A main transformer gas relay linkage protection device and protection mode

Abstract

The application provides a main transformer gas relay linkage protection device and protection mode, which comprises a main transformer, a gas relay, a linkage protection device, a control module, a linkage protection electromagnetic valve, a filter, a palladium grid hydrogen sensitive sensor, an infrared acetylene sensor, a damping block, a volume flow sensor and a micro variable frequency air pump; when gas in the gas relay gathers to a volume threshold value, a light gas alarm contact in the gas relay is triggered, and the gas relay sends a light gas alarm signal; one end of the linkage protection electromagnetic valve is connected to a gas discharge pipe of the gas relay, and the other end is connected to the filter, the palladium grid hydrogen sensitive sensor, the infrared acetylene sensor, the damping block, the volume flow sensor and the micro variable frequency air pump through a pipeline in sequence; the application can automatically detect hydrogen and acetylene, two kinds of fault characteristic gases in the main transformer gas relay on line, and can automatically control the main transformer to trip and isolate the main transformer from the power grid.

Description

Technical Field

[0001] This invention relates to the field of main transformer equipment technology in the power industry, and in particular to a main transformer gas relay linkage protection device and protection method. Background Technology

[0002] The gas relay is the most important non-electrical protection device for the main transformer. However, currently, there is no linkage device that can automatically detect and release the gas accumulated inside the main transformer's gas relay online. When the main transformer is running, the gas accumulates inside the gas relay, pushing down the oil level. When the low-voltage alarm is triggered, the gas relay sends a low-voltage alarm signal, reminding staff to bring professional sampling instruments to the substation main transformer site as soon as possible to sample and release the gas from the main transformer while it is energized. The sample is then taken back to the laboratory for testing to determine whether it contains fault characteristic gas or is just air. If fault characteristic gas is found, and its concentration is determined, appropriate measures are taken. However, for main transformers with sudden and severe faults, this often causes delays, making it impossible to shut down and isolate the main transformer with a severe fault in the first instance, which seriously affects the safe operation of the power grid. If a device could be invented that can detect the gas accumulated inside the gas relay in the first instance, determine whether it is fault characteristic gas or ordinary air, and then trip and shut down the main transformer with a sudden and severe fault to isolate it from the power grid, it would be of great significance for protecting the safe operation of the power grid.

[0003] The gas relay is the most important non-electrical protection device for the main transformer. When the main transformer experiences an overheating or discharge fault, it will decompose the transformer oil around the fault point, releasing several characteristic gases, including hydrogen and acetylene. Whether the fault is overheating, discharge, or moisture, the transformer oil will decompose or undergo a chemical reaction to produce hydrogen. Because acetylene has a triple bond, a high-energy fault is required for the transformer oil to decompose and produce triple-bonded acetylene gas. Therefore, the presence of a large amount of acetylene indicates a serious fault inside the main transformer, requiring immediate power outage for inspection and handling. When the main transformer experiences a severe overheating or discharge fault, or when the fault develops rapidly, the characteristic gases may not have time to dissolve in the transformer oil, or the oil may be saturated. These free characteristic gases will rise from the transformer oil and accumulate on the oil surface inside the sight glass of the gas relay installed on top of the main transformer.

[0004] Currently, for these fault characteristic gases that have entered the gas relay window, the procedure is to have staff use a special gas sampling tool (gas is prone to leakage) to collect a mixed gas sample and an oil sample containing the free characteristic gas from the gas relay while it is energized. The sample is then brought back to the laboratory, where a chromatograph is used to detect the content of the fault characteristic gas in the mixed gas sample and the oil sample. This is done to determine whether a fault has occurred, the type of fault, and the extent of the fault. In daily operation, traditional gas relays may produce gas that is mainly air and does not contain fault-specific gases due to poor sealing or during processes such as oil filtration, maintenance, pre-testing, or replacement of the breather's silica gel desiccant. In such cases, existing gas relays work by accumulating gas and forcing an internal float to descend, triggering an electrical contact and issuing a light gas alarm. This alerts personnel to go to the substation's main transformer site to collect gas and oil samples from the gas relay. These samples are then taken back to the laboratory and analyzed using chromatographs to determine if they contain fault-specific gases. Gas accumulated in the gas relay's viewing window is manually released by energizing the system. However, existing main transformer gas relays lack the function of online automatic detection of characteristic gases and automatic gas release, making it impossible to determine in a timely manner whether the gas inside the gas relay contains fault-specific gases or is simply air.

