Degassing device for on-line monitoring of gas in transformer oil and control method thereof

Abstract

The invention discloses a degassing device for on-line monitoring of gas in transformer oil and a control method thereof.The device comprises an oil way module, a gas way module and a controller module, in the oil way module, an oil inlet and an oil outlet of an oil storage tank are communicated with an oil taking opening of a transformer through an oil pump and an oil inlet valve in sequence, and the oil inlet and the oil outlet are further communicated with an oil outlet valve through the oil pump; a heating unit is arranged in the oil storage tank, and the controller module is connected with the oil pump, the oil inlet valve, the oil outlet valve and the control end of the heating unit so as to achieve oil feeding and oil discharging of the oil storage tank and accelerate release of gas molecules dissolved in oil. The gas circuit module comprises a gas pump, an optical gas chamber, a gas inlet valve and a gas outlet valve which are sequentially communicated to form a loop, the optical gas chamber is communicated with a gas outlet of the oil storage tank, and the controller module is connected with the control ends of the gas pump, the gas inlet valve and the gas outlet valve so as to achieve gas circuit purging and internal negative pressure of the oil storage tank. The oil-gas separator is simple in structure, capable of increasing the oil-gas separation speed and long in service life.

Description

Technical Field

[0001] The invention relates to transformer state monitoring technology, and in particular to a degassing device for online monitoring of gas in transformer oil and a control method thereof. Background Art

[0002] As one of the important equipment in the power system, the "health status" of the transformer directly affects the safe and stable operation of the power grid. Therefore, it is very meaningful and necessary to analyze the transformer failure. An in-depth analysis of transformer failure cases in recent years shows that when the transformer fails, the content of H2, C2H2, total hydrocarbons and other gases dissolved in the oil will increase and continue to increase. This may be caused by loose shielding caps or bolts, core vibration, insulation damage, etc. It is very meaningful to monitor the content of each component gas dissolved in the transformer oil in real time. It can reflect most of the possible early faults of the transformer and reflect the development trend and severity of the fault.

[0003] At present, the most important means of transformer status monitoring is online monitoring of dissolved gases in transformer oil. Specifically, a degassing device is used to release H2, CO, CO2, CH4, C2H4, C2H6, C2H2 and other gases dissolved in the transformer oil, and then a gas detection device such as a tdlas detector is used to detect the content of these gases to determine the operation status of the transformer.

[0004] The current degassing devices mainly use dynamic headspace degassing and vacuum degassing. The dynamic headspace degassing method heats the sample to release the volatile components, blows them out with a carrier gas, and then captures these components for further analysis, but the degassing efficiency is not high and the amount of sample obtained is insufficient. The vacuum degassing method releases the gas dissolved or adsorbed in the sample by reducing the air pressure around the sample. It is often used to remove dissolved gases in liquids, such as air in water or oil. Compared with the headspace degassing method, the vacuum degassing method releases gas more completely, but the degassing device using the vacuum degassing method has a relatively complex structure, low reliability, limited service life, and is prone to produce oil mist to contaminate the gas detection device, affecting the detection work. Summary of the invention

[0005] The technical problem to be solved by the present invention is as follows: In view of the above-mentioned problems in the prior art, a degassing device for online monitoring of gas in transformer oil and a control method thereof are provided, which can accelerate the speed of oil-gas separation, has a simple structure and a long service life.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A degassing device for online monitoring of gas in transformer oil comprises an oil circuit module, a gas circuit module and a controller module, wherein the oil circuit module comprises an oil storage tank, an oil pump, an oil inlet valve and an oil outlet valve, the oil inlet and outlet of the oil storage tank are connected in sequence through the oil pump, the oil inlet valve and the oil inlet of the transformer, the oil inlet and outlet of the oil storage tank are also connected through the oil pump and the oil outlet valve, a heating unit is arranged inside the oil storage tank, the controller module is connected to the control ends of the oil pump, the oil inlet valve, the oil outlet valve and the heating unit respectively, so as to control the oil inlet valve and the oil pump to realize oil inlet of the oil storage tank, control the heating unit to accelerate the release of gas molecules dissolved in the oil, and control the oil outlet valve and the oil pump to realize oil discharge of the oil storage tank;

[0008] The air circuit module includes an air pump, an optical air chamber, an air inlet valve and an exhaust valve which are connected in sequence to form a loop. The optical air chamber is connected to the air outlet of the oil storage tank. The controller module is connected to the control ends of the air pump, the air inlet valve and the exhaust valve respectively to control the air pump, the air inlet valve and the exhaust valve to achieve air circuit purge, and also control the air pump and the exhaust valve to achieve internal negative pressure in the oil storage tank.

[0009] Furthermore, a valve is provided at the gas outlet of the oil storage tank, and a filter unit is provided between the valve and the gas outlet of the oil storage tank, and the controller module is connected to the control end of the valve.

[0010] Furthermore, an oxygen sensor and a trace water sensor are provided in sequence between the oil inlet valve and the oil intake port of the transformer, a hydrogen sensor is provided between the optical air chamber and the gas outlet of the oil storage tank, and the data acquisition end of the controller module is connected to the oxygen sensor, the trace water sensor, and the hydrogen sensor respectively.

