Dissolved gas detection system and method in transformer oil based on plasma detection

Abstract

A system and method for detecting dissolved gas in transformer oil based on plasma detection, belonging to the technical field of transformer fault detection, solves the problem that it is difficult to accurately evaluate the operation status of transformers and carry out equipment fault diagnosis; a degassing device of the detection system adopts a fixed oil tank and a first quantitative ring to ensure the sampling accuracy, the whole degassing process is carried out inside the degassing device, no manual operation is required, and the interference error of manual operation is avoided, the device has strong stability, strong repeatability and high accuracy; an enrichment sampling device enriches the dissolved gas in transformer oil by adsorption and desorption, and the concentration of the characteristic gas in the transformer oil is increased, which is beneficial to subsequent detection; a component separation device separates the input characteristic gas into different combined peaks by connecting and switching multiple switching valves with chromatographic columns, and there is no interference peak between the components; the detection accuracy is improved, which is beneficial to accurately evaluate the operation status of transformers and carry out equipment fault diagnosis.

Description

Technical Field

[0001] The invention belongs to the technical field of transformer fault detection, and relates to a system and method for detecting dissolved gas in transformer oil based on plasma detection. Background Art

[0002] With the construction of UHV power grid, more and more high-voltage transformers are put into use. How to effectively prevent serious failures of oil-filled equipment and ensure the safety of UHV power grid is a major problem facing the development and operation of power grid. The dissolved gas components in transformer oil are important information carriers and "indicators" that reflect the internal status and fault degree of transformer equipment. The analysis and detection of dissolved gas components in transformer oil is currently one of the most effective ways to evaluate the operating status of transformers and conduct equipment fault diagnosis.

[0003] At present, the laboratory detection of dissolved gas in oil mainly adopts gas chromatography, which uses carrier gas to transport gas samples into the chromatographic column for gas separation, and then uses thermal conductivity cell (TCD) or hydrogen flame ionization detector (FID) to detect the volume fraction of gas components. The advantages of this method are good selectivity and high separation performance, but there are still some shortcomings: 1) The oil sample is sent to the laboratory after being collected from the site. In this process, it not only takes time, but also the collection, transportation, and storage will cause changes in the concentration of dissolved gas in the oil; 2) When quantitatively analyzing the gas, the operation steps are cumbersome, not only there may be errors in the degassing link, but also the manual correction of the detection curve will cause errors. The results obtained by different staff using the same gas chromatograph sometimes differ by 10%. The cumbersome operation, inevitable errors and the inability to track the transformer operation status in real time have limited the gas chromatography technology to play a better early warning role in transformer fault detection.

[0004] Chromatography is the most commonly used and reliable method for detecting dissolved gas components in transformer oil. In the chromatographic analysis process, oil-gas separation is an important link that affects the detection accuracy. It is a "bridge" connecting the chromatographic detection results with the actual concentration of the oil sample. The results of chromatographic detection need to be converted through the oil-gas separation coefficient to obtain the concentration of dissolved gas in the oil.

[0005] However, the quality of oil samples under different voltage levels, different equipment types (sealed type, open type), different usage conditions, and different fault types are not the same, which leads to significant differences in key indicators such as water content, gas content, and low-boiling point hydrocarbons in the oil.

[0006] The existing method of oil-gas separation by oscillation degassing is: inject 40 ml of oil sample into a measuring cylinder, inject 5 ml of nitrogen into the oil sample, put it into an oscillator, heat it to 50°C, oscillate for 20 minutes, replace the dissolved gas in the oil sample with nitrogen, let it stand for 10 minutes, and then use a two-way needle and a 5 ml syringe to remove all the gas. This method requires manual oil sampling and gas extraction throughout the process, which is complicated to operate and has large errors. It is difficult to ensure the stability and repeatability of degassing between different oil samples, and it seriously interferes with the accurate determination of gas components in the oil sample. In addition, for oil samples at the initial stage of the fault, the concentration of characteristic gases in the oil is extremely low, and the error of the oil-gas separation process will be magnified in the detection results of low-concentration oil samples. That is to say, the oil-gas separation process has a greater impact on the accurate determination of low-concentration oil samples. According to relevant reports from the International Conference on Large Electric Systems (CIGRE), the impact of the oil-gas separation process on the accuracy of the detection results is even up to 20%. Therefore, in order to achieve the detection of trace gas in oil, it is necessary to reduce the interference error generated by the oil-gas separation process.

[0007] Generally, the amount of characteristic gas generated by early failures inside the equipment is small. After oil circulation, it is dispersed in the transformer oil. Some of it is adsorbed by materials such as insulating cardboard, resulting in a very low content of gas components in the oil (10 -8 V / V level or even lower). Usually, the amount of characteristic gas generated by early faults is generally less than 1mL. If 1mL of gas is completely dispersed into the main oil of ±1100kV converter transformer (oil weight is about 160 tons), the concentration of gas in the oil is about 5×10 -9 L / L, that is, it reaches the ppb level; the content of hydrogen, carbon monoxide, carbon dioxide, methane, ethylene, ethane, acetylene, propylene, propane and propyne components in the dissolved gas in transformer oil is often at the μmol / mol level, which is difficult to achieve by direct sampling, especially the detection of ethylene, ethane, acetylene, propylene, propane and propyne components is very difficult.

[0008] Transformers are often filled with mineral insulating oil for insulation. It is a mixture of hydrocarbon molecules of different molecular weights, containing CH3-, CH2-, and CH- chemical groups bonded together by CC bonds. When an electrical or thermal fault occurs, some C-CH bonds and CH bonds break, accompanied by the generation of a small amount of active hydrogen atoms and unstable hydrocarbon free radicals such as CH3 * 、CH2 * , CH * , C *, and these hydrogen atoms or free radicals quickly recombine through complex chemical reactions to generate hydrogen and low molecular hydrocarbon gases, such as methane, ethane, ethylene, acetylene, propylene, propane, propyne, etc. These components include inorganic and organic components and the content is often at the μmol / mol level. Currently, thermal conductivity cell detectors, hydrogen flame ionization detectors combined with nickel catalytic converters are used to analyze their component content, and manual sampling has a large error.

[0009] Plasma discharge detection technology was developed in the 1950s. It is a high-precision detection technology based on the principle of plasma discharge. After years of development and application, the technology has become mature. Plasma discharge detectors can achieve high-precision detection of all characteristic gases, so they have important development prospects in oil chromatographs. Colorimeter based on helium ionization detection technology has been applied to the detection of decomposition products of SF6, which shows excellent detection performance and can achieve ppm to ppb level determination of various decomposition products. At present, plasma detectors often use helium as carrier gas. Since helium is a scarce gas, the cost of use is very expensive. At the same time, helium is a strategic resource, and using helium as a chromatographic carrier gas will result in huge waste of resources. The plasma detection device is to apply a high-frequency, high-intensity electromagnetic field around the quartz cell of the detector. Under the action of the high-frequency, high-intensity electromagnetic field, the carrier gas is ionized into a higher energy plasma. When the quartz cell of the detector contains other impurity gases, the ionization effect is affected. Summary of the invention

[0010] The technical problem to be solved by the present invention is how to design a system and method for detecting dissolved gas in transformer oil based on plasma detection, so as to solve the problem that it is difficult to accurately evaluate the operating status of the transformer and carry out equipment fault diagnosis due to the large amount of oil in the ultra-high voltage transformer, the small amount of gas generated by early faults, and the low concentration of characteristic gases contained in the oil.

[0011] The present invention solves the above technical problems through the following technical solutions:

[0012] The transformer oil dissolved gas detection system based on plasma detection comprises: a degassing device, an enrichment sampling device, a component separation device, and a plasma detection device; the output end of the degassing device is sealedly connected to the input end of the enrichment sampling device, the output end of the enrichment sampling device is sealedly connected to the input end of the component separation device, and the input end of the plasma detection device is sealedly connected to the detection port of the component separation device; the degassing device extracts a quantitative oil sample to be tested and injects it into a fixed oil tank, then degasses the quantitative oil sample to be tested in the fixed oil tank, stores the degassed characteristic gas in a quantitative loop, and then outputs the characteristic gas to the enrichment sampling device by carrying nitrogen; the desorption tube of the enrichment sampling device switches back and forth between low temperature and high temperature, the desorption tube performs adsorption enrichment at low temperature, and performs high-temperature desorption after enrichment, and the desorbed gas is input into the component separation device as a sample gas; the component separation device separates the input characteristic gas into different combined peaks through the connection and switching of a plurality of switching valves with the chromatographic column, and uses the plasma detection device for analysis and detection.

[0013] The degassing device of the detection system of the present invention adopts a fixed oil tank and a quantitative ring to ensure the accuracy of sampling. The entire degassing process is carried out inside the degassing device without manual operation, thereby avoiding interference errors caused by manual operation. The device has strong stability, strong repeatability and high accuracy. The enrichment sampling device enriches the dissolved gas in the transformer oil through adsorption and desorption, thereby increasing the concentration of the characteristic gas dissolved in the transformer oil, which is beneficial to subsequent detection. The component separation device separates the input characteristic gas into different combined peaks through the connection and switching of multiple switching valves with the chromatographic column, and there is no interference peak between the components. The problem of difficulty in accurately evaluating the transformer operation status and conducting equipment fault diagnosis caused by the large amount of oil in the ultra-high voltage transformer, the small amount of gas generated by early faults and the low concentration of characteristic gas contained in the oil is completely solved.

