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

Abstract

The invention discloses a degassing device and method for online monitoring of dissolved gas in transformer insulating oil, the degassing device comprises a degassing cylinder, the degassing cylinder is composed of a cylinder body, a piston and a piston rod, the piston is arranged in the cylinder body, a piston cavity is formed between the piston and the cylinder body, one end of the piston rod is connected with the piston, and the other end of the piston rod is connected with the degassing cylinder; an oil inlet and return opening is formed in the bottom of the piston cavity and is connected with an oil inlet and an oil return opening of an external transformer; the output end of the driving module is connected with the other end of the piston rod and used for driving the piston rod to move; the bottom of the oil-proof bottle is communicated with the top of the piston cavity, a liquid level sensor and a pressure sensor are arranged in the oil-proof bottle, and the top of the oil-proof bottle is communicated with an external detector and an external emptying area; and the heating and stirring mechanism is used for heating and stirring the piston cavity. The invention has the beneficial effects of good air tightness, high quantitative precision, more accurate test result and good repeatability.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power detection, and in particular to a degassing device and a method for online monitoring of dissolved gas in transformer insulating oil. Background Art

[0002] The power system is an important infrastructure of modern society, providing a stable power supply for industrial production and residents' lives. As a key power transmission and transformation equipment in the power system, the transformer undertakes important tasks such as voltage conversion and power transmission. The stability and safety of its operation are crucial to the normal operation of the entire power system. Once a transformer fails, it may cause a large-scale power outage, affect production and life, and cause huge economic losses. Therefore, it is necessary to closely monitor the operating status of the transformer.

[0003] During the operation of the transformer, due to internal insulation aging, local overheating, discharge and other faults, the insulation material will decompose and various gases will be dissolved in the transformer oil. The gas components and contents produced by different types of faults are different. For example, local overheating faults will produce methane, ethylene and other gases, and discharge faults will produce acetylene, hydrogen and other gases. Therefore, by analyzing the composition, content and change trend of dissolved gases in transformer oil, the operating status and potential fault types of the transformer can be effectively judged.

[0004] Whether it is based on gas chromatography or spectroscopy to monitor the dissolved gas content in transformer oil, oil-gas separation technology is an indispensable part of the analysis of dissolved gas in oil. The oil-gas separation technologies currently used include polymer membrane permeation degassing, dynamic headspace degassing, vacuum degassing and other methods. Among them, the polymer membrane permeation degassing method has low degassing efficiency and long equilibrium time, which does not meet the real-time requirements. Dynamic headspace degassing generally involves continuous introduction of inert gas into the sample, so that the oil sample after detection cannot be returned to the transformer. Vacuum degassing requires a vacuum pump, and the degassing structure is complex and has poor repeatability.

[0005] In order to solve the problems of oil-gas separation, the present invention provides a degassing system and a method for online monitoring of dissolved gas in transformer insulating oil. Summary of the invention

[0006] According to an embodiment of the present invention, a degassing device for online monitoring of dissolved gas in transformer insulating oil is provided, comprising: The degassing cylinder is composed of a cylinder body, a piston and a piston rod. The piston is arranged in the cylinder body to form a piston cavity with the cylinder body. One end of the piston rod is connected to the piston. An oil inlet and return port is arranged at the bottom of the piston cavity. The oil inlet and return port are connected to the oil inlet and return port of the external transformer. A driving module, the output end of which is connected to the other end of the piston rod, and is used to drive the piston rod to move and control the pressure inside the piston chamber; The bottom of the oil-proof bottle is connected to the top of the piston chamber, a liquid level sensor and a pressure sensor are arranged inside the oil-proof bottle, and the top of the oil-proof bottle is connected to an external detector and an external venting area; The heating and stirring mechanism is connected to the degassing cylinder and is used for heating and stirring the piston cavity.

[0007] Furthermore, a connecting hole is provided in the axial direction of the piston rod for connecting the top of the piston cavity and the bottom of the oil-proof bottle.

