Degassing device and method for online monitoring of dissolved gases in transformer insulating oil

Abstract

A degassing device and method for online monitoring of dissolved gases in transformer insulating oil. The degassing device comprises: a degassing cylinder consisting of a cylinder body, a piston and a piston rod, the piston being arranged in the cylinder body, a piston chamber being formed between the piston and the cylinder body, one end of the piston rod being connected to the piston, the piston chamber being provided with an oil intake and return port at the bottom, and the oil intake and return port being connected to an oil intake port and an oil return port of an external transformer; a driving module, an output end of which is connected to the other end of the piston rod, the driving module being configured to drive the piston rod to move; an oil-proof bottle, the bottom of which is in communication with the top of the piston chamber, a liquid level sensor and a pressure sensor being provided inside the oil-proof bottle, and the top of the oil-proof bottle being in communication with an external detector and an external venting area; and a heating and stirring mechanism configured to heat and stir the piston chamber. The present application has the beneficial effects of good air tightness, high dosing accuracy, more accurate test results, and good repeatability.

Description

Degassing device and method for online monitoring of dissolved gases in transformer insulating oil

[0001] [Amended according to Rule 91 19.08.2025] This application claims priority to Chinese Patent Application No. 2024116531574, filed on January 2, 2025, entitled “A Degassing Device and Method for Online Monitoring of Dissolved Gases in Transformer Insulating Oil”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of power detection technology, and in particular to a degassing device and method for online monitoring of dissolved gases in transformer insulating oil. Background Technology

[0003] The power system is a vital infrastructure of modern society, providing a stable power supply for industrial production and residential life. Transformers, as key transmission and transformation equipment in the power system, undertake important tasks such as voltage transformation and power transmission. Their operational stability and safety are crucial to the normal operation of the entire power system. A transformer failure can lead to widespread power outages, disrupting production and daily life, and causing significant economic losses. Therefore, close monitoring of the transformer's operating status is essential.

[0004] During transformer operation, internal faults such as insulation aging, localized overheating, and electrical discharge can cause the insulation material to decompose, producing various gases that dissolve in the transformer oil. The composition and content of these gases vary depending on the type of fault. For example, localized overheating faults produce gases such as methane and ethylene, while electrical discharge faults produce gases such as acetylene and hydrogen. Therefore, analyzing the composition, content, and trends of dissolved gases in transformer oil can effectively determine the transformer's operating status and potential fault types.

[0005] Whether using gas chromatography or spectroscopy to monitor dissolved gas content in transformer oil, oil-gas separation technology is an essential step in dissolved gas analysis. Currently, commonly used oil-gas separation techniques include polymer membrane permeation degassing, dynamic headspace degassing, and vacuum degassing. Among these, polymer membrane permeation degassing has low degassing efficiency, long equilibrium time, and does not meet real-time requirements. Dynamic headspace degassing typically involves continuously introducing inert gas into the sample, preventing the oil sample from being returned to the transformer. Vacuum degassing requires a vacuum pump, has a complex degassing structure, and poor repeatability.

[0006] To address these issues related to oil-gas separation, this application provides a method for online monitoring and degassing of dissolved gases in transformer insulating oil. Summary of the Invention

[0007] According to an embodiment of this application, a degassing device for online monitoring of dissolved gases in transformer insulating oil is provided, comprising:

[0008] The degassing cylinder consists of a cylinder body, a piston, and a piston rod. The piston is located inside the cylinder body, forming a piston chamber. One end of the piston rod is connected to the piston. The bottom of the piston chamber is provided with an oil inlet and return port, which are connected to the oil inlet and return port of the external transformer.

[0009] The drive module, whose output end is connected to the other end of the piston rod, is used to drive the piston rod to move and control the pressure inside the piston chamber.

[0010] The oil-proof bottle has its bottom connected to the top of the piston chamber. The oil-proof bottle is equipped with a liquid level sensor and a pressure sensor. The top of the oil-proof bottle is connected to an external detector and an external venting area.

[0011] The heating and stirring mechanism is connected to the degassing cylinder and is used to heat and stir the piston chamber.

[0012] Furthermore, the piston rod has an axial connecting hole for connecting the top of the piston chamber and the bottom of the oil-proof bottle.

[0013] Furthermore, the degassing device for online monitoring of dissolved gases in transformer insulating oil in this application also includes: a first pipeline, which is connected between the connecting hole and the bottom of the oil-proof bottle, and the first pipeline is a PA hose with a diameter of 2mm.