[0014] Furthermore, the degassing device comprises: a nitrogen gas storage cylinder (1), a pressure reducing valve (2), a flat three-way valve (3), a two-way ball valve (4), a first three-way solenoid valve (5), a first recovery tank (6), an oil tank (7), a second three-way solenoid valve (8), an oil pump (9), an oil storage tank (10), a six-way valve (11), a chromatographic injector (12), a third three-way solenoid valve (13), a degassing unit (14), a second recovery tank (15), a first quantitative ring (16), and an air pump (17); the outlet of the nitrogen gas storage cylinder (1) is connected to the air inlet of the pressure reducing valve (2), the air outlet of the pressure reducing valve (2) is connected to the first interface of the flat three-way valve (3), the second interface of the flat three-way valve (3) is connected to the air inlet of the two-way ball valve (4), and the air outlet of the two-way ball valve (4) is connected to the first three-way valve (11). The first interface of the solenoid valve (5) and the third interface of the first three-way solenoid valve (5) are connected to the first recovery tank (6). The second interface of the first three-way solenoid valve (5) is connected to the air inlet of the fixed oil tank (7). The air outlet of the fixed oil tank (7) is connected to the first interface of the second three-way solenoid valve (8). The second interface of the second three-way solenoid valve (8) is connected to the air inlet of the oil pump (9). The air outlet of the oil pump (9) is connected to the oil storage tank (10). The third interface of the second three-way solenoid valve (8) is connected to the lower interface of the degassing unit (14). The upper interface of the degassing unit (14) is connected to the first interface of the third three-way solenoid valve (13). The third interface of the third three-way solenoid valve (13) is connected to the air pump (17). The third interface of the planar three-way valve (3) is connected to the 6 of the six-way valve (11). # Port, 1 of 6-way valve (11) # The port is connected to the chromatograph injector (12), and one end of the first quantitative loop (16) is connected to the two ends of the six-way valve (11). # The other end of the first quantitative ring (16) is connected to the 5th port of the six-way valve (11). # Port connection, 3 of the six-way valve (11) # The port is connected to the second port of the third three-way solenoid valve (13), and the 4th port of the six-way valve (11) is connected to the second port of the third three-way solenoid valve (13). # The port is connected to the second recovery tank (15).

[0015] Furthermore, the working process of the degassing device includes:

[0016] S11, flushing the fixed oil tank; closing the two-way ball valve (4), starting the oil pump (9) to extract the oil sample to be tested from the oil storage tank (10) into the fixed oil tank (7), flushing the fixed oil tank (7) and its affiliated pipelines, and the waste oil after flushing flows into the first recovery tank (6) through the first three-way solenoid valve (5) for recovery;

[0017] S12, taking the oil sample to be tested from the fixed oil tank; closing the first three-way solenoid valve (5), starting the oil pump (9) to extract a fixed amount of the oil sample to be tested from the oil storage tank (10) and injecting it into the fixed oil tank (7);

[0018] S13, degassing the oil sample to be tested; opening and closing the two-way ball valve (4), the nitrogen in the nitrogen storage bottle (1) carries a fixed amount of the oil sample to be tested in the fixed oil tank (7) into the degassing unit (14) through the second three-way solenoid valve (8), and the oil sample to be tested entering the degassing unit (14) is heated to a certain temperature for oil-gas separation and degassing. At this time, the role of the nitrogen is to replace the characteristic gas dissolved in the oil sample;

[0019] S14, taking characteristic gas in a quantitative loop; opening the third three-way solenoid valve (13), the characteristic gas flows out from the interface at the top of the degassing unit (14), passes through the third three-way solenoid valve (13), the six-way valve (11) and the 3 # 2 of the six-way valve (11) # After passing through the mouth, the liquid is stored in a first quantitative ring (16);

[0020] S15, nitrogen carries characteristic gas for output detection; the nitrogen in the nitrogen storage bottle (1) passes through the flat three-way valve (3) and the six-way valve (11) # 5 of the six-way valve (11) # After entering the first quantitative ring (16), it passes through the 2 ports of the six-way valve (11) together with the characteristic gas. # 1 of the six-way valve (11) # After the sample is injected into the chromatograph through the chromatographic injector (12) for detection;

[0021] S16, air purge to recover the oil sample after oil and gas separation; open the third three-way solenoid valve (13), start the air pump (17), and let the air enter from the upper interface of the degassing unit (14) and then leave from the lower interface of the degassing unit (14). The air carries the oil sample after degassing in the degassing unit (14) to the second three-way solenoid valve (8), the fixed oil tank (7), the first three-way solenoid valve (5), and then to the first recovery tank (6);

[0022] S17, nitrogen purges the entire device; open the two-way ball valve (4), the nitrogen in the nitrogen storage bottle (1) passes through the pressure reducing valve (2), the flat three-way (3), the two-way ball valve (4), the first three-way solenoid valve (5), the fixed oil tank (7), the second three-way solenoid valve (8), enters from the lower interface of the degassing unit (14), and then exits from the upper interface of the degassing unit (14), passes through the third three-way solenoid valve (13), the three-way valve of the six-way valve (11), and enters from the lower interface of the degassing unit (14). # 2 of the six-way valve (11) # port, the first quantitative ring (16), the 5 # 4 of the six-way valve (11)# The outlet is directed to the second recovery tank (15).

[0023] Furthermore, the enrichment sampling device comprises: a base (21), a sliding block (22), a screw transmission device (23), a cooling device (24), a heating device (25), a desorption tube mounting frame (27), a desorption tube (28), a connecting piece (29), and a mounting bracket (30); a limited position slide groove (31) is provided below the base (21); the cooling device (24) and the heating device (25) are aligned and arranged above the base (21); and the cooling device (24) and the heating device (25) are aligned and arranged above the base (21). Each end is provided with a first slot (32), and the first slot (32) of the cooling device (24) and the first slot (32) of the heating device (25) are arranged opposite to each other; the sliding block (22) is installed in the limiting slot (31), and the screw transmission device (23) is fixed to the base (21) through the mounting bracket (30); the transmission end of the screw transmission device (23) is fixedly connected to the middle of the connecting member (29), the lower end of the connecting member (29) is fixedly connected to the sliding block (22), and the upper end of the connecting member (29) is fixedly connected to the sliding block (22). The end of the connecting member (29) is fixedly connected to one end of the analysis tube mounting frame (27), and the other end of the analysis tube mounting frame (27) spans the cooling device (24) and the heating device (25), and the analysis tube (28) is stuck in the analysis tube mounting frame (27); the screw transmission device (23) drives the connecting member (29) to reciprocate, and the lower end of the connecting member (29) drives the sliding block (22) to reciprocate left and right in the limiting slide groove (31), and at the same time, the upper end of the connecting member (29) drives the analysis tube mounting frame (27), thereby driving the analysis tube (28) to move in the limiting slide groove (31). The first slot (32) of the cooling device (24) and the first slot (32) of the heating device (25) are switched back and forth; the desorption tube (28) moves to the left and enters the first slot (32) at the end of the cooling device (24) to perform low-temperature adsorption; the adsorption capacity of the medium filled in the desorption tube (28) is enhanced at low temperatures, and the dissolved gas in the transformer oil is adsorbed, thereby enriching the low-concentration dissolved gas; after enrichment, the desorption tube (28) moves to the right and enters the first slot (32) at the end of the heating device (25) to perform high-temperature desorption.

[0024] Furthermore, the enrichment sampling device further comprises: a desorption tube moving guide rail (26); there are two desorption tube moving guide rails (26), which are respectively fixedly mounted in parallel on both sides of the cooling device (24) and the heating device (25).

[0025] Furthermore, a second slot (13) is provided in the middle of the analytical tube moving guide rail (26), and the second slot (13) matches the first slot (32) of the cooling device (24) and the first slot (32) of the heating device (25), and the analytical tube (28) reciprocates in the second slot (13) provided in the middle of the moving guide rail (6).

[0026] Furthermore, both ends of the analysis tube mounting frame (27) are provided with bayonet holes (34), the bayonet holes (34) match with the second slot (13) provided in the middle of the analysis tube moving guide rail (26), and both ends of the analysis tube (28) are clamped on the bayonet holes (34) at both ends of the analysis tube mounting frame (27).

[0027] Furthermore, the component separation device comprises: a first switching valve (41), a second quantitative ring (42), a first chromatographic column (43), a second chromatographic column (44), a second switching valve (45), a third switching valve (46), a third chromatographic column (47), a fourth chromatographic column (48), a fourth switching valve (49), a first plane tee (50), a second plane tee (51), a third plane tee (52), a fourth plane tee (53), a fifth plane tee (54), a sixth plane tee (55), a seventh plane tee (56), a first needle valve (57), and a second needle valve (58). , a third needle valve (59); the first switching valve (41) is a ten-way switching valve, the second switching valve (45) is a four-way switching valve, the third switching valve (46) is a ten-way switching valve, and the fourth switching valve (49) is a four-way switching valve; port 1 of the first switching valve (41) is connected to the injection port, port 10 of the first switching valve (41) is connected to the input port of the second quantitative ring (42), the output port of the second quantitative ring (42) is connected to port 3 of the first switching valve (41), port 2 of the first switching valve (41) is connected to the sample outlet, port 4 of the first switching valve (41) is connected to port 2 of the fourth flat three-way (53), and the output port of the second quantitative ring (42) is connected to port 3 of the first switching valve (41). # The interface is connected, the No. 5 port of the first switching valve (41) is connected to the output end of the first chromatographic column (43), the input end of the first chromatographic column (43) is connected to the No. 9 port of the first switching valve (41), and the No. 7 port of the first switching valve (41) is connected to the No. 3 port of the third plane tee (52). # The interface is connected between port 8 of the first switching valve (41) and port 2 of the first needle valve (57). # The interface is connected, port 6 of the first switching valve (41) is connected to the input end of the second chromatographic column (44); the output end of the second chromatographic column (44) is connected to port 2 of the second switching valve (45); port 3 of the second switching valve (45) is connected to port 1 of the third switching valve (46); port 4 of the second switching valve (45) is connected to port 3 of the fifth flat tee (54); #The interface is connected, the No. 5 port of the second switching valve (45) is connected to the No. 6 port of the second switching valve (45), and the No. 1 port of the second switching valve (45) is connected to the No. 3 port of the sixth plane three-way (55). # Interface connection; port 2 of the third switching valve (46) is connected to the input end of the fourth chromatographic column (48), the output end of the fourth chromatographic column (48) is connected to port 5 of the third switching valve (46), and port 3 of the third switching valve (46) is connected to port 1 of the fourth planar tee (53). # The interface is connected between port 4 of the third switching valve (46) and port 2 of the second needle valve (58). # The interface is connected between the No. 6 port of the third switching valve (46) and the No. 2 port of the sixth flat tee (55). # The interface is connected, the port 7 of the third switching valve (46) is connected to the output end of the third chromatographic column (47), the input end of the third chromatographic column (47) is connected to the port 10 of the third switching valve (46), and the port 8 of the third switching valve (46) is connected to the port 2 of the third needle valve (59). # The interface is connected between the No. 9 port of the third switching valve (46) and the No. 2 port of the fifth flat tee (54). # Interface connection; port 1 of the fourth switching valve (49) is connected to the carrier gas port, and port 2 of the fourth switching valve (49) is connected to port 3 of the second plane tee (51). # The interface is connected between the No. 3 port of the fourth switching valve (49) and the No. 3 port of the first plane tee (50). # The interface is connected, the No. 4 port of the fourth switching valve (49) is connected to the exhaust port; the No. 1 port of the first plane tee (50) is connected to the exhaust port; # Interface with the seventh plane tee (56) 1 # Interface connection, first plane tee (50) 2 # Interface with the first needle valve (57) 1 # Interface connection, second plane tee (51) 1 # Interface with the fifth plane tee (54) 1 # Interface connection, second plane tee (51) 2 # Interface with the third plane tee (52) 1 # Interface connection, third plane tee (52) 2 # Interface with the fourth plane tee (53) 3 # Interface connection, sixth plane tee (55) 1 # The interface is connected to the detection port, 2 of the seventh plane tee (56) # Interface with the second needle valve (58) 1 # Interface connection, seventh plane tee (56) 3 # Interface with the third needle valve (59) 1 # Interface connection.