[0011] Furthermore, the intake valve and the exhaust valve are both channel switching valves, the air pump is connected to one end of the optical air chamber, and the other end of the optical air chamber is connected to the air pump through the first channel of the intake valve and the first channel of the exhaust valve in sequence, the air pump is connected to the atmosphere through the second channel of the exhaust valve to exhaust the gas in the airway, and the air pump is connected to the air filter through the optical air chamber and the second channel of the intake valve in sequence to inhale external air.

[0012] Furthermore, the oil inlet end of the oil inlet valve and the oil outlet end of the oil outlet valve are both provided with a check valve.

[0013] Furthermore, the oil inlet valve is a channel switching valve, the oil inlet and outlet are arranged at the bottom of the oil storage tank, and the top of the oil storage tank is also provided with an oil inlet, the oil inlet is connected to the oil inlet and outlet through the first channel of the oil inlet valve and the oil pump in sequence, and the oil pump is connected to the oil intake port of the transformer through the second channel of the oil inlet valve.

[0014] Furthermore, a pressure sensor and a liquid level sensor are also provided in the oil storage tank, and the data acquisition end of the controller module is connected to the pressure sensor and the liquid level sensor.

[0015] The present invention also provides a control method for a degassing device for online monitoring of gas in transformer oil as described in any one of the above, wherein the controller module is programmed or configured to perform the following steps:

[0016] S1) judging whether there is residual oil in the oil storage tank, otherwise executing step S2, if yes, enabling the oil outlet valve and controlling the oil pump to reverse, until there is no residual oil in the oil storage tank, cutting off the power to the oil outlet valve and the oil pump, and executing step S2;

[0017] S2) enabling the oil inlet valve and controlling the oil pump to rotate forward, after waiting for a first time, the oil inlet valve and the oil pump are powered off, the oil outlet valve is enabled, and the oil pump is controlled to rotate reversely, until there is no residual oil in the oil storage tank, and the oil outlet valve and the oil pump are powered off;

[0018] S3) enabling the valve and repeatedly performing external purge of the gas circuit, then de-energizing the valve and performing internal purge of the gas circuit, the external purge of the gas circuit specifically enables the exhaust valve and the air pump, waits for the pressure of the oil storage tank to meet the requirements, de-energizes the exhaust valve and the air pump and enables the intake valve, waits for a second time, and de-energizes the intake valve; the internal purge of the gas circuit specifically enables the intake valve, the exhaust valve, and the air pump, waits for a third time, and de-energizes the intake valve, the exhaust valve, and the air pump;

[0019] S4) enabling the valve again and repeating the purge outside the gas line, and then disconnecting the power supply to the valve;

[0020] S5) enabling the exhaust valve, valve and air pump, and cutting off the power of the exhaust valve and air pump after the pressure of the oil storage tank meets the requirement;

[0021] S6) enabling the oil inlet valve and controlling the oil pump to rotate forward, waiting for the liquid level in the oil storage tank to meet the requirements, cutting off the power to the oil inlet valve, the oil pump and the valve, and enabling the heating unit;

[0022] S7) controlling the oil pump to reverse, and after waiting for a fourth time, powering off the oil pump and the heating unit;

[0023] S8) enabling the valve after waiting for a fifth time, obtaining the internal pressure of the oil storage tank and powering off the valve after waiting for a sixth time, enabling the exhaust valve and the air pump, obtaining data of the hydrogen sensor between the optical gas chamber and the gas outlet of the oil storage tank in real time, and powering off the exhaust valve and the air pump after the pressure of the oil storage tank meets the requirements, enabling the air pump after the gas detection is completed and waiting for a seventh time before powering off the air pump;

[0024] S9) Enable the air intake valve, valve, oil inlet valve and oil outlet valve, control the oil pump to reverse until there is no residual oil in the oil storage tank, and cut off the power to the oil pump, air intake valve, valve, oil inlet valve and oil outlet valve.

[0025] Furthermore, step S5 specifically includes:

[0026] Enable the exhaust valve, valve, and air pump, wait for the pressure of the oil storage tank to meet the first pressure condition, then cut off the power to the exhaust valve, valve, and air pump, and measure the pressure of the oil storage tank at this time as the background value;

[0027] Enable the exhaust valve, valve, and air pump, wait for the pressure of the oil storage tank to meet the second pressure condition, then de-energize the exhaust valve and air pump, and then wait for the oil and air circuits to stabilize, measure the pressure of the oil storage tank at this time, and adjust the measurement result by the background value. Use the adjusted measurement result as the pressure compensation value. The pressure value of the second pressure condition is greater than the pressure value of the first pressure condition.

[0028] Further, in step S6, after the oil inlet valve is enabled and the oil pump is controlled to rotate forward, the process includes: obtaining oxygen content data and water content data in real time through an oxygen sensor and a micro-water sensor at the oil inlet end of the oil inlet valve; if the oxygen content data and / or the water content data are abnormal, it is determined that the transformer is faulty, and the process jumps to step S9; if both the oxygen content data and the water content data are normal, waiting for the liquid level of the oil storage tank to meet the requirements;

[0029] In step S8, after the data of the hydrogen sensor between the optical gas chamber and the gas outlet of the oil storage tank is obtained in real time, it includes: if the data of the hydrogen sensor is abnormal, it is determined that the transformer is faulty and jumps to step S9; if the data of the hydrogen sensor is normal, wait for the gas detection in the optical chamber to be completed.

