Helium Ionization Gas Chromatograph for Dissolved Gas Analysis in Transformer Oil

Abstract

The present invention provides a helium ionization gas chromatograph for analyzing dissolved gases in transformer oil, comprising: a gas cleaning and purging system, a medium and heavy hydrocarbon cutting and backflushing system, an air interference cutting system, a sampling system, a helium ion detector, and a control system. The gas cleaning and purging system is connected to the medium and heavy hydrocarbon cutting and backflushing system; the medium and heavy hydrocarbon cutting and backflushing system is respectively connected to the air interference cutting system and the sampling system; the air interference cutting system is connected to the sampling system; and the sampling system is connected to the helium ion detector. The present invention avoids the interference of high molecular hydrocarbons on low molecular hydrocarbons, improves the efficiency of continuous sample analysis, and improves the reliability and repeatability of sample analysis results. At the same time, the helium ion detector has a wide analysis range and high detection limit sensitivity, which is conducive to timely discovering internal faults of detection equipment, enabling equipment with potential faults to be repaired plannedly and economically, and avoiding equipment damage and unplanned power outages.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and more particularly, to a helium ionization gas chromatograph for analyzing dissolved gases in transformer oil. Background Art

[0002] At present, transformers are the most important equipment in the power system and are widely used. With the increase of the operation time, the insulating oil and organic insulating materials in the transformer will gradually age and decompose under the long-term action of heat and electricity, and produce a very small amount of gases. These gases dissolved in the oil include hydrogen, methane, ethylene, ethane, acetylene, carbon monoxide and carbon dioxide, etc. However, when a fault occurs inside the transformer, the content of the gases in the oil will change greatly. As the fault develops, when the gas production amount is greater than the dissolution amount, a part of the gases will be released in the form of free gases. Practice has proved that the vast majority of initial defects of transformers will show early signs. Therefore, measuring and analyzing the content of the gases dissolved in the oil can detect the internal faults of the transformer as early as possible.

[0003] At present, the common method is to configure a gas chromatograph with three detectors, namely a double hydrogen flame ionization detector and a thermal conductivity detector. The problems of this method are as follows: The types of working gases need to be configured with three detectors of nitrogen, hydrogen and air, involving many types and having a low safety factor; involving many types of detectors, the structure is complex and not easy to maintain; the analysis range is narrow and the versatility is poor: Although the thermal conductivity detector (TCD) responds to all substances, its sensitivity is low; the flame ionization detector (FID) responds to almost all organic substances, but it cannot be used to analyze inorganic substances and permanent gases; the detection sensitivity is low, and potential problems cannot be discovered in time.

[0004] Therefore, there is an urgent need for a helium ionization gas chromatograph to solve the above problems. Summary of the Invention

[0005] In view of this, the present invention provides a helium ionization gas chromatograph for analyzing dissolved gases in transformer oil, aiming to solve the problem of improving the efficiency of continuous sample analysis of the helium ionization gas chromatograph.

[0006] In one aspect, the present invention provides a helium ionization gas chromatograph for analyzing dissolved gases in transformer oil, comprising: a gas cleaning and purging system, a medium and heavy hydrocarbon cutting and backflushing system, an air interference cutting system, a sampling system, a helium ion detector, and a control system. Among them, the gas cleaning and purging system is connected to the medium and heavy hydrocarbon cutting and backflushing system; the medium and heavy hydrocarbon cutting and backflushing system is respectively connected to the air interference cutting system and the sampling system; the air interference cutting system is connected to the sampling system; the sampling system is connected to the helium ion detector; the control system is electrically connected to the gas cleaning and purging system, the medium and heavy hydrocarbon cutting and backflushing system, the air interference cutting system, the sampling system, and the helium ion detector.

[0007] Further, the gas cleaning and purging system includes a six-way valve, and the medium and heavy hydrocarbon cutting and backflushing system includes two ten-way valves, namely a first ten-way valve and a second ten-way valve. Among them, the port 1 of the six-way valve is connected to the sampling port, the port 2 of the six-way valve is used for gas venting, the port 3 of the six-way valve is connected to the port 1 of the second ten-way valve, the port 4 of the six-way valve is connected to the port 2 of the second ten-way valve, the port 5 of the six-way valve is connected to the port 2 of the first ten-way valve, and the port 6 of the six-way valve is connected to the port 1 of the first ten-way valve.

[0008] Further, the port 1 of the six-way valve is connected to a purge helium branch, and the sampling port is arranged on the purge helium branch; a pressure stabilizing valve is also arranged on the purge helium branch, and the pressure stabilizing valve is arranged between the port 1 of the six-way valve and the sampling port.

[0009] Further, the port 3 of the first ten-way valve is connected to the port 10 of the first ten-way valve through a first quantitative loop, the port 4 of the first ten-way valve is connected to a first carrier gas, the port 5 of the first ten-way valve is connected to the port 9 of the first ten-way valve through a first chromatographic column, the port 6 of the first ten-way valve is connected to the air interference cutting system, the port 7 of the first ten-way valve is connected to a second carrier gas, and the port 8 of the first ten-way valve is used for sample venting.

[0010] Further, the port 3 of the second ten-way valve is connected to the port 10 of the second ten-way valve through a second quantitative loop, the port 4 of the second ten-way valve is connected to a third carrier gas, the port 5 of the second ten-way valve is connected to the port 9 of the second ten-way valve through an analytical column, the port 6 of the second ten-way valve is used for sample venting, the port 7 of the second ten-way valve is connected to a fourth carrier gas, and the port 8 of the second ten-way valve is connected to the sampling system.