[0028] Furthermore, the working process of the component separation device is as follows:

[0029] S21, sampling process; specifically, the No. 1 port and the No. 10 port of the first switching valve (41) are connected, and the No. 2 port and the No. 3 port of the first switching valve (41) are connected, the sample enters from the sampling port, passes through the No. 1 port of the first switching valve (41), the No. 10 port of the first switching valve (41), the second quantitative ring (42), and the No. 3 port of the first switching valve (41) in sequence, and finally flows from the No. 2 port of the first switching valve (41) to the sampling port, and the second quantitative ring (42) stores a certain amount of sample, thereby completing the sampling process;

[0030] S22, sample pre-separation process; specifically: the carrier gas passes through port No. 4 of the first switching valve (41), port No. 3 of the first switching valve (41), the second quantitative loop (42), port No. 10 of the first switching valve (41), and port No. 9 of the first switching valve (41) in sequence, carrying the sample stored in the second quantitative loop (42) into the first chromatographic column (43); the sample is pre-separated in the first chromatographic column (43), and the pre-separated sample flows through port No. 5 of the first switching valve (41) and port No. 6 of the first switching valve (41) to the second chromatographic column (44) to be separated into three combined peaks, and the order in which the three combined peaks flow out of the second chromatographic column (44) is: hydrogen methane carbon monoxide combined peak, carbon dioxide ethylene ethane acetylene combined peak, propylene propane propyne combined peak;

[0031] S23, the process of detecting the combined peak of hydrogen, methane and carbon monoxide; specifically, the combined peak of hydrogen, methane and carbon monoxide flows out from the second chromatographic column (44), passes through port No. 2 of the second switching valve (45), port No. 3 of the second switching valve (45), port No. 1 of the third switching valve (46), and port No. 10 of the third switching valve (46) to the third chromatographic column (47), is separated into hydrogen, methane and carbon monoxide again in the third chromatographic column (47), and then flows through port No. 7 of the third switching valve (46) and port No. 6 of the third switching valve (46) to port No. 2 of the sixth flat tee (55). # Interface, sixth plane tee (55) 1 # Interface, and finally flow into the detection port to detect the component contents of hydrogen, methane and carbon monoxide;

[0032] S24, the process of detecting the combined peak of carbon dioxide, ethylene, ethane and acetylene; specifically, after the combined peak of hydrogen, methane and carbon monoxide is detected, the third switching valve (46) is switched, and the carrier gas carrying the combined peak of carbon dioxide, ethylene, ethane and acetylene flows out from the second chromatographic column (44), passes through port No. 2 of the second switching valve (45), port No. 3 of the second switching valve (45), port No. 1 of the third switching valve (46), and port No. 2 of the third switching valve (46) to the fourth chromatographic column (48), is separated into carbon dioxide, ethylene, ethane and acetylene again in the fourth chromatographic column (48), and then flows through port No. 5 of the third switching valve (46) and port No. 6 of the third switching valve (46) to port 2 of the sixth flat tee (55). # Interface, sixth plane tee (55) 1 # The interface finally flows into the detection port to detect the component contents of carbon dioxide, ethylene, ethane and acetylene;

[0033] S25, detecting the combined peak of propylene, propane, and propyne; specifically, after the combined peak of carbon dioxide, ethylene, ethane, and acetylene is detected, the second switching valve (45) is switched, and the carrier gas carrying the combined peak of propylene, propane, and propyne is separated into propylene, propane, and propyne in the second chromatographic column (44), and flows through the No. 2 port of the second switching valve (45) and the No. 1 port of the second switching valve (45) to the No. 3 port of the sixth plane tee (55). # Interface, sixth plane tee (55) 1 # The gas flows into the detection port to detect the component contents of propylene, propane and propyne.

[0034] Furthermore, the plasma detection device comprises: a discharge chamber (61), a probe, a component gas connecting pipe (64), a carrier gas connecting pipe (65), an exhaust connecting pipe (66), a composite electrode (67), and a vacuum pumping device (68); the component gas connecting pipe (64) is connected to one end of the discharge chamber (61), the exhaust connecting pipe (66) is connected to the other end of the discharge chamber (61), and the carrier gas connecting pipe (65) is connected to the component gas connecting pipe (64); two probes are arranged opposite to each other at the upper and lower ends of the discharge chamber (61); the composite electrode (67) is arranged in the cavity of the discharge chamber (61), and the vacuum pumping device (68) is connected to the exhaust connecting pipe (66).

[0035] Furthermore, the probe comprises: an optical interference filter, a photodiode, an amplifier, a conductive electrode and a shell; the optical interference filter, photodiode and amplifier are all encapsulated inside the shell, the optical interference filter, photodiode and amplifier are arranged in sequence along the negative direction of the y-axis, one end of the conductive electrode is connected to the amplifier, and the other end extends out of the shell.

[0036] Furthermore, the central axis of the component gas connecting pipe (64) and the central axis of the exhaust connecting pipe (66) are in a straight line.

[0037] Furthermore, the vacuum extraction device (68) comprises: a filter (81), a flat four-way connection (82), a first flat three-way connection (83), a one-way valve (84), a vacuum pump (85), a second flat three-way connection (86), a two-way ball valve (87), a pressure gauge (88), and a flow meter (89); the input end of the filter (81) is connected to the exhaust connection pipe (66), and the output end of the filter (81) is connected to the 1 of the flat four-way connection (82). # Interface connection, flat cross (82) 2 # Interface with the first flat tee (83) 1 # Interface connection, first plane tee (83) 2 # The interface is connected to the input end of the one-way valve (84), the output end of the one-way valve (84) is connected to the input end of the vacuum pump (85), and the output end of the vacuum pump (85) is connected to the 1 end of the second plane tee (86). # Interface connection, second plane tee (86) 2 # The interface is used as the output port of the vacuum pumping device, and the pressure gauge (88) is connected to the plane cross-connect (82) # The flow meter (89) is connected to the plane cross-way (82) by an interface. # Interface connection, first plane tee (83) 3 # Interface with two-way ball valve (87) 1 # Port connection, 2-way ball valve (87) # Interface with the second flat tee (86) 3 # Interface connection.

[0038] The advantages of the present invention are:

[0039] (1) The degassing device uses a fixed oil tank (7) and a first quantitative ring (16) to ensure the accuracy of sampling. The entire degassing process is carried out inside the degassing device without manual operation, thus avoiding interference errors caused by human operation. The device has strong stability, strong repeatability and high accuracy.

[0040] (2) The analysis tube (28) of the enrichment sampling device switches back and forth between the cooling device (24) and the heating device (25); the analysis tube (28) enters the cooling device (24) for low-temperature adsorption enrichment, and after enrichment, the analysis tube (28) enters the heating device (25) for high-temperature desorption, and the desorbed gas is input into the component separation device as the sample gas; after the dissolved gas in the transformer oil is enriched by adsorption and desorption, the concentration of the special gas dissolved in the transformer oil increases, which is beneficial to subsequent detection;

[0041] (3) The component separation device uses a central cutting analysis method to analyze the dissolved gas hydrogen, methane, carbon monoxide, carbon dioxide, ethylene, ethane, acetylene, propylene, propane, and propyne in the transformer oil by connecting and switching between the first switching valve (41), the second switching valve (45), the third switching valve (46), and the fourth switching valve (49) and the first chromatographic column (43), the second chromatographic column (44), the third chromatographic column (47), and the fourth chromatographic column (48), and there is no interference peak between the components;

[0042] (4) The component separation device is provided with a second quantitative loop (42) for sampling, thereby achieving accurate quantitative analysis, greatly reducing sampling errors, and achieving a sensitivity of μmol / mol level;

[0043] (5) The plasma detection device uses nitrogen as a carrier gas, which greatly reduces the cost of use; the plasma detection device is designed with a vacuum pumping device (68) to evacuate the plasma detection device before use, thereby solving the problem of impurity gases affecting the ionization effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a block diagram of a transformer oil dissolved gas detection system based on plasma detection according to an embodiment of the present invention;

