Fault early warning device and method for oil immersed transformer

Abstract

The invention discloses an oil immersed transformer fault early warning device and method. The device comprises an oil sample acquisition module, an environmental parameter acquisition module, a degassing module and a fault early warning module. The oil sample collection module is used for extracting an oil sample; the environmental parameter acquisition module acquires oil tank temperature, micro-water content in oil and oil tank pressure; the degassing module separates gas dissolved in the oil and generates gas concentration data. And the fault early warning module calculates a dissolved gas ratio according to the gas concentration data, and generates a fault prediction result of the transformer based on a preset ratio diagnosis rule. The theoretical gas concentration is generated through the multiple regression model in combination with environmental parameter fitting, and the absolute difference value between the gas concentration and the theoretical concentration is calculated to obtain an environmental compensation difference value. According to the environment compensation difference value and the fault prediction result, an early warning signal of the oil immersed transformer is generated, and accurate fault monitoring and early warning are achieved. According to the invention, the accuracy and reliability of fault early warning can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of dissolved gas in oil fault diagnosis, and particularly relates to an oil-immersed transformer fault early warning device and method. Background Art

[0002] Oil-immersed transformers are widely used in scenarios such as urban and rural power grid renovation, industrial and mining enterprise power supply systems, as well as combined transformers and prefabricated substations. As a high-performance transformer with excellent performance, its three-dimensional wound core structure makes the magnetic circuit have no air gap, reduces core loss, decreases noise, and achieves three-phase balance. However, during the operation of an oil-immersed transformer, a certain amount of gas will inevitably be dissolved in its internal insulating oil. When faults such as local overheating, arc discharge, or partial discharge occur inside the transformer, the insulating material and insulating oil will undergo thermal decomposition or electrochemical reactions, releasing characteristic gases such as hydrogen, methane, ethane, ethylene, and acetylene. By monitoring the types, concentrations, and ratio changes of the dissolved gases in the oil, abnormal signs can be captured in the early stage of the fault, so that maintenance or replacement measures can be taken in a timely manner to avoid serious damage to the transformer or even power grid accidents. Therefore, establishing an accurate oil-immersed transformer fault early warning mechanism is crucial for ensuring the safe operation of the power grid.

[0003] The existing oil-immersed transformer fault early warning technologies mainly rely on the dissolved gas analysis (DGA) method. However, the current technologies still have the following problems and defects: First, some early warning systems only focus on the concentration changes of the dissolved gases and do not fully consider the influence of environmental parameters (such as tank temperature, micro water content, tank pressure) on the gas concentration, resulting in the risk of false alarms or missed alarms when the external conditions fluctuate; Second, some devices lack a systematic health index evaluation mechanism and only rely on a single gas index or ratio combination for judgment, making it difficult to comprehensively reflect the overall operating state of the transformer. These deficiencies not only affect the accuracy of fault early warning but may also delay crucial operation and maintenance decisions. Summary of the Invention

[0004] An embodiment of the present invention provides an oil-immersed transformer fault early warning device and method. By implementing the present invention, the overall operating state of the oil-immersed transformer can be more accurately reflected, thereby improving the accuracy and reliability of fault early warning.

[0005] An embodiment of the present invention provides an oil-immersed transformer fault early warning device, including: an oil sample collection module, an environmental parameter collection module, a degassing module, and a fault early warning module;

[0006] The oil sample collection module is used to extract the oil sample of the oil-immersed transformer;

[0007] The environmental parameter collection module is used to collect the tank temperature of the oil-immersed transformer, the micro water content in the oil, and the tank pressure;

[0008] The degassing module is used to separate the dissolved gases in the oil sample and generate concentration data of the dissolved gases in the oil; wherein, the dissolved gases in the oil include hydrogen, methane, ethane, ethylene and acetylene;

[0009] The fault warning module is used to calculate and generate the ratio between the dissolved gases in the oil according to the concentration data of the dissolved gases in the oil;

[0010] Generate a fault prediction result of the oil-immersed transformer according to the ratio between the dissolved gases in the oil;

[0011] For each dissolved gas in the oil, based on the corresponding preset multiple regression model, fit and generate the corresponding theoretical gas concentration according to the tank temperature, the micro water content in the oil and the tank pressure;

[0012] Calculate the absolute difference between the concentration data of each dissolved gas in the oil and the corresponding theoretical gas concentration to obtain the environmental compensation difference of the dissolved gases in the oil;

[0013] Generate a warning signal for the oil-immersed transformer according to the environmental compensation difference and the fault prediction result.