[0008] Furthermore, the degassing device for online monitoring of dissolved gas in transformer insulating oil of the present invention also includes: a first pipeline, the first pipeline 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 2 mm.

[0009] Furthermore, the degassing device for online monitoring of dissolved gas in transformer insulating oil of the present invention further comprises: A second pipeline, 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, which is connected to the second pipeline and is used to control the on-off between the oil inlet and return port and the oil inlet of the transformer; The oil return solenoid valve is connected to the second pipeline and is used to control the on-off between the oil return port and the oil return port of the transformer.

[0010] Furthermore, the second pipeline is a copper pipe with a diameter of 8 mm.

[0011] Further, the heating and stirring mechanism comprises: A heating and heat preservation module, which is connected to the cylinder body and is used to heat the inside of the cylinder body; A stirring module stirs the interior of the cylinder body.

[0012] Further, the stirring module comprises: A six-blade propeller stirrer, the six-blade propeller stirrer is arranged inside the piston cavity; The magnetic stirrer motor is connected to the six-blade propeller stirrer through magnetic force and is used to drive the six-blade propeller stirrer to rotate.

[0013] Furthermore, the degassing device for online monitoring of dissolved gas in transformer insulating oil of the present invention further comprises: 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 between the oil-proof bottle and the detector; The vent solenoid valve is connected to the top of the oil-proof bottle and the venting area, and is used to control the on-off between the oil-proof bottle and the venting area.

[0014] Furthermore, the driving module is a through-type stepping motor, which is connected to the other end of the piston rod through a screw rod and is used to drive the piston rod to move and control the pressure inside the piston chamber.