[0011] Further, the air interference cutting system includes a first four-way valve. The port 1 of the first four-way valve is communicated with the sampling system. The port 2 of the first four-way valve is communicated with the fifth carrier gas. The port 3 of the first four-way valve is used for sample venting. The port 4 of the first four-way valve is communicated with the port 6 of the first ten-way valve through a first 5A analytical column.

[0012] Further, the sampling system includes a second four-way valve. The port 1 of the second four-way valve is communicated with the port 1 of the first four-way valve through a second 5A analytical column. The port 2 of the second four-way valve is communicated with the helium ion detector. The port 3 of the second four-way valve is communicated with the port 8 of the second ten-way valve through a second chromatographic column. The port 4 of the second four-way valve is used for sample venting.

[0013] Further, the control system includes a gas chromatograph central controller, a chromatographic data processing and control workstation, a communication interface, and a chromatographic analysis database. The gas chromatograph central controller is used to control the actions of the gas cleaning and purging system, the medium and heavy hydrocarbon cutting and backflushing system, and the air interference cutting system. The communication interface is used to connect to external devices for communication and data transmission.

[0014] Further, the gas chromatograph central controller controls the actions of the gas cleaning and purging system, the medium and heavy hydrocarbon cutting and backflushing system, and the air interference cutting system according to the following formula (1):

[0015]

[0016] Wherein, represents the comparison value of the chromatographic analysis database selection value information and the data information of the basic chromatographic analysis database selection value. M i represents the i-th chromatographic analysis database information. N j represents the selection value F of the i-th chromatographic analysis database information. U ij represents the correlation degree between the basic chromatographic analysis database selection value data information and the i-th chromatographic analysis database. i represents the number of the chromatographic analysis database. d represents the correction coefficient, and the value of d is 0.995. J represents the gain value of the chromatographic analysis database. T represents the preset time value.

[0017] Further, the correlation degree U ij is calculated by the following formula (2):

[0018]

[0019] Wherein, x represents the basic data in the i-th basic chromatographic analysis database. y represents the existing data of the basic chromatographic analysis database j. M i represents the data volume of the i-th basic chromatographic analysis database. Nj The selection value A representing the data information of a certain existing basic chromatographic analysis database.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows. The helium ionization gas chromatograph for dissolved gas analysis in transformer oil in the present invention avoids the interference of high molecular hydrocarbons on low molecular hydrocarbons, improves the efficiency of continuous sample analysis, and improves the reliability and repeatability of sample analysis results. At the same time, the helium ion detector has a wide analysis range and high detection limit sensitivity, which is conducive to timely discovering internal faults of detection equipment, enabling equipment with potential faults to be repaired plannedly and economically, and avoiding equipment damage and unplanned power outages. Description of the Drawings

[0021] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to limit the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0022] Figure 1 It is a schematic structural diagram of the helium ionization gas chromatograph for dissolved gas analysis in transformer oil provided by an embodiment of the present invention;

[0023] Figure 2 It is a schematic diagram of the connection structure in the first working state provided by an embodiment of the present invention;

[0024] Figure 3 It is a schematic diagram of the connection structure in the second working state provided by an embodiment of the present invention. Detailed Embodiments

[0025] Hereinafter, the exemplary embodiments of the present disclosure will be described in more detail with reference to the drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. Hereinafter, the present invention will be described in detail with reference to the drawings and in combination with the embodiments.

[0026] Refer to Figure 1As shown in the figure, this embodiment provides a helium ionization gas chromatograph for analyzing dissolved gases in transformer oil, including: a gas cleaning and purging system 2, a medium and heavy hydrocarbon cutting and backflushing system 3, an air interference cutting system 4, a sampling system 5, a helium ion detector 12, and a control system 1. Among them, the gas cleaning and purging system 2 is connected to the medium and heavy hydrocarbon cutting and backflushing system 3; the medium and heavy hydrocarbon cutting and backflushing system 3 is respectively connected to the air interference cutting system 4 and the sampling system 5; the air interference cutting system 4 is connected to the sampling system 5; the sampling system 5 is connected to the helium ion detector 12; the control system 1 is electrically connected to the gas cleaning and purging system 2, the medium and heavy hydrocarbon cutting and backflushing system 3, the air interference cutting system 4, the sampling system 5, and the helium ion detector 12.

[0027] Specifically, the control system 1 includes a gas chromatograph central controller, a chromatographic data processing and control workstation, a communication interface, and a chromatographic analysis database. The gas chromatograph central controller is used to control the operations of the gas cleaning and purging system 2, the medium and heavy hydrocarbon cutting and backflushing system 3, and the air interference cutting system 4. The communication interface is used to connect to external devices for communication and data transmission.

[0028] Specifically, the above-mentioned gas chromatograph central controller is an automated gas chromatograph central controller, the communication interface is a networked and data communication interface, and the chromatographic data processing and control workstation is an automated chromatographic data processing and control workstation. The chromatographic analysis database stores chromatographic analysis database information and basic chromatographic analysis database information.

[0029] Specifically, the above-mentioned helium ionization gas chromatograph uses embedded technology, software component technology, and networked technology to realize the integration of the gas chromatograph control system 1 in the management and processing analysis process, making the overall sample analysis more integrated from analysis process control, data acquisition, chromatographic processing and analysis, to statistical reports.