[0014] Further, the generating a fault prediction result of the oil-immersed transformer according to the ratio between the dissolved gases in the oil includes:

[0015] Calculate the concentration ratio of methane to hydrogen to generate a first concentration ratio;

[0016] Calculate the concentration ratio of acetylene to ethylene to generate a second concentration ratio;

[0017] Calculate the concentration ratio of ethane to acetylene to generate a third concentration ratio;

[0018] When the first concentration ratio is less than a preset first threshold, it is determined that the oil-immersed transformer is suspected of having a partial discharge fault;

[0019] When the second concentration ratio is greater than a preset second threshold, it is determined that the oil-immersed transformer is suspected of having an arc discharge fault;

[0020] When the third concentration ratio is greater than a preset third threshold, it is determined that the oil-immersed transformer is suspected of having a low-temperature overheating fault.

[0021] Further, the generating a warning signal for the oil-immersed transformer according to the environmental compensation difference and the fault prediction result includes:

[0022] Generate a concentration over-limit deduction score for the dissolved gases in the oil according to the environmental compensation difference and the corresponding compensation threshold;

[0023] Generate a fault deduction value for the oil-immersed transformer according to the fault prediction result and the corresponding deduction weight;

[0024] Calculate the health index of the oil-immersed transformer through a preset health index calculation formula according to the concentration over-standard deduction value and the fault deduction value;

[0025] Determine the warning level according to the health index, and then generate a corresponding warning signal according to the warning level;

[0026] Among them, the health index calculation formula includes:

[0027]

[0028] Among them, HI is the health index of the oil-immersed transformer; I HI is the upper limit value of the health index; n is the number of types of dissolved gases in the oil; S i is the concentration over-standard deduction value of the i-th dissolved gas in the oil; W is the weight value of the concentration over-standard deduction value; F is the fault deduction value of the oil-immersed transformer.

[0029] Further, the multiple regression model is specifically:

[0030] C = β0 + β1T + β2H + β3P + ε

[0031] Among them, C is the theoretical gas concentration; β0 is the intercept term; T is the tank temperature; β1 is the regression coefficient of the tank temperature; H is the micro water content in the oil; β2 is the regression coefficient of the micro water content in the oil; P is the tank pressure; β3 is the regression coefficient of the tank pressure; ε is the error term.

[0032] Further, the oil sample collection module includes a mounting frame, a movable block, a mounting convex block, a first telescopic rod, a bottom plate, a liquid suction head, a pump, a connecting hose, and an infusion tube;

[0033] The movable block is slidably arranged on the mounting frame; the side wall of the movable block is provided with a mounting convex block; the bottom surface of the mounting convex block is provided with a first telescopic rod; the bottom end of the first telescopic rod is connected with a bottom plate; a liquid suction head is mounted on the bottom plate; a pump is mounted in the mounting convex block; the lower inlet of the pump is connected with a connecting hose; the connecting hose is connected with the liquid suction head; the upper outlet of the pump is connected with an infusion tube; the infusion tube is connected with one end of the degassing module; a solenoid valve is arranged at the upper end of the infusion tube.

[0034] Further, the mounting frame includes an upper mounting frame body, a lower mounting frame body, a connecting ear, a sliding track, an external rack, and a plurality of mounting blocks;

[0035] The upper mounting frame body is fixedly connected with the lower mounting frame body through a connecting ear;

[0036] Sliding tracks are provided on the opposite surfaces of the upper frame body and the lower frame body of the mounting frame;

[0037] External racks are provided on the side walls of the lower frame body of the mounting frame;

[0038] A number of mounting blocks are provided on the top surface of the upper frame body of the mounting frame.

[0039] Furthermore, an adjustment motor is installed inside the movable block, the output end of the adjustment motor is connected with an adjustment gear, and the adjustment gear is meshed with the external rack.

[0040] Furthermore, the degassing module includes a degassing column, a piston head, a second telescopic rod, a top plate, a lifting column, a connecting rod, a connecting tooth plate, a rotating shaft, a connecting gear and a number of stirring blades;

[0041] One end of the degassing module is the degassing column;

[0042] The degassing column is of a hollow structure; a piston head is arranged inside the degassing column; a second telescopic rod is arranged above the degassing column; the bottom end of the second telescopic rod is connected with a top plate; a lifting column is connected to the bottom surface of one end of the top plate; the lifting column is inserted into the degassing column and fixedly connected with the piston head; a connecting rod is connected to the bottom surface of the other end of the top plate; the bottom end of the connecting rod is connected with a connecting tooth plate; a rotating shaft is rotatably installed on the side wall of the degassing column; one end of the rotating shaft is connected with a connecting gear; the connecting gear is meshed with the connecting tooth plate; a number of stirring blades are arranged on the end of the rotating shaft inserted into the degassing column.

[0043] Furthermore, several temperature adjustment blocks are arranged on the side wall of the degassing column; a gas guide pipe is arranged on the side wall of the degassing column; a solenoid valve II is arranged on the gas guide pipe; the gas guide pipe is connected with the fault warning module.