[0015] According to another embodiment of the present invention, a degassing method for online monitoring of dissolved gas in transformer insulating oil is provided, comprising the following steps: Step 1, oil circuit cleaning process, 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 position to discharge the excess gas in the piston chamber; Close the vent solenoid valve, and the through-type stepper motor drives the piston to move upward a certain distance, so that the piston cavity is in a negative pressure state; Open the oil inlet solenoid valve, and the insulating oil enters the piston cavity by the negative pressure in the piston cavity and the pressure of the transformer itself; Close the oil inlet solenoid valve, open the venting solenoid valve, and the through-type stepper motor drives the piston to move downward to discharge the excess gas in the piston cavity until the liquid level sensor in the oil-proof bottle detects the liquid level signal; Close the vent solenoid valve, open the oil return solenoid valve, and the through-type stepper motor drives the piston to continue moving downward until the piston moves to the bottom limit of the piston cavity, returning the insulating oil to the oil tank of the transformer; Repeat the above steps several times to complete the cleaning of the oil circuit and piston chamber; Step 2, the cleaning process of the gas line and the oil-proof bottle is as follows: The detector is switched to the injection state, the oil inlet solenoid valve, the oil return solenoid valve, the venting solenoid valve and the injection solenoid valve are closed, and 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; The detector is switched to the degassing state, and the injection solenoid valve is opened. At this time, 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, and the venting solenoid valve is closed; Repeat the above steps several times to complete the cleaning of the gas line and the oil-proof bottle; Step 3, oil sample quantification process, is as follows: Close the oil inlet solenoid valve, oil return solenoid valve, vent solenoid valve and sample injection solenoid valve, and the through-type stepper motor drives the piston to move upward to a certain distance, so that the piston cavity is in a negative pressure state; Open the oil inlet solenoid valve, and the oil sample is sucked into the piston cavity under the negative pressure in the piston cavity; After the pressure in the piston chamber returns to a standard atmospheric pressure, the venting solenoid valve is opened, and the through-type stepper motor drives the piston to move down slowly. After the liquid level detector detects the liquid level signal, the venting solenoid valve is closed, the oil return solenoid valve is opened, and the through-type stepper motor drives the piston to continue to move down to the specified position, and the oil return solenoid valve is closed; Step 4, headspace degassing process, is as follows: Close the oil inlet solenoid valve, oil return solenoid valve, vent solenoid valve and injection solenoid valve, control the heating and insulation module to heat the inside of the piston chamber, and control the temperature at 50°C; Start the magnetic stirrer motor to drive the six-blade propeller stirrer to rotate, and the through-type stepper motor drives the piston to move upward, forming a negative pressure between the bottom of the piston and the oil sample; The dissolved gas in the insulating oil is continuously precipitated under the action of specific temperature, stirring and negative pressure, and under the action of buoyancy, the precipitated gas moves to the oil-proof bottle and the top of the piston cavity; Step 5, the balancing process, is as follows: After degassing is completed, stop the motor of the magnetic stirrer, restore the atmospheric pressure inside the piston chamber to a standard atmospheric pressure, continue to maintain the temperature of the piston chamber at 50°C, and let it stand for a certain period of time to allow the degassing gas and the dissolved gas in the insulating oil to reach equilibrium; Step 6, the sampling analysis process, is as follows: After the headspace degassing is completed, close the vent solenoid valve, open the injection solenoid valve, and the through-type stepper motor drives the piston to move downward to send the precipitated gas into the detector; Keep the pressure inside the detector constant, then switch the detector to the injection state, let the escaped gas enter the chromatographic analysis module of the detector, and analyze the solubility of each component of the gas sample through the chromatographic analysis module; Step 7, oil return process, as follows: After the injection analysis process is completed, the injection solenoid valve is closed, the venting solenoid valve is opened, and the through-type stepper motor drives the piston to move down to exhaust excess gas; Until the liquid level sensor detects the liquid level signal, the vent solenoid valve is closed, the oil return solenoid valve is opened, and the through-type stepper motor drives the piston to continue to move down to the bottom limit of the piston chamber, and the insulating oil with degassing is slowly sent back to the oil tank of the transformer through the pressure of the piston; Step 8, calculation process, is as follows: After the 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 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 atmospheric pressure is recorded. The distance L moved by the piston is calculated based on the number of moving steps N and the step length S of the through-type stepper motor, that is, L=N*S; According to the distance L moved by the piston, the total volume V of the gas and liquid in the piston chamber is calculated, V=Vt-L*S1, where Vt is the volume of the piston chamber and S1 is the cross-sectional area of ​​the piston chamber; According to the total volume V of the gas and liquid, minus the volume Vl of the liquid, the volume Vg of the escaped gas can be calculated, that is, Vg=V-Vl; Finally, the concentration of each component in the degassing gas is analyzed using the chromatography analysis module, and the concentration of each component of the dissolved gas in the insulating oil is calculated using the calculation formula of the headspace degassing method.

[0016] According to an embodiment of the present invention, a degassing device and method for online monitoring of dissolved gas in transformer insulating oil have the following beneficial effects: 1. It can greatly shorten the degassing time and ensure efficient operation; the structural design is simple, stable and reliable, easy to maintain and use; 2. Have good repeatability to ensure the consistency of each monitoring result; 3. It can significantly reduce errors and improve data accuracy during the measurement process; 4. When analyzing oil samples, the device does not need to inject inert gas for replacement operation, which simplifies the operation process; at the same time, the oil samples after testing do not need special treatment, which saves time and reduces costs.

[0017] It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the technology as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The figure is a schematic structural diagram of a degassing device for online monitoring of dissolved gas in transformer insulating oil according to an embodiment of the present invention.

[0019] Figure 2 The present invention is a schematic structural diagram of a degassing device for online monitoring of dissolved gas in transformer insulating oil according to an embodiment of the present invention when it is specifically applied.

[0020] Figure 3 The figure is a flow chart of a degassing method for online monitoring of dissolved gas in transformer insulating oil according to an embodiment of the present invention.

[0021] Figure 4The figure is a formula diagram of a calculation formula of a headspace degassing method in a degassing method for online monitoring of dissolved gas in transformer insulating oil according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings to further illustrate the present invention.

