A comprehensive analysis platform for insulating oil and a dynamic tracking and calibration method for chromatographic analysis

Abstract

This invention proposes a comprehensive analysis platform for insulating oil and a dynamic tracking calibration method for chromatographic analysis, including a control and management unit, an automatic sample quantitative distribution unit, an automatic chromatographic calibration unit, a multi-parameter analysis unit, and a sample sequence. The control and management unit includes an analysis control unit, a sample data management unit, and an analysis cycle management unit. After obtaining chromatographic analysis data, the control and management unit prepares a standard mixed gas with a concentration close to the preliminary test results, based on the analysis items, and uses it as the calibration sample for chromatographic analysis. The chromatographic analysis unit performs dynamic calibration based on the prepared gas calibration sample and then recalculates the sample. This invention can achieve consistent calibration of all components in the chromatographic analysis system, solving the problems of low calibration and high application when instrument conditions or large deviations between the concentration of the analytical sample and the concentration of the standard gas are large during single-point calibration, and the problem that only one component is close to a single mixed standard gas while other components differ significantly, resulting in inaccurate analysis results.

Description

Technical Field

[0001] This invention relates to the field of detection technology, and in particular to a comprehensive analysis platform for insulating oil and a dynamic tracking and calibration method for chromatographic analysis. Background Technology

[0002] The accuracy of laboratory analysis data for transformer oil is fundamental to detecting the operating status of transformers. However, different laboratories produce significantly different analytical data for specific items. Statistics show that the chromatographic technology level of most domestic oil chemical laboratories is such that the comparison error of the same sample between different laboratories reaches more than 30%, and the parallel analysis error of the same sample within the same laboratory reaches more than 15%. This results in the inability to accurately obtain gas increments in the oil within 10%, leading to delayed transformer early warnings, difficulty in unifying diagnostic conclusions, and repeated delays in fault diagnosis.

[0003] There are many reasons for errors in laboratory insulating oil analysis data, with the performance of the instrument itself and the operator's technique being the main factors. Currently, the vast majority of experiments are conducted manually, with only a few projects capable of automation. In addition, due to the limited chromatographic analysis skills and fault diagnosis experience of some laboratory oil specialists and maintenance personnel, they may not be able to effectively utilize fault diagnosis tools and methods, leading to incorrect judgments and causing false alarms or missed alarms.

[0004] Meanwhile, traditional chromatographic analysis of dissolved gases in insulating oil is limited by conditions and environment, and all methods use single-point calibration with multi-component mixed standard gases. When the instrument conditions or the concentration of the analyzed sample deviates significantly from the concentration of the standard gas, or when only one component is close to the corresponding component of a single mixed standard gas while other components differ significantly, the analysis results cannot be accurately reflected. Furthermore, the manual multi-point calibration procedure is complex and inefficient.

[0005] In summary, it is necessary to propose a comprehensive analysis platform for insulating oil samples and a dynamic calibration method for automatic tracking of dissolved gas concentration chromatographic analysis. Summary of the Invention

[0006] This invention proposes a comprehensive analysis platform for insulating oil and a dynamic tracking calibration method for chromatographic analysis. The platform enables automatic batch analysis of dissolved gas concentration, trace moisture content, withstand voltage, acid value, and dielectric loss in insulating oil. Furthermore, for the concentration of dissolved gases in insulating oil, a dynamic matching calibration technique is provided to dynamically track the concentration of each target component. This aims to verify the correctness and accuracy of the insulating oil sample analysis results. By calibrating the sample concentrations with those of components in close ranges, the accuracy of the analytical data is improved. Simultaneously, it can also be used as a standard gas preparation device to prepare dynamically mixed component matching standard samples for analysis. This solves the problems of large deviations between instrument conditions or the concentrations of the analyzed sample and the standard gas during single-point calibration, as well as the issue that only one component is close to the corresponding component in the mixed standard gas, while other components differ significantly, failing to accurately reflect the analytical results.

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

[0008] An integrated analysis platform for insulating oil includes a control and management unit, an automatic sample quantitative distribution unit, an automatic chromatographic calibration unit, a multi-parameter analysis unit, and a sample sequence. The control and management unit includes an analysis control unit, a sample data management unit, and an analysis cycle management unit. The multi-parameter analysis unit and the automatic sample quantitative distribution unit automatically analyze the samples. After obtaining chromatographic analysis data through preliminary testing, the control and management unit, based on the sample analysis items recommended by the analysis cycle management system, controls the automatic chromatographic calibration unit, the multi-parameter analysis unit, and the standard substance storage cabinet to prepare a standard mixed gas with a concentration close to that of the preliminary test results. This gas is used as the gas calibration sample for the chromatographic analysis unit. The chromatographic analysis unit performs dynamic calibration based on the prepared gas calibration sample and then recalculates the sample based on the standard gas analysis results.

[0009] The control and management unit includes an industrial control computer with management software installed;

[0010] The multi-parameter analysis unit includes a multi-parameter automatic analysis module, which is used to automatically analyze batch samples of insulating oil samples for dissolved gas concentration, trace moisture, withstand voltage, acid value, and dielectric loss.

[0011] The automatic chromatographic calibration unit is used for automatic dynamic calibration of the chromatographic analysis unit;

[0012] The equipment for performing automated dynamic calibration operations includes a control and management unit, an automated chromatographic calibration unit, and a standard substance storage cabinet.

[0013] The standard substance storage cabinet includes multiple single-component standard gas cylinder storage compartments for storing standard gas cylinders of multiple single-component standard gas components and carrier gas containers; each storage compartment is separated by a solenoid valve group containing multiple switching solenoid valves, and each switching solenoid valve is used to individually control the gas path of a certain component standard gas cylinder or carrier gas container, controlled by the host computer command of the control management unit.