[0005] This invention patent application discloses a main transformer gas relay linkage protection device and protection method, which can automatically detect hydrogen and acetylene, two fault characteristic gases, in the main transformer gas relay online. When a small amount of hydrogen and acetylene are detected in the gas, an alarm signal can be issued. If the acetylene content reaches the main transformer tripping set value, the device can automatically control the main transformer to trip and isolate the main transformer from the power grid, which is of great significance for ensuring the safe operation of the power grid. Summary of the Invention

[0006] This invention proposes a main transformer gas relay linkage protection device and protection method, which can automatically detect hydrogen and acetylene, two fault characteristic gases, in the main transformer gas relay online, and can automatically control the main transformer to trip, isolating the main transformer from the power grid, which is of great significance for ensuring the safe operation of the power grid.

[0007] The present invention adopts the following technical solution.

[0008] A main transformer gas relay linkage protection device includes a main transformer, a gas relay, a linkage protection device, a control module, a linkage protection solenoid valve, a filter, a palladium grid hydrogen sensor, an infrared acetylene sensor, a damping block, a volumetric flow sensor, and a miniature variable frequency air pump. The gas relay is installed on the top of the main transformer. The oil outlet on the side of the gas relay is connected upward to the oil tank of the main transformer through an outlet valve, and the oil inlet of the gas relay is connected downward to the main transformer body through an inlet valve. The transformer oil in the main transformer body is connected to the transformer oil in the oil tank through the gas relay. The oil tank balances the oil pressure in the main transformer body by the rise and fall of the oil level. When gas is generated inside the main transformer body, the gas accumulates inside the gas relay and presses down the oil level of the gas relay. When the gas in the gas relay accumulates to the volume threshold, it triggers the light gas alarm contact in the gas relay, and the gas relay sends a light gas alarm signal.

[0009] One end of the linkage protection solenoid valve is connected to the gas relay vent pipe, and the other end is connected in sequence to a filter, a palladium grid hydrogen sensor, an infrared acetylene sensor, a damping block, a volumetric flow sensor, and a miniature variable frequency air pump through a pipeline.

[0010] When the gas accumulated in the gas relay reaches the set threshold, the light gas alarm contact closes. The control module first activates the palladium-grid hydrogen sensor, the infrared acetylene sensor, and the volumetric flow sensor. Then, it sequentially activates the linkage protection solenoid valve and the miniature variable frequency air pump. The miniature variable frequency air pump, through the linkage protection solenoid valve, the palladium-grid hydrogen sensor, and the infrared acetylene sensor, extracts and vents the gas accumulated on the oil surface of the gas relay.

[0011] The volumetric flow sensor is preset with a gas relay venting threshold. When the extracted gas reaches the venting threshold, the volumetric flow sensor transmits a signal to the control module, which then automatically controls the micro air pump to stop and closes the linkage protection solenoid valve to prevent the oil in the gas relay from being extracted.

[0012] The filter is used to filter out solid impurities and oil droplets entrained in the gas, so as to prevent the subsequent palladium grid hydrogen sensor and infrared acetylene sensor from being contaminated.

[0013] The palladium grating hydrogen sensor is used to detect the hydrogen components contained in the flowing gas and transmit the detection data to the control module via optical fiber.

[0014] The infrared acetylene sensor is used to detect the acetylene component in the flowing gas and transmit the detection data to the control module via optical fiber.

[0015] The damping block is used to slow down the gas flow rate to facilitate the operation of the palladium grating hydrogen sensor and the infrared acetylene sensor.