[0023] First, combine Figure 1~2 A degassing device for online monitoring of dissolved gas in transformer insulating oil according to an embodiment of the present invention is described. The degassing device is used for online monitoring of dissolved gas in transformer insulating oil and has a wide range of application scenarios.

[0024] like Figure 1~2 As shown, a degassing device for online monitoring of dissolved gas in transformer insulating oil according to an embodiment of the present invention comprises a degassing cylinder, a driving module, an oil-proof bottle 300 and a heating and stirring mechanism.

[0025] Specifically, Figure 1~2 As shown, the degassing cylinder is composed of a cylinder body 101, a piston 102 and a piston rod 103. The piston 102 is arranged in the cylinder body 101, and a piston cavity 104 is formed between the piston 102 and the cylinder body 101. One end of the piston rod 103 is connected to the piston 102. The bottom of the piston cavity 104 is provided with an oil inlet and return port 105, and the oil inlet and return port 105 are connected to the oil inlet and oil return port of the external transformer 500.

[0026] Specifically, Figure 1~2 As shown, the output end of the driving module is connected to the other end of the piston rod 103 . The driving module is a through-type stepping motor 200 . The through-type stepping motor 200 is connected to the other end of the piston rod 103 through a screw rod and is used to drive the piston rod 103 to move and control the pressure inside the piston chamber 104 .

[0027] Specifically, Figure 1~2 As shown, the bottom of the oil-proof bottle 300 is connected to the top of the piston chamber 104, a liquid level sensor 301 and a pressure sensor 302 are arranged inside the oil-proof bottle 300, and 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 a space for discharging gas, which can be selected based on the discharge requirements. The space inside the oil-proof bottle 300 is as small as possible, such as less than 0.5 ml, to avoid affecting the gas collection of the subsequent detector.

[0028] Specifically, Figure 1~2As shown, the heating and stirring mechanism is connected to the degassing cylinder, and is used to heat and stir the piston cavity 104. The heating and stirring mechanism includes: a heating and heat preservation module 401 and a stirring module. The heating and heat preservation module 401 is connected to the cylinder body 101, and is used to heat the inside of the cylinder body 101. The heating and heat preservation module 401 can be a combination of a heater and a heat preservation layer; the stirring module stirs the inside of the cylinder body 101.

[0029] Further, if Figure 1~2 As shown, the stirring module includes: a six-blade propeller stirrer 402 and a magnetic stirrer motor 403. The six-blade propeller stirrer 402 is arranged inside the piston cavity 104; the magnetic stirrer motor 403 is connected to the six-blade propeller stirrer 402 through magnetic force, and is used to drive the six-blade propeller stirrer 402 to rotate.

[0030] Further, if Figure 1~2 As shown, a connecting hole 106 is provided in the axial direction of the piston rod 103 for connecting the top of the piston cavity 104 and the bottom of the oil-proof bottle 300 .

[0031] Further, if Figure 1~2 As shown, the degassing device for online monitoring of dissolved gas in transformer insulating oil of the present invention further comprises: a first pipeline 601, the first pipeline 601 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 2 mm.

[0032] Further, if Figure 1~2 As shown, a degassing device for online monitoring of dissolved gas in transformer insulating oil of the present invention further comprises: a second pipeline 701, an oil inlet solenoid valve 702 and an oil return solenoid valve 703; the second pipeline 701 is used to connect the oil inlet and return port 105 with the oil inlet and oil 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 between the oil inlet and return port 105 and the oil inlet of the transformer 500; the oil return solenoid valve 703 is connected to the second pipeline 701, and is used to control the on-off between the oil inlet and return port 105 and the oil return port of the transformer 500.

[0033] Furthermore, in this embodiment, the second pipeline 701 is a copper tube with a diameter of 8 mm.

[0034] Furthermore, the degassing device for online monitoring of dissolved gas in transformer insulating oil of the present invention further comprises: an injection solenoid valve 801 and a venting solenoid valve 802. The injection 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 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 between the oil-proof bottle 300 and the venting area.