[0014] Furthermore, the degassing device for online monitoring of dissolved gases in transformer insulating oil according to this application also includes:

[0015] The second pipeline is used to connect the oil inlet and return port with the oil inlet and return port of the transformer;

[0016] The oil inlet solenoid valve is connected to the second pipeline and is used to control the on / off connection between the oil inlet / outlet and the transformer oil inlet.

[0017] The return oil solenoid valve is connected to the second pipeline and is used to control the on / off connection between the return oil inlet and the return oil outlet of the transformer.

[0018] Furthermore, the second conduit is a copper pipe with a diameter of 8mm.

[0019] Furthermore, the heating and stirring mechanism includes:

[0020] The heating and heat preservation module is connected to the cylinder body and is used to heat the inside of the cylinder body.

[0021] The stirring module stirs the inside of the cylinder block.

[0022] Furthermore, the stirring module includes:

[0023] A six-bladed propeller agitator, with the six-bladed propeller agitator located inside the piston chamber;

[0024] The magnetic stirrer motor is magnetically connected to the six-bladed propeller stirrer and is used to drive the six-bladed propeller stirrer to rotate.

[0025] Furthermore, the degassing device for online monitoring of dissolved gases in transformer insulating oil according to this application also includes:

[0026] The sample injection solenoid valve is connected to the top of the oil-proof bottle and the detector, and is used to control the on / off connection between the oil-proof bottle and the detector.

[0027] The venting solenoid valve connects the top of the oil-proof bottle to the venting area and is used to control the on / off connection between the oil-proof bottle and the venting area.

[0028] Furthermore, the drive module is a through-type stepper motor, which is connected to the other end of the piston rod via a lead screw to drive the piston rod to move and control the pressure inside the piston chamber.

[0029] According to another embodiment of this application, a degassing method for online monitoring of dissolved gases in transformer insulating oil is provided, comprising the following steps:

[0030] Step 1, oil system cleaning process, is as follows:

[0031] Close the injection solenoid valve, open the venting solenoid valve, and the through-type stepper motor drives the piston to move downward to the bottom limit, venting the excess gas in the piston chamber.

[0032] When the venting solenoid valve is closed, the through-type stepper motor drives the piston to move upward a certain distance, so that the piston chamber is in a negative pressure state.

[0033] When the oil inlet solenoid valve is opened, insulating oil enters the piston chamber due to the negative pressure inside the piston chamber and the transformer's own pressure.

[0034] Close the oil inlet solenoid valve, open the vent solenoid valve, and the through-type stepper motor drives the piston to move downward to expel excess gas from the piston chamber until the liquid level sensor in the oil bottle detects the liquid level signal.

[0035] Close the venting solenoid valve and open the return oil solenoid valve. The through-type stepper motor drives the piston to continue moving downward until the piston moves to the bottom limit of the piston chamber, returning the insulating oil to the transformer's oil tank.

[0036] Repeat the above steps multiple times to complete the cleaning of the oil passage and piston chamber;

[0037] Step 2, the cleaning process of the gas line and oil-proof bottle, is as follows:

[0038] When the detector switches to the sample injection state, the oil inlet solenoid valve, oil return solenoid valve, venting solenoid valve and sample injection solenoid valve are closed. The through-type stepper motor drives the piston to move upward to the top of the piston chamber, so that the piston chamber is in a negative pressure state.

[0039] When the detector switches to degassing mode and the injection solenoid valve is opened, the carrier gas in the detector enters the piston chamber through the oil-proof bottle under the negative pressure in the piston chamber.

[0040] The detector switches back to the injection state, the injection solenoid valve is closed, and the carrier gas fills the detector again. At this time, the venting solenoid valve is opened, and the through-type stepper motor drives the piston to move downward to the bottom limit of the piston chamber to discharge excess gas. The venting solenoid valve is then closed.

[0041] Repeat the above steps several times to complete the cleaning of the gas line and oil-proof bottle;

[0042] Step 3, the oil sample quantification process, is as follows:

[0043] The oil inlet solenoid valve, oil return solenoid valve, venting solenoid valve and sample injection solenoid valve are closed. The through-type stepper motor drives the piston to move upward to a certain distance, so that the piston chamber is in a negative pressure state.

[0044] When the oil inlet solenoid valve is opened, the oil sample is drawn into the piston chamber under the negative pressure.

[0045] Once the pressure inside the piston chamber returns to a standard atmosphere, open the venting solenoid valve. The through-type stepper motor drives the piston to slowly move downwards. Once the liquid level detector detects the liquid level signal, close the venting solenoid valve, open the return oil solenoid valve, and the through-type stepper motor drives the piston to continue moving downwards to the designated position. Then, close the return oil solenoid valve.