[0016] The linkage protection device is assembled in an insulating protection box and installed near the gas relay of the main transformer via an insulating bracket.

[0017] The thresholds pre-set in the control module control program include: low concentration hydrogen content alarm setting value, high concentration hydrogen content alarm setting value, low concentration acetylene content alarm setting value, high concentration acetylene content main transformer trip setting value, and extraction volume setting value.

[0018] The control module is used to control the start and stop of the equipment. The control program includes: control programs for the palladium grid hydrogen sensor, infrared acetylene sensor, linkage protection solenoid valve, and miniature variable frequency air pump.

[0019] The input of the control module is electrically connected via optical fiber to the contacts of the gas relay light gas alarm, as well as the outputs of the palladium grid hydrogen sensor, infrared acetylene sensor, and volumetric flow sensor.

[0020] The output of the control module is electrically connected via optical fiber to the inputs of the following devices: linkage protection solenoid valve, miniature frequency conversion air pump, main transformer trip device, low-concentration hydrogen alarm, high-concentration hydrogen alarm, and low-concentration acetylene alarm.

[0021] The gas relay has a glass window on its side that allows observation of the accumulated gas.

[0022] The gas generated inside the main transformer falls into two categories.

[0023] Situation A: Due to poor sealing of the main transformer, or during oil filtration, oil filling, oil draining, maintenance, pre-testing, and replacement of the silica gel desiccant in the breather, the gas generated is mainly air and does not contain fault characteristic gases. It is sufficient to perform a gas release operation on the gas relay.

[0024] Scenario B: When the main transformer experiences severe overheating or discharge faults, or when the fault develops rapidly, the fault characteristic gases may not have enough time to dissolve in the transformer oil, or the transformer oil may be saturated with dissolved gases. The fault characteristic gases will overflow from the oil, rising and accumulating on the oil surface inside the gas relay window on the top of the main transformer. In this case, if the gas contains a large amount of acetylene, it indicates that a severe discharge or severe overheating fault has occurred inside the main transformer. In this situation, the power should be cut off immediately, and the main transformer should be isolated from the power grid to prevent the accident from escalating.

[0025] A protection operation method for a main transformer gas relay linkage protection device, the operation of which includes the following steps;

[0026] Step S1: Pre-design and program the following in the control module: alarm setting values ​​for low concentration hydrogen content, alarm setting values ​​for high concentration hydrogen content, alarm setting values ​​for low concentration acetylene content, main transformer power switch trip setting value for high concentration acetylene content, volumetric flow rate setting value, and control programs for starting and stopping the palladium grid hydrogen sensor, infrared acetylene sensor, volumetric flow rate sensor, linkage protection solenoid valve, micro frequency conversion air pump, etc.

[0027] Step S2: When the gas relay (3) of the main transformer is running normally, the gas relay is filled with transformer oil (19), and the main transformer gas relay linkage protection device (10) is in the normally closed state.

[0028] Step S3: When gas accumulates (20) in the gas relay, the accumulated gas presses down the oil level (19) in the gas relay. When the accumulated gas reaches the set volume threshold, it touches the gas relay light contact and turns on the gas relay linkage protection device control module.

[0029] Step S4: The control module first turns on the palladium gate hydrogen sensor (17), infrared acetylene sensor (16), and volumetric flow sensor (14) in sequence to start normal operation;

[0030] Step S5: The control module then activates the linkage protection solenoid valve (12) and the micro frequency conversion air pump (13) to extract the gas accumulated in the gas relay.

[0031] Step S6: The extracted gas first passes through the filter (18) to remove impurities and oil droplets, and then passes through the palladium grid hydrogen sensor (17), infrared acetylene sensor (16), damping block (15), volume flow sensor (14), and micro variable frequency pump (13) in sequence. Finally, it is discharged through the exhaust port (11). During this process, the damping block slows down the airflow to facilitate the detection work of the palladium grid hydrogen sensor and infrared acetylene sensor. The micro variable frequency pump (13) can adjust its pumping output condition according to the amount of gas accumulated in the gas relay.