[0045] Figure 2 1 is a schematic diagram of the structure of a degassing device without sample introduction in a transformer oil dissolved gas detection system based on plasma detection according to an embodiment of the present invention;

[0046] Figure 3 1 is a schematic diagram of the sampling structure of a degassing device of a transformer oil dissolved gas detection system based on plasma detection according to an embodiment of the present invention;

[0047] Figure 4 It is a working flow chart of a degassing device of a transformer oil dissolved gas detection system based on plasma detection according to an embodiment of the present invention;

[0048] Figure 5 is a structural diagram of an enrichment sampling device of a transformer oil dissolved gas detection system based on plasma detection according to an embodiment of the present invention;

[0049] Figure 6 1 is a schematic structural diagram of a component separation device of a detection system for dissolved gas in transformer oil based on plasma detection according to an embodiment of the present invention;

[0050] Figure 7 It is a schematic diagram of the sampling state of the component separation device of the transformer oil dissolved gas detection system based on plasma detection and the component state of analysis and detection of hydrogen, methane and carbon monoxide in an embodiment of the present invention;

[0051] Figure 8 It is a schematic diagram of analyzing and detecting the component states of ethylene, ethane and acetylene of a component separation device of a transformer oil dissolved gas detection system based on plasma detection according to an embodiment of the present invention;

[0052] Fig. 9 It is a schematic diagram of analyzing and detecting the component states of carbon dioxide, propylene, propane, and propyne in a component separation device of a detection system for dissolved gas in transformer oil based on plasma detection according to an embodiment of the present invention;

[0053] Fig.10 is a schematic diagram of carrier gas flow path analysis of a component separation device of a transformer oil dissolved gas detection system based on plasma detection according to an embodiment of the present invention;

[0054] Fig.11 It is a work flow chart of a component separation device of a transformer oil dissolved gas detection system based on plasma detection according to an embodiment of the present invention;

[0055] Fig.12 is a structural diagram of a nitrogen carrier gas plasma detection device of a transformer oil dissolved gas detection system based on plasma detection according to an embodiment of the invention;

[0056] Fig.13 It is a structural diagram of a vacuum pumping device of a transformer oil dissolved gas detection system based on plasma detection according to an embodiment of the present invention. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments:

[0059] Embodiment 1

[0060] like Figure 1As shown, a detection system for dissolved gas in transformer oil based on plasma detection comprises: a degassing device, an enrichment sampling device, a component separation device, and a plasma detection device; the output end of the degassing device is sealedly connected to the input end of the enrichment sampling device, the output end of the enrichment sampling device is sealedly connected to the input end of the component separation device, and the input end of the plasma detection device is sealedly connected to the detection port of the component separation device; the dissolved gas in the transformer oil is enriched and sampled after degassing, and the components of the enriched and sampled gas are separated and then detected by plasma discharge.

[0061] like Figure 2 As shown, the degassing device comprises: a nitrogen gas storage cylinder (1), a pressure reducing valve (2), a flat three-way valve (3), a two-way ball valve (4), a first three-way solenoid valve (5), a first recovery tank (6), a fixed oil tank (7), a second three-way solenoid valve (8), an oil pump (9), an oil storage tank (10), a six-way valve (11), a chromatographic injector (12), a third three-way solenoid valve (13), a degassing unit (14), a second recovery tank (15), a first quantitative ring (16), and an air pump (17); the fixed oil tank (7) is used to measure a certain volume of an oil sample to be tested; the chromatographic injector (12) is used to quantitatively inject a sample into a gas chromatograph; a heating rod and a platinum resistor are installed inside the degassing unit (14), the heating rod heats the oil sample to be tested to a certain temperature and stabilizes it, and the platinum resistor is used for real-time temperature measurement. The first quantitative ring (16) is used to measure a certain volume of characteristic gas.

[0062] The outlet of the nitrogen gas storage cylinder (1) is connected to the air inlet of the pressure reducing valve (2) through a pipeline, and the air outlet of the pressure reducing valve (2) is connected to the 1 of the flat tee (3) through a pipeline. # Interface, 2 of the flat tee (3) # The interface is connected to the air inlet of the two-way ball valve (4) through a pipeline, and the air outlet of the two-way ball valve (4) is connected to the 1st of the first three-way solenoid valve (5) through a pipeline. # Interface, 3 of the first three-way solenoid valve (5) # The interface is connected to the first recovery tank (6) through a pipeline, and the first three-way solenoid valve (5) is connected to the first recovery tank (6) through a pipeline. # The interface is connected to the air inlet of the fixed oil tank (7) through a pipeline, and the air outlet of the fixed oil tank (7) is connected to the 1 of the second three-way solenoid valve (8) through a pipeline. # Interface, the second three-way solenoid valve (8) 2 # The interface is connected to the air inlet of the oil pump (9) through a pipeline, and the air outlet of the oil pump (9) is connected to the oil storage tank (10) through a pipeline. The 3 #The interface is connected to the lower interface of the degassing unit (14) through a pipeline, and the upper interface of the degassing unit (14) is connected to the 1st of the third three-way solenoid valve (13) through a pipeline. # Interface, 3rd 3-way solenoid valve (13) # The interface is connected to the air pump (17) through a pipeline, and the plane tee (3) is 3 # The interface is connected to the 6-way valve (11) through a pipe. # Port, 1 of 6-way valve (11) # The port is connected to the chromatographic injector (12) through a pipeline, and one end of the first quantitative loop (16) is connected to the two ends of the six-way valve (11) through a pipeline. # The other end of the first quantitative ring (16) is connected to the 5 port of the six-way valve (11) through a pipeline. # Port connection, 3 of the six-way valve (11) # The port is connected to the 2nd port of the third three-way solenoid valve (13) through a pipe. # Interface, 6-way valve (11) 4 # The outlet is connected to the second recovery tank (15) through a pipeline.

[0063] like Figure 4 As shown, the working process of the degassing device is as follows:

[0064] Step 1: Rinse the oil tank

[0065] like Figure 2 As shown, the two-way ball valve (4) is closed, and the oil pump (9) is started to extract the oil sample to be tested from the oil storage tank (10) into the fixed oil tank (7), and the fixed oil tank (7) and its affiliated pipelines are flushed. The waste oil after flushing flows into the first recovery tank (6) through the first three-way solenoid valve (5) for recovery.

[0066] Step 2: Take the oil sample to be tested from the oil tank

[0067] like Figure 2 As shown, the first three-way solenoid valve (5) is closed, and the oil pump (9) is started to extract a volume V1 of the oil sample to be tested from the oil storage tank (10) and inject it into the fixed oil tank (7).

[0068] Step 3: Degassing the oil sample to be tested

[0069] like Figure 2 As shown, the two-way ball valve (4) is opened and closed, and the nitrogen in the nitrogen storage bottle (1) carries the oil sample to be tested with a volume V1 in the fixed oil tank (7) into the degassing unit (14) through the second three-way solenoid valve (8), and the oil sample to be tested entering the degassing unit (14) is heated to a certain temperature for oil-gas separation and degassing. At this time, the role of the nitrogen is to replace the characteristic gas dissolved in the oil sample.

[0070] Step 4: Quantitative loop sampling of characteristic gases

[0071] The third three-way solenoid valve (13) is opened, and the characteristic gas flows out from the interface at the top of the degassing unit (14), passes through the third three-way solenoid valve (13), the six-way valve (11) and the # 2 of the six-way valve (11) # After being discharged from the outlet, the liquid is stored in the first quantitative ring (16).

[0072] Step 5: The characteristic gas is injected into the chromatograph through the chromatographic injector for detection

[0073] Switch the six-way valve (11) to Figure 3 In the state shown, the nitrogen in the nitrogen storage cylinder (1) passes through the flat three-way valve (3) and the six-way valve (11). # 5 of the six-way valve (11) # After entering the first quantitative ring (16), it passes through the 2 ports of the six-way valve (11) together with the characteristic gas. # 1 of the six-way valve (11) # After entering the chromatographic instrument through the chromatographic injector (12), the sample is detected.

[0074] Step 6: Air purge to recover oil sample after oil and gas separation

[0075] After the detection is completed, the third three-way solenoid valve (13) is opened, and the air pump (17) is turned on. Air enters from the upper interface of the degassing unit (14) and then exits from the lower interface of the degassing unit (14). The air carries the oil sample after degassing in the degassing unit (14) to the second three-way solenoid valve (8), the fixed oil tank (7), the first three-way solenoid valve (5), and then to the first recovery tank (6).

[0076] Step 7: Purge the entire device with nitrogen

[0077] Switch the six-way valve (11) to Figure 2 In the state shown, the two-way ball valve (4) is opened, and the nitrogen in the nitrogen storage cylinder (1) passes through the pressure reducing valve (2), the flat three-way valve (3), the two-way ball valve (4), the first three-way solenoid valve (5), the fixed oil tank (7), and the second three-way solenoid valve (8), and enters from the lower interface of the degassing unit (14), and then exits from the upper interface of the degassing unit (14), passes through the third three-way solenoid valve (13), and the three-way valve of the six-way valve (11). # 2 of the six-way valve (11) # port, the first quantitative ring (16), the 5 # 4 of the six-way valve (11) # The outlet is sent to the second recovery tank (15), and after nitrogen purging for a period of time, steps one to seven are recycled.