[0014] The gas paths of the standard substance storage cabinet converge after passing through the solenoid valve group and are then connected to the standard gas mixing structure. Under the action of the slight positive pressure of the standard gas cylinder, each single gas component is delivered to the standard gas mixing structure. Through quantitative gas mixing of different components, a standard mixed gas with the concentration of each component of the preliminary test sample is dynamically prepared.

[0015] The carrier gas container is connected to the end of all single-component standard gas lines and is used to purge the standard material storage cabinet and the downstream pipeline when the carrier gas solenoid valve is opened, as well as to purge the insulating oil distribution device in the multi-parameter analysis platform for insulating oil samples.

[0016] The standard gas mixing structure is a cylinder mechanism based on a stepper motor for quantitative operation. It includes a standard gas mixing and injection structure with a metering cylinder and a mixing cylinder as the main components. In the standard gas mixing and injection structure, the metering cylinder and the mixing cylinder are connected to different stepper motors. Under the control of the gas path control system of the control management unit, the stepper motors, in conjunction with the opening and closing of the solenoid valve group, drive the piston movement of the metering cylinder and the mixing cylinder to realize gas transfer and purging between the metering cylinder and the mixing cylinder.

[0017] The top of both the metering cylinder and the mixing cylinder is connected to the air circuit of the air pump. The air pump is used to extract and empty the gas in the metering cylinder or the mixing cylinder to form a negative pressure inside the cylinder. By cooperating with the purging of the carrier gas, the residual gas inside the metering cylinder and the mixing cylinder can be quickly cleaned.

[0018] The mixing cylinder is surrounded by a heating module, which controls the temperature of the mixing cylinder to simulate the temperature state of the insulating oil sample during degassing.

[0019] When a single-component gas is quantitatively extracted from the standard substance storage cabinet, the piston of the quantitative cylinder is pulled down, using the slight positive pressure of the standard gas bottle to extract the single-component gas from the standard gas bottle.

[0020] The dynamic tracking calibration method for chromatographic analysis of the insulating oil comprehensive analysis platform, using the aforementioned insulating oil comprehensive analysis platform, involves the following specific steps when mixing quantitative gases of different components: First, the pistons of the quantitative cylinder and the mixing cylinder push and pull, transferring a quantitative amount of single-component gas from the quantitative cylinder to the mixing cylinder. By sequentially transferring multiple single-component standard gases and carrier gases into the mixing cylinder, the multi-component gases are mixed to the required concentration. Then, the piston of the mixing cylinder repeatedly expands and compresses the gas inside the cylinder through repeated pulling and pulling, completing the rapid mixing of non-uniform gases. Finally, the piston of the mixing cylinder moves upward to push the gas inside the cylinder, delivering the prepared standard gas under positive pressure into the external insulating oil analysis platform for dynamic standard mixed gas component calibration of the chromatographic analysis system on the platform.

[0021] After the chromatographic analysis system is calibrated, it recalculates the analysis results of the sample based on the secondary calibration results, thus obtaining the recalibrated analysis results.

[0022] When preparing standard gases, the control method of the gas circuit control system includes the following steps;

[0023] Step S1: Read the concentration calculation results of the chromatographic analysis of the insulating oil sample by the multi-parameter analysis platform, and use them for gas volume calculation;

[0024] Step S2: Read the manually preset concentrations of each component standard gas from the host computer of the analysis platform of the control and management unit;

[0025] Step S3: Substitute the concentrations of each component standard gas in the standard substance storage cabinet read in steps S1 and S2, the concentration of the oil sample analysis result, or the target concentration preset by humans, and the volume of the final mixed gas in the mixing cylinder to calculate the required gas volume of each component standard gas for the mixed gas.

[0026] Step S4: The control command of the analysis platform is sent to the solenoid valve group of the standard gas mixing and injection structure and the standard substance storage cabinet. The stepper motor drives the piston to move up and down. Different channels of the solenoid valve group cooperate with the piston switch to realize the mixing and preparation of single-component standard gases of different components.

[0027] Before sample analysis, the calibration system of the control management unit first calibrates the cylinder volume of the standard gas mixing structure. The specific method is as follows: the cylinder piston moves upwards to the top, the solenoid valve is opened to connect with the atmosphere, the current pressure value P1 is recorded, and after the solenoid valve is closed, the cylinder piston moves downwards a certain distance, resulting in a volume V. c Record the current cylinder pressure value P2, and then calculate the dead volume inside the cylinder using the following formula:

[0028]

[0029] Where Vt This represents the dead volume inside the cylinder; both fixed-displacement cylinders and mixing cylinders are calculated in this way.

[0030] Before sample analysis, the analysis platform's system has two built-in formulas for calculating gas volume; one is for preparing the sample at a manually set target concentration, with the following formula:

[0031] (i = 1, 2, ..., n; n equals the number of groups);

[0032] Secondly, the target concentration is prepared based on the sample analysis results, and the volume calculation expression is as follows:

[0033] (i = 1, 2, ..., n; n equals the number of groups)

[0034] In the formula, C i S represents the concentration of a component in the analysis results of an insulation sample. i X represents the concentration of a certain component in an artificially set standard gas. is This indicates the concentration of the component in the corresponding standard gas cylinder in the standard substance storage cabinet, and requires X during preparation. is >C i V B This represents the total volume of the final mixed gas in the mixing cylinder, and the volume of the mixed gas V... B The volume should be smaller than the maximum volume V2 of the mixing cylinder, and V 1s +V 2s +…+V ns +V t <V B The remaining ones have not reached V B The volume is partially filled with carrier gas, and the filling volume V d =V B -(V 1s +…+V ns +V t ).