[0032] Step S7: The palladium grating hydrogen sensor detects the hydrogen contained in the flowing gas and transmits the detection data to the control module.

[0033] Step S8: The infrared acetylene sensor detects the acetylene contained in the flowing gas and transmits the detection data to the control module.

[0034] Step S9: The control module compares the hydrogen content detected by the palladium gate hydrogen sensor with the pre-set programming program. If the hydrogen content reaches the minor fault setting value, a minor fault alarm is issued; if the hydrogen content reaches the serious fault setting value, a serious fault alarm is issued.

[0035] Step S10: The control module compares the acetylene content detected by the infrared acetylene sensor with the pre-set programming program. If the value reaches the minor fault value, a minor fault alarm is issued. If the value reaches the serious fault setting value, the control module controls the main transformer to trip, isolating the main transformer from the power grid to prevent the accident from escalating further.

[0036] Step S11: When the pumping volume of the miniature variable frequency air pump reaches the preset volumetric flow rate setting value, the linkage protection solenoid valve, the miniature variable frequency air pump, the palladium grid hydrogen sensor and the infrared acetylene sensor are automatically shut off in sequence, ending the online detection and automatic exhaust work.

[0037] This invention proposes a main transformer gas relay linkage protection device and protection method, which is an innovation in the field of main transformer gas relay equipment. It can automatically detect hydrogen and acetylene, two fault characteristic gases, within the main transformer gas relay online. First, it determines whether the gas accumulated within the gas relay is a fault characteristic gas or ordinary air. When a small amount of hydrogen and acetylene is detected, an alarm signal is issued. If the acetylene content exceeds the tripping set value, it can automatically control the main transformer to trip, isolating the main transformer from the power grid. The beneficial effects of this invention are as follows:

[0038] 1. The gas relay equipment innovatively integrates online detection of characteristic gases and gas extraction and emission into one system;

[0039] 2. In gas relay equipment, a palladium-grid hydrogen sensor and an infrared acetylene sensor are innovatively used for online detection of fault characteristic gases. Furthermore, in the event of a sudden severe fault in the main transformer, the system can automatically control the main transformer to trip for protection in the first instance.

[0040] 3. Innovations have been achieved in the protection method of the main transformer gas relay linkage protection device. Attached Figure Description

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0042] Appendix Figure 1 This is a schematic diagram showing the installation location of a main transformer gas relay linkage protection device.

[0043] Appendix Figure 2 This is a schematic diagram of the working process of a main transformer gas relay linkage protection device.

[0044] Appendix Figure 3 This is a block diagram illustrating the control principle of a main transformer gas relay linkage protection device control module.

[0045] In the diagram: 1-Main transformer body; 2-Oil conservator; 3-Gas relay; 4-Glass window (oil level window of gas relay); 5-Oil inlet valve; 6-Oil outlet valve; 7-Oil outlet pipe connected to oil conservator; 8-Oil inlet pipe connected to main transformer body; 9-Gas relay vent pipe;

[0046] 10-Interlocking protection device; 11-Exhaust port of interlocking protection device; 12-Interlocking protection solenoid valve; 13-Miniature variable frequency air pump; 14-Volume flow sensor; 15-Damping block; 16-Infrared acetylene sensor; 17-Palladium grid hydrogen sensor; 18-Filter; 19-Transformer oil inside the gas relay window; 20-Gas accumulated inside the gas relay. Detailed Implementation

[0047] As shown in the figure, a main transformer gas relay linkage protection device includes a main transformer, a gas relay, a linkage protection device, a control module, a linkage protection solenoid valve, a filter, a palladium grid hydrogen sensor, an infrared acetylene sensor, a damping block, a volumetric flow sensor, and a miniature variable frequency air pump. The gas relay is installed on the top of the main transformer. The oil outlet on the side of the gas relay is connected upward to the oil tank of the main transformer through an outlet valve 6, and the oil inlet of the gas relay is connected downward to the main transformer body through an inlet valve 5. The transformer oil in the main transformer body is connected to the transformer oil in the oil tank through the gas relay. The oil tank balances the oil pressure in the main transformer body by the rise and fall of the oil level. When gas is generated inside the main transformer body, the gas accumulates inside the gas relay and presses down the oil level of the gas relay. When the gas in the gas relay accumulates to the volume threshold, it triggers the light gas alarm contact inside the gas relay, and the gas relay sends a light gas alarm signal.