[0046] Step 4, headspace degassing process, is as follows:

[0047] Close the oil inlet solenoid valve, oil return solenoid valve, venting solenoid valve and sample injection solenoid valve, and control the heating and heat preservation module to heat the inside of the piston chamber and control the temperature at 50℃.

[0048] Start the magnetic stirrer motor to drive the six-bladed propeller stirrer to rotate, and the through stepper motor drives the piston to move upward, creating a negative pressure between the bottom of the piston and the oil sample;

[0049] Dissolved gases in insulating oil are continuously released under specific temperature, stirring and negative pressure, and under the action of buoyancy, the released gases move to the top of the oil-proof bottle and piston chamber;

[0050] Step 5, the balancing process, is as follows:

[0051] After degassing is complete, stop the magnetic stirrer motor, restore the atmospheric pressure inside the piston chamber to one standard atmosphere, continue to maintain the temperature of the piston chamber at 50°C, and let it stand for a period of time to allow the degassing gas and the dissolved gas in the insulating oil to reach equilibrium.

[0052] Step 6, the sample injection and analysis process, is as follows:

[0053] After headspace degassing is completed, the venting solenoid valve is closed and the injection solenoid valve is opened. The through-type stepper motor drives the piston to move down and sends the precipitated gas into the detector.

[0054] Maintain a constant pressure inside the detector, then switch the detector to sample injection mode, and introduce the extracted gas into the chromatographic analysis module of the detector. The solubility of each component of the gas sample is obtained through the chromatographic analysis module.

[0055] Step 7, the oil return process, is as follows:

[0056] After the sample injection analysis is completed, the sample injection solenoid valve is closed, the venting solenoid valve is opened, and the through-type stepper motor drives the piston to move down to expel excess gas.

[0057] Until the liquid level sensor detects the liquid level signal, the venting solenoid valve is closed and the return oil solenoid valve is opened. The through-type stepper motor drives the piston to continue moving down to the bottom limit of the piston chamber. The pressure of the piston slowly sends the degassed insulating oil back to the transformer's oil tank.

[0058] Step 8, the calculation process, is as follows:

[0059] After headspace degassing is completed, the piston is at the top of the piston chamber, and the pressure is measured by the pressure sensor.

[0060] The position of the piston is adjusted by a through-type stepper motor. After multiple fine adjustments, the number of steps N is recorded when the through-type stepper motor moves the piston from the top zero point of the piston chamber until the pressure sensor measures a constant pressure of one standard atmosphere.

[0061] The distance L that the piston moves is calculated based on the number of steps N and the step length S of the through stepper motor, i.e., L = N * S;

[0062] Based on the distance L that the piston moves, calculate the total volume V of the gas and liquid in the piston chamber, V = Vt - L * S1, where Vt is the volume of the piston chamber and S1 is the cross-sectional area of ​​the piston chamber.

[0063] The volume of gas released, Vg, can be calculated by subtracting the volume of liquid, Vl, from the total volume of gas and liquid, i.e., Vg = V - Vl.

[0064] Finally, the concentration of each component in the extracted gas was analyzed using a chromatographic analysis module, and the concentration of each component of the dissolved gas in the insulating oil was calculated using the headspace degassing method calculation formula.

[0065] The degassing device and method for online monitoring of dissolved gases in transformer insulating oil described in this application have the following beneficial effects:

[0066] 1. It can significantly shorten the degassing time and ensure efficient operation; the structural design is simple, robust and reliable, and easy to maintain and apply;

[0067] 2. It has good repeatability to ensure the consistency of monitoring results each time;

[0068] 3. It can significantly reduce errors and improve data accuracy during the measurement process;

[0069] 4. When analyzing oil samples, this device does not require additional inert gas for replacement, simplifying the operation process; at the same time, the tested oil samples do not require special treatment, saving both time and reducing costs.

[0070] It should be understood that both the foregoing general description and the following detailed description are exemplary and intended to provide further illustration of the claimed technology. Attached Figure Description

[0071] Figure 1 is a schematic diagram of a degassing device for online monitoring of dissolved gases in transformer insulating oil according to an embodiment of this application.

[0072] Figure 2 is a schematic diagram of the structure of a degassing device for online monitoring of dissolved gases in transformer insulating oil according to an embodiment of this application.

[0073] Figure 3 is a flowchart illustrating a degassing method for online monitoring of dissolved gases in transformer insulating oil according to an embodiment of this application.

[0074] Figure 4 is a formula diagram of the calculation formula for headspace degassing in a degassing method for online monitoring of dissolved gases in transformer insulating oil according to an embodiment of this application. Detailed Implementation

[0075] The preferred embodiments of this application will be described in detail below with reference to the accompanying drawings, further illustrating this application.