[0035] The insulating oil comprehensive analysis platform employs the following steps when preparing and injecting mixed gases for analysis:

[0036] Step A1: The system initiates a preliminary cleaning process of the carrier gas into the standard gas mixing and injection structure, the gas path and cylinder of the standard substance storage cabinet, and simultaneously starts the mixing cylinder to heat up and stabilize. The gas path control system opens the solenoid valve corresponding to the carrier gas in the standard substance storage cabinet. The carrier gas passes through the first solenoid valve group (Y1), the metering cylinder, the third solenoid valve group (Y3), the mixing cylinder, and finally exits from port C of the second solenoid valve group (Y2), thus performing a preliminary purging of the entire gas path.

[0037] Step A2: The system starts the carrier gas to re-clean the two cylinders of the standard gas mixing and injection structure; as the two cylinders move up to the top in sequence, the AC and BC channels of the third solenoid valve group (Y3) are opened in sequence, and the air pump is started to extract the gas in the cylinder to a negative pressure state.

[0038] Step A3: Start the air replenishment and cleaning process for the two cylinders, starting with the metering cylinder; after opening the carrier gas solenoid valve of the standard substance storage cabinet and the AB channel of the first solenoid valve group (Y1), the piston of the metering cylinder is pulled down to the bottom. When the gas pressure inside the cylinder is greater than atmospheric pressure, the BC channel of the first solenoid valve group (Y1) is opened, and the metering cylinder moves upward to discharge the gas from the C port of the first solenoid valve group (Y1). Repeat this process multiple times to ensure that the cylinder is clean.

[0039] The next step is the air replenishment and cleaning process for the mixing cylinder. Open the carrier gas solenoid valve, the AB channels of the first solenoid valve group (Y1), and the AB channels of the third solenoid valve group (Y3). The piston in the mixing cylinder is pulled down to the bottom. When the cylinder pressure exceeds atmospheric pressure, the third solenoid valve group (Y3) is closed, and the AC channel of the second solenoid valve group (Y2) is opened. The piston moves upward, expelling gas from port C. This process is repeated multiple times to ensure thorough cleaning. Finally, the carrier gas solenoid valve is closed, and the AC and BC channels of the first solenoid valve group (Y1) are opened sequentially to release pressure, completing the initial cleaning process for the carrier gas.

[0040] Step A4: The system starts the mixed gas preparation process. When the first component gas in the standard substance storage cabinet is taken, the standard gas solenoid valve corresponding to the first component and the AC channel of the first solenoid valve group (Y1) are opened to discharge the residual gas and fill the pipeline with the standard gas of that component. The system calculates the required volume of the component and sends a stepper motor of the given cylinder to move it down a specified number of steps. Then, the AB channel of the first solenoid valve group (Y1) is opened. After the gas stabilizes, the BC channel is switched to open to balance the gas pressure and then the first solenoid valve group (Y1) is closed to complete the gas taking and pressure balancing of the single component. The method for taking the remaining component gases in the standard substance storage cabinet is similar to the method described in this step.

[0041] Step A5: The gas path control system controls the stepper motor corresponding to the mixing cylinder to move the piston of the mixing cylinder down to the bottom. Then, it controls the motor of the metering cylinder to move up, and simultaneously opens the AB channel of the third solenoid valve group (Y3) to transfer the gas in the metering cylinder to the mixing cylinder. Then, it closes the third solenoid valve group (Y3), and the piston of the mixing cylinder moves up to return to the calculated volume V of the components in the cylinder. 1s When mixing multiple components, the volume recovers to the sum of the volumes of the already mixed components, V. 1s +V 2s +…+V ns ;

[0042] Step A6: After all component gases are mixed, the solenoid valve of the standard substance storage cabinet switches to open the carrier gas solenoid valve, opening the AC channel of the first solenoid valve group (Y1) to purge any remaining components. Then, the metering cylinder motor descends, with a descending volume of V. d The carrier gas solenoid valve is closed, and the first solenoid valve group (Y1) switches the BC channel to stabilize the gas pressure in the metering cylinder before closing it. After the piston of the mixing cylinder descends to the bottom, the piston of the metering cylinder rises to the top while simultaneously opening the AB channel of the third solenoid valve group (Y3) to add carrier gas into the mixing cylinder. Subsequently, the third solenoid valve group (Y3) is closed, and the piston of the mixing cylinder rises back to the cylinder volume of V. B ;

[0043] Step A7: After completing the gas transfer and stabilizing the temperature of the mixing cylinder, execute the gas mixing process; the piston of the mixing cylinder is pulled down to the bottom, then moved up until the gas pressure inside the cylinder is slightly higher than atmospheric pressure. Repeat the above process several times to allow the gas inside the cylinder to expand and contract to achieve mixing. Then the piston returns to its original volume V. B ;

[0044] Step A8: After the gas mixture stabilizes, the chromatograph starts the standard sample analysis process according to the current procedure. The B outlet of the second solenoid valve group (Y2) is connected to the quantitative tube of the chromatograph. When the chromatograph performs the purging and quantification process, the piston of the mixing cylinder moves upward and opens the AB channel of the second solenoid valve group (Y2) to purge and quantify the quantitative tube with the prepared standard mixed gas. After quantification, the chromatograph performs sample injection analysis.

[0045] Step A9: Use the results obtained from the standard gas analysis by the chromatograph to analyze the oil sample and recalculate the analysis results of the insulating oil sample.

[0046] The insulating oil sample analysis platform of this invention enables automatic batch analysis of dissolved gas concentration, trace moisture content, withstand voltage, acid value, and dielectric loss in insulating oil. Furthermore, for the concentration of dissolved gases in insulating oil, a calibration technique is provided that can dynamically track the target concentration. This aims to verify the correctness and accuracy of the insulating oil sample analysis results. Calibration with sample concentrations close to the sample concentration range improves the accuracy of the analytical data. Simultaneously, it can also serve as a standard gas preparation device for standard sample analysis, solving the problem that when instrument conditions are limited or the deviation between the analyzed sample concentration and the standard gas concentration is large during single-point calibration, the analysis results cannot be accurately reflected.