[0044] An embodiment of the present invention provides a method for fault warning of an oil-immersed transformer, which is applicable to the fault warning module of an oil-immersed transformer fault warning device, and includes:

[0045] Obtain the oil tank temperature, the micro water content in the oil, the oil tank pressure and the concentration data of each dissolved gas in the oil of the oil-immersed transformer; wherein, the dissolved gases in the oil include hydrogen, methane, ethane, ethylene and acetylene;

[0046] Calculate and generate the ratio between each dissolved gas in the oil according to the concentration data of each dissolved gas in the oil;

[0047] Based on the preset diagnosis rule of the ratio of dissolved gases in the oil, generate the fault prediction result of the oil-immersed transformer according to the ratio between each dissolved gas in the oil;

[0048] For each dissolved gas in oil, based on the corresponding preset multiple regression model, according to the tank temperature, the micro - water content in oil, and the tank pressure, a corresponding theoretical gas concentration is fitted and generated;

[0049] Calculate the absolute difference between each dissolved gas concentration data in oil and the corresponding theoretical gas concentration to obtain the environmental compensation difference of each dissolved gas in oil;

[0050] According to the environmental compensation difference and the fault prediction result, calculate the health index of the oil - immersed transformer;

[0051] Based on the preset health index grading rules, generate a warning signal for the oil - immersed transformer according to the health index.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] The embodiment of the present invention provides an oil - immersed transformer fault warning device and method. The device extracts an oil sample through an oil sample collection module, separates the dissolved gas in oil through a degassing module and generates gas concentration data. At the same time, an environmental parameter collection module monitors the tank temperature, the micro - water content in oil, and the tank pressure in real - time. The fault warning module calculates the gas ratio based on the dissolved gas ratio diagnosis rule, generates a fault prediction result of the transformer, and uses a multiple regression model to perform environmental compensation on the gas concentration. Finally, it evaluates the operating state of the transformer through the health index and generates a warning signal according to the preset grading rules, so as to achieve accurate fault warning.

[0054] The present invention obtains the tank temperature, the micro - water content in oil, and the tank pressure in real - time through the environmental parameter collection module, and uses a multiple regression model in the fault warning module to perform environmental compensation on the dissolved gas concentration, solving the problems of false alarms or missed alarms caused by not considering environmental factors in the prior art. In addition, by calculating the dissolved gas ratio and combining with the health index evaluation, the limitations of existing devices that only rely on a single gas index or a combination of ratios are overcome, more accurately reflecting the overall operating state of the oil - immersed transformer, thereby improving the accuracy and reliability of fault warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 is a schematic flowchart of an oil - immersed transformer fault warning device provided by an embodiment of the present invention.

[0056] Figure 2 is a schematic flowchart of an oil - immersed transformer fault warning device provided by another embodiment of the present invention.

[0057] Figure 3 is a schematic structural diagram of an oil - immersed transformer fault warning device provided by another embodiment of the present invention.

[0058] Figure 4 It is a schematic enlarged structure diagram of area A provided by an embodiment of the present invention.

[0059] Figure 5 It is a schematic connection structure diagram of the movable block provided by an embodiment of the present invention.

[0060] Figure 6 It is a schematic structure diagram of the degassing module provided by an embodiment of the present invention.

[0061] Figure 7 It is a schematic structure diagram of the degassing column provided by an embodiment of the present invention.

[0062] Figure 8 It is a schematic flow diagram of a method for early warning of oil-immersed transformer faults provided by an embodiment of the present invention.

[0063] Description of reference numerals:

[0064] 1. Mounting frame; 101. Upper frame of the mounting frame; 102. Lower frame of the mounting frame; 103. Connecting ear; 104. Sliding track; 105. External rack; 106. Mounting block; 2. Movable block; 3. Mounting convex block; 4. Adjusting motor; 5. Adjusting gear; 6. First telescopic rod; 7. Bottom plate; 8. Liquid suction head; 9. Pump; 10. Connecting hose; 11. Infusion tube; 1101. Solenoid valve; 12. Degassing column; 1201. Temperature adjusting block; 13. Piston head; 14. Lifting column; 15. Top plate; 16. Second telescopic rod; 17. Link; 18. Connecting toothed plate; 19. Rotating shaft; 20. Connecting gear; 21. Stirring blade; 22. Air duct; 23. Fault warning module. Detailed implementation manners

[0065] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0066] As shown in Figure 1 、 2 、3, 4, 5, 6, 7, an embodiment of the present invention provides an oil-immersed transformer fault warning device, including: an oil sample collection module, an environmental parameter collection module, a degassing module, and a fault warning module 23;

[0067] The oil sample collection module is used to extract the oil sample of the oil-immersed transformer;

[0068] Specifically, when obtaining the dissolved gases in oil, the oil can be pumped into the degassing column 12 for separation by starting the pump 9. The bottom plate 7 carrying the liquid suction head 8 is lowered by extending the first telescopic rod 6, and the oil in the lower layer can be sucked. By controlling the start of the adjusting motor 4 to drive the adjusting gear 5 to rotate, the adjusting gear 5 rolls on the external rack 105, and then the moving block 2 moves along the mounting rack 1 within the sliding track 104, so that the liquid suction head 8 can suck the oil at multiple positions in the transformer for detection, with higher accuracy.