[0035] 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 injection solenoid valve 801 are all connected to the electronic control system, and the electronic control system controls the operation of the through-type stepper motor 200, the magnetic stirrer motor 403, the heating and insulation module 401, the vent solenoid valve 802, the 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 sensor.

[0036] As described above, a degassing device for online monitoring of dissolved gas in transformer insulating oil according to an embodiment of the present invention has the following beneficial effects: 1. It can greatly shorten the degassing time and ensure efficient operation; the structural design is simple, stable and reliable, easy to maintain and use; 2. Have good repeatability to ensure the consistency of each monitoring result; 3. It can significantly reduce errors and improve data accuracy during the measurement process; 4. When analyzing oil samples, the device does not need to inject inert gas for replacement operation, which simplifies the operation process; at the same time, the oil samples after testing do not need special treatment, which saves time and reduces costs.

[0037] The above combined with Figure 1~2 A degassing device for online monitoring of dissolved gas in transformer insulating oil according to an embodiment of the present invention is described. Further, the present invention can also be applied to a degassing method for online monitoring of dissolved gas in transformer insulating oil.

[0038] like Figure 3~4 As shown, according to another embodiment of the present invention, a degassing method for online monitoring of dissolved gas in transformer insulating oil is provided, comprising the following steps: Step 1, oil circuit cleaning process, as follows: Close the injection solenoid valve 801, open the venting solenoid valve 802, and the through-type stepper motor 200 drives the piston 102 to move downward to the bottom limit position to discharge the excess gas in the piston chamber 104; The venting solenoid valve 802 is closed, and the through-type stepping motor 200 drives the piston 102 to move upward by a certain distance, so that the piston chamber 104 is in a negative pressure state; Open the oil inlet solenoid valve 702, and the insulating oil enters the piston chamber 104 by the negative pressure in the piston chamber 104 and the pressure of the transformer 500 itself; The oil inlet solenoid valve 702 is closed, the venting solenoid valve 802 is opened, and the through-type stepper motor 200 drives the piston 102 to move downward to discharge the excess gas in the piston chamber 104 until the liquid level sensor 301 in the oil-proof bottle 300 detects a liquid level signal; The vent solenoid valve 802 is closed, and the oil return solenoid valve 703 is opened. The through-type stepper motor 200 drives the piston 102 to continue to move downward until the piston 102 moves to the bottom limit of the piston chamber 104, and the insulating oil is returned to the oil tank of the transformer 500; Repeat the above steps several times to complete the cleaning of the oil circuit and the piston chamber 104 .

[0039] Step 2, the cleaning process of the gas line and the oil-proof bottle 300 is as follows: The detector is switched to the injection state, the oil inlet solenoid valve 702, the oil return solenoid valve 703, the venting solenoid valve 802 and the injection solenoid valve 801 are closed, and 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; The detector is switched to the degassing state, and the injection solenoid valve 801 is opened. At this time, 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; 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, and the venting solenoid valve 802 is closed; Repeat the above steps several times to complete the cleaning of the gas circuit and the oil-proof bottle 300. The so-called gas circuit is the pipeline connecting the oil-proof bottle and the detector.

[0040] Step 3, oil sample quantification process, is as follows: The oil inlet solenoid valve 702, the oil return solenoid valve 703, the venting solenoid valve 802 and the injection solenoid valve 801 are closed, and 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; Open the oil inlet solenoid valve 702, and the oil sample is sucked into the piston chamber 104 under the negative pressure in the piston chamber 104; After the pressure in the piston chamber 104 recovers to a standard atmospheric pressure, the venting solenoid valve 802 is opened, and the through-type stepper motor 200 drives the piston 102 to move slowly downward. After the liquid level detector detects the liquid level signal, the venting solenoid valve 802 is closed, and the oil return solenoid valve 703 is opened. The through-type stepper motor 200 drives the piston 102 to continue to move downward to the specified position, and the oil return solenoid valve 703 is closed.