[0030] It can be seen that the helium ionization gas chromatograph for analyzing dissolved gases in transformer oil in this embodiment avoids the interference of high molecular hydrocarbons on low molecular hydrocarbons, improves the efficiency of continuous sample analysis, and improves the reliability and repeatability of sample analysis results; at the same time, the helium ion detector 12 has a wide analysis range and high detection limit sensitivity, which is conducive to timely discovering internal faults of the detection equipment, enabling equipment with latent faults to be repaired planned and economically, and avoiding equipment damage and unplanned power outages.

[0031] Specifically, the gas chromatograph central controller controls the operations of the gas cleaning and purging system 2, the medium and heavy hydrocarbon cutting and backflushing system 3, and the air interference cutting system 4 according to the following formula (1):

[0032]

[0033] Among them, Indicates the comparison value of the chromatographic analysis database selection value information and the data information of the basic chromatographic analysis database selection value, M i Indicates the i-th chromatographic analysis database information, N j Indicates the selection value F of the i-th chromatographic analysis database information, U ij Indicates the correlation degree between the basic chromatographic analysis database selection value data information and the i-th chromatographic analysis database. i represents the number of the chromatographic analysis database, d represents the correction coefficient, and the value of d is 0.995; |J| represents the gain value of the chromatographic analysis database, and T represents the preset time value.

[0034] Specifically, the correlation degree U ij Is calculated by the following formula (2):

[0035]

[0036] Where, x represents the basic data in the i-th basic chromatographic analysis database, y represents the existing data of the basic chromatographic analysis database j, M i Indicates the data volume of the i-th basic chromatographic analysis database, N j Indicates the selection value A of the data information of a certain existing basic chromatographic analysis database.

[0037] The gain value J of the chromatographic analysis database is determined by the following formula (3),

[0038]

[0039] Where, M i Indicates the data volume of the i-th basic chromatographic analysis database, and i represents the number of the chromatographic analysis database.

[0040] The output value of is determined by M i and N j Decided,

[0041]

[0042] When M i > N j At that time, The output value is When M i ≤ N j At that time, The output value of is 0;

[0043] If The output value of is 0, then directly replace the next basic database, repeat the comparison, and finally When the output value is not 0, the gas chromatography central controller controls the operations of the gas cleaning and purging system 2, the medium and heavy hydrocarbon cutting and backflushing system 3, and the air interference cutting system 4, that is, the gas chromatography central controller controls the gas cleaning and purging system 2, the medium and heavy hydrocarbon cutting and backflushing system 3, and the air interference cutting system 4 to switch.

[0044] Specifically, when the output value is not 0, the gas chromatography central controller stores the output value. When the output value is not less than the preset function value ζ, the chromatographic analysis database selection value at this time is used to establish the chromatographic analysis database; if the output function is less than the preset function value ζ, the chromatographic analysis database selection value is returned to reselect until the output function is not less than the preset function value ζ.

[0045] Specifically, the preset function value ζ can be set by the administrator according to actual needs, and generally takes a value of 0.98.

[0046] Specifically, the helium ionization gas chromatography instrument for dissolved gas analysis in transformer oil in the embodiment of the present invention establishes a two-dimensional database by combining the chromatographic analysis database with the basic chromatographic analysis database. During the selection process, according to the user's needs, two-dimensional matrix information based on the chromatographic analysis database is input, and through a weighted and iterative algorithm, the selected chromatographic analysis database selection value is compared and optimized to obtain the chromatographic analysis database corresponding to the chromatographic analysis database selection value, thereby improving the accuracy of the final calculation result.

[0047] Specifically, in combination with Figure 2 and 3 as shown, the gas cleaning and purging system 2 includes a six-way valve 7, and ports 1-6 are arranged on the six-way valve 7. The medium and heavy hydrocarbon cutting and backflushing system 3 includes two ten-way valves, and ports 1-10 are arranged on the ten-way valves. The two ten-way valves are the first ten-way valve 8 and the second ten-way valve 9 respectively.

[0048] Specifically, port 1 of the six-way valve 7 is connected to the injection port 13, and port 2 of the six-way valve 7 is used for gas venting, that is, port 2 of the six-way valve 7 is connected to a gas venting branch to perform gas venting. Port 3 of the six-way valve 7 is connected to port 1 of the second ten-way valve 9, port 4 of the six-way valve 7 is connected to port 2 of the second ten-way valve 9, port 5 of the six-way valve 7 is connected to port 2 of the first ten-way valve 8, and port 6 of the six-way valve 7 is connected to port 1 of the first ten-way valve 8.

[0049] Specifically, the port 1 of the six-way valve 7 is connected to the purge helium branch, and the purge helium branch is used to input purge helium into the port 1 of the six-way valve 7. The injection port 13 is arranged on the purge helium branch; a pressure stabilizing valve 14 is also arranged on the purge helium branch, and the pressure stabilizing valve 14 is arranged between the port 1 of the six-way valve 7 and the injection port 13, that is, the pressure stabilizing valve 14 is arranged on the purge helium branch and is located between the port 1 of the six-way valve 7 and the injection port 13.

[0050] Specifically, the port 3 of the first ten-way valve 8 is connected to the port 10 of the first ten-way valve 8 through the first quantitative loop 15, and a communication gas path is arranged between the port 3 of the first ten-way valve 8 and the port 10 of the first ten-way valve 8. The first quantitative loop 15 is arranged on the communication gas path; the port 4 of the first ten-way valve 8 is connected to the first carrier gas He1, the port 5 of the first ten-way valve 8 is connected to the port 9 of the first ten-way valve 8 through the first chromatographic column 16, and a communication gas path is arranged between the port 5 of the first ten-way valve 8 and the port 9 of the first ten-way valve 8. The first chromatographic column 16 is arranged on the communication gas path; the port 6 of the first ten-way valve 8 is connected to the air interference cutting system 4, the port 7 of the first ten-way valve 8 is connected to the second carrier gas He2, and the port 8 of the first ten-way valve 8 is used for sample venting.