[0069] The environmental parameter acquisition module is used to acquire the tank temperature, the micro water content in the oil, and the tank pressure of the oil-immersed transformer.

[0070] Specifically, the tank temperature can be acquired by the tank temperature sensor set at the top of the tank. The tank temperature sensor can also be set elsewhere, such as near the winding or at the oil conservator. The micro water content in the oil can be acquired by the micro water content sensor in the oil. The micro water content sensor in the oil can be set in the circulation pipeline integrated at the outlet of the oil pump or near the liquid suction head, or can also be set at the inlet of the degassing column, without limitation. The tank pressure can be acquired by the tank pressure sensor, and the tank pressure sensor can be set at the top of the tank.

[0071] The degassing module is used to separate the dissolved gases in the oil sample to generate the concentration data of the dissolved gases in the oil; among them, the dissolved gases in the oil include hydrogen, methane, ethane, ethylene, and acetylene.

[0072] Specifically, when separating the gas, the oil is pumped into the degassing column 12. By controlling the second telescopic rod 16 to pull up the top plate 15, the lifting column 14 then pulls the piston head 13 to rise, reducing the air pressure inside the degassing column 12, so that the dissolved gas begins to precipitate. And the connecting rod 17 rises with the top plate 15, the connecting toothed plate 18 rises accordingly and drives the connecting gear 20, and then the rotating shaft 19 drives the stirring blade 21 to rotate inside the degassing column 12. The stirring blade 21 stirs the oil and the temperature regulating block 1201 heats the degassing column 12, which is more conducive to the separation of gas and oil. The dissolved gases in the oil can also include carbon monoxide, carbon dioxide, etc.

[0073] The fault warning module 23 is used to calculate and generate the ratio between the dissolved gases in the oil according to the concentration data of the dissolved gases in the oil.

[0074] According to the ratio between the dissolved gases in the oil, generate the fault prediction result of the oil-immersed transformer.

[0075] Specifically, this solution dynamically calculates key gas ratio combinations by collecting the concentration data of hydrogen, methane, ethane, ethylene, and acetylene dissolved in the oil of oil-immersed transformers in real time and based on the threshold rules preset by the IEC 60599 standard. The ratio of methane to hydrogen is used to identify the critical state between partial discharge and arc discharge. The ratio of acetylene to ethylene is used to capture the characteristic signals of arc discharge. The ratio of ethane to acetylene is then used to assist in determining the trend of low-temperature overheating and insulation aging.

[0076] For each gas dissolved in the oil, based on the corresponding preset multiple regression model, according to the tank temperature, the moisture content in the oil, and the tank pressure, the corresponding theoretical gas concentration is fitted and generated.

[0077] The preset multiple regression model fits the regression coefficients using historical data through the following steps:

[0078] Step 1: From the long-term operation data of multiple oil-immersed transformers, collect the measured concentrations of the tank temperature, the moisture content in the oil, the tank pressure, and each gas dissolved in the oil. After removing outliers, perform Z-score standardization on the tank temperature, the moisture content in the oil, and the tank pressure to eliminate the dimension difference.

[0079] Step 2: For each type of gas, establish a multiple linear regression equation and use the least squares method to optimize the objective function to solve for the regression coefficients. After the model is deployed, add the newly added operation data to the training set regularly (e.g., monthly), and refit the coefficients through a rolling window (e.g., the data in the most recent 1 year) to ensure that the model parameters are adaptively adjusted as the equipment ages or the environment changes.

[0080] Calculate the absolute difference between the concentration data of each gas dissolved in the oil and the corresponding theoretical gas concentration to obtain the environmental compensation difference of each gas dissolved in the oil.

[0081] It should be noted here that in the fault warning of oil-immersed transformers, the core purpose of calculating the absolute difference (environmental compensation difference) between the actual gas concentration and the theoretical gas concentration is to strip the natural interference of environmental factors on the gas concentration, so as to accurately identify the abnormal signals caused by real faults. The concentration of the gas dissolved in the oil is directly affected by environmental parameters such as temperature, humidity, and pressure. For example, an increase in temperature reduces the solubility of the gas in the insulating oil, resulting in the natural escape of the gas and an increase in concentration (e.g., the hydrogen concentration may increase due to an increase in temperature, not due to a fault). An increase in the internal pressure of the tank inhibits the release of the gas, and conversely, a decrease in pressure accelerates the escape of the gas. The reaction between moisture and insulating materials may generate gases such as hydrogen and carbon monoxide, causing fluctuations in concentration.