[0076] First, a degassing device for online monitoring of dissolved gases in transformer insulating oil according to an embodiment of this application will be described with reference to Figures 1-2. It is used for degassing in online monitoring of dissolved gases in transformer insulating oil and has a wide range of applications.

[0077] As shown in Figures 1 and 2, a degassing device for online monitoring of dissolved gases in transformer insulating oil according to an embodiment of this application includes a degassing cylinder, a drive module, an oil-proof bottle 300, and a heating and stirring mechanism.

[0078] Specifically, as shown in Figures 1-2, the degassing cylinder consists of a cylinder body 101, a piston 102, and a piston rod 103. The piston 102 is located inside the cylinder body 101, forming a piston chamber 104 between it and the cylinder body 101. One end of the piston rod 103 is connected to the piston 102. The bottom of the piston chamber 104 is provided with an oil inlet / outlet 105, which is connected to the oil inlet and outlet of the external transformer 500.

[0079] Specifically, as shown in Figures 1-2, the output end of the drive module is connected to the other end of the piston rod 103. The drive module is a through-type stepper motor 200, which is connected to the other end of the piston rod 103 through a lead screw to drive the piston rod 103 to move and control the pressure inside the piston chamber 104.

[0080] Specifically, as shown in Figures 1 and 2, the bottom of the oil-proof bottle 300 is connected to the top of the piston chamber 104. The oil-proof bottle 300 contains a liquid level sensor 301 and a pressure sensor 302. The top of the oil-proof bottle 300 is connected to an external detector and an external venting area. The external venting area refers to the space used for venting gas and can be selected based on venting requirements. The internal space of the oil-proof bottle 300 should be as small as possible, such as 0.5 ml, to avoid affecting the gas collection of the subsequent detector.

[0081] Specifically, as shown in Figures 1 and 2, the heating and stirring mechanism is connected to the degassing cylinder and is used to heat and stir the piston chamber 104. The heating and stirring mechanism includes a heating and insulation module 401 and a stirring module. The heating and insulation module 401 is connected to the cylinder body 101 and is used to heat the inside of the cylinder body 101. The heating and insulation module 401 can be a combination of a heater and an insulation layer; the stirring module stirs the inside of the cylinder body 101.

[0082] Further, as shown in Figures 1 and 2, the mixing module includes a six-bladed propeller mixer 402 and a magnetic stirrer motor 403. The six-bladed propeller mixer 402 is disposed inside the piston chamber 104; the magnetic stirrer motor 403 is magnetically connected to the six-bladed propeller mixer 402 and is used to drive the six-bladed propeller mixer 402 to rotate. The magnetic stirrer motor 403 is disposed outside the piston chamber 104.

[0083] Furthermore, as shown in Figures 1 and 2, the piston rod 103 is provided with a connecting hole 106 in the axial direction for connecting the top of the piston chamber 104 and the bottom of the oil-proof bottle 300.

[0084] Furthermore, as shown in Figures 1-2, the degassing device for online monitoring of dissolved gases in transformer insulating oil of this application further includes: a first pipeline 601, which is connected between the connecting hole 106 and the bottom of the oil-proof bottle 300, and the first pipeline 601 is a PA hose with a diameter of 2mm.

[0085] Furthermore, as shown in Figures 1 and 2, the degassing device for online monitoring of dissolved gases in transformer insulating oil according to this application further includes: a second pipeline 701, an oil inlet solenoid valve 702, and a return oil solenoid valve 703; the second pipeline 701 is used to connect the oil inlet / return port 105 with the oil inlet and return port of the transformer 500; the oil inlet solenoid valve 702 is connected to the second pipeline 701 and is used to control the on / off connection between the oil inlet / return port 105 and the oil inlet of the transformer 500; the return oil solenoid valve 703 is connected to the second pipeline 701 and is used to control the on / off connection between the oil inlet / return port 105 and the return oil port of the transformer 500.

[0086] Furthermore, in this embodiment, the second pipeline 701 is a copper pipe with a diameter of 8mm.

[0087] Furthermore, the degassing device for online monitoring of dissolved gases in transformer insulating oil according to this application further includes: a sampling solenoid valve 801 and a venting solenoid valve 802. The sampling solenoid valve 801 is connected to the top of the oil-proof bottle 300 and the detector, and is used to control the on / off connection between the oil-proof bottle 300 and the detector; the venting solenoid valve 802 is connected to the top of the oil-proof bottle 300 and the venting area, and is used to control the on / off connection between the oil-proof bottle 300 and the venting area.