[0048] One end of the linkage protection solenoid valve is connected to the gas relay vent pipe, and the other end is connected in sequence to a filter, a palladium grid hydrogen sensor, an infrared acetylene sensor, a damping block, a volumetric flow sensor, and a miniature variable frequency air pump through a pipeline.

[0049] When the gas accumulated in the gas relay reaches the set threshold, the light gas alarm contact closes. The control module first activates the palladium-grid hydrogen sensor, the infrared acetylene sensor, and the volumetric flow sensor. Then, it sequentially activates the linkage protection solenoid valve and the miniature variable frequency air pump. The miniature variable frequency air pump, through the linkage protection solenoid valve, the palladium-grid hydrogen sensor, and the infrared acetylene sensor, extracts and vents the gas accumulated on the oil surface of the gas relay.

[0050] The volumetric flow sensor is preset with a gas relay venting threshold. When the extracted gas reaches the venting threshold, the volumetric flow sensor transmits a signal to the control module, which then automatically controls the micro air pump to stop and closes the linkage protection solenoid valve to prevent the oil in the gas relay from being extracted.

[0051] The filter is used to filter out solid impurities and oil droplets entrained in the gas, so as to prevent the subsequent palladium grid hydrogen sensor and infrared acetylene sensor from being contaminated.

[0052] The palladium grating hydrogen sensor is used to detect the hydrogen components contained in the flowing gas and transmit the detection data to the control module via optical fiber.

[0053] The infrared acetylene sensor is used to detect the acetylene component in the flowing gas and transmit the detection data to the control module via optical fiber.

[0054] The damping block is used to slow down the gas flow rate to facilitate the operation of the palladium grating hydrogen sensor and the infrared acetylene sensor.

[0055] The linkage protection device is assembled in an insulating protection box and installed near the gas relay of the main transformer via an insulating bracket.

[0056] The thresholds pre-set in the control module control program include: low concentration hydrogen content alarm setting value, high concentration hydrogen content alarm setting value, low concentration acetylene content alarm setting value, high concentration acetylene content main transformer trip setting value, and extraction volume setting value.

[0057] The control module is used to control the start and stop of the equipment. The control program includes: control programs for the palladium grid hydrogen sensor, infrared acetylene sensor, linkage protection solenoid valve, and miniature variable frequency air pump.

[0058] The input of the control module is electrically connected via optical fiber to the contacts of the gas relay light gas alarm, as well as the outputs of the palladium grid hydrogen sensor, infrared acetylene sensor, and volumetric flow sensor.

[0059] The output of the control module is electrically connected via optical fiber to the inputs of the following devices: linkage protection solenoid valve, miniature frequency conversion air pump, main transformer trip device, low-concentration hydrogen alarm, high-concentration hydrogen alarm, and low-concentration acetylene alarm.

[0060] The gas relay has a glass window 4 on its side for observing the accumulated gas.

[0061] The gas generated inside the main transformer falls into two categories.

[0062] Situation A: Due to poor sealing of the main transformer, or during oil filtration, oil filling, oil draining, maintenance, pre-testing, and replacement of the silica gel desiccant in the breather, the gas generated is mainly air and does not contain fault characteristic gases. It is sufficient to perform a gas release operation on the gas relay.