[0041] Step 4, headspace degassing process, is as follows: Close the oil inlet solenoid valve 702, the oil return solenoid valve 703, the venting solenoid valve 802 and the injection solenoid valve 801, control the heating and heat preservation module 401 to heat the interior of the piston chamber 104, and control the temperature at 50°C; The magnetic stirrer motor 403 is started to drive the six-blade propeller stirrer 402 to rotate, and the through-type stepper motor 200 drives the piston 102 to move upward, forming a negative pressure between the bottom of the piston 102 and the oil sample; The dissolved gas in the insulating oil is continuously precipitated under the action of specific temperature, stirring and negative pressure, and the precipitated gas moves to the oil-proof bottle 300 and the top of the piston chamber 104 under the action of buoyancy.

[0042] Step 5, the balancing process, is as follows: After degassing is completed, the magnetic stirrer motor 403 is stopped, the atmospheric pressure inside the piston chamber 104 is restored to a standard atmospheric pressure, the temperature of the piston chamber 104 is continued to be maintained at 50°C, and it is kept still for a certain period of time so that the degassing gas and the dissolved gas in the insulating oil reach equilibrium; the volume of the degassing gas is calculated based on the position of the piston 102 under a standard atmospheric pressure, and the concentration of each component gas and the solubility coefficient between gas and liquid under the current temperature and atmospheric pressure are further analyzed using a thermal conductivity sensor to calculate the concentration of the dissolved gas in the transformer 500 oil.

[0043] Step 6, the sampling analysis process, is as follows: After the headspace degassing is completed, the venting solenoid valve 802 is closed, the injection solenoid valve 801 is opened, and the through-type stepper motor 200 drives the piston 102 to move downward to send the precipitated gas into the detector; The pressure inside the detector is kept constant, and then the detector is switched to the injection state, and the escaped gas enters the chromatographic analysis module of the detector, and the solubility of each component of the gas sample is obtained through the chromatographic analysis module.

[0044] Step 7, oil return process, as follows: After the sample injection and analysis process is completed, the sample injection solenoid valve 801 is closed, the venting solenoid valve 802 is opened, and the through-type stepper motor 200 drives the piston 102 to move downward to exhaust excess gas; Until the liquid level sensor 301 detects the liquid level signal, the vent solenoid valve 802 is closed, the oil return solenoid valve 703 is opened, and the through-type stepper motor 200 drives the piston 102 to continue to move downward to the bottom limit of the piston chamber 104, and the pressure of the piston 102 slowly returns the degassed insulating oil to the oil tank of the transformer 500.

[0045] After the sampling and analysis process, the degassed insulating oil sample needs to be returned to the oil tank of the transformer 500, and the degassed gas cannot enter the oil tank of the transformer 500, so step 7 is adopted to achieve it. Since a six-blade propeller stirrer 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 degassing. It is necessary to perform oil circuit circulation cleaning before each analysis. Through multiple flushing, it is ensured that the oil sample detected each time can reflect the actual situation of the transformer 500.

[0046] Step 8, calculation process, is as follows: After the headspace degassing is completed, the piston 102 is at the top of the piston chamber 104, and the pressure is measured by the pressure sensor 302; The position of the piston 102 is adjusted by the through-type stepper motor 200. After multiple fine adjustments, the number of moving steps N of the through-type stepper motor 200 moving the piston 102 from the top zero point of the piston chamber 104 is recorded until the pressure sensor 302 measures a constant pressure of one standard atmospheric pressure. The distance L moved by the piston 102 is calculated according to the number of moving steps N and the step length S of the through-type stepping motor 200, that is, L=N*S; According to the distance L moved by the piston 102, the total volume V of the gas and liquid in the piston chamber 104 is calculated, 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; According to the total volume V of the gas and liquid, minus the volume Vl of the liquid, the volume Vg of the escaped gas can be calculated, that is, Vg=V-Vl; Finally, the concentration of each component in the degassing gas is analyzed by the chromatography analysis module, and the calculation formula of the headspace degassing method (such as the attached Figure 4 As shown in the figure), calculate the concentration of each component of dissolved gas in insulating oil.