[0088] Furthermore, in this embodiment, the magnetic stirrer motor 403, the oil inlet solenoid valve 702, the oil return solenoid valve 703, the through-type stepper motor 200, the liquid level sensor 301, the pressure sensor 302, the vent solenoid valve 802, and the sample injection solenoid valve 801 are all connected to the electronic control system. The electronic control system controls the operation of the through-type stepper motor 200, the magnetic stirrer motor 403, the heating and heat preservation module 401, the vent solenoid valve 802, the sample injection solenoid valve 801, the oil inlet solenoid valve 702, and the oil return solenoid valve 703 according to the process and the status of the sensors.

[0089] As described above, the degassing device for online monitoring of dissolved gases in transformer insulating oil according to an embodiment of this application has the following beneficial effects:

[0090] 1. It can significantly shorten the degassing time and ensure efficient operation; the structural design is simple, robust and reliable, and easy to maintain and apply;

[0091] 2. It has good repeatability to ensure the consistency of monitoring results each time;

[0092] 3. It can significantly reduce errors and improve data accuracy during the measurement process;

[0093] 4. When analyzing oil samples, this device does not require additional inert gas for replacement, simplifying the operation process; at the same time, the tested oil samples do not require special treatment, saving both time and reducing costs.

[0094] The above description, in conjunction with Figures 1 and 2, describes a degassing device for online monitoring of dissolved gases in transformer insulating oil according to an embodiment of this application. Furthermore, this application can also be applied to a degassing method for online monitoring of dissolved gases in transformer insulating oil.

[0095] As shown in Figures 3 and 4, according to another embodiment of this application, a degassing method for online monitoring of dissolved gases in transformer insulating oil is provided, comprising the following steps:

[0096] Step 1, oil system cleaning process, is as follows:

[0097] Close the injection solenoid valve 801, open the venting solenoid valve 802, and the through stepper motor 200 drives the piston 102 to move downward to the bottom limit, venting the excess gas in the piston chamber 104.

[0098] When the venting solenoid valve 802 is closed, the through-type stepper motor 200 drives the piston 102 to move upward a certain distance, so that the piston chamber 104 is in a negative pressure state.

[0099] When the oil inlet solenoid valve 702 is opened, insulating oil enters the piston chamber 104 by the negative pressure in the piston chamber 104 and the pressure of the transformer 500 itself.

[0100] Close the oil inlet solenoid valve 702, open the venting solenoid valve 802, and the through stepper motor 200 drives the piston 102 to move downward, expelling excess gas in the piston chamber 104 until the liquid level sensor 301 in the oil bottle 300 detects the liquid level signal.

[0101] Close the venting solenoid valve 802, open the return oil solenoid valve 703, and the through stepper motor 200 drives the piston 102 to continue moving downward until the piston 102 moves to the bottom limit of the piston chamber 104, returning the insulating oil to the oil tank of the transformer 500.

[0102] Repeat the above steps multiple times to complete the cleaning of the oil passage and piston chamber 104.

[0103] Step 2, the 300-level cleaning process for the gas line and oil-proof bottle, is as follows:

[0104] When the detector switches to the sample injection state, the oil inlet solenoid valve 702, the oil return solenoid valve 703, the venting solenoid valve 802 and the sample injection solenoid valve 801 are closed. The through-type stepper motor 200 drives the piston 102 to move upward to the top of the piston chamber 104, so that the piston chamber 104 is in a negative pressure state.

[0105] When the detector switches to the degassing state and the injection solenoid valve 801 is opened, the carrier gas in the detector enters the piston chamber 104 through the oil-proof bottle 300 under the negative pressure in the piston chamber 104.

[0106] When the detector switches back to the injection state, the injection solenoid valve 801 is closed, and the carrier gas fills the detector again. At this time, the venting solenoid valve 802 is opened, and the through-type stepper motor 200 drives the piston 102 to move downward to the bottom limit of the piston chamber 104 to discharge excess gas. Then the venting solenoid valve 802 is closed.

[0107] Repeat the above steps several times to complete the cleaning of the gas path and the oil-proof bottle 300. The gas path refers to the tubing connecting the oil-proof bottle and the detector.

[0108] Step 3, the oil sample quantification process, is as follows:

[0109] When the oil inlet solenoid valve 702, the oil return solenoid valve 703, the venting solenoid valve 802, and the sample injection solenoid valve 801 are closed, the through-type stepper motor 200 drives the piston 102 to move upward to a certain distance, so that the piston chamber 104 is in a negative pressure state.

[0110] When the oil inlet solenoid valve 702 is opened, the oil sample is drawn into the piston chamber 104 under the negative pressure.

