A method and device for monitoring oil leakage of oil-immersed transformer

Abstract

The present invention discloses a method and device for monitoring oil leakage of an oil-immersed transformer, the method comprising: monitoring the current insulating oil level of the oil-immersed transformer, and judging whether the insulating oil level has dropped according to the insulating oil level; if it is determined that the insulating oil level has dropped, judging whether the current insulating oil temperature and the current internal pressure of the box conform to the temperature-pressure variation law, and judging whether the current oil level drop distance and the current internal pressure of the box conform to the oil level-pressure variation law; if it does not conform to the temperature-pressure variation law, or does not conform to the oil level-pressure variation law, it is determined that the oil-immersed transformer has oil leakage. By adopting the embodiments of the present invention, the false oil leakage phenomenon caused by the natural change of the oil temperature and the pressure in the box, as well as the false oil leakage phenomenon caused only by the natural change of the pressure in the box, can be fully considered, and the accuracy of monitoring can be improved.

Description

Technical Field

[0001] The invention relates to the field of transformer oil level detection, and in particular to a method and a device for monitoring oil leakage of an oil-immersed transformer. Background Art

[0002] At present, the methods for monitoring insulating oil leakage in oil-immersed transformers are mainly divided into manual operation and maintenance and online monitoring. The manual operation and maintenance method has problems with timeliness and accuracy in determining distribution transformer faults. The general method used for online monitoring of distribution transformers is mainly to monitor by installing intelligent AI cameras, but this method has high hardware deployment costs, and the early warning and monitoring accuracy are not high due to oil level fluctuations or false oil leaks, and staff still need to be deployed for observation. Summary of the invention

[0003] The invention provides a method and device for monitoring oil leakage of an oil-immersed transformer, so as to solve the technical problem that the accuracy of the current online monitoring method for oil leakage of an oil-immersed transformer is low.

[0004] In order to solve the above technical problems, an embodiment of the present invention provides an oil-immersed transformer oil leakage monitoring method, comprising:

[0005] Monitoring the current insulating oil level of the oil-immersed transformer and judging whether the insulating oil level has dropped according to the insulating oil level;

[0006] If it is determined that the insulating oil level drops, the current insulating oil temperature and the internal pressure of the oil-immersed transformer are monitored, and it is determined whether the current insulating oil temperature and the current internal pressure of the box conform to the temperature-pressure variation law, and the current oil level drop distance is calculated according to the current insulating oil level, and it is determined whether the current oil level drop distance and the current internal pressure of the box conform to the oil level pressure variation law; wherein the temperature-pressure variation law is fitted based on the temperature historical data and the internal pressure historical data of the oil-immersed transformer; the oil level pressure variation law is fitted based on the oil level drop distance historical data and the internal pressure historical data of the oil-immersed transformer;

[0007] If the current insulating oil temperature and the current internal pressure of the box do not conform to the temperature-pressure variation law, or the current oil level drop distance and the current internal pressure of the box do not conform to the oil level-pressure variation law, it is determined that the oil-immersed transformer has an oil leak.

[0008] The present invention first determines whether the insulating oil level has dropped, and based on the oil level drop, determines whether there is an oil leakage according to the current oil temperature and the current pressure in the box combined with the oil temperature and pressure variation law, fully considering the false oil leakage caused by the natural change of the oil temperature and the pressure in the box, thereby improving the monitoring accuracy; in addition, based on the oil level drop, determines whether there is an oil leakage according to the current oil level drop distance and the current pressure in the box combined with the oil level pressure variation law, fully considering the false oil leakage caused only by the natural change of the pressure in the box, thereby improving the monitoring accuracy.

[0009] Furthermore, the temperature and pressure variation law is obtained by fitting based on the temperature history data of the oil-immersed transformer and the pressure history data inside the box, specifically:

[0010] According to the temperature history data and the box internal pressure history data, a plurality of data pairs are established; wherein each data pair includes the insulating oil temperature and the box internal pressure at the same time;

[0011] Fitting calculations are performed on the plurality of data pairs to obtain a temperature-pressure variation relationship.

[0012] Further, the current insulating oil temperature and the internal pressure of the oil-immersed transformer are monitored to determine whether the current insulating oil temperature and the current internal pressure of the box conform to the temperature and pressure variation law, specifically:

[0013] Monitor the current insulating oil temperature and internal pressure of the oil-immersed transformer;

[0014] Substituting the insulating oil temperature and the internal pressure of the box into the temperature-pressure change relationship equation to determine whether the temperature-pressure change relationship equation holds;

[0015] When the temperature-pressure variation relationship is established, it is determined that the current insulating oil temperature and the current internal pressure of the box body conform to the temperature-pressure variation law;

[0016] When the temperature-pressure variation relationship does not hold, it is determined that the current insulating oil temperature and the current internal pressure of the box body do not conform to the temperature-pressure variation law.

[0017] The present invention fits a temperature-pressure expression that accurately reflects the temperature-pressure variation law based on the transformer environment historical data, and determines whether the expression is valid by substituting the current insulating oil temperature and the current internal pressure of the box into the temperature-pressure expression. It can accurately judge whether the current insulating oil temperature and the current internal pressure of the box conform to the temperature-pressure variation law, thereby improving the accuracy of monitoring.

[0018] Furthermore, the oil level pressure variation law is obtained by fitting based on the historical data of the oil level drop distance of the oil-immersed transformer and the historical data of the internal pressure of the box, specifically:

[0019] According to the historical data of the oil level drop distance and the historical data of the internal pressure of the tank, a plurality of data pairs are established; wherein each data pair includes the oil level drop distance and the internal pressure of the tank at the same time;

[0020] Fitting calculations are performed on the plurality of data pairs to obtain an oil level pressure variation relationship.