[0078] like Figure 5 As shown, the enrichment sampling device includes: a base (21), a sliding block (22), a screw transmission device (23), a cooling device (24), a heating device (25), a decomposition tube moving guide rail (26), a decomposition tube mounting frame (27), a decomposition tube (28), a connecting piece (29), and a mounting bracket (30). The cooling device (24) and the heating device (25) are aligned and arranged above the base (21), and one end of the cooling device (24) and the heating device (25) are provided with a first slot (32); the temperature control range of the cooling device (24) is -20℃~25℃, and the temperature control range of the heating device (25) is 50℃~400℃; the middle of the decomposition tube moving guide rail (26) is provided with a second slot (33), and there are two decomposition tube moving guide rails (26), which are respectively fixedly mounted in parallel on the cooling device ( 24) and both sides of the heating device (25); the second slot (33) opened in the middle of the desorption tube moving guide rail (26) matches the first slot (32) opened at the ends of the cooling device (24) and the heating device (25); both ends of the desorption tube mounting frame (27) are provided with a bayonet (34), and the bayonet (34) matches the second slot (33) opened in the middle of the desorption tube moving guide rail (26); the desorption tube (28) is filled with a medium for absorbing gas dissolved in transformer oil; the desorption tube (28) ) are clamped on the bayonet (34) at both ends of the analytical tube mounting frame (27); the analytical tube (28) is a columnar tube with a length of 80 mm and an outer diameter of 6 mm; the interior of the analytical tube (28) is used to accommodate the sample; the screw transmission device (23) is transversely fixed to the base (21) through the mounting bracket (30); the transmission end of the screw transmission device (23) is fixedly connected to the middle of the connecting member (29); the lower end of the connecting member (29) is fixedly connected to the sliding block (22); the upper end of the connecting member (29) is fixedly connected to the sliding block (22); The base (21) is fixedly connected to one end of the analysis tube mounting frame (27), the other end of the analysis tube mounting frame (27) spans the cooling device (24) and the heating device (25), and the bayonet (34) at the other end of the analysis tube mounting frame (27) matches with a second slot (33) provided in the middle of the analysis tube moving guide rail (26) fixed on the back of the cooling device (24) and the heating device (25); a limit slide groove (31) is provided laterally below the base (21), and the sliding block (22) is installed in the limit slide groove (31).

[0079] The working principle of the enrichment sampling device is as follows:

[0080] The driving end of the screw drive device (23) drives the connecting member (29) to reciprocate left and right, and the lower end of the connecting member (29) drives the sliding block (22) to reciprocate left and right in the limiting sliding groove (31). At the same time, the upper end of the connecting member (29) drives the analysis tube mounting frame (27), and the analysis tube mounting frame (27) drives the analysis tube (28) clamped on the clamping holes (34) at both ends to reciprocate left and right in the second slot (33) opened in the middle of the analysis tube moving guide rail (26); the analysis tube (28) moves to the left and enters the first slot (32) at the end of the cooling device (24) for low-temperature adsorption. The medium filled in the analysis tube (28) has enhanced adsorption capacity at low temperature, and can adsorb more dissolved gas in the transformer oil, thereby enriching the low-concentration dissolved gas; after enrichment, the analysis tube (28) moves to the right and enters the first slot (32) at the end of the heating device (25) for high-temperature desorption, and the desorbed gas is introduced to the injection end of the gas chromatograph as the sample gas.

[0081] like Figure 6 As shown, the component separation device comprises: a first switching valve (41), a second quantitative ring (42), a first chromatographic column (43), a second chromatographic column (44), a second switching valve (45), a third switching valve (46), a third chromatographic column (47), a fourth chromatographic column (48), a fourth switching valve (49), a first plane tee (50), a second plane tee (51), a third plane tee (52), a fourth plane tee (53), a fifth plane tee (54), a sixth plane tee (55), a seventh plane tee (56), a first needle valve (57), a second needle valve (58), and a third needle valve (59); the first switching valve (41) is a ten-way switching valve, the second switching valve (45) is a four-way switching valve, the third switching valve (46) is a ten-way switching valve, and the fourth switching valve (49) is a four-way switching valve; the first chromatographic column (43), the second chromatographic column (44), and the fourth chromatographic column (48) are all polymer chromatographic columns, and the third chromatographic column (47) is a molecular sieve chromatographic column.

[0082] Port 1 of the first switching valve (41) is connected to the injection port, port 10 of the first switching valve (41) is connected to the input port of the second quantitative ring (42), the output port of the second quantitative ring (42) is connected to port 3 of the first switching valve (41), port 2 of the first switching valve (41) is connected to the sample outlet, port 4 of the first switching valve (41) is connected to port 2 of the fourth flat three-way (53), and the output port of the second quantitative ring (42) is connected to port 3 of the first switching valve (41). # The interface is connected, the No. 5 port of the first switching valve (41) is connected to the output end of the first chromatographic column (43), the input end of the first chromatographic column (43) is connected to the No. 9 port of the first switching valve (41), and the No. 7 port of the first switching valve (41) is connected to the No. 3 port of the third plane tee (52). # The interface is connected between port 8 of the first switching valve (41) and port 2 of the first needle valve (57).# The interface is connected, port 6 of the first switching valve (41) is connected to the input end of the second chromatographic column (44); the output end of the second chromatographic column (44) is connected to port 2 of the second switching valve (45); port 3 of the second switching valve (45) is connected to port 1 of the third switching valve (46); port 4 of the second switching valve (45) is connected to port 3 of the fifth flat tee (54); # The interface is connected, the No. 5 port of the second switching valve (45) is connected to the No. 6 port of the second switching valve (45), and the No. 1 port of the second switching valve (45) is connected to the No. 3 port of the sixth plane three-way (55). # Interface connection; port 2 of the third switching valve (46) is connected to the input end of the fourth chromatographic column (48), the output end of the fourth chromatographic column (48) is connected to port 5 of the third switching valve (46), and port 3 of the third switching valve (46) is connected to port 1 of the fourth planar tee (53). # The interface is connected between port 4 of the third switching valve (46) and port 2 of the second needle valve (58). # The interface is connected between the No. 6 port of the third switching valve (46) and the No. 2 port of the sixth flat tee (55). # The interface is connected, the port 7 of the third switching valve (46) is connected to the output end of the third chromatographic column (47), the input end of the third chromatographic column (47) is connected to the port 10 of the third switching valve (46), and the port 8 of the third switching valve (46) is connected to the port 2 of the third needle valve (59). # The interface is connected between the No. 9 port of the third switching valve (46) and the No. 2 port of the fifth flat tee (54). # The fourth switching valve (49) is connected to the carrier gas device through port 1, and the fourth switching valve (49) is connected to the second plane tee (51) through port 2. # The interface is connected between the No. 3 port of the fourth switching valve (49) and the No. 3 port of the first plane tee (50). # The No. 4 port of the fourth switching valve (49) is connected to the exhaust gas recovery device; the No. 1 port of the first plane tee (50) is connected to the exhaust gas recovery device; # Interface with the seventh plane tee (56) 1 # Interface connection, first plane tee (50) 2 # Interface with the first needle valve (57) 1 # Interface connection, second plane tee (51) 1 # Interface with the fifth plane tee (54) 1 # Interface connection, second plane tee (51) 2 # Interface with the third plane tee (52) 1 # Interface connection, third plane tee (52) 2 # Interface with the fourth plane tee (53) 3 # Interface connection, sixth plane tee (55) 1# The interface is connected to the detection port, the detection port is connected to the plasma detector, and the seventh plane tee (56) is 2 # Interface with the second needle valve (58) 1 # Interface connection, seventh plane tee (56) 3 # Interface with the third needle valve (59) 1 # Interface connection.

[0083] The path of the carrier gas flow of the component separation device is as follows:

[0084] like Fig.10 As shown, before the sample enters the device, the entire device is filled with carrier gas. In this embodiment, nitrogen is selected as the carrier gas. The carrier gas has three functions: the first is to protect the first chromatographic column (43), the second chromatographic column (44), the third chromatographic column (47), and the fourth chromatographic column (48); the second is to carry out the components separated from the first chromatographic column (43), the second chromatographic column (44), the third chromatographic column (47), and the fourth chromatographic column (48); and the third is to carry out the exhaust gas in the device after the detection is completed and input it into the exhaust gas treatment device for treatment.

[0085] (1) The path of the first carrier gas flow is as follows:

[0086] Port 1 of the fourth switching valve (49) → Port 2 of the fourth switching valve (49) → Port 3 of the second flat tee (51) # Interface → Second plane tee (51) 2 # Interface → Third plane tee (52) 1 # Interface → Third plane tee (52) 3 # Interface → Port No. 7 of the first switching valve (41) → Port No. 6 of the first switching valve (41) → Second chromatographic column (44) → Port No. 2 of the second switching valve (45) → Port No. 3 of the second switching valve (45) → Port No. 1 of the third switching valve (46) → Port No. 10 of the third switching valve (46) → Third chromatographic column (47) → Port No. 7 of the third switching valve (46) → Port No. 6 of the third switching valve (46) → Port No. 2 of the sixth flat tee (55) # Interface → Sixth plane tee (55) 1 # Interface → plasma detector;

[0087] (2) The path of the second carrier gas flow is as follows:

[0088] Port 1 of the fourth switching valve (49) → Port 2 of the fourth switching valve (49) → Port 3 of the second flat tee (51) # Interface → Second plane tee (51) 2 # Interface → Third plane tee (52) 1 #Interface → Third plane tee (52) 2 # Interface → 3 of the fourth plane tee (53) # Interface → 2 of the fourth plane tee (53) # Interface → Port 4 of the first switching valve (41) → Port 5 of the first switching valve (41) → First chromatographic column (43) → Port 9 of the first switching valve (41) → Port 8 of the first switching valve (41) → Port 2 of the first needle valve (57) # Interface → 1st needle valve (57) # Interface → First plane tee (50) 2 # Interface → First plane tee (50) 3 # Interface→Port No. 3 of the fourth switching valve (49)→Port No. 4 of the fourth switching valve (49)→Exhaust gas treatment device;

[0089] (3) The path of the third carrier gas flow is as follows:

[0090] Port 1 of the fourth switching valve (49) → Port 2 of the fourth switching valve (49) → Port 3 of the second flat tee (51) # Interface → 1 of the second plane tee (51) # Interface → Fifth plane tee (54) 1 # Interface → Fifth plane tee (54) 3 # Interface → Port 4 of the second switching valve (45) → Port 5 of the second switching valve (45) → Port 6 of the second switching valve (45) → Port 1 of the second switching valve (45) → Port 3 of the sixth flat tee (55) # Interface → Sixth plane tee (55) 1 # Interface → plasma detector;