[0047] It should be noted that, in this specification, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprises..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0048] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A degassing device for online monitoring of dissolved gas in transformer insulating oil, characterized in that: Include: A degassing cylinder, the degassing cylinder is composed of a cylinder body, a piston and a piston rod, the piston is arranged in the cylinder body, and a piston cavity is formed between the piston and the cylinder body, one end of the piston rod is connected to the piston, and an oil inlet and return port is provided at the bottom of the piston cavity, and the oil inlet and return port are connected to the oil inlet and oil return port of an external transformer; A driving module, the output end of which is connected to the other end of the piston rod, for driving the piston rod to move and controlling the pressure inside the piston chamber; 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 are provided inside the oil-proof bottle, and the top of the oil-proof bottle is in communication with an external detector and an external venting area; A heating and stirring mechanism is connected to the degassing cylinder and is used for heating and stirring the piston cavity.

2. The degassing device for online monitoring of dissolved gas in transformer insulating oil according to claim 1, characterized in that: A connecting hole is provided in the axial direction of the piston rod for connecting the top of the piston cavity and the bottom of the oil-proof bottle.

3. The degassing device for online monitoring of dissolved gas in transformer insulating oil as claimed in claim 2, characterized in that: It 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 2 mm.

4. The degassing device for online monitoring of dissolved gas in transformer insulating oil according to claim 1, characterized in that: Also includes: A second pipeline, 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, the oil inlet solenoid valve is connected to the second pipeline and is used to control the on-off between the oil inlet and return port and the oil inlet of the transformer; An oil return solenoid valve is connected to the second pipeline and is used to control the on-off between the oil return port and the oil return port of the transformer.

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

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

7. The degassing device for online monitoring of dissolved gas in transformer insulating oil as claimed in claim 6, characterized in that: The stirring module comprises: A six-blade propeller stirrer, wherein the six-blade propeller stirrer is arranged inside the piston cavity; A magnetic stirrer motor is connected to the six-blade propeller stirrer through magnetic force and is used to drive the six-blade propeller stirrer to rotate.

8. The degassing device for online monitoring of dissolved gas in transformer insulating oil according to claim 1, characterized in that: Also includes: An injection solenoid valve, the injection solenoid valve is connected to the top of the oil-proof bottle and the detector, and is used to control the on-off between the oil-proof bottle and the detector; A venting solenoid valve is connected between the top of the oil-proof bottle and the venting area, and is used to control the on-off between the oil-proof bottle and the venting area.

9. The degassing device for online monitoring of dissolved gas in transformer insulating oil according to claim 1, characterized in that: The driving module is a through-type stepping motor, which is connected to the other end of the piston rod through a screw rod and is used to drive the piston rod to move and control the pressure inside the piston chamber.