[0047] Compared with the prior art, the advantages of the present invention are as follows:

[0048] 1. A multi-parameter automated analysis system was proposed. It can automatically analyze batch samples of insulating oil, including dissolved gas concentration, trace moisture, withstand voltage, acid value, and dielectric loss, and can also dynamically calibrate the chromatographic analysis system.

[0049] 2. The automatic chromatographic calibration unit of this device uses multiple dynamic single-component standard gases to prepare a mixed gas with concentrations matching those of each component in the analyte. This function is achieved by two piston-equipped cylinders. The first cylinder quantifies the single-component gas, while the second cylinder mixes and injects the gas. The two cylinders work together to transfer the gas, enabling more precise preparation of standard gases. This overcomes the problem of large deviations between instrument conditions or the concentrations of the analyzed sample and the standard gas during single-point calibration, particularly when only one component is close to its corresponding component in the mixed standard gas, while other components differ significantly, thus failing to accurately reflect the analytical results.

[0050] 3. The device employs three different purging methods for the gas path: carrier gas purging, negative pressure purging, and positive pressure purging. Combining these methods ensures a thorough and effective purging of the gas path.

[0051] 4. This device can extract different volumes of gas from each component according to the different concentrations of the standard gas for each component, so as to achieve the specified mixing concentration, making it more flexible and efficient in use.

[0052] 5. This device uses expansion and compression to achieve uniform gas mixing, avoiding interference from problems such as purging caused by circulation methods. Attached Figure Description

[0053] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0054] Appendix Figure 1 This is a schematic diagram of the workflow of the present invention;

[0055] Appendix Figure 2 This is a schematic diagram illustrating the principle of the present invention;

[0056] Appendix Figure 3 This is a schematic diagram of the workflow of the present invention during dynamic calibration of a chromatograph. Detailed Implementation

[0057] As shown in the figure, an insulating oil comprehensive analysis platform includes a control and management unit, an automatic sample quantitative distribution unit, an automatic chromatographic calibration unit, a multi-parameter analysis unit, and a sample sequence. The control and management unit includes an analysis control unit, a sample data management unit, and an analysis cycle management unit. The multi-parameter analysis unit and the automatic sample quantitative distribution unit automatically analyze the samples. After obtaining chromatographic analysis data through preliminary testing, the control and management unit, based on the sample analysis items recommended by the analysis cycle management system, controls the automatic chromatographic calibration unit, the multi-parameter analysis unit, and the standard substance storage cabinet to prepare a standard mixed gas with a concentration close to that of the preliminary test results. This gas is used as the gas calibration sample for the chromatographic analysis unit. The chromatographic analysis unit performs dynamic calibration based on the prepared gas calibration sample and then recalculates the sample based on the standard gas analysis results.

[0058] The control and management unit includes an industrial control computer with management software installed;

[0059] The multi-parameter analysis unit includes a multi-parameter automatic analysis module, which is used to automatically analyze batch samples of insulating oil samples for dissolved gas concentration, trace moisture, withstand voltage, acid value, and dielectric loss.

[0060] The automatic chromatographic calibration unit is used for automatic dynamic calibration of the chromatographic analysis unit;

[0061] The equipment for performing automated dynamic calibration operations includes a control and management unit, an automated chromatographic calibration unit, and a standard substance storage cabinet.

[0062] The standard substance storage cabinet includes multiple single-component standard gas cylinder storage compartments for storing standard gas cylinders of multiple single-component standard gas components and carrier gas containers; each storage compartment is separated by a solenoid valve group containing multiple switching solenoid valves, and each switching solenoid valve is used to individually control the gas path of a certain component standard gas cylinder or carrier gas container, controlled by the host computer command of the control management unit.

[0063] The gas paths of the standard substance storage cabinet converge after passing through the solenoid valve group and are then connected to the standard gas mixing structure. Under the action of the slight positive pressure of the standard gas cylinder, each single gas component is delivered to the standard gas mixing structure. Through quantitative gas mixing of different components, a standard mixed gas with the concentration of each component of the preliminary test sample is dynamically prepared.

[0064] The carrier gas container is connected to the end of all single-component standard gas lines and is used to purge the standard material storage cabinet and the downstream pipeline when the carrier gas solenoid valve is opened, as well as to purge the insulating oil distribution device in the multi-parameter analysis platform for insulating oil samples.

[0065] The standard gas mixing structure is a cylinder mechanism based on a stepper motor for quantitative operation. It includes a standard gas mixing and injection structure with a metering cylinder and a mixing cylinder as the main components. In the standard gas mixing and injection structure, the metering cylinder and the mixing cylinder are connected to different stepper motors. Under the control of the gas path control system of the control management unit, the stepper motors, in conjunction with the opening and closing of the solenoid valve group, drive the piston movement of the metering cylinder and the mixing cylinder to realize gas transfer and purging between the metering cylinder and the mixing cylinder.

[0066] The top of both the metering cylinder and the mixing cylinder is connected to the air circuit of the air pump. The air pump is used to extract and empty the gas in the metering cylinder or the mixing cylinder to form a negative pressure inside the cylinder. By cooperating with the purging of the carrier gas, the residual gas inside the metering cylinder and the mixing cylinder can be quickly cleaned.

[0067] The mixing cylinder is surrounded by a heating module, which controls the temperature of the mixing cylinder to simulate the temperature state of the insulating oil sample during degassing.

[0068] When a single-component gas is quantitatively extracted from the standard substance storage cabinet, the piston of the quantitative cylinder is pulled down, using the slight positive pressure of the standard gas bottle to extract the single-component gas from the standard gas bottle.