[0051] Preferably, the first chromatographic column 16 is preferably a HayesepQ analytical column.

[0052] Specifically, the port 3 of the second ten-way valve 9 is connected to the port 10 of the second ten-way valve 9 through the second quantitative loop 21, and a communication gas path is arranged between the port 3 of the second ten-way valve 9 and the port 10 of the second ten-way valve 9. The second quantitative loop 21 is arranged on the communication gas path; the port 4 of the second ten-way valve 9 is connected to the third carrier gas He3, the port 5 of the second ten-way valve 9 is connected to the port 9 of the second ten-way valve 9 through the analytical column 20, and a communication gas path is arranged between the port 5 of the second ten-way valve 9 and the port 9 of the second ten-way valve 9. The analytical column 20 is arranged on the communication gas path; the port 6 of the second ten-way valve 9 is used for sample venting, the port 7 of the second ten-way valve 9 is connected to the fourth carrier gas He4, and the port 8 of the second ten-way valve 9 is connected to the injection system 5.

[0053] Specifically, the air interference cutting system 4 includes a first four-way valve 10. The first four-way valve 10 is provided with ports 1-4. The port 1 of the first four-way valve 10 is connected to the injection system 5, the port 2 of the first four-way valve 10 is connected to the fifth carrier gas He5, the port 3 of the first four-way valve 10 is used for sample venting, and the port 4 of the first four-way valve 10 is connected to the port 6 of the first ten-way valve 8 through the first 5A analytical column 17. A communication gas path is arranged between the port 4 of the first four-way valve 10 and the port 6 of the first ten-way valve 8, and the first 5A analytical column 17 is arranged on the communication gas path.

[0054] Specifically, the sample injection system 5 includes a second four-way valve 11. The second four-way valve 11 is provided with ports numbered 1-4. The port No. 1 of the second four-way valve 11 is connected to the port No. 1 of the first four-way valve 10 through a second 5A analytical column 18. A connecting gas path is provided between the port No. 1 of the second four-way valve 11 and the port No. 1 of the first four-way valve 10, and the second 5A analytical column 18 is arranged on the connecting gas path. The port No. 2 of the second four-way valve 11 is connected to a helium ion detector 12. The port No. 3 of the second four-way valve 11 is connected to the port No. 8 of a twentieth-way valve 9 through a second chromatographic column 19. A connecting gas path is provided between the port No. 3 of the second four-way valve 11 and the port No. 8 of the twentieth-way valve 9, and the second chromatographic column 19 is arranged on the connecting gas path. The port No. 4 of the second four-way valve 11 is used for sample venting.

[0055] Preferably, the second chromatographic column 19 is preferably a HayesepQ analytical column.

[0056] It can be seen that the helium ionization gas chromatograph for dissolved gas analysis in transformer oil described above requires fewer types of working gases and has a high safety factor. The helium ionization gas chromatograph is equipped with valve center cutting and backflush technologies, which can achieve the separation and determination of 9 components (H2, O2, N2, CH4, C2H6, C2H4, C2H2, CO, CO2) of the dissolved gas in transformer oil. The detection limits of each component all reach the 10-9 magnitude. The peak signal value of the detector is greatly enhanced, and the detection limits are increased by 5 to 80 times respectively. Moreover, no hydrogen is required as an auxiliary gas, reducing potential safety hazards.

[0057] At the same time, the helium ionization gas chromatograph for dissolved gas analysis in transformer oil described above is easy to operate. The instrument is equipped with a backflush system for C3+ and above components in the transformer oil sample. The system includes two twentieth-way valves, two four-way valves, a purge valve, and a helium ion detector 12. The present invention is convenient to operate, has a high safety factor, the detection limit can reach 5 ppb level, and at the same time solves the problems of mutual influence of sample gases and interference of other impurities in the gas released from the oil on the test. Moreover, the instrument has a short stabilization time and high test accuracy.

[0058] In specific implementation, when the transformer insulating oil is heated or there is high-energy discharge in the oil-filled equipment, etc., the insulating oil will crack, generating characteristic gases such as hydrogen or low-molecular hydrocarbons. By analyzing the characteristic gases, equipment failures can be detected at an early stage. The commonly used characteristic gases mainly include: methane CH4, ethylene C2H4, ethane C2H6, acetylene C2H2, etc. However, in the actual decomposition products of insulating oil, there may also be high-molecular hydrocarbons such as C3 and C4, such as propylene C3H6, propane C3H8, vinyl acetylene C4H4, etc. When analyzing an insulating oil sample with the configuration of a traditional gas chromatography analyzer, the larger the number of high-molecular hydrocarbon molecules contained in the sample, the longer the retention time in the chromatographic column. If all hydrocarbons elute at a relatively low chromatographic column temperature, such as 60 °C, it takes about one hour, seriously affecting the analysis efficiency. If samples are continuously injected after separating low-molecular hydrocarbons, problems such as overlap between the previous high-molecular hydrocarbon sample and the current low-molecular hydrocarbon sample will occur, affecting the analysis results.