[0063] Scenario B: When the main transformer experiences severe overheating or discharge faults, or when the fault develops rapidly, the fault characteristic gases may not have enough time to dissolve in the transformer oil, or the transformer oil may be saturated with dissolved gases. The fault characteristic gases will overflow from the oil, rising and accumulating on the oil surface inside the gas relay window on the top of the main transformer. In this case, if the gas contains a large amount of acetylene, it indicates that a severe discharge or severe overheating fault has occurred inside the main transformer. In this situation, the power should be cut off immediately, and the main transformer should be isolated from the power grid to prevent the accident from escalating.

[0064] A protection operation method for a main transformer gas relay linkage protection device, the operation of which includes the following steps;

[0065] Step S1: Pre-design and program the following in the control module: alarm setting values ​​for low concentration hydrogen content, alarm setting values ​​for high concentration hydrogen content, alarm setting values ​​for low concentration acetylene content, main transformer power switch trip setting value for high concentration acetylene content, volumetric flow rate setting value, and control programs for starting and stopping the palladium grid hydrogen sensor, infrared acetylene sensor, volumetric flow rate sensor, linkage protection solenoid valve, micro frequency conversion air pump, etc.

[0066] Step S2: When the gas relay 3 of the main transformer is running normally, the gas relay is filled with transformer oil 19, and the main transformer gas relay linkage protection device 10 is in the normally closed state.

[0067] Step S3: When gas 20 accumulates in the gas relay, the accumulated gas presses down the oil level 19 in the gas relay. When the accumulated gas reaches the set volume threshold, it triggers the gas relay light contact and activates the gas relay linkage protection device control module.

[0068] Step S4: The control module first turns on the palladium gate hydrogen sensor 17, the infrared acetylene sensor 16, and the volumetric flow sensor 14 in sequence to start normal operation.

[0069] Step S5: The control module then activates the linkage protection solenoid valve 12 and the miniature frequency conversion air pump 13 to extract the gas accumulated in the gas relay.

[0070] Step S6: The extracted gas first passes through filter 18 to remove impurities and oil droplets, then passes sequentially through palladium grid hydrogen sensor 17, infrared acetylene sensor 16, damping block 15, volumetric flow sensor 14, and miniature variable frequency pump 13, and finally is discharged through exhaust port 11. During this process, the damping block slows down the airflow to facilitate the detection work of the palladium grid hydrogen sensor and infrared acetylene sensor. The miniature variable frequency pump 13 can adjust its pumping output according to the amount of gas accumulated in the gas relay.

[0071] Step S7: The palladium grating hydrogen sensor detects the hydrogen contained in the flowing gas and transmits the detection data to the control module.

[0072] Step S8: The infrared acetylene sensor detects the acetylene contained in the flowing gas and transmits the detection data to the control module.

[0073] Step S9: The control module compares the hydrogen content detected by the palladium gate hydrogen sensor with the pre-set programming program. If the hydrogen content reaches the minor fault setting value, a minor fault alarm is issued; if the hydrogen content reaches the serious fault setting value, a serious fault alarm is issued.

[0074] Step S10: The control module compares the acetylene content detected by the infrared acetylene sensor with the pre-set programming program. If the value reaches the minor fault value, a minor fault alarm is issued. If the value reaches the serious fault setting value, the control module controls the main transformer to trip, isolating the main transformer from the power grid to prevent the accident from escalating further.

[0075] Step S11: When the pumping volume of the miniature variable frequency air pump reaches the preset volumetric flow rate setting value, the linkage protection solenoid valve, the miniature variable frequency air pump, the palladium grid hydrogen sensor and the infrared acetylene sensor are automatically shut off in sequence, ending the online detection and automatic exhaust work.

[0076] In this example, both the inlet valve and the outlet valve are butterfly valves.

[0077] In this example, the gas relay is connected to the oil circuit inside the oil conservator via the oil outlet pipe 7, and is connected to the oil circuit inside the transformer body via the oil inlet pipe 8 of the main transformer body. The gas relay vents gas through the gas relay vent pipe 9.