[0030] Compared with the prior art, the advantages of the present invention are:

[0031] The oil circuit module of the present invention is provided with a heating unit in the oil storage tank, which can greatly enhance the activity of oil and gas molecules and accelerate the release of gas molecules dissolved in the oil from the oil. An air pump is provided in the gas circuit module of the present invention, and the circuit where the air pump is located is connected to the air outlet of the oil storage tank. The air pump is used to pump air to generate negative pressure in the oil storage tank, thereby accelerating the precipitation of gas molecules from the transformer oil.

[0032] The gas module of the present invention is provided with a hydrogen sensor, and the hydrogen sensor and the air pump are arranged on the same circuit, so that the hydrogen sensor can be exposed to more hydrogen per unit time, thereby reducing the detection limit of the hydrogen sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the overall structure of the device according to an embodiment of the present invention.

[0034] Figure 2 Schematic diagram of the control relationship of the functional modules of an embodiment of the present invention.

[0035] Figure 3 Schematic diagram of the channel switching valve structure according to an embodiment of the present invention.

[0036] Figure 4 Schematic diagram of a circuit in a gas circuit module according to an embodiment of the present invention.

[0037] Figure 5 Flowchart of a control method according to an embodiment of the present invention.

[0038] Legend: 1-Oil circuit module, 2-Air circuit module, 3-Controller module, 11-Oil storage tank, 12-Oil pump, 13-Oil inlet valve, 14-Oil outlet valve, 15-Valve, 16-Oxygen sensor, 17-Micro water sensor, 18-Check valve, 21-Air pump, 22-Optical air chamber, 23-Inlet valve, 24-Exhaust valve, 25-Hydrogen sensor, 26-Air filter, 101-Oil inlet and outlet, 102-Heating unit, 103-Air outlet, 104-Filter unit, 105-Oil inlet, 106-Pressure sensor, 107-Liquid level sensor. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0040] Before introducing the specific embodiments of the present invention, related concepts are first explained.

[0041] Removing dissolved gas from oil is an important step in controlling gas chromatography analysis errors. To this end, the following basic requirements are imposed on degassing devices and degassing methods:

[0042] (1) The dissolved gases, especially the components of the characteristic gases, must be removed from the oil as completely as possible.

[0043] (2) When using the vacuum degassing method, the device should ensure a high vacuum degree and good sealing. The vacuum pump must be connected to a vacuum gauge to monitor the vacuum degree. It is generally required that the residual pressure of the vacuum system before degassing is not higher than 40Pa. When the vacuum pump stops pumping, the residual pressure does not rise significantly within twice the time required for degassing. When using the solution equilibrium method for degassing, it is necessary to check and ensure that the glass syringe is well sealed.

[0044] (3) After the gas is removed from the oil, it is necessary to try to prevent these gas components from selectively dissolving back into the oil sample.

[0045] (4) Before the escaping gas is injected into the chromatograph, it should be kept mixed evenly and sampled and analyzed as quickly as possible.

[0046] (5) After degassing, the residual oil and residual gas can be completely discharged to ensure that there is no residual oil or residual gas in the degassing device to contaminate the new oil sample.

[0047] (6) The degassing device should be reliably connected to the sampling container to prevent air from being introduced when the oil sample is injected into the degassing device.

[0048] (7) During degassing, the volume of the degassed oil sample and the volume of the degassed gas must be measured as accurately as possible. The volume measurement should be accurate to two significant figures. The same amount of oil sample should be used for each degassing using the same device as much as possible.

[0049] (8) In order to improve the degassing rate and reduce the minimum detectable concentration, when using the vacuum method, the volume of the degassing chamber should be as large as possible relative to the volume of the oil sample; for the solubility equilibrium method, the optimal gas-liquid volume ratio should be selected. On the premise of meeting the injection volume requirements, the liquid phase volume should be as large as possible relative to the gas phase volume.

[0050] (9) If the incomplete degassing method is used, the degassing rate of each component to be measured by the degassing device used should be measured so that the analysis results can be corrected to the actual concentration dissolved in the oil.

[0051] Embodiment 1

[0052] This embodiment proposes a degassing device for online monitoring of gas in transformer oil, which can use the heating-oil circulation (spraying)-negative pressure method to quickly precipitate dissolved gas in transformer oil and quickly achieve oil-gas balance.