[0111] After the pressure in the piston chamber 104 returns to a standard atmosphere, the venting solenoid valve 802 is opened, and the through-type stepper motor 200 drives the piston 102 to move slowly downward. Once the liquid level detector detects the liquid level signal, the venting solenoid valve 802 is closed, the return oil solenoid valve 703 is opened, and the through-type stepper motor 200 drives the piston 102 to continue moving downward to the designated position, and the return oil solenoid valve 703 is closed.

[0112] Step 4, headspace degassing process, is as follows:

[0113] Close the oil inlet solenoid valve 702, the oil return solenoid valve 703, the venting solenoid valve 802, and the sample injection solenoid valve 801, and control the heating and heat preservation module 401 to heat the inside of the piston chamber 104 and control the temperature at 50℃.

[0114] Start the magnetic stirrer motor 403, which drives the six-bladed propeller stirrer 402 to rotate. The through stepper motor 200 drives the piston 102 to move upward, creating a negative pressure between the bottom of the piston 102 and the oil sample.

[0115] Dissolved gases in insulating oil are continuously released under specific temperature, stirring and negative pressure, and under the action of buoyancy, the released gases move to the top of the oil-proof bottle 300 and the piston chamber 104.

[0116] Step 5, the balancing process, is as follows:

[0117] After degassing is completed, the magnetic stirrer motor 403 is stopped, and the atmospheric pressure inside the piston chamber 104 is restored to one standard atmosphere. The temperature of the piston chamber 104 is maintained at 50°C, and the chamber is left to stand for a period of time to allow the degassing gas and the dissolved gas in the insulating oil to reach equilibrium. The volume of the degassing gas is calculated based on the position of the piston 102 under one standard atmosphere. The concentration of each component gas and the solubility coefficient between the gas and liquid at the current temperature and atmospheric pressure are further analyzed using a thermal conductivity sensor to calculate the concentration of dissolved gas in the transformer 500 oil.

[0118] Step 6, the sample injection and analysis process, is as follows:

[0119] After headspace degassing is completed, close the venting solenoid valve 802 and open the sample injection solenoid valve 801. The through-type stepper motor 200 drives the piston 102 to move down and send the precipitated gas into the detector.

[0120] Maintain a constant pressure inside the detector, then switch the detector to sample injection mode, and introduce the extracted gas into the chromatographic analysis module of the detector. The solubility of each component of the gas sample is obtained through the chromatographic analysis module.

[0121] Step 7, the oil return process, is as follows:

[0122] After the sample injection analysis is completed, close the sample injection solenoid valve 801, open the venting solenoid valve 802, and the through-type stepper motor 200 drives the piston 102 to move down to expel excess gas;

[0123] Until the liquid level sensor 301 detects the liquid level signal, the venting solenoid valve 802 is closed and the return oil solenoid valve 703 is opened. The through-type stepper motor 200 drives the piston 102 to continue moving down to the bottom limit of the piston chamber 104. The pressure of the piston 102 slowly sends the degassed insulating oil back to the oil tank of the transformer 500.

[0124] Because the degassed insulating oil sample needs to be returned to the transformer 500's oil tank after the sample injection analysis, and the degassed gas must not enter the transformer 500's oil tank, step 7 is used to achieve this. Since a six-bladed propeller-type agitator 402 is placed at the bottom of the piston chamber 104, a trace amount of oil will remain in the piston chamber 104 after each degassed process. Therefore, oil circulation cleaning is required before each analysis. Through multiple flushes, it is ensured that each tested oil sample reflects the true condition of the transformer 500.

[0125] Step 8, the calculation process, is as follows:

[0126] After headspace degassing is completed, piston 102 is at the top of piston chamber 104, and the pressure is measured by pressure sensor 302;

[0127] The position of piston 102 is adjusted by a through stepper motor 200. After multiple fine adjustments, the number of steps N is recorded when piston 102 moves from the top zero point of piston chamber 104 until the pressure sensor 302 measures a constant pressure of one standard atmosphere.

[0128] The distance L that piston 102 moves is calculated based on the number of steps N and the step length S of the through stepper motor 200, i.e., L = N * S;

[0129] Based on the distance L that the piston 102 moves, calculate the total volume V of the gas and liquid in the piston chamber 104, V = Vt - L * S1, where Vt is the volume of the piston chamber 104 and S1 is the cross-sectional area of ​​the piston chamber 104.

[0130] The volume of gas released, Vg, can be calculated by subtracting the volume of liquid, Vl, from the total volume of gas and liquid, i.e., Vg = V - Vl.

[0131] Finally, the concentration of each component in the extracted gas was analyzed using a chromatographic analysis module, and the concentration of each component of the dissolved gas in the insulating oil was calculated by combining the calculation formula of the headspace degassing method (as shown in Figure 4).