[0082] For example, a certain transformer operates under high temperature in summer. The temperature of the oil tank rises from 30°C to 50°C, and the measured concentration of hydrogen gas rises from 80 ppm to 120 ppm. If a fixed threshold is directly used (such as an alarm when hydrogen gas > 100 ppm), it will be misjudged as a fault. However, through theoretical model calculation, it is found that the theoretical concentration of H2 caused by the temperature rise should be 110 ppm, and the difference between the actual concentration of 120 ppm is only 10 ppm (not exceeding the standard), thus avoiding false alarms.

[0083] Generate an early warning signal for the oil-immersed transformer according to the environmental compensation difference and the fault prediction result.

[0084] In a preferred embodiment, the generating the fault prediction result of the oil-immersed transformer according to the ratios between the dissolved gases in the oil includes:

[0085] Calculate the concentration ratio of methane to hydrogen gas to generate a first concentration ratio;

[0086] Calculate the concentration ratio of acetylene to ethylene to generate a second concentration ratio;

[0087] Calculate the concentration ratio of ethane to acetylene to generate a third concentration ratio;

[0088] When the first concentration ratio is less than a preset first threshold, it is determined that the oil-immersed transformer is suspected of having a partial discharge fault;

[0089] When the second concentration ratio is greater than a preset second threshold, it is determined that the oil-immersed transformer is suspected of having an arc discharge fault;

[0090] When the third concentration ratio is greater than a preset third threshold, it is determined that the oil-immersed transformer is suspected of having a low-temperature overheating fault.

[0091] Specifically, based on the dissolved gas concentration data generated after degassing the oil sample, the ratio relationships between the respective dissolved gases are calculated to identify possible fault types inside the oil-immersed transformer. Specifically, the concentration ratio of methane to hydrogen is calculated to generate a first concentration ratio, which is used to reflect the intensity of partial discharge activity; the concentration ratio of acetylene to ethylene is calculated to generate a second concentration ratio, which is used to determine whether there is a high-energy arc discharge phenomenon; the concentration ratio of ethane to acetylene is calculated to generate a third concentration ratio, which is used to analyze the correlation between overheating decomposition and discharge phenomena. When the first concentration ratio is less than a preset first threshold, it indicates that the amount of methane generated is insufficient compared to hydrogen, and it is determined that the oil-immersed transformer is suspected of having a partial discharge fault; when the second concentration ratio is greater than a preset second threshold, it means that the acetylene concentration far exceeds that of ethylene, indicating strong arc discharge activity, and thus it is determined that the oil-immersed transformer is suspected of having an arc discharge fault. The above thresholds can be set based on the dissolved gas ratio diagnostic rules in IEC 60599 standards and can be dynamically adjusted according to the actual operating conditions and historical data of the transformer to improve the accuracy and sensitivity of fault prediction. The calculation and determination results of each ratio will be used as the basis for further generating the fault prediction result, providing support for the evaluation of the transformer operating state and the triggering of warning signals.

[0092] In a preferred embodiment, generating a warning signal for the oil-immersed transformer according to the environmental compensation difference and the fault prediction result includes:

[0093] Generating a concentration over-standard deduction score for each dissolved gas in the oil according to the environmental compensation difference and the corresponding compensation threshold;

[0094] Generating a fault deduction score for the oil-immersed transformer according to the fault prediction result and the corresponding deduction weight;

[0095] Calculating the health index of the oil-immersed transformer through a preset health index calculation formula according to the concentration over-standard deduction score and the fault deduction score;

[0096] Determining the warning level according to the health index, and then generating a corresponding warning signal according to the warning level;

[0097] Among them, the health index calculation formula includes:

[0098]

[0099] Among them, HI is the health index of the oil-immersed transformer; I HI is the upper limit value of the health index; n is the number of types of dissolved gases in the oil; S i is the concentration over-standard deduction score of the i-th dissolved gas in the oil; W is the weight value of the concentration over-standard deduction score; F is the fault deduction score of the oil-immersed transformer.

[0100] In one embodiment, the system first determines whether each gas exceeds the standard by comparing the environmental compensation difference (the absolute difference between the actual concentration and the theoretical concentration) with the compensation threshold (such as 3 times the historical residual standard deviation σ). For example, if the environmental compensation difference ΔC of hydrogen is 20 ppm and the historical σ is 5 ppm, then ΔC / σ = 4, exceeding the threshold of 3, triggering an over-standard deduction. The deduction rule is: for every 1-fold exceedance of the threshold of ΔC / σ, 5 points are deducted (e.g., if ΔC / σ = 4, then 5×(4 - 3) = 5 points are deducted).