[0053] In this embodiment, the device includes an oil circuit module 1, a gas circuit module 2 and a controller module 3. Figure 1 As shown, the oil circuit module 1 includes an oil storage tank 11, an oil pump 12, an oil inlet valve 13 and an oil outlet valve 14. The oil inlet and outlet 101 of the oil storage tank 11 are connected to the oil inlet of the transformer through the oil pump 12, the oil inlet valve 13 and the oil inlet of the transformer in sequence. The oil inlet and outlet 101 of the oil storage tank 11 are also connected to the oil outlet valve 14 through the oil pump 12 (the inlet of the oil outlet valve 14 is connected to the channel between the oil pump 12 and the oil inlet valve 13). A heating unit 102 (not shown in the figure) is provided inside the oil storage tank 11. Figure 2 As shown, the controller module 3 is connected to the control ends of the oil pump 12, the oil inlet valve 13, the oil outlet valve 14, and the heating unit 102, respectively, so as to control the oil inlet valve 13 and the oil pump 12 to allow the oil storage tank 11 to enter, and to control the heating unit 102 to accelerate the release of gas molecules dissolved in the oil, and also to control the oil outlet valve 14 and the oil pump 12 to allow the oil storage tank 11 to discharge.

[0054] like Figure 1 As shown, the gas circuit module 2 in this embodiment includes an air pump 21, an optical gas chamber 22, an air inlet valve 23 and an exhaust valve 24 which are sequentially connected to form a loop, wherein the optical gas chamber 22 is connected to the gas outlet 103 of the oil storage tank 11 (the gas outlet 103 of the oil storage tank 11 and the channel between the optical gas chamber 22 and the air inlet valve 23 are connected) to obtain the dissolved gas in the oil separated in the oil storage tank 11 for detection by the gas detection device, such as Figure 2As shown, the controller module 3 is connected to the control ends of the air pump 21, the air intake valve 23, and the exhaust valve 24 respectively to control the air pump 21, the air intake valve 23, and the exhaust valve 24 to achieve air path purge, and also control the air pump 21 and the exhaust valve 24 to achieve internal negative pressure in the oil storage tank 11.

[0055] like Figure 1 As shown, in this embodiment, the gas outlet 103 of the oil storage tank 11 is provided with a valve 15, and the controller module 3 is connected to the control end of the valve 15, and the valve 15 is controlled to remain closed before the gas dissolved in the oil is fully released, so as to ensure the accuracy of gas detection. In addition, in this embodiment, a filter unit 104 is provided between the valve 15 and the gas outlet 103 of the oil storage tank 11. After the valve 15 is opened, the filter unit 104 can prevent the oil mist in the gas of the oil storage tank 11 from entering the gas circuit module 2, thereby extending the service life of the air pump 21, the optical air chamber 22, the air inlet valve 23 and the exhaust valve 24 in the gas circuit module 2.

[0056] like Figure 1 As shown, in this embodiment, an oxygen sensor 16 and a water sensor 17 are provided between the oil inlet valve 13 and the oil inlet of the transformer. Figure 2 As shown, the data acquisition end of the controller module 3 is connected to the oxygen sensor 16 and the micro-water sensor 17 respectively, so that the oxygen content and the water content of the transformer oil entering the oil circuit module 1 can be obtained in real time. When the oxygen content or the water content does not meet the requirements, it can be considered that the transformer may have a fault, thereby saving the subsequent oil and gas separation and gas detection procedures.

[0057] like Figure 1 As shown, in this embodiment, a hydrogen sensor 25 is provided between the optical gas chamber 22 and the gas outlet 103 of the oil storage tank 11. Figure 2 As shown, the data acquisition end of the controller module 3 is also connected to the hydrogen sensor 25 to detect the hydrogen content in the gas after oil and gas separation in real time. In this embodiment, the hydrogen sensor 25 is arranged on the channel between the optical gas chamber 22 and the air inlet valve 23, so that the hydrogen sensor 25 and the air pump 21 are located in the same loop, and the air pump 21 can accelerate the gas flow in the loop, so that the hydrogen sensor 25 can contact more hydrogen per unit time. The lower limit of detection can reach 0.5ppm after testing, which meets the requirement of the lower limit of detection of hydrogen content in transformer oil.

[0058] In this embodiment, the oil inlet valve 13, the air inlet valve 23 and the exhaust valve 24 are all channel switching valves, specifically SMC solenoid valves, such as Figure 3 As shown, when power is lost, the first channel between ARs is connected, and when power is on, the solenoid valve is enabled and the second channel between APs is connected.

[0059] Thus, the controller module 3 can realize the oil inlet and oil circulation of the oil storage tank 11 by controlling the channel switching of the oil inlet valve 13. Figure 1 As shown, the oil inlet and outlet 101 is arranged at the bottom of the oil storage tank 11, and the top of the oil storage tank 11 is also provided with an oil inlet 105, which is connected to the oil inlet and outlet 101 through the first channel of the oil inlet valve 13 and the oil pump 12 in turn, and the oil pump 12 is connected to the oil intake port of the transformer through the second channel of the oil inlet valve 13. Therefore, when the oil is inlet, a high level is sent to the oil inlet valve 13 to enable it to be powered, and the oil pump 12 is controlled to rotate forward to achieve oil inlet. When the oil circulates, a low level is sent to the oil inlet valve 13 to de-energize it, so that the oil in the oil storage tank 11 passes through the oil inlet and outlet 101, the oil pump 12, and the first channel of the oil inlet valve 13 of the oil storage tank 11 in turn to reach the oil inlet 105 of the oil storage tank 11, and realizes circulation in this channel from the bottom of the oil storage tank 11 to the top of the oil storage tank 11 under the action of gravity, which can accelerate the heating speed of the oil in the oil storage tank 11.