[0069] The dynamic tracking calibration method for chromatographic analysis of the insulating oil comprehensive analysis platform, using the aforementioned insulating oil comprehensive analysis platform, involves the following specific steps when mixing quantitative gases of different components: First, the pistons of the quantitative cylinder and the mixing cylinder push and pull, transferring a quantitative amount of single-component gas from the quantitative cylinder to the mixing cylinder. By sequentially transferring multiple single-component standard gases and carrier gases into the mixing cylinder, the multi-component gases are mixed to the required concentration. Then, the piston of the mixing cylinder repeatedly expands and compresses the gas inside the cylinder through repeated pulling and pulling, completing the rapid mixing of non-uniform gases. Finally, the piston of the mixing cylinder moves upward to push the gas inside the cylinder, delivering the prepared standard gas under positive pressure into the external insulating oil analysis platform for dynamic standard mixed gas component calibration of the chromatographic analysis system on the platform.

[0070] After the chromatographic analysis system is calibrated, it recalculates the analysis results of the sample based on the secondary calibration results, thus obtaining the recalibrated analysis results.

[0071] When preparing standard gases, the control method of the gas circuit control system includes the following steps;

[0072] Step S1: Read the concentration calculation results of the chromatographic analysis of the insulating oil sample by the multi-parameter analysis platform, and use them for gas volume calculation;

[0073] Step S2: Read the manually preset concentrations of each component standard gas from the host computer of the analysis platform of the control and management unit;

[0074] Step S3: Substitute the concentrations of each component standard gas in the standard substance storage cabinet read in steps S1 and S2, the concentration of the oil sample analysis result, or the target concentration preset by humans, and the volume of the final mixed gas in the mixing cylinder to calculate the required gas volume of each component standard gas for the mixed gas.

[0075] Step S4: The control command of the analysis platform is sent to the solenoid valve group of the standard gas mixing and injection structure and the standard substance storage cabinet. The stepper motor drives the piston to move up and down. Different channels of the solenoid valve group cooperate with the piston switch to realize the mixing and preparation of single-component standard gases of different components.

[0076] Before sample analysis, the calibration system of the control management unit first calibrates the cylinder volume of the standard gas mixing structure. The specific method is as follows: the cylinder piston moves upwards to the top, the solenoid valve is opened to connect with the atmosphere, the current pressure value P1 is recorded, and after the solenoid valve is closed, the cylinder piston moves downwards a certain distance, resulting in a volume V. c Record the current cylinder pressure value P2, and then calculate the dead volume inside the cylinder using the following formula:

[0077]

[0078] Where V t This represents the dead volume inside the cylinder; both fixed-displacement cylinders and mixing cylinders are calculated in this way.

[0079] Before sample analysis, the analysis platform's system has two built-in formulas for calculating gas volume; one is for preparing the sample at a manually set target concentration, with the following formula:

[0080] (i = 1, 2, ..., n; n equals the number of groups);

[0081] Secondly, the target concentration is prepared based on the sample analysis results, and the volume calculation expression is as follows:

[0082] (i = 1, 2, ..., n; n equals the number of groups)

[0083] In the formula, C i S represents the concentration of a component in the analysis results of an insulation sample. i X represents the concentration of a certain component in an artificially set standard gas. is This indicates the concentration of the component in the corresponding standard gas cylinder in the standard substance storage cabinet, and requires X during preparation. is >C i V B This represents the total volume of the final mixed gas in the mixing cylinder, and the volume of the mixed gas V... B The volume should be smaller than the maximum volume V2 of the mixing cylinder, and V 1s+V 2s +…+V ns +V t <V B The remaining ones have not reached V B The volume is partially filled with carrier gas, and the filling volume V d =V B -(V 1s +…+V ns +V t ).

[0084] The insulating oil comprehensive analysis platform employs the following steps when preparing and injecting mixed gases for analysis:

[0085] Step A1: The system initiates the initial cleaning process of the carrier gas into the standard gas mixing and injection structure, the gas path and cylinder of the standard substance storage cabinet, and simultaneously starts the temperature stabilization of the mixing cylinder; the gas path control system opens the solenoid valve corresponding to the carrier gas in the standard substance storage cabinet, and the carrier gas passes through the first solenoid valve group Y1, the metering cylinder, the third solenoid valve group (Y3), the mixing cylinder, and finally exits from port C of the second solenoid valve group Y2, performing an initial purging of the entire gas path;

[0086] Step A2: The system starts the carrier gas to re-clean the two cylinders of the standard gas mixing and injection structure; as the two cylinders move up to the top in sequence, the AC and BC channels of the third solenoid valve group Y3 are opened in sequence, and the air pump is started to extract the gas in the cylinder to a negative pressure state.

[0087] Step A3: Start the air replenishment and cleaning process for the two cylinders, starting with the metering cylinder; after opening the carrier gas solenoid valve of the standard substance storage cabinet and the AB channel of the first solenoid valve group Y1, the piston of the metering cylinder is pulled down to the bottom. When the air pressure inside the cylinder is greater than the atmospheric pressure, the BC channel of the first solenoid valve group Y1 is opened, and the metering cylinder moves upward to discharge the gas from the C port of the first solenoid valve group Y1. Repeat this process multiple times to ensure that the purging is clean.

[0088] The next step is the air replenishment and cleaning process for the mixing cylinder. Open the carrier gas solenoid valve, the AB channels of the first solenoid valve group Y1, and the AB channels of the third solenoid valve group (Y3). The piston in the mixing cylinder is pulled down to the bottom. When the cylinder pressure exceeds atmospheric pressure, the third solenoid valve group (Y3) is closed, and the AC channel of the second solenoid valve group Y2 is opened. The piston moves upward, expelling gas from port C. This process is repeated multiple times to ensure thorough cleaning. Finally, close the carrier gas solenoid valve and sequentially open the AC and BC channels of the first solenoid valve group Y1 to release pressure, completing the initial cleaning process for the carrier gas.