[0101] Meanwhile, the fault prediction results (such as partial discharge, arc discharge) are deducted points according to the preset weights: 5 points are deducted for partial discharge, 10 points are deducted for arc discharge, and 3 points are deducted for low-temperature overheating. For example, if arc discharge is detected, 10 points are directly deducted.

[0102] Suppose a certain transformer has 5 points deducted for exceeding the standard of hydrogen, 3 points deducted for exceeding the standard of methane, and 10 points deducted for arc discharge, then HI = 100 - 5 - 3 - 10 = 82.

[0103] The early warning level is divided as follows:

[0104] HI ≥ 90: The equipment is normal, routine inspection;

[0105] 80 ≤ HI < 90: Potential risk, shorten the monitoring period;

[0106] 70 ≤ HI < 80: Moderate risk, repair within 30 days;

[0107] HI < 70: High-risk fault, stop immediately.

[0108] For example, when HI = 75, an orange early warning is triggered, and the system automatically pushes a work order to the mobile phone of the operation and maintenance personnel, prompting "Arc discharge risk detected, it is recommended to arrange power outage repair within 7 days". Through the dynamic threshold and multi-dimensional deduction mechanism, this solution can avoid false alarms (such as natural gas fluctuations caused by high temperature in summer) and accurately capture early fault signals.

[0109] In a preferred embodiment, the multiple regression model is specifically:

[0110] C = β0 + β1T + β2H + β3P + ε

[0111] Wherein, C is the theoretical gas concentration; β0 is the intercept term; T is the oil tank temperature; β1 is the regression coefficient of the oil tank temperature; H is the micro water content in the oil; β2 is the regression coefficient of the micro water content in the oil; P is the oil tank pressure; β3 is the regression coefficient of the oil tank pressure; ε is the error term.

[0112] In a preferred embodiment, the oil sample collection module includes a mounting rack 1, a movable block 2, a mounting convex block 3, a first telescopic rod 6, a bottom plate 7, a liquid suction head 8, a pump 9, a connecting hose 10, and an infusion tube 11;

[0113] A movable block 2 is slidably arranged on the mounting rack 1; a mounting convex block 3 is arranged on the side wall of the movable block 2; a first telescopic rod 6 is mounted on the bottom surface of the mounting convex block 3; the bottom end of the first telescopic rod 6 is connected with a bottom plate 7; a liquid suction head 8 is mounted on the bottom plate 7; a pump 9 is mounted in the mounting convex block 3; a connecting hose 10 is connected to the lower inlet of the pump 9; the connecting hose 10 is connected with the liquid suction head 8; an infusion tube 11 is connected to the upper outlet of the pump 9; the infusion tube 11 is connected with one end of the degassing module; a solenoid valve 1101 is arranged at the upper end of the infusion tube 11.

[0114] In a preferred embodiment, the mounting rack 1 includes an upper mounting rack body 101, a lower mounting rack body 102, a connecting ear 103, a sliding track 104, an external rack 105 and a plurality of mounting blocks 106;

[0115] The upper mounting rack body 101 is fixedly connected with the lower mounting rack body 102 through the connecting ear 103;

[0116] Sliding tracks 104 are provided on the opposite surfaces of the upper mounting rack body 101 and the lower mounting rack body 102;

[0117] An external rack 105 is arranged on the side wall of the lower mounting rack body 102;

[0118] A plurality of mounting blocks 106 are arranged on the top surface of the upper mounting rack body 101.

[0119] In a preferred embodiment, an adjusting motor 4 is installed inside the movable block 2, an output end of the adjusting motor 4 is connected with an adjusting gear 5, and the adjusting gear 5 is meshed with the external rack 105.

[0120] In a preferred embodiment, the degassing module includes a degassing column 12, a piston head 13, a second telescopic rod 16, a top plate 15, a lifting column 14, a connecting rod 17, a connecting toothed plate 18, a rotating shaft 19, a connecting gear 20 and a plurality of stirring blades 21;

[0121] One end of the degassing module is the degassing column 12;

[0122] The degassing column 12 has a hollow structure; a piston head 13 is arranged inside the degassing column 12; a second telescopic rod 16 is arranged above the degassing column 12; the bottom end of the second telescopic rod 16 is connected to a top plate 15; a lifting column 14 is connected to the bottom surface of one end of the top plate 15; the lifting column 14 is inserted into the degassing column 12 and fixedly connected to the piston head 13; a connecting rod 17 is connected to the bottom surface of the other end of the top plate 15; the bottom end of the connecting rod 17 is connected to a connecting toothed plate 18; a rotating shaft 19 is rotatably installed on the side wall of the degassing column 12; one end of the rotating shaft 19 is connected to a connecting gear 20; the connecting gear 20 is meshed and connected with the connecting toothed plate 18; a plurality of stirring blades 21 are arranged on the end of the rotating shaft 19 inserted into the interior of the degassing column 12.