[0060] Similarly, the controller module 3 can realize the inlet and exhaust of the gas circuit through a single air pump 21 by controlling the channel switching of the inlet valve 23 and the exhaust valve 24. Figure 1 As shown, the air pump 21 is connected to one end of the optical air chamber 22, and the other end of the optical air chamber 22 is connected to the air pump 21 through the first channel of the intake valve 23 and the first channel of the exhaust valve 24 in sequence. The air pump 21 is connected to the atmosphere through the second channel of the exhaust valve 24 to exhaust the gas in the airway, and the air pump 21 is connected to the air filter 26 through the optical air chamber 22 and the second channel of the intake valve 23 in sequence to inhale external air.

[0061] Therefore, when taking in air, a high level is sent to the intake valve 23 to enable it, and a low level is sent to the exhaust valve 24 to de-energize it, and enable the air pump 21, so that the external air enters the air path module 2 through the air filter 26 in turn and flows along the second channel of the intake valve 23, the optical air chamber 22, the air pump 21, and the exhaust valve 24.

[0062] When exhausting, a low level is sent to the intake valve 23 to de-energize it, and a high level is sent to the exhaust valve 24 to energize it and enable the air pump 21, so that the gas in the air path module 2 is discharged along the path of the second channel of the intake valve 23, the optical air chamber 22, the air pump 21, and the exhaust valve 24.

[0063] In addition, when performing gas detection, a low level is sent to the intake valve 23 and the exhaust valve 24 to de-energize them, so that the optical gas chamber 22, the air pump 21, the first channel of the exhaust valve 24 and the first channel of the intake valve 23 form a connected loop, and the air pump 21 is enabled, so that the gas in the oil storage tank 11 enters the gas path module 2. Figure 4As shown in the direction of the middle arrow, the gas circulates through the hydrogen sensor 25, the optical gas chamber 22, the air pump 21, the first channel of the exhaust valve 24, and the first channel of the intake valve 23, and the hydrogen content can be detected and then other components of the gas can be detected in the optical gas chamber.

[0064] like Figure 1 As shown, in this embodiment, the oil inlet end of the oil inlet valve 13 (i.e. Figure 1 A check valve 18 is provided at the P end of the transformer 1 to prevent the oil from returning to the transformer from the oil inlet valve 13 during oil circulation. Similarly, a check valve 18 is also provided at the oil outlet end of the oil outlet valve 14 of this embodiment to prevent the oil from reversely entering the oil circuit module 1 from the oil outlet valve 14 during oil discharge.

[0065] In this embodiment, the oil storage tank 11 is also provided with a pressure sensor 106 and a liquid level sensor 107. Figure 2 As shown, the data acquisition end of the controller module 3 is connected to the pressure sensor 106 and the liquid level sensor 107 to obtain the amount of oil in the oil storage tank 11 and the internal pressure of the oil storage tank 11 in real time.

[0066] In this embodiment, there are at least two liquid level sensors 107, which are respectively arranged at the upper limit height and the lower limit height of the liquid level in the oil storage tank 11 to determine whether the amount of oil in the oil storage tank 11 meets the requirements.

[0067] The oil storage tank 11 in this embodiment is made of metal, specifically aluminum alloy, which can take into account both strength and lightness, and has good thermal conductivity, which is conducive to the heating unit 102 to quickly heat the internal oil.

[0068] Embodiment 2

[0069] This embodiment proposes a control method for the degassing device for online monitoring of gas in transformer oil described in Embodiment 1, such as Figure 5 As shown, the controller module 3 is programmed or configured to perform the following steps:

[0070] S1) Treatment of residual oil in oil storage tank:

[0071] The data of the liquid level sensor 107 at the bottom of the oil storage tank 11 is used to determine whether there is residual oil in the oil storage tank 11. If not, step S2 is executed. If yes, the oil outlet valve 14 is enabled and the oil pump 12 is controlled to reverse until there is no residual oil in the oil storage tank 11. The oil outlet valve 14 and the oil pump 12 are powered off and step S2 is executed.

[0072] S2) Oil tank flushing:

[0073] The oil inlet valve 13 is enabled, and the oil pump 12 is controlled to rotate forward. After waiting for a first time (20 seconds in this embodiment), the oil inlet valve 13 and the oil pump 12 are powered off, and then the oil outlet valve 14 is enabled, and the oil pump 12 is controlled to rotate reversely until there is no residual oil in the oil storage tank 11, and the oil outlet valve 14 and the oil pump 12 are powered off;

[0074] S3) Purge inside and outside the gas circuit:

[0075] Enable the valve 15 and repeat the external purge of the gas circuit, then cut off the power of the valve 15 and perform the internal purge of the gas circuit. The external purge of the gas circuit specifically enables the exhaust valve 24 and the air pump 21, obtains the internal pressure of the oil storage tank 11 through the pressure sensor 106, waits for the pressure of the oil storage tank 11 to meet the requirement (-90kpa in this embodiment), cuts off the power of the exhaust valve 24 and the air pump 21, and enables the intake valve 23, waits for the second time (3 seconds in this embodiment) and then cuts off the power of the intake valve 23; the internal purge of the gas circuit specifically enables the intake valve 23, the exhaust valve 24 and the air pump 21, waits for the third time (5 seconds in this embodiment) and then cuts off the power of the intake valve 23, the exhaust valve 24 and the air pump 21;

[0076] S4) External purge of gas line:

[0077] Enable valve 15 again and repeat the purge outside the gas line, then de-energize valve 15;

[0078] S5) Pumping negative pressure from oil tank:

[0079] Enable the exhaust valve 24, the valve 15 and the air pump 21, and wait for the pressure of the oil storage tank 11 to meet the requirements before de-energizing the exhaust valve 24 and the air pump 21, specifically including:

[0080] Enable the exhaust valve 24, the valve 15, and the air pump 21, obtain the internal pressure of the oil storage tank 11 through the pressure sensor 106, wait for the pressure of the oil storage tank 11 to meet the first condition (-90 kPa in this embodiment), then cut off the power to the exhaust valve 24, the valve 15, and the air pump 21, and measure the pressure of the oil storage tank 11 at this time as the background value;

[0081] Enable the exhaust valve 24, valve 15, and air pump 21, obtain the internal pressure of the oil storage tank 11 through the pressure sensor 106, wait for the pressure of the oil storage tank 11 to meet the second condition (-96kpa in this embodiment), then power off the exhaust valve 24 and the air pump 21, and then wait for the oil circuit and the air circuit to stabilize (wait for about 10 seconds in this embodiment), measure the pressure of the oil storage tank 11 at this time, and adjust the measurement result by the background value, and use the adjusted measurement result as the pressure compensation value. In this embodiment, the pressure compensation value is measured 10 times and printed to the log;

[0082] S6) Oil filling of oil storage tank:

[0083] Enable the oil inlet valve 13, and control the oil pump 12 to rotate forward, determine whether the liquid level of the oil storage tank 11 meets the requirements according to the data of the liquid level sensor 107 at the upper limit position and the lower limit position of the liquid level of the oil storage tank 11, wait for the liquid level of the oil storage tank 11 to meet the requirements (that is, the liquid level sensor 107 at the upper limit position of the liquid level feedbacks a liquid level not reached signal and the liquid level sensor 107 at the lower limit position of the liquid level feedbacks a liquid level reached signal, or the liquid level sensor 107 at the upper limit position and the liquid level sensor 107 at the lower limit position both feedback a liquid level reached signal), cut off the power to the oil inlet valve 13, the oil pump 12 and the valve 15, and enable the heating unit 102;

[0084] S7) Circulation degassing:

[0085] The oil pump 12 is controlled to reverse, and after waiting for the fourth time, the oil pump 12 and the heating unit 102 are powered off. It should be noted that in this step, in order to ensure that the gas molecules are fully released, the oil pump 12 is controlled to reverse at a specified ratio (60%) of the full speed operation power when it is reversed, and in other steps, in order to improve the efficiency of oil intake or oil discharge, the full speed operation power is used for forward and reverse rotation. In addition, the fourth time of this step is adjustable, and is specifically adjusted according to the actual oil volume during the test;

[0086] S8) Gas constant pressure measurement:

[0087] After waiting for the fifth time (5 seconds in this embodiment), the valve 15 is enabled. After waiting for the sixth time (10 seconds in this embodiment), the internal pressure of the oil storage tank 11 is obtained through the pressure sensor 106 and the valve 15 is powered off. The internal pressure of the oil storage tank 11 is obtained for pressure compensation. In this embodiment, the pressure is measured 10 times and printed into the log.

[0088] Enable the exhaust valve 24 and the air pump 21, obtain the internal pressure of the oil storage tank 11 through the pressure sensor 106, and wait for the pressure of the oil storage tank 11 to meet the requirement (-90kpa in this embodiment), then cut off the power of the exhaust valve 24 and the air pump 21, obtain the data of the hydrogen sensor 25 in real time, and wait for the gas detection in the optical chamber 22 to be completed, then enable the air pump 21 and wait for the seventh time (5 minutes in this embodiment), and then cut off the power of the air pump 21;

[0089] S9) Oil tank drain:

[0090] Enable the air intake valve 23, valve 15, oil intake valve 13 and oil outlet valve 14, control the oil pump 12 to reverse until there is no residual oil in the oil storage tank 11, cut off the power to the oil pump 12, air intake valve 23, valve 15, oil intake valve 13 and oil outlet valve 14, and wait for the next gas detection.

[0091] It should be noted that, since the device in the first embodiment further includes an oxygen sensor 16 and a micro-water sensor 17 to detect the oxygen content and water content of the oil entering the oil circuit module 1, the aforementioned steps S7 and S8 are steps when there is no abnormal data of the oxygen content and the water content. In step S6 of this embodiment, after enabling the oil inlet valve 13 and controlling the oil pump 12 to rotate forward, the following steps are also included:

[0092] The oxygen content data and the moisture content data are obtained in real time through the oxygen sensor 16 and the micro-water sensor 17. If the oxygen content data and / or the moisture content data are abnormal, it is determined that the transformer is faulty and the process jumps to step S9; if the oxygen content data and the moisture content data are normal, the process waits for the liquid level of the oil storage tank 11 to meet the requirements.