10. A degassing method for online monitoring of dissolved gas in transformer insulating oil, characterized in that: The following steps are included: Step 1, oil circuit cleaning process, 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 position to discharge the excess gas in the piston chamber; Close the vent solenoid valve, and the through-type stepper motor drives the piston to move upward a certain distance, so that the piston cavity is in a negative pressure state; Open the oil inlet solenoid valve, and the insulating oil enters the piston cavity by the negative pressure in the piston cavity and the pressure of the transformer itself; Close the oil inlet solenoid valve, open the venting solenoid valve, and the through-type stepper motor drives the piston to move downward to discharge the excess gas in the piston cavity until the liquid level sensor in the oil-proof bottle detects the liquid level signal; Close the vent solenoid valve, open the oil return solenoid valve, and the through-type stepper motor drives the piston to continue moving downward until the piston moves to the bottom limit of the piston cavity, returning the insulating oil to the oil tank of the transformer; Repeat the above steps several times to complete the cleaning of the oil circuit and piston chamber; Step 2, the cleaning process of the gas line and the oil-proof bottle is as follows: The detector is switched to the injection state, the oil inlet solenoid valve, the oil return solenoid valve, the venting solenoid valve and the injection solenoid valve are closed, and 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; The detector is switched to the degassing state, and the injection solenoid valve is opened. At this time, 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, and the venting solenoid valve is closed; Repeat the above steps several times to complete the cleaning of the gas line and the oil-proof bottle; Step 3, oil sample quantification process, is as follows: Close the oil inlet solenoid valve, oil return solenoid valve, vent solenoid valve and sample injection solenoid valve, and the through-type stepper motor drives the piston to move upward to a certain distance, so that the piston cavity is in a negative pressure state; Open the oil inlet solenoid valve, and the oil sample is sucked into the piston cavity under the negative pressure in the piston cavity; After the pressure in the piston chamber returns to a standard atmospheric pressure, the venting solenoid valve is opened, and the through-type stepper motor drives the piston to move down slowly. After the liquid level detector detects the liquid level signal, the venting solenoid valve is closed, the oil return solenoid valve is opened, and the through-type stepper motor drives the piston to continue to move down to the specified position, and the oil return solenoid valve is closed; Step 4, headspace degassing process, is as follows: Close the oil inlet solenoid valve, oil return solenoid valve, vent solenoid valve and injection solenoid valve, control the heating and insulation module to heat the inside of the piston chamber, and control the temperature at 50°C; Start the magnetic stirrer motor to drive the six-blade propeller stirrer to rotate, and the through-type stepper motor drives the piston to move upward, forming a negative pressure between the bottom of the piston and the oil sample; The dissolved gas in the insulating oil is continuously precipitated under the action of specific temperature, stirring and negative pressure, and under the action of buoyancy, the precipitated gas moves to the oil-proof bottle and the top of the piston cavity; Step 5, the balancing process, is as follows: After degassing is completed, stop the motor of the magnetic stirrer, restore the atmospheric pressure inside the piston chamber to a standard atmospheric pressure, continue to maintain the temperature of the piston chamber at 50°C, and let it stand for a certain period of time to allow the degassing gas and the dissolved gas in the insulating oil to reach equilibrium; Step 6, the sampling analysis process, is as follows: After the headspace degassing is completed, close the vent solenoid valve, open the injection solenoid valve, and the through-type stepper motor drives the piston to move downward to send the precipitated gas into the detector; Keep the pressure inside the detector constant, then switch the detector to the injection state, let the escaped gas enter the chromatographic analysis module of the detector, and analyze the solubility of each component of the gas sample through the chromatographic analysis module; Step 7, oil return process, as follows: After the injection analysis process is completed, the injection solenoid valve is closed, the venting solenoid valve is opened, and the through-type stepper motor drives the piston to move down to exhaust excess gas; Until the liquid level sensor detects the liquid level signal, the vent solenoid valve is closed, the oil return solenoid valve is opened, and the through-type stepper motor drives the piston to continue to move down to the bottom limit of the piston chamber, and the insulating oil with degassing is slowly sent back to the oil tank of the transformer through the pressure of the piston; Step 8, calculation process, is as follows: After the 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 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 atmospheric pressure is recorded. The distance L moved by the piston is calculated based on the number of moving steps N and the step length S of the through-type stepper motor, that is, L=N*S; According to the distance L moved by the piston, the total volume V of the gas and liquid in the piston chamber is calculated, V=Vt-L*S1, where Vt is the volume of the piston chamber and S1 is the cross-sectional area of ​​the piston chamber; According to the total volume V of the gas and liquid, minus the volume Vl of the liquid, the volume Vg of the escaped gas can be calculated, that is, Vg=V-Vl; Finally, the concentration of each component in the degassing gas is analyzed using the chromatography analysis module, and the concentration of each component of the dissolved gas in the insulating oil is calculated using the calculation formula of the headspace degassing method.

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