[0123] In a preferred embodiment, several temperature regulating blocks 1201 are arranged on the side wall of the degassing column 12; a gas guide pipe 22 is arranged on the side wall of the degassing column 12; the gas guide pipe 22 is provided with a second solenoid valve; the gas guide pipe 22 is connected to the fault warning module 23.

[0124] As Figure 8 shown, an embodiment of the present invention provides an oil-immersed transformer fault warning method, which is applicable to the fault warning module of an oil-immersed transformer fault warning device, and at least includes the following steps:

[0125] Step S1: Obtain the oil tank temperature, micro water content in oil, oil tank pressure and concentration data of each dissolved gas in oil of the oil-immersed transformer; wherein, the dissolved gases in oil include hydrogen, methane, ethane, ethylene and acetylene;

[0126] Step S2: Calculate and generate the ratio between each dissolved gas in oil according to the concentration data of each dissolved gas in oil;

[0127] Step S3: Based on the preset dissolved gas ratio diagnosis rule in oil, generate a fault prediction result of the oil-immersed transformer according to the ratio between each dissolved gas in oil;

[0128] Step S4: For each dissolved gas in oil, based on the corresponding preset multiple regression model, fit and generate the corresponding theoretical gas concentration according to the oil tank temperature, micro water content in oil and oil tank pressure;

[0129] Step S5: Calculate the absolute difference between the concentration data of each dissolved gas in oil and the corresponding theoretical gas concentration to obtain the environmental compensation difference of each dissolved gas in oil;

[0130] Step S6: Calculate the health index of the oil-immersed transformer according to the environmental compensation difference and the fault prediction result;

[0131] Step S7: Based on the preset health index grading rule, generate a warning signal of the oil-immersed transformer according to the health index.

[0132] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0133] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A fault warning device for an oil-immersed transformer, characterized in that: include: Oil sample collection module, environmental parameter collection module, degassing module and fault warning module; The oil sample collection module is used to extract oil samples from the oil-immersed transformer; The environmental parameter acquisition module is used to collect the oil tank temperature, the water content in the oil and the oil tank pressure of the oil-immersed transformer; The degassing module is used to separate the dissolved gases in each oil in the oil sample and generate concentration data of the dissolved gases in each oil; wherein the dissolved gases in the oil include hydrogen, methane, ethane, ethylene and acetylene; The fault warning module is used to calculate and generate the ratio between the dissolved gases in each oil according to the concentration data of the dissolved gases in each oil; Generate the fault prediction result of oil-immersed transformer according to the ratio between dissolved gases in each oil; For each gas dissolved in the oil, based on the corresponding preset multivariate regression model, the corresponding theoretical gas concentration is fitted according to the oil tank temperature, the water content in the oil and the oil tank pressure; Calculate the absolute difference between each dissolved gas concentration data in the oil and the corresponding theoretical gas concentration to obtain the environmental compensation difference of the dissolved gas in each oil; A warning signal for the oil-immersed transformer is generated according to the environmental compensation difference and the fault prediction result.

2. The oil-immersed transformer fault warning device according to claim 1, characterized in that: The method of generating a fault prediction result of the oil-immersed transformer according to the ratio of the dissolved gases in each oil includes: Calculating a concentration ratio of methane to hydrogen to generate a first concentration ratio; calculating the concentration ratio of acetylene to ethylene to generate a second concentration ratio; calculating a concentration ratio of ethane to acetylene to generate a third concentration ratio; When the first concentration ratio is less than a preset first threshold, it is determined that the oil-immersed transformer is suspected of having a partial discharge fault; When the second concentration ratio is greater than a preset second threshold value, it is determined that an arc discharge fault is suspected to exist in the oil-immersed transformer; When the third concentration ratio is greater than a preset third threshold, it is determined that the oil-immersed transformer is suspected of having a low-temperature overheating fault.

3. The oil-immersed transformer fault warning device according to claim 2, characterized in that: The generating of the early warning signal of the oil-immersed transformer according to the environmental compensation difference and the fault prediction result includes: Generate a deduction value for excessive concentration of dissolved gas in each oil according to the environmental compensation difference and the corresponding compensation threshold; Generate a fault deduction value for the oil-immersed transformer according to the fault prediction result and the corresponding deduction weight; Calculate the health index of the oil-immersed transformer according to the concentration exceeding standard deduction value and the fault deduction value by using a preset health index calculation formula; Determine a warning level according to the health index, and then generate a corresponding warning signal according to the warning level; The health index calculation formula includes: Among them, HI is the health index of the oil-immersed transformer; I HI is the upper limit of the health index; n is the number of types of dissolved gas in the oil; S i is the penalty value for excessive concentration of dissolved gas in the i-th oil; W is the weight value of the penalty value for excessive concentration; F is the penalty value for fault of the oil-immersed transformer.