[0093] Similarly, in step S8, after the data of the hydrogen sensor 25 is acquired in real time, the following steps are performed: if the data of the hydrogen sensor 25 is abnormal, it is determined that the transformer is faulty, and the process jumps to step S9; if the data of the hydrogen sensor 25 is normal, the process waits for the gas detection in the optical chamber 22 to be completed.

[0094] In summary, the present invention discloses a degassing device for online monitoring of gas in transformer oil and a control method thereof, which can greatly prolong the maintenance time of the oil-gas separation system and save material costs and labor costs.

[0095] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A degassing device for online monitoring of gas in transformer oil, characterized in that: The invention comprises an oil circuit module (1), an air circuit module (2) and a controller module (3); the oil circuit module (1) comprises an oil storage tank (11), an oil pump (12), an oil inlet valve (13) and an oil outlet valve (14); the oil inlet and outlet (101) of the oil storage tank (11) are connected to the oil inlet of the transformer via the oil pump (12), the oil inlet valve (13) and the oil outlet of the transformer in sequence; the oil inlet and outlet (101) of the oil storage tank (11) are also connected to the oil outlet valve (14) via the oil pump (12); A heating unit (102) is provided inside the oil storage tank (11), and the controller module (3) is respectively connected to the oil pump (12), the oil inlet valve (13), the oil outlet valve (14), and the control end of the heating unit (102) to control the oil inlet valve (13) and the oil pump (12) to allow oil to enter the oil storage tank (11), control the heating unit (102) to accelerate the release of gas molecules dissolved in the oil, and control the oil outlet valve (14) and the oil pump (12) to allow oil to be discharged from the oil storage tank (11); The gas circuit module (2) comprises an air pump (21), an optical gas chamber (22), an air intake valve (23) and an exhaust valve (24) which are connected in sequence to form a loop; the optical gas chamber (22) is connected to an air outlet (103) of an oil storage tank (11); the controller module (3) is connected to control ends of the air pump (21), the air intake valve (23) and the exhaust valve (24) respectively, so as to control the air pump (21), the air intake valve (23) and the exhaust valve (24) to achieve gas circuit purging, and also to control the air pump (21) and the exhaust valve (24) to achieve internal negative pressure of the oil storage tank (11).

2. The degassing device for online monitoring of gas in transformer oil according to claim 1, characterized in that: The gas outlet (103) of the oil storage tank (11) is provided with a valve (15), and a filter unit (104) is provided between the valve (15) and the gas outlet (103) of the oil storage tank (11), and the controller module (3) is connected to the control end of the valve (15).

3. The degassing device for online monitoring of gas in transformer oil according to claim 1, characterized in that: An oxygen sensor (16) and a trace water sensor (17) are arranged in sequence between the oil inlet valve (13) and the oil inlet of the transformer, a hydrogen sensor (25) is arranged between the optical air chamber (22) and the gas outlet (103) of the oil storage tank (11), and a data acquisition end of the controller module (3) is connected to the oxygen sensor (16), the trace water sensor (17), and the hydrogen sensor (25), respectively.

4. The degassing device for online monitoring of gas in transformer oil according to claim 1, characterized in that: The air inlet valve (23) and the air exhaust valve (24) are both channel switching valves; the air pump (21) is connected to one end of the optical air chamber (22), and the other end of the optical air chamber (22) is connected to the air pump (21) through a first channel of the air inlet valve (23) and a first channel of the air exhaust valve (24) in sequence; the air pump (21) is connected to the atmosphere through a second channel of the air exhaust valve (24) to exhaust gas in the airway; and the air pump (21) is connected to an air filter (26) through the optical air chamber (22) and the second channel of the air inlet valve (23) in sequence to inhale external air.

5. The degassing device for online monitoring of gas in transformer oil according to claim 1, characterized in that: The oil inlet end of the oil inlet valve (13) and the oil outlet end of the oil outlet valve (14) are both provided with a check valve (18).

6. The degassing device for online monitoring of gas in transformer oil according to claim 1, characterized in that: The oil inlet valve (13) is a channel switching valve. The oil inlet and outlet (101) are arranged at the bottom of the oil storage tank (11). The top of the oil storage tank (11) is also provided with an oil inlet (105). The oil inlet (105) is connected to the oil inlet and outlet (101) through a first channel of the oil inlet valve (13) and an oil pump (12) in sequence. The oil pump (12) is connected to an oil intake port of a transformer through a second channel of the oil inlet valve (13).

7. The degassing device for online monitoring of gas in transformer oil according to claim 1, characterized in that: The oil storage tank (11) is also provided with a pressure sensor (106) and a liquid level sensor (107), and the data acquisition end of the controller module (3) is connected to the pressure sensor (106) and the liquid level sensor (107).