[0059] It can be understood that the helium ionization gas chromatography instrument for analyzing dissolved gases in transformer oil avoids the interference of high-molecular hydrocarbons on low-molecular hydrocarbons, improves the efficiency of continuous sample analysis, and improves the reliability and repeatability of sample analysis results; at the same time, the helium ion detector 12 has a wide analysis range and high detection limit sensitivity, which is conducive to timely detecting internal faults of the detection equipment, enabling equipment with latent faults to be repaired planned and economically, and avoiding equipment damage and unplanned power outages.

[0060] Specifically, when the above-mentioned embodiment is specifically implemented, refer to Figure 2 As shown, the analysis process of the gas chromatography instrument is as follows: The sample gas sequentially enters port 1 of the six-port valve 7, port 6 of the six-port valve 7, port 1 of the first ten-port valve 8, port 10 of the first ten-port valve 8, the first quantitative loop 15, port 3 of the first ten-port valve 8, port 2 of the first ten-port valve 8, port 5 of the six-port valve 7, port 4 of the six-port valve 7, port 2 of the second ten-port valve 9, port 3 of the second ten-port valve 9, the second quantitative loop 21, port 10 of the second ten-port valve 9, and port 1 of the second ten-port valve 9. The first ten-port valve 8 and the injection second ten-port valve 9 are controlled by the built-in software of the gas chromatography instrument central controller to achieve sample collection.

[0061] Furthermore, in combination with Figure 3As shown, after the central controller of the gas chromatograph controls the switching of the first ten-way valve 8, the sample enters the 10th port of the first ten-way valve 8, the 9th port of the first ten-way valve 8, the first chromatographic column 16, the 5th port of the first ten-way valve 8, the 6th port of the first ten-way valve 8, and the first 5A analytical column 17 in sequence through the first quantitative loop 15. After the interference of air in a large amount of sample gas is eliminated by controlling the switching of the first four-way valve 10 through the central controller of the gas chromatograph, the sample gas to be analyzed enters the helium ion detector 12 (PDD) through the second 5A analytical column 18, the 1st port of the second four-way valve 11, and the 2nd port of the second four-way valve 11 for inorganic gas analysis.

[0062] Further, in combination with Figure 2 and 3 As shown, the organic gas analysis process is as follows: The sample gas enters the 9th port of the second ten-way valve 9, the analytical column 20, the 5th port of the second ten-way valve 9, and the 6th port of the second ten-way valve 21 in sequence through the second quantitative loop 21. After the inorganic gas analyzed by the first ten-way valve 8 is vented, the second ten-way valve 9 is switched. The sample gas will pass through the 5th port of the second ten-way valve 9, the analytical column 20, the 9th port of the second ten-way valve 9, and the 8th port of the second ten-way valve 9 in sequence and enter the 3rd port of the second four-way valve 11 and the 2nd port of the second four-way valve 11, and finally enter the helium ion detector 12 (PDD) through the 2nd port of the second four-way valve 11 for analysis.

[0063] Specifically, when the above-mentioned embodiment is specifically implemented, refer to Figure 2 As shown, the sample gas sampling process is as follows: After the sample gas passes through the 1st port and the 6th port of the six-way valve 7, it enters the 1st port of the inlet first ten-way valve 8, the 10th port of the first ten-way valve 8, the first quantitative loop 15, the 3rd port of the first ten-way valve 8, and the 2nd port of the first ten-way valve 8, and then passes through the 5th port and the 4th port of the six-way valve 7 and enters the 2nd port and the 3rd port of the second ten-way valve 9, the second quantitative loop 21, the 10th port of the second ten-way valve 9, and the 1st port of the second ten-way valve 9, and then flows through the 3rd port and the 2nd port of the six-way valve 7 for venting. Thus, the sample gas is replaced and sampled in the above flow path, so that the measured sample fills the entire sampling system in real time.

[0064] Specifically, when the above-mentioned embodiment is specifically implemented, refer to Figure 3 As shown, the first sample gas injection process: All valves in the analysis system adopt embedded technology and software component technology and are automatically operated and switched after the parameters are set by the computer, that is, automatically controlled by the central controller of the gas chromatograph. After the sample gas is replaced in the system according to the sampling process for 0.5 minutes, the process is as follows: The six-way valve 7 changes from the Figure 2 state to Figure 3At this state, the states of the first ten-way valve 8 and the second ten-way valve 9 remain unchanged. The samples sampled by the first metering loop 15 and the second metering loop 21 in the first ten-way valve 8 and the second ten-way valve 9 are respectively intercepted in the first metering loop 15 and the second metering loop 21. According to the analysis requirements, controlled by the central controller of the gas chromatograph, after 0.1 min, the first ten-way valve 8 operates. Driven by the first carrier gas He1, the sample passes through port 4 of the sample injection first ten-way valve 8, port 3 of the first ten-way valve 8, the first metering loop 15, port 10 of the first ten-way valve 8, and port 9 of the first ten-way valve 8 to enter the first chromatographic column 16 for the analysis process.