Claims

1. A main transformer gas relay linkage protection mechanism, characterized in that: The system includes a main transformer, a gas relay, a linkage protection device, and a control module. The linkage protection device includes a linkage protection solenoid valve, a filter, a palladium grid hydrogen sensor, an infrared acetylene sensor, a damping block, a volumetric flow sensor, and a miniature frequency conversion air pump. The gas relay is installed on the top of the main transformer. The oil outlet on the side of the gas relay is connected upward to the oil tank of the main transformer through an outlet valve, and the oil inlet of the gas relay is connected downward to the main transformer body through an inlet valve. The transformer oil in the main transformer body is connected to the transformer oil in the oil tank through the gas relay. The oil tank balances the oil pressure in the main transformer body by the rise and fall of the oil level. When gas is generated inside the main transformer body, the gas accumulates inside the gas relay and presses down the oil level of the gas relay. When the gas in the gas relay accumulates to the volume threshold, it triggers the light gas alarm contact inside the gas relay, and the gas relay sends a light gas alarm signal. One end of the linkage protection solenoid valve is connected to the gas relay vent pipe, and the other end is connected in sequence to a filter, a palladium grid hydrogen sensor, an infrared acetylene sensor, a damping block, a volumetric flow sensor, and a miniature variable frequency air pump through a pipeline. When the gas accumulated in the gas relay reaches the set threshold, the light gas alarm contact closes. The control module first activates the palladium-grid hydrogen sensor, the infrared acetylene sensor, and the volumetric flow sensor. Then, it sequentially activates the linkage protection solenoid valve and the miniature variable frequency air pump. The miniature variable frequency air pump, through the linkage protection solenoid valve, the palladium-grid hydrogen sensor, and the infrared acetylene sensor, extracts and vents the gas accumulated on the oil surface of the gas relay. The volumetric flow sensor is preset to the gas relay's venting threshold. When the extracted gas reaches the venting threshold, the volumetric flow sensor transmits a signal to the control module, which then automatically controls the micro air pump to stop and closes the linkage protection solenoid valve to prevent the oil in the gas relay from being extracted. The filter is used to filter out solid impurities and oil droplets entrained in the gas, so as to prevent the subsequent palladium grid hydrogen sensor and infrared acetylene sensor from being contaminated. The palladium grating hydrogen sensor is used to detect the hydrogen components contained in the flowing gas and transmit the detection data to the control module via optical fiber. The infrared acetylene sensor is used to detect the acetylene component in the flowing gas and transmit the detection data to the control module via optical fiber. The damping block is used to slow down the gas flow rate to facilitate the operation of the palladium grating hydrogen sensor and the infrared acetylene sensor. The linkage protection device is assembled in an insulating protection box and installed near the gas relay of the main transformer via an insulating bracket.

2. The main transformer gas relay linkage protection mechanism according to claim 1, characterized in that: The thresholds pre-set in the control module control program include: low concentration hydrogen content alarm setting value, high concentration hydrogen content alarm setting value, low concentration acetylene content alarm setting value, high concentration acetylene content main transformer trip setting value, and extraction volume setting value. The control module is used to control the start and stop of the equipment. The control program includes: control programs for the palladium grid hydrogen sensor, infrared acetylene sensor, linkage protection solenoid valve, and miniature variable frequency air pump. The input of the control module is electrically connected via optical fiber to the contacts of the gas relay light gas alarm, as well as the outputs of the palladium grid hydrogen sensor, infrared acetylene sensor, and volumetric flow sensor. The output of the control module is electrically connected via optical fiber to the inputs of the following devices: linkage protection solenoid valve, miniature frequency conversion air pump, main transformer trip device, low-concentration hydrogen alarm, high-concentration hydrogen alarm, and low-concentration acetylene alarm.

3. The main transformer gas relay linkage protection mechanism according to claim 1, characterized in that: The gas relay has a glass window on its side that allows observation of the accumulated gas.