[0091] (4) The path of the fourth carrier gas flow is as follows:

[0092] Port 1 of the fourth switching valve (49) → Port 2 of the fourth switching valve (49) → Port 3 of the second flat tee (51) # Interface → 1 of the second plane tee (51) # Interface → Fifth plane tee (54) 1 # Interface → Port 9 of the third switching valve (46) → Port 8 of the third switching valve (46) → Port 2 of the third needle valve (59) # Interface → 1 of the third needle valve (59) # Interface → Seventh plane tee (56) 3 # Interface → Seventh plane tee (56) 1 # Interface → 1st flat tee (50) # Interface → First plane tee (50) 3 #Interface→Port No. 3 of the fourth switching valve (49)→Port No. 4 of the fourth switching valve (49)→Exhaust gas treatment device;

[0093] (5) The path of the fifth carrier gas flow is as follows:

[0094] Port 1 of the fourth switching valve (49) → Port 2 of the fourth switching valve (49) → Port 3 of the second flat tee (51) # Interface → Second plane tee (51) 2 # Interface → Third plane tee (52) 1 # Interface → Third plane tee (52) 2 # Interface → 3 of the fourth plane tee (53) # Interface → 1 of the fourth plane tee (53) # Interface → Port 3 of the third switching valve (46) → Port 2 of the third switching valve (46) → Fourth chromatographic column (48) → Port 5 of the third switching valve (46) → Port 4 of the third switching valve (46) → Port 2 of the second needle valve (58) # Interface → 1 of the second needle valve (58) # Interface → Seventh plane tee (56) 2 # Interface → Seventh plane tee (56) 1 # Interface → 1st flat tee (50) # Interface → First plane tee (50) 3 # Interface→Port No. 3 of the fourth switching valve (49)→Port No. 4 of the fourth switching valve (49)→Exhaust gas treatment device.

[0095] The working process of the component separation device is as follows:

[0096] like Fig.11 As shown, the working process of the device includes the following processes:

[0097] (1) Sampling process

[0098] like Figure 6 As shown, the first switching valve (41) is switched, and port No. 1 of the first switching valve (41) is connected to port No. 10, and port No. 2 of the first switching valve (41) is connected to port No. 3. The sample enters from the sample inlet, passes through port No. 1 of the first switching valve (41), port No. 10 of the first switching valve (41), the second quantitative ring (42), and port No. 3 of the first switching valve (41) in sequence, and finally flows from port No. 2 of the first switching valve (41) to the sample outlet. In this process, the second quantitative ring (42) stores a certain amount of sample to complete sampling.

[0099] (2) Sample pre-separation process

[0100] like Figure 7As shown, the first switching valve (41) is switched, and the second carrier gas passes through port No. 4 of the first switching valve (41), port No. 3 of the first switching valve (41), the second quantitative ring (42), port No. 10 of the first switching valve (41), and port No. 9 of the first switching valve (41) in sequence, carrying the sample stored in the second quantitative ring (42) into the first chromatographic column (43); the sample is pre-separated in the first chromatographic column (43), and the pre-separated sample flows through port No. 5 of the first switching valve (41) and port No. 6 of the first switching valve (41) to the second chromatographic column (44) to be separated into three combined peaks, and the order in which the three combined peaks flow out of the second chromatographic column (44) is: hydrogen, methane, carbon monoxide combined peak, carbon dioxide, ethylene, ethane, acetylene combined peak, and propylene, propane, and propyne combined peak.

[0101] A plasma detector is connected to the detection port of the device to detect the component contents of the three combined peaks. The processes are as follows:

[0102] (3) Process of detecting the combined peak of hydrogen, methane and carbon monoxide

[0103] like Figure 7 As shown, the combined peak of hydrogen, methane and carbon monoxide first flows out from the second chromatographic column (44), passes through port 2 of the second switching valve (45), port 3 of the second switching valve (45), port 1 of the third switching valve (46), and port 10 of the third switching valve (46) to the third chromatographic column (47), is separated into hydrogen, methane and carbon monoxide again in the third chromatographic column (47), and then flows through port 7 of the third switching valve (46) and port 6 of the third switching valve (46) to port 2 of the sixth flat tee (55). # Interface, sixth plane tee (55) 1 # The gas then flows into the plasma detector to detect the content of hydrogen, methane and carbon monoxide.

[0104] (4) The process of detecting the combined peak of carbon dioxide, ethylene, ethane and acetylene

[0105] After the combined peak of hydrogen, methane and carbon monoxide is detected, Figure 8 The third switching valve (46) is switched as shown, and the first carrier gas carrying the combined peak of carbon dioxide, ethylene, ethane and acetylene flows out of the second chromatographic column (44), passes through port No. 2 of the second switching valve (45), port No. 3 of the second switching valve (45), port No. 1 of the third switching valve (46), and port No. 2 of the third switching valve (46) to flow to the fourth chromatographic column (48), and is separated into carbon dioxide, ethylene, ethane and acetylene again in the fourth chromatographic column (48), and then flows through port No. 5 of the third switching valve (46) and port No. 6 of the third switching valve (46) to port 2 of the sixth flat tee (55). # Interface, sixth plane tee (55) 1 #The gas then flows into the plasma detector to detect the component contents of carbon dioxide, ethylene, ethane and acetylene.

[0106] (5) Detection of the combined peak of propylene, propane and propyne

[0107] After the combined peak of carbon dioxide, ethylene, ethane and acetylene is detected, Fig. 9 The second switching valve (45) is switched as shown, and the first carrier gas carrying the propylene, propane and propyne peak is separated into propylene, propane and propyne in the second chromatographic column (44), and flows through the No. 2 port of the second switching valve (45) and the No. 1 port of the second switching valve (45) to the No. 3 port of the sixth plane tee (55). # Interface, sixth plane tee (55) 1 # The gas flows into the plasma detector to detect the content of propylene, propane and propyne.

[0108] like Fig.12 As shown, the plasma detection device comprises: a discharge chamber (61), a first probe (62), a second probe (63), a component gas connecting pipe (64), a carrier gas connecting pipe (65), and a carrier gas connecting pipe (66); the component gas connecting pipe (64) is connected to the left end of the discharge chamber (61), and the carrier gas connecting pipe (66) is connected to the right end of the discharge chamber (61), and the central axis of the component gas connecting pipe (64) and the central axis of the carrier gas connecting pipe (66) are on a straight line; the carrier gas connecting pipe (65) is connected to the component gas connecting pipe (64); the first probe (62) and the second probe (63) are respectively arranged at the upper and lower ends of the discharge chamber (61). A composite electrode (67) is arranged in the cavity of the discharge chamber (61), and a high-frequency and high-intensity electromagnetic field is loaded on the composite electrode (67). Under the action of the high-frequency and high-intensity electromagnetic field, the mixed gas of the nitrogen carrier gas and the component gas is ionized into a high-energy plasma.

[0109] The structures of the first probe (62) and the second probe (63) are completely the same. The first probe (62) comprises: an optical interference filter (621), a photodiode (622), an amplifier (623), a conductive electrode (624) and a shell (625). The optical interference filter (621), the photodiode (622) and the amplifier (623) are all encapsulated inside the shell (625). The optical interference filter (621), the photodiode (622) and the amplifier (623) are arranged in sequence along the negative direction of the y-axis. One end of the conductive electrode (624) is connected to the amplifier (623), and the other end extends out of the shell (625) and is connected to the gas chromatograph through a signal line.

[0110] The working process of the plasma detection device is as follows:

[0111] The component gas and the nitrogen carrier gas enter the discharge chamber (61) from the component gas connecting pipe (64) and the carrier gas connecting pipe (65) respectively for ionization. The ionization signal is filtered by the optical interference filter (621) and then enters the photodiode (622) for photoelectric signal conversion. The electrical signal is amplified by the amplifier (623) and then transmitted from the conductive electrode (624) to the gas chromatograph for signal processing.

[0112] In order to prevent other impurity gases from affecting the ionization effect of the carrier gas, this embodiment also provides a vacuum pumping device, such as Fig.13 As shown, the vacuum pumping device (68) comprises: a filter (81), a plane four-way (82), a first plane three-way (83), a one-way valve (84), a vacuum pump (85), a second plane three-way (86), a two-way ball valve (87), a pressure gauge (88), and a flow meter (89); the input end of the filter (81) is connected to the carrier gas connecting pipe (66), and the output end of the filter (81) is connected to the 1 of the plane four-way (82). # Interface connection, flat cross (82) 2 # Interface with the first flat tee (83) 1 # Interface connection, first plane tee (83) 2 # The interface is connected to the input end of the one-way valve (84), the output end of the one-way valve (84) is connected to the input end of the vacuum pump (85), and the output end of the vacuum pump (85) is connected to the 1 end of the second plane tee (86). # Interface connection, second plane tee (86) 2 # The interface is used as the output port of the vacuum pumping device, and the pressure gauge (88) is connected to the plane cross-connect (82) # The flow meter (89) is connected to the plane cross-way (82) by an interface. # Interface connection, first plane tee (83) 3 # Interface with two-way ball valve (87) 1 # Port connection, 2-way ball valve (87) # Interface with the second flat tee (86) 3 # Interface connection.

[0113] The working process of the vacuum pumping device is as follows:

[0114] The input end of the filter (81) is sealedly connected to the carrier gas connecting pipe (66), the two-way ball valve (87) is closed, and the vacuum pump (85) is started to evacuate the air; the air flow path for evacuating the air is: carrier gas connecting pipe (66) → filter (81) → flat four-way (82) → first flat three-way (83) → one-way valve (84) → vacuum pump (85) → second flat three-way (86) → exhaust port.