[0089] Step A4: The system initiates the mixed gas preparation process. When the first component gas from the standard substance storage cabinet is taken, the solenoid valve corresponding to the first component and the AC channel of the first solenoid valve group Y1 are opened to discharge the residual gas and fill the pipeline with the standard gas of that component. The system calculates the required volume of the component and sends a stepper motor to the given cylinder to move it down a specified number of steps. Then, the AB channel of the first solenoid valve group Y1 is opened. After the gas stabilizes, the BC channel is switched to open to balance the gas pressure and then the first solenoid valve group Y1 is closed, completing the gas taking and pressure balancing of the single component. The method for taking the remaining component gases from the standard substance storage cabinet is similar to the method described in this step.

[0090] Step A5: The gas path control system controls the stepper motor corresponding to the mixing cylinder to move the piston of the mixing cylinder down to the bottom. Then, it controls the motor of the metering cylinder to move up, and simultaneously opens the AB channel of the third solenoid valve group (Y3) to transfer the gas in the metering cylinder to the mixing cylinder. Then, it closes the third solenoid valve group (Y3), and the piston of the mixing cylinder moves up to return to the calculated volume V of the components in the cylinder. 1s When mixing multiple components, the volume recovers to the sum of the volumes of the already mixed components, V. 1s +V 2s +…+V ns ;

[0091] Step A6: After all component gases are mixed, the solenoid valve of the standard substance storage cabinet switches to open the carrier gas solenoid valve, opening the AC channel of the first solenoid valve group Y1 to purge any remaining components. Then, the metering cylinder motor descends, with a descending volume of V. d The carrier gas solenoid valve is closed, and the first solenoid valve group Y1 switches the BC channel to stabilize the gas pressure in the metering cylinder before closing. After the piston of the mixing cylinder descends to the bottom, the piston of the metering cylinder rises to the top while simultaneously opening the AB channel of the third solenoid valve group (Y3) to add carrier gas into the mixing cylinder. Subsequently, the third solenoid valve group (Y3) is closed, and the piston of the mixing cylinder rises back to the cylinder volume of V. B ;

[0092] Step A7: After completing the gas transfer and stabilizing the temperature of the mixing cylinder, execute the gas mixing process; the piston of the mixing cylinder is pulled down to the bottom, then moved up until the gas pressure inside the cylinder is slightly higher than atmospheric pressure. Repeat the above process several times to allow the gas inside the cylinder to expand and contract to achieve mixing. Then the piston returns to its original volume V. B ;

[0093] Step A8: After the gas mixture stabilizes, the chromatograph starts the standard sample analysis process according to the current procedure. The B outlet of the second solenoid valve group Y2 is connected to the quantitative tube of the chromatograph. When the chromatograph performs the purging and quantification process, the piston of the mixing cylinder moves upward and opens the AB channel of the second solenoid valve group Y2 to purge and quantify the quantitative tube with the prepared standard mixed gas. After quantification, the chromatograph performs sample injection analysis.

[0094] Step A9: Use the results obtained from the standard gas analysis by the chromatograph to analyze the oil sample and recalculate the analysis results of the insulating oil sample.

[0095] In this example, the metering cylinder and the mixing cylinder are each connected to different pressure sensors to accurately measure the pressure inside the cylinder, making the preparation of the standard gas more accurate.

[0096] This example presents a comprehensive analysis platform for insulating oil samples and an automated tracking and calibration method for dissolved gas concentration chromatographic analysis. The comprehensive analysis platform for insulating oil samples includes a control and management unit, an automatic sample quantitative distribution unit, an automatic chromatographic calibration unit, a multi-parameter analysis unit, a sample sequence, and a standard substance storage cabinet. This platform can achieve fully automated analysis of multiple parameters of insulating oil and automatic calibration of the detection units.

[0097] This example can dynamically track the target concentration of the sample. By using a piston, the action of sequentially transferring multiple single-component standard gases and carrier gases into the mixing cylinder can realize the preparation of multi-component mixed standard gases of arbitrary concentration (traditional dynamic gas mixing is generally based on the dynamic gas mixing method of flow controller). This enables multi-point calibration of the chromatographic analysis system and solves the problem that when the instrument conditions or the concentration of the analytical sample and the concentration of the standard gas are large during single-point calibration, the low calibration and high usage cannot accurately reflect the analytical results.

Claims

1. An integrated platform for comprehensive analysis of insulating oil, characterized by: The control management unit, the automatic sample quantitative distribution unit, the chromatographic automatic calibration unit, the multi-parameter analysis unit, and the sample sequence; the control management unit includes an analysis control unit, a sample data management unit, and an analysis cycle management unit; the multi-parameter analysis unit and the automatic sample quantitative distribution unit automatically analyze the sample, the control management unit controls the chromatographic automatic calibration unit, the multi-parameter analysis unit, and the standard substance storage cabinet according to the sample analysis project recommended by the analysis cycle management system after obtaining the chromatographic analysis data through preliminary testing, prepares and preliminarily tests the standard mixed gas with the same concentration as the sample, uses the standard mixed gas as the gas calibration sample of the chromatographic analysis unit, and performs dynamic calibration on the chromatographic analysis unit according to the prepared gas calibration sample, and recalculates the sample according to the standard gas analysis result; The standard substance storage cabinet includes a plurality of single-component standard gas bottle storage compartments for storing a plurality of single-component standard gas component calibration gas bottles and carrier gas containers; each storage compartment is separated by an electromagnetic valve group including a plurality of on-off electromagnetic valves, and each on-off electromagnetic valve is used for separately controlling the opening and closing of the gas path corresponding to a certain component calibration gas bottle or carrier gas container and is controlled by the host computer of the control management unit; The gas paths of the standard substance storage cabinet are collected after passing through the electromagnetic valve group and are connected to the standard gas mixing structure, the single gas components are transported to the standard gas mixing structure under the action of the slight positive pressure of the calibration gas bottle, and the standard mixed gas with the same concentration as each component of the preliminary test sample is dynamically prepared by quantitative gas mixing of different components; The carrier gas container is connected to the end of all single-component calibration gas paths and is used for purging the standard substance storage cabinet and the rear-end pipeline when the carrier gas electromagnetic valve is opened and is used for purging the insulating oil distribution device in the insulating oil sample multi-parameter analysis platform; The standard gas mixing structure is a cylinder mechanism for quantitative operation based on a stepper motor and includes a standard gas mixing sample inlet structure with a quantitative cylinder and a mixing cylinder as the main body, the quantitative cylinder and the mixing cylinder in the standard gas mixing sample inlet structure are connected to different stepper motors, the stepper motors are controlled by the gas path control system of the control management unit, the opening and closing of the electromagnetic valve group, and the piston movement of the quantitative cylinder and the mixing cylinder to realize the gas transfer and purging between the quantitative cylinder and the mixing cylinder.