[0065] Specifically, when the above-mentioned embodiments are specifically implemented, in combination with Figure 2 and 3 As shown, for the sample gas analysis process 1: The first carrier gas He1 drives the sample gas through port 4 of the sample injection first ten-way valve 8, port 3 of the first ten-way valve 8, the first metering loop 15, port 10 of the first ten-way valve 8, and port 9 of the first ten-way valve 8 to enter the first chromatographic column 16, where the sample gas is preliminarily separated. When hydrogen, oxygen, nitrogen, methane, and carbon monoxide enter the first 5A analytical column 17 and carbon dioxide does not flow out, reset the first ten-way valve 8. At this time, the second carrier gas He2 passes through port 7 of the first ten-way valve 8, port 6 of the first ten-way valve 8, the first 5A analytical column 17, port 4 of the first four-way valve 10, and port 1 of the first four-way valve 10. After 0.4 min, when hydrogen flows out of the first four-way valve 10, the first four-way valve 10 switches to Figure 3 state. After venting oxygen and nitrogen, after 1.4 min, the first four-way valve 10 is reset. Methane and carbon monoxide enter the second 5A analytical column 18 for further separation, and enter the helium ion detector 12 through port 1 of the second four-way valve 11 and port 2 of the second four-way valve 11 ( Figure 2 the state of the second four-way valve 11 shown).

[0066] Specifically, when the above-mentioned embodiments are specifically implemented, in combination with Figure 3 As shown, for the sample gas injection process 2: After waiting for 5 min and after the above sample gas analysis process 1 ends, the second ten-way valve 9 switches to Figure 3 state. Driven by the third carrier gas He3, the sample gas passes through port 4 of the second ten-way valve 9, port 3 of the second ten-way valve 9, the second metering loop 21, port 10 of the second ten-way valve 9, and port 9 of the second ten-way valve 9 to enter the pre-column for the analysis process

[0067] Specifically, when the above-mentioned embodiments are specifically implemented, in combination with Figure 3As shown in the figure, Sample Gas Analysis Process 2: The third carrier gas He3 carries the sample gas through Port 4 of the 20th three-way valve 9, Port 3 of the 20th three-way valve 9, the second metering loop 21, Port 10 of the 20th three-way valve 9, and Port 9 of the 20th three-way valve 9 into the analytical column 20, where the sample gas is preliminarily separated. After 0.2 minutes, when hydrogen, oxygen, nitrogen, methane, and carbon monoxide flow out while carbon dioxide, ethane, ethylene, and acetylene do not flow out, reset the 20th three-way valve 9 to Figure 2 the state in. At this time, the third carrier gas He3 carries the unflowed carbon dioxide, ethane, ethylene, and acetylene through Port 4 of the 20th three-way valve 9, Port 5 of the 20th three-way valve 9, the analytical column 20, Port 9 of the 20th three-way valve 9, Port 8 of the 20th three-way valve 9, and the second chromatographic column 19, and enters the helium ion detector 12 through Port 3 of the 24th two-way valve 11 and Port 2 of the 24th two-way valve 11 for analysis.

[0068] Specifically, when the above-mentioned embodiment is specifically implemented, in combination with Figure 3 As shown in the figure, Heavy Hydrocarbon Venting Process: After 6 minutes, when the C2 component enters the second chromatographic column 19 and the C3+ and above heavy hydrocarbon components do not flow out of the analytical column 20, switch valve 5 to Figure 3 the state. The fourth carrier gas He4 will carry carbon dioxide, ethane, ethylene, and acetylene through Port 7 of the 20th three-way valve 9, Port 8 of the 20th three-way valve 9, and the second chromatographic column 19, and enter the helium ion detector 12 through Port 3 of the 24th two-way valve 11 and Port 2 of the 24th two-way valve 11; the C3+ and above heavy hydrocarbon components are vented by the third carrier gas He3 through Port 4 of the 20th three-way valve 9, Port 3 of the 20th three-way valve 9, the second metering loop 21, Port 10 of the 20th three-way valve 9, Port 9 of the 20th three-way valve 9, the analytical column 20, Port 5 of the 20th three-way valve 9, and Port 6 of the 20th three-way valve 9.

[0069] Specifically, when the above-mentioned embodiment is specifically implemented, in combination with Figure 2 As shown in the figure, the sample gas cleaning and purging process is as follows: Before the sample gas analysis process is completed and before entering the next analysis process, perform the purging work on the first metering loop 15 and the second metering loop 21. The purging helium passes through Port 1 of the six-way valve 7, Port 6 of the six-way valve 7, enters Port 1 of the 10th three-way valve 8, Port 10 of the 10th three-way valve 8, the first metering loop 15, Port 3 of the 10th three-way valve 8, and Port 2 of the 10th three-way valve 8, and then enters Port 5 of the six-way valve 7, Port 4 of the six-way valve 7, and then enters Port 2 of the 20th three-way valve 9, Port 3 of the 20th three-way valve 9, the second metering loop 21, Port 10 of the 20th three-way valve 9, and Port 1 of the 20th three-way valve 9, and then flows through Port 3 of the six-way valve 7 and Port 2 of the six-way valve 7 for venting.

[0070] Specifically, when the above-mentioned embodiment is specifically implemented, in combination with Figure 2As shown in the figure, the air interference cutting process in the sample gas is as follows: The second carrier gas He2 passes through the 7th port of the first ten-way valve 8, the 6th port of the first ten-way valve 8, the first 5A analytical column 17, the 4th port of the first four-way valve 10, and the 1st port of the first four-way valve 10. After 0.4 minutes, when hydrogen flows out of the first four-way valve 10, the first four-way valve 10 switches to Figure 3 a state where oxygen and nitrogen are vented through the 4th port and the 3rd port of the first four-way valve 10. After 1.4 minutes, the first four-way valve 10 resets to Figure 1 a state where methane and carbon monoxide enter the second 5A analytical column 18 for further separation and enter the helium ion detector 12 for analysis through the 1st port and the 2nd port of the second four-way valve 11.