[0115] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A transformer oil dissolved gas detection system based on plasma detection, characterized in that: include: A degassing device, an enrichment sampling device, a component separation device and a plasma detection device; the output end of the degassing device is sealedly connected to the input end of the enrichment sampling device, the output end of the enrichment sampling device is sealedly connected to the input end of the component separation device, and the input end of the plasma detection device is sealedly connected to the detection port of the component separation device; the degassing device extracts a quantitative oil sample to be tested and injects it into a fixed oil tank, then degasses the quantitative oil sample to be tested in the fixed oil tank, and the degassed characteristic gas is stored in a quantitative loop, and then the characteristic gas is output to the enrichment sampling device by nitrogen; the desorption tube of the enrichment sampling device switches back and forth between low temperature and high temperature, the desorption tube performs adsorption enrichment at low temperature, and the desorption tube performs high-temperature desorption after enrichment, and the desorbed gas is input into the component separation device as a sample gas; The component separation device separates the input characteristic gas into different combined peaks through the connection and switching of multiple switching valves and chromatographic columns, and uses a plasma detection device for analysis and detection; In the enrichment sampling device, a limited sliding groove (31) is provided below the base (21), a cooling device (24) and a heating device (25) are aligned and arranged above the base (21), a first slot (32) is provided at one end of the cooling device (24) and the heating device (25), and the first slot (32) of the cooling device (24) and the first slot (32) of the heating device (25) are arranged opposite to each other; the sliding block (22) is installed in the limited sliding groove (31), and the screw transmission device (23) is fixed to the base (21) through the mounting bracket (30); the transmission end of the screw transmission device (23) is fixedly connected to the middle of the connecting member (29), and the lower end of the connecting member (29) is connected to the sliding block The connecting member (29) is fixedly connected to the cooling device (24) and the heating device (25), the upper end of the connecting member (29) is fixedly connected to one end of the analysis tube mounting frame (27), the other end of the analysis tube mounting frame (27) spans the cooling device (24) and the heating device (25), and the analysis tube (28) is stuck in the analysis tube mounting frame (27); the screw transmission device (23) drives the connecting member (29) to reciprocate, the lower end of the connecting member (29) drives the sliding block (22) to reciprocate left and right in the limiting sliding groove (31), and at the same time, the upper end of the connecting member (29) drives the analysis tube mounting frame (27), thereby driving the analysis tube (28) to switch back and forth between the first slot (32) of the cooling device (24) and the first slot (32) of the heating device (25).

2. The transformer oil dissolved gas detection system based on plasma detection according to claim 1, characterized in that: The degassing device comprises: a nitrogen gas storage cylinder (1), a pressure reducing valve (2), a flat three-way connection (3), a two-way ball valve (4), a first three-way solenoid valve (5), a first recovery tank (6), an oil tank (7), a second three-way solenoid valve (8), an oil pump (9), an oil storage tank (10), a six-way valve (11), a chromatographic injector (12), a third three-way solenoid valve (13), a degassing unit (14), a second recovery tank (15), a first quantitative ring (16) and an air pump (17); the outlet of the nitrogen gas storage cylinder (1) is connected to the air inlet of the pressure reducing valve (2), the air outlet of the pressure reducing valve (2) is connected to the first interface of the flat three-way connection (3), the second interface of the flat three-way connection (3) is connected to the air inlet of the two-way ball valve (4), and the air outlet of the two-way ball valve (4) is connected to the first three-way solenoid valve The first interface of the first three-way solenoid valve (5) is connected to the first recovery tank (6), the second interface of the first three-way solenoid valve (5) is connected to the air inlet of the fixed oil tank (7), the air outlet of the fixed oil tank (7) is connected to the first interface of the second three-way solenoid valve (8), the second interface of the second three-way solenoid valve (8) is connected to the air inlet of the oil pump (9), the air outlet of the oil pump (9) is connected to the oil storage tank (10), the third interface of the second three-way solenoid valve (8) is connected to the lower interface of the degassing unit (14), the upper interface of the degassing unit (14) is connected to the first interface of the third three-way solenoid valve (13), the third interface of the third three-way solenoid valve (13) is connected to the air pump (17), and the third interface of the plane three-way (3) is connected to the 6 of the six-way valve (11). # Port, 1 of 6-way valve (11) # The first quantitative loop (16) is connected to the chromatograph sample injector (12), and one end of the first quantitative loop (16) is connected to the 2 end of the six-way valve (11). # The other end of the first quantitative ring (16) is connected to the 5th port of the six-way valve (11). # Port connection, 3 of the six-way valve (11) # The port is connected to the second port of the third three-way solenoid valve (13), and the 4th port of the six-way valve (11) is connected to the second port of the third three-way solenoid valve (13). # The port is connected to the second recovery tank (15).

3. The transformer oil dissolved gas detection system based on plasma detection according to claim 2, characterized in that: The working process of the degassing device includes: S11, flushing the fixed oil tank; closing the two-way ball valve (4), starting the oil pump (9) to extract the oil sample to be tested from the oil storage tank (10) into the fixed oil tank (7), flushing the fixed oil tank (7) and its affiliated pipelines, and the waste oil after flushing flows into the first recovery tank (6) through the first three-way solenoid valve (5) for recovery; S12, taking the oil sample to be tested from the fixed oil tank; closing the first three-way solenoid valve (5), starting the oil pump (9) to extract a fixed amount of the oil sample to be tested from the oil storage tank (10) and injecting it into the fixed oil tank (7); S13, degassing the oil sample to be tested; opening and closing the two-way ball valve (4), the nitrogen in the nitrogen storage bottle (1) carries a fixed amount of the oil sample to be tested in the fixed oil tank (7) into the degassing unit (14) through the second three-way solenoid valve (8), and the oil sample to be tested entering the degassing unit (14) is heated to a certain temperature for oil-gas separation and degassing. At this time, the role of the nitrogen is to replace the characteristic gas dissolved in the oil sample; S14, taking characteristic gas in a quantitative loop; opening the third three-way solenoid valve (13), the characteristic gas flows out from the interface at the top of the degassing unit (14), passes through the third three-way solenoid valve (13), the six-way valve (11) and the 3 # 2 of the six-way valve (11) # After passing through the mouth, the liquid is stored in a first quantitative ring (16); S15, nitrogen carries characteristic gas for output detection; the nitrogen in the nitrogen storage bottle (1) passes through the flat three-way valve (3) and the six-way valve (11) # 5 of the six-way valve (11) # After entering the first quantitative ring (16), it passes through the 2 ports of the six-way valve (11) together with the characteristic gas. # 1 of the six-way valve (11) # After the sample is injected into the chromatograph through the chromatographic injector (12) for detection; S16, air purge to recover the oil sample after oil and gas separation; open the third three-way solenoid valve (13), start the air pump (17), and let the air enter from the upper interface of the degassing unit (14) and then leave from the lower interface of the degassing unit (14). The air carries the oil sample after degassing in the degassing unit (14) to the second three-way solenoid valve (8), the fixed oil tank (7), the first three-way solenoid valve (5), and then to the first recovery tank (6); S17, nitrogen purges the entire device; open the two-way ball valve (4), the nitrogen in the nitrogen storage bottle (1) passes through the pressure reducing valve (2), the flat three-way (3), the two-way ball valve (4), the first three-way solenoid valve (5), the fixed oil tank (7), the second three-way solenoid valve (8), enters from the lower interface of the degassing unit (14), and then exits from the upper interface of the degassing unit (14), passes through the third three-way solenoid valve (13), the three-way valve of the six-way valve (11), and enters from the lower interface of the degassing unit (14). # 2 of the six-way valve (11) # port, the first quantitative ring (16), the 5 # 4 of the six-way valve (11) # The outlet is directed to the second recovery tank (15).

4. The transformer oil dissolved gas detection system based on plasma detection according to claim 1, characterized in that: The desorption tube (28) moves to the left and enters the first slot (32) at the end of the cooling device (24) to perform low-temperature adsorption. The medium filled in the desorption tube (28) has enhanced adsorption capacity at low temperatures, and adsorbs dissolved gas in the transformer oil, thereby enriching low-concentration dissolved gas. After enrichment, the desorption tube (28) moves to the right and enters the first slot (32) at the end of the heating device (25) to perform high-temperature desorption.

5. The transformer oil dissolved gas detection system based on plasma detection according to claim 4, characterized in that: The enrichment sampling device also includes: a desorption tube moving guide rail (26); there are two desorption tube moving guide rails (26), which are respectively fixedly mounted in parallel on both sides of the cooling device (24) and the heating device (25).

6. The transformer oil dissolved gas detection system based on plasma detection according to claim 5, characterized in that: A second slot (13) is provided in the middle of the analytical tube moving guide rail (26), and the second slot (13) matches the first slot (32) of the cooling device (24) and the first slot (32) of the heating device (25). The analytical tube (28) reciprocates in the second slot (13) provided in the middle of the moving guide rail (6).

7. The transformer oil dissolved gas detection system based on plasma detection according to claim 6, characterized in that: Both ends of the analysis tube mounting frame (27) are provided with bayonet holes (34), which match with a second slot (13) provided in the middle of the analysis tube moving guide rail (26), and both ends of the analysis tube (28) are clamped on the bayonet holes (34) at both ends of the analysis tube mounting frame (27).