8. The control method of the degassing device for online monitoring of gas in transformer oil according to any one of claims 1 to 7, characterized in that: The controller module (3) is programmed or configured to perform the following steps: S1) determines whether there is residual oil in the oil storage tank (11), if not, executes step S2, if yes, enables the oil outlet valve (14), and controls the oil pump (12) to reverse, until there is no residual oil in the oil storage tank (11), cuts off the power to the oil outlet valve (14) and the oil pump (12), and executes step S2; S2) enabling the oil inlet valve (13) and controlling the oil pump (12) to rotate forward, after waiting for a first time, the oil inlet valve (13) and the oil pump (12) are powered off, the oil outlet valve (14) is enabled, and the oil pump (12) is controlled to rotate reversely, until there is no residual oil in the oil storage tank (11), and the oil outlet valve (14) and the oil pump (12) are powered off; S3) enabling the valve (15) and repeatedly performing external purging of the gas circuit, then disconnecting the power supply of the valve (15) and performing internal purging of the gas circuit, the external purging of the gas circuit specifically includes enabling the exhaust valve (24) and the air pump (21), disconnecting the power supply of the exhaust valve (24) and the air pump (21) and enabling the intake valve (23) after the pressure of the oil storage tank (11) meets the requirement, and disconnecting the power supply of the intake valve (23) after waiting for a second time; the internal purging of the gas circuit specifically includes enabling the intake valve (23), the exhaust valve (24) and the air pump (21), and disconnecting the power supply of the intake valve (23), the exhaust valve (24) and the air pump (21) after waiting for a third time; S4) re-enabling the valve (15) and repeating the purge outside the gas path, and then de-energizing the valve (15); S5) enabling the exhaust valve (24), the valve (15) and the air pump (21), and then disconnecting the exhaust valve (24) and the air pump (21) after the pressure of the oil storage tank (11) meets the requirement; S6) enabling the oil inlet valve (13) and controlling the oil pump (12) to rotate forward, waiting for the liquid level of the oil storage tank (11) to meet the requirement, de-energizing the oil inlet valve (13), the oil pump (12) and the valve (15), and enabling the heating unit (102); S7) controlling the oil pump (12) to rotate in reverse, and after waiting for a fourth time, powering off the oil pump (12) and the heating unit (102); S8) after waiting for a fifth time, enable the valve (15); after waiting for a sixth time, obtain the internal pressure of the oil storage tank (11) and cut off the power to the valve (15); enable the exhaust valve (24) and the air pump (21); after waiting for the pressure of the oil storage tank (11) to meet the requirements, cut off the power to the exhaust valve (24) and the air pump (21); obtain data of the hydrogen sensor (25) between the optical gas chamber (22) and the gas outlet (103) of the oil storage tank (11) in real time; after waiting for the gas detection in the optical chamber (22) to be completed, enable the air pump (21) and wait for a seventh time before cutting off the power to the air pump (21); S9) enables the air intake valve (23), the valve (15), the oil intake valve (13) and the oil outlet valve (14), controls the oil pump (12) to reverse, until there is no residual oil in the oil storage tank (11), and cuts off the power to the oil pump (12), the air intake valve (23), the valve (15), the oil intake valve (13) and the oil outlet valve (14).

9. The control method of the degassing device for online monitoring of gas in transformer oil according to claim 8, characterized in that: Step S5 specifically includes: Enable the exhaust valve (24), the valve (15), and the air pump (21), wait for the pressure of the oil storage tank (11) to meet the first pressure condition, then cut off the power to the exhaust valve (24), the valve (15), and the air pump (21), and measure the pressure of the oil storage tank (11) at this time as a background value; The exhaust valve (24), the valve (15), and the air pump (21) are enabled, and the exhaust valve (24) and the air pump (21) are de-energized after the pressure of the oil storage tank (11) meets the second pressure condition. Then, after the oil circuit and the air circuit are stabilized, the pressure of the oil storage tank (11) is measured at this time, and the measurement result is adjusted by the background value. The adjusted measurement result is used as the pressure compensation value. The pressure value of the second pressure condition is greater than the pressure value of the first pressure condition.

10. The control method of the degassing device for online monitoring of gas in transformer oil according to claim 8, characterized in that: In step S6, after the oil inlet valve (13) is enabled and the oil pump (12) is controlled to rotate forward, the following steps include: obtaining oxygen content data and water content data in real time through an oxygen sensor (16) and a micro-water sensor (17) at the oil inlet end of the oil inlet valve (13); if the oxygen content data and / or the water content data are abnormal, it is determined that the transformer is faulty and the process jumps to step S9; if both the oxygen content data and the water content data are normal, waiting for the liquid level of the oil storage tank (11) to meet the requirements; In step S8, after the data of the hydrogen sensor (25) between the optical gas chamber (22) and the gas outlet (103) of the oil storage tank (11) is obtained in real time, the following steps are included: if the data of the hydrogen sensor (25) is abnormal, it is determined that the transformer is faulty and the process jumps to step S9; if the data of the hydrogen sensor (25) is normal, the process waits for the gas detection in the optical chamber (22) to be completed.

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