[0071] Specifically, when the above-mentioned embodiments are implemented, in combination with Figure 3 As shown in the figure, the first cutting process is as follows: The first carrier gas He1 vents the C3+ and above heavy hydrocarbon components and carbon dioxide and other components to be analyzed through the 4th port, the 5th port of the first ten-way valve 8, the first chromatographic column 16, the 9th port, and the 8th port of the first ten-way valve 8, completing the cutting and backflushing process.

[0072] Specifically, when the above-mentioned embodiments are implemented, in combination with Figure 3 As shown in the figure, the second cutting process is as follows: The third carrier gas He3 vents through the 4th port, the 3rd port of the second ten-way valve 9, the second quantitative loop 21, the 10th port, the 9th port of the second ten-way valve 9, the analytical column 20, the 5th port, and the 6th port of the second ten-way valve 9, completing the cutting process for C3+ and above heavy hydrocarbon components.

[0073] Specifically, when the above-mentioned embodiments are implemented, in combination with Figure 3 As shown in the figure, the center cutting process is as follows: When there is a large amount of oxygen and nitrogen in the sample gas, the excess oxygen and nitrogen are vented through the 7th port, the 6th port of the first ten-way valve 8, the first 5A analytical column 17, the 4th port, and the 3rd port of the first four-way valve 10 to eliminate the excess oxygen and nitrogen in the sample gas, thereby avoiding the interference of the excess oxygen and nitrogen on the sample analysis and improving the accuracy of the analysis results.

[0074] Specifically, when the above-mentioned embodiments are implemented, in combination with Figure 2 and 3As shown in the figure, the switching of the helium ion detector 12: When the first ten-way valve 8 is used for sample injection and analysis, the analysis gas enters the helium ion detector 12 through port 1 and port 2 of the second four-way valve 11 for sample analysis; when the second ten-way valve 9 is used for sample injection and analysis, the second four-way valve 11 is switched, and the analysis gas enters the helium ion detector 12 through port 3 and port 4 of the second four-way valve 11 for sample analysis.

[0075] The gas chromatograph with a helium ionization detector in the above embodiment is equipped with one six-way valve 7 for purging, two ten-way valves for sample injection, namely the first ten-way valve 8 and the second ten-way valve 9, and two four-way valves for cutting, namely the first four-way valve 10 and the second four-way valve 11; the six-way valve 7 is used to purge the quantitative loops on the two sample injection valves, namely the first ten-way valve 8 and the second ten-way valve 9, and to purge and replace the residual samples in the quantitative tubes during manual sample injection. After sample injection, the trace samples are locked in the quantitative loops for sample injection analysis exchange between the two ten-way valves; the first ten-way valve 8 is used for sample injection cutting and backflushing. When H2, O2, N2, and CH4 enter the first four-way valve 10, the first ten-way valve 8 vents the remaining components; when the O2 and N2 contents in the sample are high, the first four-way valve 10 performs center cutting to reduce the impact on their analysis, and the second four-way valve 11 is used as the selection of the sample injection valve detector; the second ten-way valve 9 is used for sample injection cutting and analysis of SF6\C2\CO2.

[0076] It can be seen that the helium ionization gas chromatograph for dissolved gas analysis in transformer oil described above avoids the interference of high molecular hydrocarbons on low molecular hydrocarbons, improves the efficiency of continuous sample analysis, and improves the reliability and repeatability of sample analysis results; at the same time, the helium ionization detector has a wide analysis range and high detection limit sensitivity, which is conducive to timely detecting internal faults of the detection equipment, enabling equipment with potential faults to be repaired planned and economically, and avoiding equipment damage and unplanned power outages.

[0077] Specifically, the above-mentioned first carrier gas He1, second carrier gas He2, third carrier gas He3, fourth carrier gas He4, and fifth carrier gas He5 are preferably helium.

[0078] Specifically, the central controller of the gas chromatograph controls the actions of the six-way valve 7, the first ten-way valve 8, the second ten-way valve 9, the first four-way valve 10, and the second four-way valve 11 according to the following formula (1), that is, the central controller of the gas chromatograph controls the state switching of the six-way valve 7, the first ten-way valve 8, the second ten-way valve 9, the first four-way valve 10, and the second four-way valve 11 according to the following formula (1):

[0079]

[0080] Among them, Indicates the comparison value between the chromatographic analysis database selection value information and the data information of the basic chromatographic analysis database selection value, M i Indicates the i-th chromatographic analysis database information, N j Indicates the selection value F of the i-th chromatographic analysis database information, U ij Indicates the correlation degree between the basic chromatographic analysis database selection value data information and the i-th chromatographic analysis database. i represents the number of the chromatographic analysis database, d represents the correction coefficient, and the value of d is 0.995; J represents the gain value of the chromatographic analysis database, and T represents the preset time value.

[0081] Specifically, the correlation degree U ij Is calculated by the following formula (2):

[0082]

[0083] Among them, x represents the basic data in the i-th basic chromatographic analysis database, y represents the existing data of the basic chromatographic analysis database j, M i Indicates the data volume of the i-th basic chromatographic analysis database, N j Indicates the selection value A of the data information of a certain existing basic chromatographic analysis database.

[0084] The gain value J of the chromatographic analysis database is determined by the following formula (3),

[0085]

[0086] Among them, M i Indicates the data volume of the i-th basic chromatographic analysis database, and i represents the number of the chromatographic analysis database.