8. The transformer oil dissolved gas detection system based on plasma detection according to claim 1, characterized in that: The component separation device comprises: a first switching valve (41), a second quantitative ring (42), a first chromatographic column (43), a second chromatographic column (44), a second switching valve (45), a third switching valve (46), a third chromatographic column (47), a fourth chromatographic column (48), a fourth switching valve (49), a first plane tee (50), a second plane tee (51), a third plane tee (52), a fourth plane tee (53), a fifth plane tee (54), a sixth plane tee (55), a seventh plane tee (56), a first needle valve (57), a second needle valve (58) and a third The needle valve (59) is a ten-way switching valve, the second switching valve (45) is a four-way switching valve, the third switching valve (46) is a ten-way switching valve, and the fourth switching valve (49) is a four-way switching valve; port 1 of the first switching valve (41) is connected to the injection port, port 10 of the first switching valve (41) is connected to the input port of the second quantitative ring (42), the output port of the second quantitative ring (42) is connected to port 3 of the first switching valve (41), port 2 of the first switching valve (41) is connected to the sample outlet, port 4 of the first switching valve (41) is connected to port 2 of the fourth flat three-way (53), and the output port of the second quantitative ring (42) is connected to port 3 of the first switching valve (41). # The interface is connected, the No. 5 port of the first switching valve (41) is connected to the output end of the first chromatographic column (43), the input end of the first chromatographic column (43) is connected to the No. 9 port of the first switching valve (41), and the No. 7 port of the first switching valve (41) is connected to the No. 3 port of the third plane tee (52). # The interface is connected between port 8 of the first switching valve (41) and port 2 of the first needle valve (57). # The interface is connected, port 6 of the first switching valve (41) is connected to the input end of the second chromatographic column (44); the output end of the second chromatographic column (44) is connected to port 2 of the second switching valve (45); port 3 of the second switching valve (45) is connected to port 1 of the third switching valve (46); port 4 of the second switching valve (45) is connected to port 3 of the fifth flat tee (54); # The interface is connected, the No. 5 port of the second switching valve (45) is connected to the No. 6 port of the second switching valve (45), and the No. 1 port of the second switching valve (45) is connected to the No. 3 port of the sixth plane three-way (55). # Interface connection; port 2 of the third switching valve (46) is connected to the input end of the fourth chromatographic column (48), the output end of the fourth chromatographic column (48) is connected to port 5 of the third switching valve (46), and port 3 of the third switching valve (46) is connected to port 1 of the fourth planar tee (53). # The interface is connected between port 4 of the third switching valve (46) and port 2 of the second needle valve (58). # The interface is connected between the No. 6 port of the third switching valve (46) and the No. 2 port of the sixth flat tee (55). # The interface is connected, the port 7 of the third switching valve (46) is connected to the output end of the third chromatographic column (47), the input end of the third chromatographic column (47) is connected to the port 10 of the third switching valve (46), and the port 8 of the third switching valve (46) is connected to the port 2 of the third needle valve (59). # The interface is connected between the No. 9 port of the third switching valve (46) and the No. 2 port of the fifth flat tee (54). # Interface connection; port 1 of the fourth switching valve (49) is connected to the carrier gas port, and port 2 of the fourth switching valve (49) is connected to port 3 of the second plane tee (51). # The interface is connected between the No. 3 port of the fourth switching valve (49) and the No. 3 port of the first plane tee (50). # The interface is connected, the No. 4 port of the fourth switching valve (49) is connected to the exhaust port; the No. 1 port of the first plane tee (50) is connected to the exhaust port; # Interface with the seventh plane tee (56) 1 # Interface connection, first plane tee (50) 2 # Interface with the first needle valve (57) 1 # Interface connection, second plane tee (51) 1 # Interface with the fifth plane tee (54) 1 # Interface connection, second plane tee (51) 2 # Interface with the third plane tee (52) 1 # Interface connection, third plane tee (52) 2 # Interface with the fourth plane tee (53) 3 # Interface connection, sixth plane tee (55) 1 # The interface is connected to the detection port, 2 of the seventh plane tee (56) # Interface with the second needle valve (58) 1 # Interface connection, seventh plane tee (56) 3 # Interface with the third needle valve (59) 1 # Interface connection.

9. The transformer oil dissolved gas detection system based on plasma detection according to claim 8, characterized in that: The working process of the component separation device is as follows: S21, sampling process; specifically, the No. 1 port and the No. 10 port of the first switching valve (41) are connected, and the No. 2 port and the No. 3 port of the first switching valve (41) are connected, the sample enters from the sampling port, passes through the No. 1 port of the first switching valve (41), the No. 10 port of the first switching valve (41), the second quantitative ring (42), and the No. 3 port of the first switching valve (41) in sequence, and finally flows from the No. 2 port of the first switching valve (41) to the sampling port, and the second quantitative ring (42) stores a certain amount of sample, thereby completing the sampling process; S22, sample pre-separation process; specifically: the carrier gas passes through port No. 4 of the first switching valve (41), port No. 3 of the first switching valve (41), the second quantitative loop (42), port No. 10 of the first switching valve (41), and port No. 9 of the first switching valve (41) in sequence, carrying the sample stored in the second quantitative loop (42) into the first chromatographic column (43); the sample is pre-separated in the first chromatographic column (43), and the pre-separated sample flows through port No. 5 of the first switching valve (41) and port No. 6 of the first switching valve (41) to the second chromatographic column (44) to be separated into three combined peaks, and the order in which the three combined peaks flow out of the second chromatographic column (44) is: hydrogen methane carbon monoxide combined peak, carbon dioxide ethylene ethane acetylene combined peak, propylene propane propyne combined peak; S23, the process of detecting the combined peak of hydrogen, methane and carbon monoxide; specifically, the combined peak of hydrogen, methane and carbon monoxide flows out from the second chromatographic column (44), passes through port No. 2 of the second switching valve (45), port No. 3 of the second switching valve (45), port No. 1 of the third switching valve (46), and port No. 10 of the third switching valve (46) to the third chromatographic column (47), is separated into hydrogen, methane and carbon monoxide again in the third chromatographic column (47), and then flows through port No. 7 of the third switching valve (46) and port No. 6 of the third switching valve (46) to port No. 2 of the sixth flat tee (55). # Interface, sixth plane tee (55) 1 # Interface, and finally flow into the detection port to detect the component contents of hydrogen, methane and carbon monoxide; S24, the process of detecting the combined peak of carbon dioxide, ethylene, ethane and acetylene; specifically, after the combined peak of hydrogen, methane and carbon monoxide is detected, the third switching valve (46) is switched, and the carrier gas carrying the combined peak of carbon dioxide, ethylene, ethane and acetylene flows out from the second chromatographic column (44), passes through port No. 2 of the second switching valve (45), port No. 3 of the second switching valve (45), port No. 1 of the third switching valve (46), and port No. 2 of the third switching valve (46) to the fourth chromatographic column (48), is separated into carbon dioxide, ethylene, ethane and acetylene again in the fourth chromatographic column (48), and then flows through port No. 5 of the third switching valve (46) and port No. 6 of the third switching valve (46) to port 2 of the sixth flat tee (55). # Interface, sixth plane tee (55) 1 # The interface finally flows into the detection port to detect the component contents of carbon dioxide, ethylene, ethane and acetylene; S25, detecting the combined peak of propylene, propane, and propyne; specifically, after the combined peak of carbon dioxide, ethylene, ethane, and acetylene is detected, the second switching valve (45) is switched, and the carrier gas carrying the combined peak of propylene, propane, and propyne is separated into propylene, propane, and propyne in the second chromatographic column (44), and flows through the No. 2 port of the second switching valve (45) and the No. 1 port of the second switching valve (45) to the No. 3 port of the sixth plane tee (55). # Interface, sixth plane tee (55) 1 # The gas flows into the detection port to detect the component contents of propylene, propane and propyne.

10. The transformer oil dissolved gas detection system based on plasma detection according to claim 1, characterized in that: The plasma detection device comprises: a discharge chamber (61), a probe, a component gas connecting pipe (64), a carrier gas connecting pipe (65), an exhaust connecting pipe (66), a composite electrode (67) and a vacuum pumping device (68); the component gas connecting pipe (64) is connected to one end of the discharge chamber (61), the exhaust connecting pipe (66) is connected to the other end of the discharge chamber (61), and the carrier gas connecting pipe (65) is connected to the component gas connecting pipe (64); two probes are arranged opposite to each other at the upper and lower ends of the discharge chamber (61); the composite electrode (67) is arranged in the cavity of the discharge chamber (61), and the vacuum pumping device (68) is connected to the exhaust connecting pipe (66).

11. The transformer oil dissolved gas detection system based on plasma detection according to claim 10, characterized in that: The probe includes: Optical interference filter, photodiode, amplifier, conductive electrode and shell; the optical interference filter, photodiode and amplifier are all encapsulated inside the shell, the optical interference filter, photodiode and amplifier are arranged in sequence along the negative direction of the y-axis, one end of the conductive electrode is connected to the amplifier, and the other end extends out of the shell.

12. The transformer oil dissolved gas detection system based on plasma detection according to claim 10, characterized in that: The central axis of the component gas connecting pipe (64) and the central axis of the exhaust connecting pipe (66) are in a straight line.

13. The transformer oil dissolved gas detection system based on plasma detection according to claim 10, characterized in that: The vacuum extraction device (68) comprises: a filter (81), a flat four-way connection (82), a first flat three-way connection (83), a one-way valve (84), a vacuum pump (85), a second flat three-way connection (86), a two-way ball valve (87), a pressure gauge (88) and a flow meter (89); the input end of the filter (81) is connected to the exhaust connection pipe (66), and the output end of the filter (81) is connected to the first end of the flat four-way connection (82). # Interface connection, flat cross (82) 2 # Interface with the first flat tee (83) 1 # Interface connection, first plane tee (83) 2 # The interface is connected to the input end of the one-way valve (84), the output end of the one-way valve (84) is connected to the input end of the vacuum pump (85), and the output end of the vacuum pump (85) is connected to the 1 end of the second plane tee (86). # Interface connection, second plane tee (86) 2 # The interface is used as the output port of the vacuum pumping device, and the pressure gauge (88) is connected to the 3-way flat cross (82). # Interface connection, flow meter (89) and flat cross (82) 4 # Interface connection, first plane tee (83) 3 # Interface with two-way ball valve (87) 1 # Port connection, 2-way ball valve (87) # Interface with the second flat tee (86) 3 # Interface connection.

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