4. The oil-immersed transformer fault warning device according to claim 3, characterized in that: The multiple regression model is specifically: C=β0+β1T+β2H+β3P+ε Among them, C is the theoretical gas concentration; β0 is the intercept term; T is the fuel tank temperature; β1 is the regression coefficient of the fuel tank temperature; H is the trace water content in the oil; β2 is the regression coefficient of the trace water content in the oil; P is the fuel tank pressure; β3 is the regression coefficient of the fuel tank pressure; ε is the error term.

5. The oil-immersed transformer fault warning device according to claim 4, characterized in that: The oil sample collection module includes a mounting frame, a movable block, a mounting protrusion, a first telescopic rod, a bottom plate, a liquid suction head, a pump, a connecting hose, and a liquid infusion tube; A movable block is slidably provided on the mounting frame; a mounting protrusion is provided on the side wall of the movable block; a first telescopic rod is installed on the bottom surface of the mounting protrusion; the bottom end of the first telescopic rod is connected to a base plate; a pipette head is installed on the base plate; a pump is installed in the mounting protrusion; a connecting hose is connected to the lower inlet of the pump; the connecting hose is connected to the pipette head; an infusion tube is connected to the upper outlet of the pump; the infusion tube is connected to one end of the degassing module; and a solenoid valve is provided at the upper end of the infusion tube.

6. The oil-immersed transformer fault warning device according to claim 5, characterized in that: The mounting frame comprises an upper frame body, a lower frame body, a connecting ear, a sliding track, an external rack and a plurality of mounting blocks; The upper frame of the mounting frame is fixedly connected to the lower frame of the mounting frame through connecting ears; Sliding rails are provided on the opposite surfaces of the upper frame body of the mounting frame and the lower frame body of the mounting frame; An external rack is provided on the side wall of the lower frame of the mounting frame; A plurality of mounting blocks are arranged on the top surface of the upper frame of the mounting frame.

7. The oil-immersed transformer fault warning device according to claim 6, characterized in that: An adjusting motor is installed inside the movable block, an adjusting gear is connected to the output end of the adjusting motor, and the adjusting gear is meshedly connected with the external rack.

8. The oil-immersed transformer fault warning device according to claim 7, characterized in that: The degassing module comprises a degassing column, a piston head, a second telescopic rod, a top plate, a lifting column, a connecting rod, a connecting tooth plate, a rotating shaft, a connecting gear and a plurality of stirring blades; One end of the degassing module is the degassing column; The degassing column is a hollow structure; a piston head is arranged inside the degassing column; a second telescopic rod is arranged above the degassing column; the bottom end of the second telescopic rod is connected to a top plate; a lifting column is connected to the bottom surface of one end of the top plate; the lifting column is inserted into the degassing column and fixedly connected to the piston head; a connecting rod is connected to the bottom surface of the other end of the top plate; a connecting tooth plate is connected to the bottom end of the connecting rod; a rotating shaft is rotatably installed on the side wall of the degassing column; one end of the rotating shaft is connected to a connecting gear; the connecting gear is meshed and connected to the connecting tooth plate; a plurality of stirring blades are arranged on the end of the rotating shaft inserted into the degassing column.

9. The oil-immersed transformer fault warning device according to claim 8, characterized in that: A plurality of temperature regulating blocks are arranged on the side wall of the degassing column; an air guide pipe is arranged on the side wall of the degassing column; a second solenoid valve is arranged on the air guide pipe; and the air guide pipe is connected to the fault warning module.

10. A fault early warning method for an oil-immersed transformer, characterized in that: The fault warning module applicable to the oil-immersed transformer fault warning device includes: Obtaining the oil tank temperature, water content in the oil, oil tank pressure and concentration data of the dissolved gas in each oil of the oil-immersed transformer; wherein the dissolved gas in the oil includes hydrogen, methane, ethane, ethylene and acetylene; According to the concentration data of dissolved gases in various oils, the ratios between the dissolved gases in various oils are calculated and generated; Based on the preset diagnostic rules of dissolved gas ratio in oil, the fault prediction results of oil-immersed transformer are generated according to the ratios between the dissolved gases in each oil; For each gas dissolved in the oil, based on the corresponding preset multivariate regression model, the corresponding theoretical gas concentration is fitted according to the oil tank temperature, the water content in the oil and the oil tank pressure; Calculate the absolute difference between each dissolved gas concentration data in the oil and the corresponding theoretical gas concentration to obtain the environmental compensation difference of the dissolved gas in each oil; Calculating a health index of the oil-immersed transformer according to the environmental compensation difference and the fault prediction result; Based on a preset health index classification rule, an early warning signal of the oil-immersed transformer is generated according to the health index.

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