[0132] It should be noted that, in this specification, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0133] Although the content of this application has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as a limitation of this application. Various modifications and substitutions to this application will be apparent to those skilled in the art after reading the above content. Therefore, the scope of protection of this application should be defined by the appended claims.

Claims

1. A degassing device for online monitoring of dissolved gases in transformer insulating oil, characterized in that, Include: The degassing cylinder consists of a cylinder body, a piston, and a piston rod. The piston is disposed in the cylinder body, forming a piston chamber with the cylinder body. One end of the piston rod is connected to the piston. The bottom of the piston chamber is provided with an oil inlet and return port, which are connected to the oil inlet and return port of an external transformer. A drive module, the output end of which is connected to the other end of the piston rod, is used to drive the piston rod to move and control the pressure inside the piston chamber; An oil-proof bottle, the bottom of which is connected to the top of the piston chamber, is equipped with a liquid level sensor and a pressure sensor inside the oil-proof bottle, and the top of which is connected to an external detector and an external venting area; A heating and stirring mechanism is connected to the degassing cylinder and is used to heat and stir the piston chamber.

2. The degassing device for online monitoring of dissolved gases in transformer insulating oil as described in claim 1, characterized in that, The piston rod has an axially connected hole for connecting the top of the piston chamber and the bottom of the oil-proof bottle.

3. The degassing device for online monitoring of dissolved gases in transformer insulating oil as described in claim 2, characterized in that, It also includes: a first conduit, which is connected between the connecting hole and the bottom of the oil-proof bottle, and the first conduit is a PA hose with a diameter of 2 mm.

4. The degassing device for online monitoring of dissolved gases in transformer insulating oil as described in claim 1, characterized in that, Also includes: The second pipeline is used to connect the oil inlet and return port with the oil inlet and return port of the transformer; An oil inlet solenoid valve is connected to the second pipeline and is used to control the on / off connection between the oil inlet / outlet and the oil inlet of the transformer. A return oil solenoid valve is connected to the second pipeline and is used to control the on / off connection between the oil inlet / return port and the return oil port of the transformer.

5. The degassing device for online monitoring of dissolved gases in transformer insulating oil as described in claim 4, characterized in that, The second pipeline is a copper pipe with a diameter of 8mm.

6. The degassing device for online monitoring of dissolved gases in transformer insulating oil as described in claim 1, characterized in that the heating and stirring mechanism comprises: A heating and heat preservation module is connected to the cylinder body and is used to heat the inside of the cylinder body; A stirring module is provided to stir the interior of the cylinder body.

7. The degassing device for online monitoring of dissolved gases in transformer insulating oil as described in claim 6, characterized in that, The stirring module includes: A six-bladed propeller agitator, wherein the six-bladed propeller agitator is disposed inside the piston chamber; A magnetic stirrer motor is magnetically connected to a six-bladed propeller stirrer and is used to drive the six-bladed propeller stirrer to rotate.

8. The degassing device for online monitoring of dissolved gases in transformer insulating oil as described in any one of claims 1-7, characterized in that, Also includes: An injection solenoid valve is connected to the top of the oil-proof bottle and the detector, and is used to control the on / off connection between the oil-proof bottle and the detector; A venting solenoid valve is connected to the top of the oil-proof bottle and the venting area, and is used to control the on / off connection between the oil-proof bottle and the venting area.

9. The degassing device for online monitoring of dissolved gases in transformer insulating oil as described in any one of claims 1-7, characterized in that, The drive module is a through-type stepper motor, which is connected to the other end of the piston rod via a lead screw to drive the piston rod to move and control the pressure inside the piston chamber.