2. The comprehensive analysis platform for insulating oil according to claim 1, characterized in that: The control management unit includes an industrial computer installed with management software; The multi-parameter analysis unit includes a multi-parameter automatic analysis module for automatically analyzing the dissolved gas concentration, trace moisture, pressure resistance, acid value, and dielectric loss of the insulating oil sample; The chromatographic automatic calibration unit is used for automatic dynamic calibration of the chromatographic analysis unit; The execution equipment of the automatic dynamic calibration operation includes the control management unit, the chromatographic automatic calibration unit, and the standard substance storage cabinet.

3. The integrated platform for comprehensive analysis of insulating oil according to claim 1, characterized in that: The top of the quantitative cylinder and the mixing cylinder is connected to the gas path of the air pump, the air pump is used for pumping out and emptying the gas in the quantitative cylinder or the mixing cylinder to form negative pressure in the cylinder, and the residual gas in the quantitative cylinder and the mixing cylinder is quickly cleaned through the purging of the carrier gas; The mixed gas cylinder is wrapped with a heating module, which simulates the temperature state of the insulating oil sample during degassing by controlling the temperature of the mixed gas cylinder; When the single-component gas is quantitatively extracted from the standard substance storage cabinet, the piston of the quantitative gas cylinder is pulled down to extract the single-component gas in the standard gas cylinder by using the slight positive pressure of the standard gas cylinder.

4. A chromatographic analysis dynamic tracking calibration method of an insulating oil comprehensive analysis platform, adopting the insulating oil comprehensive analysis platform of claim 3, characterized in that: In the process of mixing the quantitative gas of different components, the method is as follows: firstly, the single-component gas in the quantitative gas cylinder is transferred to the mixed gas cylinder by the push-pull action of the pistons of the quantitative gas cylinder and the mixed gas cylinder; secondly, the mixing of the multi-component gas in the mixed gas cylinder is realized by sequentially transferring the standard gas of multiple single components and the carrier gas into the mixed gas cylinder, so that the required concentration is achieved; thirdly, the piston of the mixed gas cylinder is repeatedly pulled and pushed to make the gas in the cylinder repeatedly expand and compress, so that the rapid mixing of the non-uniform gas is completed; finally, the piston of the mixed gas cylinder is pushed up to push the gas in the cylinder, and the prepared standard gas is positively fed into the external insulating oil analysis platform, so that the component calibration of the dynamic standard mixed gas of the chromatographic analysis system in the platform is carried out.

5. The chromatographic analysis dynamic tracking calibration method of the integrated insulating oil analysis platform according to claim 4, characterized in that: After the calibration of the chromatographic analysis system, the chromatographic analysis system recalculates the analysis result of the sample according to the secondary calibration result, so as to obtain the recalibrated analysis result.

6. The chromatographic analysis dynamic tracking calibration method of the comprehensive insulating oil analysis platform according to claim 5, characterized in that: In the process of preparing the standard gas, the control method of the gas path control system includes the following steps: Step S1: reading the concentration calculation result of the multi-parameter analysis platform for the chromatographic analysis of the insulating oil sample, which is used for the calculation of the gas volume; Step S2: reading the manually pre-set concentration of each component standard gas from the upper computer of the analysis platform of the control management unit; Step S3: substituting the concentration of each component standard gas in the standard substance storage cabinet, the concentration of the oil sample analysis result or the target concentration pre-set by the manual, and the volume of the final mixed gas in the mixed gas cylinder into the concentration calculation result of the multi-parameter analysis platform for the chromatographic analysis of the insulating oil sample, so as to calculate the gas volume of each component standard gas required by the mixed gas; Step S4: the control instruction of the analysis platform is sent to the electromagnetic valve group of the standard gas mixing and sampling structure and the standard substance storage cabinet, the stepping motor drives the piston to move up and down, and the different channels of the electromagnetic valve group cooperate with the piston switch to realize the mixing and preparation of the single-component standard gas of different components.

7. The chromatographic analysis dynamic tracking calibration method of the integrated insulating oil analysis platform according to claim 5, characterized in that: Before sample analysis, the correction system of the control management unit first corrects the cylinder volume of the standard gas mixture structure, in particular, the cylinder piston is raised to the top, the electromagnetic valve is opened to communicate with the atmosphere, and the current pressure value is recorded After the electromagnetic valve is closed, the cylinder piston is lowered by a distance with a volume of , and the current in-cylinder pressure value is recorded , and the in-cylinder dead volume is obtained, and the formula is: ； wherein Vd represents the dead volume in the cylinder, which is quantified for both the cylinder and the mixing cylinder in this way; Before the sample analysis, two gas volume calculation formulas are built in the system of the analysis platform; one is to prepare the target concentration set by the manual, and the calculation expression is: (i = 1,2, n; n is equal to the number of components) The other is to prepare the target concentration of the sample analysis result, and the volume calculation expression is: (i = 1,2, n; n is equal to the number of components) In the formula, represents the concentration of a component in the analysis result of the insulating sample, represents the concentration of a component in the artificially set standard gas, represents the concentration of the component in the standard gas bottle corresponding to the standard material storage cabinet, and the concentration is required when the standard gas is prepared , represents the total volume of the final mixed preparation gas in the mixing cylinder, and the volume of the preparation gas should be less than the maximum volume of the mixing cylinder , and , the remaining part not reaching the volume is filled with carrier gas, and the filling volume .

