breathing pump (23), and a second air seal valve (34) connected to a first air seal valve (24). A second monitoring mechanism (35) is fixedly installed on the side wall of the cylinder of the second tank body (30).

7. The monitoring method for an oil-immersed transformer according to claim 6, characterized in that: The recovery outlet (22) of the recovery storage tank (2) is connected to the outlet (32) of the replenishment storage tank (3) and connected to the oil filling port (102). A check valve C (46) is connected to the connecting pipe of the oil filling port (102) to prevent the oil-immersed transformer (100) from turning back. Oil flows back into the fuel tank; The suction end of the breathing pump (23) is connected to the pipeline on the recovery storage tank (2), and the exhaust end of the breathing pump (23) is connected to the top opening (33) of the replenishment storage tank (3). The outlets of the first and second gas seal valves (24, 34) are connected to the recovery storage tank (2) and the replenishment storage tank (3), respectively. The inlet ends of the first and second gas seal valves (24, 34) are connected to the protective gas buffer container through pipelines.

8. The monitoring method for an oil-immersed transformer according to claim 7, characterized in that: A shut-off valve (43) is installed on the connecting pipeline between the recovery outlet (22) of the recovery storage tank (2) and the outlet (32) of the replenishment storage tank (3); A check valve B (44) is installed on the connecting pipeline near the outlet (32) of the replenishment tank (3) to prevent oil in the recovery tank (2) from flowing into the replenishment tank (3); A three-way valve B (45) is provided on the connecting pipeline between the breathing pump (23) and the top port (33). The three-way valve B (45) is set as an L-shaped valve, and its outlet end is connected to the protective gas recovery container through a pipeline.

9. A monitoring method for an oil-immersed transformer according to claim 8, characterized in that: The first and second monitoring units (25, 35) include electrical control boxes fixedly installed on the side walls of the recovery tank and the replenishment tank (2, 3), respectively. Each electrical control box contains a real-time integrated precision oil dielectric loss tester, a power module, a communication module, and an automatic control device. The real-time integrated precision oil dielectric loss tester includes a dielectric loss oil cup, a temperature controller, a temperature sensor, a dielectric loss test bridge, an AC test power supply, and a standard capacitor, which are used to monitor the acid value, water-soluble acid content, oxidation stability, breakdown voltage, dielectric loss factor, interfacial tension, flash point / pour point, gas component content, and volume resistivity of transformer oil in real time. The power module and communication module are used to provide power to the real-time integrated precision oil dielectric loss tester and to transmit real-time data of transformer oil remotely. The breathing pump (23), three-way valve A (42), shut-off valve (43), three-way valve B (45), and booster pump are electrically connected to the control module of the automatic control device.

10. A monitoring method for an oil-immersed transformer according to claim 7, characterized in that: The monitoring method also includes oil storage protection: When the booster pump and the breathing pump (23) are running, the level of transformer oil in the recovery and replenishment tanks (2, 3) changes. The inert gas in the protective gas buffer container is connected to the inlet of the first and second gas sealing valves (24, 34) through pipelines, and enters the recovery and replenishment tanks (2, 3) respectively by the regulation of the first and second gas sealing valves (24, 34). This ensures that the transformer oil in the recovery and replenishment tanks (2, 3) only comes into contact with inert gas, preventing the transformer oil from oxidizing and deteriorating. At the same time, it maintains the gas-liquid balance in the recovery and replenishment tanks (2, 3).

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