10. A degassing method for online monitoring of dissolved gases in transformer insulating oil, characterized in that, It includes the following steps: Step 1, oil system cleaning process, is as follows: Close the injection solenoid valve, open the venting solenoid valve, and the through-type stepper motor drives the piston to move downward to the bottom limit, venting the excess gas in the piston chamber. When the venting solenoid valve is closed, the through-type stepper motor drives the piston to move upward a certain distance, so that the piston chamber is in a negative pressure state. When the oil inlet solenoid valve is opened, insulating oil enters the piston chamber due to the negative pressure inside the piston chamber and the transformer's own pressure. Close the oil inlet solenoid valve, open the vent solenoid valve, and the through-type stepper motor drives the piston to move downward to expel excess gas from the piston chamber until the liquid level sensor in the oil bottle detects the liquid level signal. Close the venting solenoid valve and open the return oil solenoid valve. The through-type stepper motor drives the piston to continue moving downward until the piston moves to the bottom limit of the piston chamber, returning the insulating oil to the transformer's oil tank. Repeat the above steps multiple times to complete the cleaning of the oil passage and piston chamber; Step 2, the cleaning process of the gas line and oil-proof bottle, is as follows: When the detector switches to the sample injection state, the oil inlet solenoid valve, oil return solenoid valve, venting solenoid valve and sample injection solenoid valve are closed. The through-type stepper motor drives the piston to move upward to the top of the piston chamber, so that the piston chamber is in a negative pressure state. When the detector switches to degassing mode and the injection solenoid valve is opened, the carrier gas in the detector enters the piston chamber through the oil-proof bottle under the negative pressure in the piston chamber. The detector switches back to the injection state, the injection solenoid valve is closed, and the carrier gas fills the detector again. At this time, the venting solenoid valve is opened, and the through-type stepper motor drives the piston to move downward to the bottom limit of the piston chamber to discharge excess gas. The venting solenoid valve is then closed. Repeat the above steps several times to complete the cleaning of the gas line and oil-proof bottle; Step 3, the oil sample quantification process, is as follows: The oil inlet solenoid valve, oil return solenoid valve, venting solenoid valve and sample injection solenoid valve are closed. The through-type stepper motor drives the piston to move upward to a certain distance, so that the piston chamber is in a negative pressure state. When the oil inlet solenoid valve is opened, the oil sample is drawn into the piston chamber under the negative pressure. Once the pressure inside the piston chamber returns to a standard atmosphere, open the venting solenoid valve. The through-type stepper motor drives the piston to slowly move downwards. Once the liquid level detector detects the liquid level signal, close the venting solenoid valve, open the return oil solenoid valve, and the through-type stepper motor drives the piston to continue moving downwards to the designated position. Then, close the return oil solenoid valve. Step 4, headspace degassing process, is as follows: Close the oil inlet solenoid valve, oil return solenoid valve, venting solenoid valve and sample injection solenoid valve, and control the heating and heat preservation module to heat the inside of the piston chamber and control the temperature at 50℃. Start the magnetic stirrer motor to drive the six-bladed propeller stirrer to rotate, and the through stepper motor drives the piston to move upward, creating a negative pressure between the bottom of the piston and the oil sample; Dissolved gases in insulating oil are continuously released under specific temperature, stirring and negative pressure, and under the action of buoyancy, the released gases move to the top of the oil-proof bottle and piston chamber; Step 5, the balancing process, is as follows: After degassing is complete, stop the magnetic stirrer motor, restore the atmospheric pressure inside the piston chamber to one standard atmosphere, continue to maintain the temperature of the piston chamber at 50°C, and let it stand for a period of time to allow the degassing gas and the dissolved gas in the insulating oil to reach equilibrium. Step 6, the sample injection and analysis process, is as follows: After headspace degassing is completed, the venting solenoid valve is closed and the injection solenoid valve is opened. The through-type stepper motor drives the piston to move down and sends the precipitated gas into the detector. Maintain a constant pressure inside the detector, then switch the detector to sample injection mode, and introduce the extracted gas into the chromatographic analysis module of the detector. The solubility of each component of the gas sample is obtained through the chromatographic analysis module. Step 7, the oil return process, is as follows: After the sample injection analysis is completed, the sample injection solenoid valve is closed, the venting solenoid valve is opened, and the through-type stepper motor drives the piston to move down to expel excess gas. Until the liquid level sensor detects the liquid level signal, the venting solenoid valve is closed and the return oil solenoid valve is opened. The through-type stepper motor drives the piston to continue moving down to the bottom limit of the piston chamber. The pressure of the piston slowly sends the degassed insulating oil back to the transformer's oil tank. Step 8, the calculation process, is as follows: After headspace degassing is completed, the piston is at the top of the piston chamber, and the pressure is measured by the pressure sensor. The position of the piston is adjusted by a through-type stepper motor. After multiple fine adjustments, the number of steps N is recorded when the through-type stepper motor moves the piston from the top zero point of the piston chamber until the pressure sensor measures a constant pressure of one standard atmosphere. The distance L that the piston moves is calculated based on the number of steps N and the step length S of the through stepper motor, i.e., L = N * S; Based on the distance L that the piston moves, calculate the total volume V of the gas and liquid in the piston chamber, V = Vt - L * S1, where Vt is the volume of the piston chamber and S1 is the cross-sectional area of ​​the piston chamber. The volume of gas released, Vg, can be calculated by subtracting the volume of liquid, Vl, from the total volume of gas and liquid, i.e., Vg = V - Vl. Finally, the concentration of each component in the extracted gas was analyzed using a chromatographic analysis module, and the concentration of each component of the dissolved gas in the insulating oil was calculated using the headspace degassing method calculation formula.

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