8. The chromatographic analysis dynamic tracking calibration method of the integrated insulating oil analysis platform according to claim 7, characterized in that: The method for executing the preparation and sampling analysis of the mixed gas includes the following steps: Step A1: the system starts the preliminary cleaning process of the gas path and the cylinder of the standard gas mixing and sampling structure and the standard substance storage cabinet by using the carrier gas, and simultaneously starts the temperature rising and stabilization of the mixed gas cylinder; the gas path control system opens the electromagnetic valve corresponding to the carrier gas in the standard substance storage cabinet, the carrier gas is discharged from the C port of the second electromagnetic valve group (Y2) after passing through the first electromagnetic valve group (Y1), the quantitative gas cylinder, the third electromagnetic valve group (Y3) and the mixed gas cylinder, and the whole gas path is preliminarily purged; Step A2, the system starts to clean the two cylinders with carrier gas; when the two cylinders go up to the top, the AC and BC channels of the third electromagnetic valve group (Y3) are opened in turn, and the air pump is started to pump the gas in the cylinders to the negative pressure state; Step A3, the gas supplement cleaning process of the two cylinders is started; first, the quantitative cylinder; after the carrier gas electromagnetic valve and the AB channel of the first electromagnetic valve group (Y1) are opened, the piston of the quantitative cylinder is pulled down to the bottom, and when the gas pressure in the cylinder is greater than the atmospheric pressure, the BC channel of the first electromagnetic valve group (Y1) is opened, the quantitative cylinder goes up to discharge the gas from the C port of the first electromagnetic valve group (Y1), and the process is repeated several times to ensure that the cylinder is clean; second, the gas supplement cleaning process of the mixing cylinder; after the carrier gas electromagnetic valve, the AB channel of the first electromagnetic valve group (Y1), and the AB channel of the third electromagnetic valve group (Y3) are opened, the piston of the mixing cylinder is pulled down to the bottom, and when the gas pressure in the cylinder is greater than the atmospheric pressure, the third electromagnetic valve group (Y3) is closed, the AC channel of the second electromagnetic valve group (Y2) is opened, and the piston goes up to discharge the gas from the C port, and the process is repeated several times to ensure that the cylinder is clean, finally the carrier gas electromagnetic valve is closed, and the AC and BC channels of the first electromagnetic valve group (Y1) are opened in turn to release the pressure, and the pre-cleaning process of the carrier gas is completed; Step A4, the system starts the mixed gas preparation process; when the first component gas of the standard substance storage cabinet is taken, the corresponding standard gas electromagnetic valve and the AC channel of the first electromagnetic valve group (Y1) are opened, and the residual gas is discharged to make the pipeline full of the component standard gas; the system calculates the required volume of the component and sends it to the stepper motor of the quantitative cylinder to make it go down by a specified number of steps, then the AB channel of the first electromagnetic valve group (Y1) is opened, and after the gas is stable, the BC channel is opened to balance the gas pressure, and then the first electromagnetic valve group (Y1) is closed, the single-component gas taking and pressure balancing are completed; the method of taking the remaining component gas of the standard substance storage cabinet is similar to the above method; Step A5, the gas path control system controls the corresponding stepper motor of the mixing cylinder, so that the mixing cylinder piston goes down to the bottom, then controls the quantitative cylinder motor to go up, and at the same time opens the AB channel of the third electromagnetic valve group (Y3), so as to transfer the gas in the quantitative cylinder to the mixing cylinder; then closes the third electromagnetic valve group (Y3), and the piston of the mixing cylinder goes up to restore the cylinder volume to the calculated volume of the components When mixing multiple components, the volume is restored to the sum of the volumes of the mixed components ; Step A6, after the completion of the mixing of each component gas, the standard substance storage cabinet electromagnetic valve switches to open the carrier gas electromagnetic valve, opens the AC channel of the first electromagnetic valve group (Y1), blows away the remaining components, and then the quantitative gas cylinder motor goes down, the down volume is , closes the carrier gas electromagnetic valve, and the first electromagnetic valve group (Y1) switches to the BC channel to stabilize the pressure in the quantitative gas cylinder, and then closes; after the mixing cylinder piston goes down to the bottom, the quantitative gas cylinder piston goes up to the top, and the AB channel of the third electromagnetic valve group (Y3) is opened to add carrier gas to the mixing cylinder; then close the third electromagnetic valve group (Y3), and the mixing cylinder piston goes up to restore the cylinder volume to ; Step A7, after the gas transfer is completed and the temperature of the mixing cylinder is stable, the gas mixing process is performed; the piston of the mixing cylinder is pulled down to the bottom, and then goes up to the cylinder pressure slightly greater than atmospheric pressure, the above process is repeated several times to make the cylinder gas expand and contract to achieve the purpose of mixing, and then the piston returns to the original volume ; Step A8, after the gas mixing is stable, the chromatograph starts the standard sample analysis process according to the current process; the B outlet of the second electromagnetic valve group (Y2) is connected with the quantitative tube of the chromatograph; when the chromatograph executes the blowing and quantifying process, the piston of the mixing cylinder goes up, and the AB channel of the second electromagnetic valve group (Y2) is opened to prepare the completed standard mixed gas to blow and quantify the quantitative tube; after the quantification is completed, the chromatograph performs sampling analysis; Step A9, the results obtained by the chromatograph from the standard gas analysis are used for oil sample analysis, and the analysis results of the insulating oil sample are recalculated.

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