[0087] The output value of is determined by M i And N j Decide,

[0088]

[0089] When M i > N j When, The output value is When M i ≤N j When, The output value of is 0;

[0090] If The output value of is 0, then directly replace the next basic database and repeat the comparison. Finally When the output value is not 0, the gas chromatography central controller controls the operations of the gas cleaning and purging system 2, the medium and heavy hydrocarbon cutting and backflushing system 3, and the air interference cutting system 4, that is, the gas chromatography central controller controls the gas cleaning and purging system 2, the medium and heavy hydrocarbon cutting and backflushing system 3, and the air interference cutting system 4 to switch.

[0091] Specifically, when the output value is not 0, the gas chromatography central controller stores the output value. When the output value is not less than the preset function value ζ, the chromatographic analysis database selection value at this time is used to establish the chromatographic analysis database; if the output function is less than the preset function value ζ, the chromatographic analysis database selection value is returned to reselect until the output function is not less than the preset function value ζ.

[0092] Specifically, the preset function value ζ can be set by the administrator according to actual needs, and generally takes a value of 0.98.

[0093] Specifically, the helium ionization gas chromatography instrument for dissolved gas analysis in transformer oil in the embodiment of the present invention establishes a two-dimensional database by combining the chromatographic analysis database with the basic chromatographic analysis database. During the selection process, according to user requirements, two-dimensional matrix information based on the chromatographic analysis database is input, and through a weighted and iterative algorithm, the selected chromatographic analysis database selection value is compared and optimized to obtain the chromatographic analysis database corresponding to the chromatographic analysis database selection value, thereby improving the accuracy of the final calculation result.

[0094] Specifically, the gas chromatography central controller is built with a processing unit, and the switching control instruction is output through the processing unit.

[0095] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these changes and modifications.

Claims

1. A helium ionization gas chromatograph for dissolved gas analysis in transformer oil, characterized in that, Comprising: A gas cleaning and purging system, a medium and heavy hydrocarbon cutting and backflushing system, an air interference cutting system, a sampling system, a helium ion detector, and a control system. Among them, The gas cleaning and purging system is connected to the medium and heavy hydrocarbon cutting and backflushing system; The medium and heavy hydrocarbon cutting and backflushing system is respectively connected to the air interference cutting system and the sampling system; The air interference cutting system is connected to the sampling system; The sampling system is connected to the helium ion detector; The control system is electrically connected to the gas cleaning and purging system, the medium and heavy hydrocarbon cutting and backflushing system, the air interference cutting system, the sampling system, and the helium ion detector respectively; The gas cleaning and purging system includes a six-way valve, and the medium and heavy hydrocarbon cutting and backflushing system includes two ten-way valves, namely the first ten-way valve and the second ten-way valve. Among them, The port 1 of the six-way valve is connected to the sampling port, the port 2 of the six-way valve is used for gas venting, the port 3 of the six-way valve is connected to the port 1 of the second ten-way valve, the port 4 of the six-way valve is connected to the port 2 of the second ten-way valve, the port 5 of the six-way valve is connected to the port 2 of the first ten-way valve, and the port 6 of the six-way valve is connected to the port 1 of the first ten-way valve; The port 3 of the first ten-way valve is connected to the port 10 of the first ten-way valve through a first quantitative loop, the port 4 of the first ten-way valve is connected to the first carrier gas, the port 5 of the first ten-way valve is connected to the port 9 of the first ten-way valve through a first chromatographic column, the port 6 of the first ten-way valve is connected to the air interference cutting system, the port 7 of the first ten-way valve is connected to the second carrier gas, and the port 8 of the first ten-way valve is used for sample venting; The port 3 of the second ten-way valve is connected to the port 10 of the second ten-way valve through a second quantitative loop, the port 4 of the second ten-way valve is connected to the third carrier gas, the port 5 of the second ten-way valve is connected to the port 9 of the second ten-way valve through an analytical column, the port 6 of the second ten-way valve is used for sample venting, the port 7 of the second ten-way valve is connected to the fourth carrier gas, and the port 8 of the second ten-way valve is connected to the sampling system; The air interference cutting system includes a first four-way valve. The port 1 of the first four-way valve is connected to the sampling system, the port 2 of the first four-way valve is connected to the fifth carrier gas, the port 3 of the first four-way valve is used for sample venting, and the port 4 of the first four-way valve is connected to the port 6 of the first ten-way valve through a first 5A analytical column; The sampling system includes a second four-way valve. The port 1 of the second four-way valve is connected to the port 1 of the first four-way valve through a second 5A analytical column, the port 2 of the second four-way valve is connected to the helium ion detector, the port 3 of the second four-way valve is connected to the port 8 of the second ten-way valve through a second chromatographic column, and the port 4 of the second four-way valve is used for sample venting.

2. The helium ionization gas chromatograph for dissolved gas analysis in transformer oil according to claim 1, wherein The port 1 of the six-way valve is connected to the purging helium branch, and the sampling port is arranged on the purging helium branch; A pressure stabilizing valve is further arranged on the purging helium branch, and the pressure stabilizing valve is arranged between the port 1 of the six-way valve and the sampling port.

3. The helium ionization gas chromatograph for dissolved gas analysis in transformer oil according to claim 1, characterized in that, The control system includes a central controller of a gas chromatograph, a chromatographic data processing and control workstation, a communication interface, and a chromatographic analysis database. The central controller of the gas chromatograph is used to control the operations of the gas cleaning and purging system, the medium and heavy hydrocarbon cutting and backflushing system, and the air interference cutting system. The communication interface is used to connect to external devices for communication and data transmission.

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