4. The main transformer gas relay linkage protection mechanism according to claim 1, characterized in that: The gas generated inside the main transformer falls into two categories. Situation A: Due to poor sealing of the main transformer, or during oil filtration, oil filling, oil draining, maintenance, pre-testing, and replacement of the silica gel desiccant in the breather, the gas generated is mainly air and does not contain fault characteristic gases. It is sufficient to perform a gas release operation on the gas relay. Scenario B: When the main transformer experiences a severe overheating or discharge fault, or when the fault develops rapidly, the fault characteristic gas may not have enough time to dissolve in the transformer oil, or the transformer oil may be saturated with the gas. The fault characteristic gas will overflow from the oil, and these free fault characteristic gases will rise from the transformer oil and accumulate on the oil surface inside the gas relay window installed on the top of the main transformer. In this case, the gas contains a large amount of acetylene, indicating that a severe discharge or severe overheating fault has occurred inside the main transformer. At this time, the power should be cut off immediately, and the main transformer should be isolated from the power grid to prevent the accident from escalating.

5. A protection operation method for a main transformer gas relay linkage protection mechanism, used in any one of claims 1 to 4, characterized in that: The working method of the protection operation includes the following steps; Step S1: Pre-design and program the following in the control module: alarm setting values ​​for low concentration hydrogen content, alarm setting values ​​for high concentration hydrogen content, alarm setting values ​​for low concentration acetylene content, main transformer trip setting values ​​for high concentration acetylene content, volumetric flow rate setting values, and control programs for starting and stopping the palladium grid hydrogen sensor, infrared acetylene sensor, volumetric flow rate sensor, linkage protection solenoid valve, and miniature variable frequency pump. Step S2: When the gas relay (3) of the main transformer is running normally, the gas relay is filled with transformer oil (19), and the main transformer gas relay linkage protection device (10) is in the normally closed state. Step S3: When gas accumulates (20) in the gas relay, the accumulated gas presses down the oil level in the gas relay. When the accumulated gas reaches the set volume threshold, it touches the gas relay light contact and opens the gas relay linkage protection device control module. Step S4: The control module first turns on the palladium gate hydrogen sensor (17), infrared acetylene sensor (16), and volumetric flow sensor (14) in sequence to start normal operation; Step S5: The control module then activates the linkage protection solenoid valve (12) and the micro frequency conversion air pump (13) to extract the gas accumulated in the gas relay. Step S6: The extracted gas first passes through the filter (18) to remove impurities and oil droplets, and then passes through the palladium grid hydrogen sensor (17), infrared acetylene sensor (16), damping block (15), volume flow sensor (14), and micro variable frequency pump (13) in sequence. Finally, it is discharged through the exhaust port (11). During this process, the damping block slows down the airflow to facilitate the detection work of the palladium grid hydrogen sensor and infrared acetylene sensor. The micro variable frequency pump (13) can adjust its pumping output condition according to the amount of gas accumulated in the gas relay. Step S7: The palladium grating hydrogen sensor detects the hydrogen contained in the flowing gas and transmits the detection data to the control module. Step S8: The infrared acetylene sensor detects the acetylene contained in the flowing gas and transmits the detection data to the control module. Step S9: The control module compares the hydrogen content detected by the palladium gate hydrogen sensor with the pre-set programming program. If the hydrogen content reaches the minor fault setting value, a minor fault alarm is issued; if the hydrogen content reaches the serious fault setting value, a serious fault alarm is issued. Step S10: The control module compares the acetylene content detected by the infrared acetylene sensor with the pre-set programming program. If the value reaches the minor fault value, a minor fault alarm is issued. If the value reaches the serious fault setting value, the control module controls the main transformer to trip, isolating the main transformer from the power grid to prevent the accident from escalating further. Step S11: When the pumping volume of the miniature variable frequency air pump reaches the preset volumetric flow rate setting value, the linkage protection solenoid valve, the miniature variable frequency air pump, the palladium grid hydrogen sensor and the infrared acetylene sensor are automatically shut off in sequence, ending the online detection and automatic exhaust work.

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