[0021] Furthermore, the current oil level drop distance is calculated based on the current insulating oil level, and it is determined whether the current oil level drop distance and the current internal pressure of the box conform to the oil level pressure change law, specifically:

[0022] Subtract the current insulating oil level from the initial insulating oil level to obtain the current oil level drop distance;

[0023] Substituting the oil level drop distance and the internal pressure of the box into the oil level pressure change relationship equation to determine whether the oil level pressure change relationship equation is established;

[0024] When the oil level pressure change relationship is established, it is determined that the current oil level drop distance and the current internal pressure of the tank conform to the oil level pressure change law;

[0025] When the oil level pressure variation relationship does not hold, it is determined that the current oil level drop distance and the current internal pressure of the tank do not conform to the oil level pressure variation law.

[0026] The present invention fits an oil level pressure expression that accurately reflects the law of oil level pressure change based on the oil level historical data and the transformer environment historical data. By substituting the current insulating oil temperature and the current internal pressure of the box into the oil level pressure expression to determine whether the expression is established, it is possible to accurately judge whether the current oil level drop distance and the current internal pressure of the box conform to the law of oil level pressure change, thereby improving the accuracy of monitoring. In addition, by substituting the currently detected data into the relationship formed by the insulating oil temperature and the internal pressure of the box, or the relationship formed by the oil level drop distance and the internal pressure of the box to judge whether the corresponding relationship is established, this judgment method is more accurate and quicker than the AI ​​camera observing through images. In addition, by additionally judging whether the oil level drop distance reaches the preset value, the error caused by the measurement can be further reduced, and the accuracy of monitoring can be improved.

[0027] Furthermore, the temperature historical data, the box internal pressure historical data and the oil level drop distance historical data are obtained through multiple monitoring, specifically:

[0028] Monitor and record the insulating oil temperature, the internal pressure of the box and the insulating oil level of the oil-immersed transformer according to a preset period, obtain a number of insulating oil temperatures and a number of internal pressures of the box, and obtain a number of insulating oil levels; wherein the insulating oil level must meet a preset accuracy;

[0029] Subtracting the insulating oil level at the initial moment from the several insulating oil levels respectively to obtain several oil level drop distances;

[0030] According to the several insulating oil temperatures and the preset cycles, temperature history data is established; according to the several box internal pressures and the preset cycles, box internal pressure history data is established; according to the several oil level drop distances and the preset cycles, the oil level drop distance history data is established.

[0031] The present invention collects various data of the oil-immersed transformer in a preset period, and collects the oil level drop distance according to a preset accuracy, taking into account the change speed of various factors of the transformer and the monitoring accuracy of the oil level position; by establishing transformer historical data and oil level drop distance historical data, various historical data are saved and the changes of various data are accurately recorded.

[0032] Further, when the current oil level drop distance and the current internal pressure of the box do not conform to the oil level pressure change law, it is determined that the oil-immersed transformer has oil leakage, specifically:

[0033] When the current oil level drop distance and the current internal pressure of the box do not conform to the oil level pressure variation law, and the current oil level drop distance is greater than or equal to the preset distance, it is determined that the oil-immersed transformer has oil leakage.

[0034] Further, after determining that the oil-immersed transformer has an oil leak, an oil leak alarm is activated.

[0035] Furthermore, if the current insulating oil temperature and the current internal pressure of the box do not conform to the temperature-pressure variation law, and the current oil level drop distance and the current internal pressure of the box do not conform to the oil level pressure variation law, and the oil leakage alarm has been activated, it is determined that a serious oil leakage accident has occurred in the oil-immersed transformer, and oil leakage protection is activated; the oil leakage protection is to notify the maintenance department so that the maintenance department can repair the oil-immersed transformer and repair the leakage.

[0036] After determining that the oil level drop distance does not conform to the oil level pressure change law, the present invention further determines whether the oil level drop distance reaches a preset value, thereby further improving the monitoring accuracy. After determining that the oil-immersed transformer has leaked oil, the oil leakage alarm prompt is activated to remind the staff to pay attention to the abnormal oil level of the transformer; in addition, according to the temperature and pressure change law, the oil level pressure change law and the oil leakage alarm prompt, it is judged whether the oil-immersed transformer has a serious oil leakage accident, and the oil level, oil temperature and whether the alarm prompt has been issued are comprehensively considered. The judgment of serious oil leakage is more strict, and the monitoring accuracy is improved.

[0037] On the other hand, an embodiment of the present invention provides an oil-immersed transformer oil leakage monitoring device, including: a monitoring module, a judgment module and a determination module;

[0038] The monitoring module is used to monitor the current insulating oil level of the oil-immersed transformer and determine whether the insulating oil level has dropped according to the insulating oil level;

[0039] The judging module is used to monitor the current insulating oil temperature and the internal pressure of the oil-immersed transformer if it is determined that the insulating oil level has dropped, and to judge whether the current insulating oil temperature and the current internal pressure of the box conform to the temperature-pressure variation law, and to calculate the current oil level drop distance according to the current insulating oil level, and to judge whether the current oil level drop distance and the current internal pressure of the box conform to the oil level pressure variation law; wherein the temperature-pressure variation law is obtained by fitting based on the temperature history data and the internal pressure history data of the oil-immersed transformer; the oil level pressure variation law is obtained by fitting based on the oil level drop distance history data and the internal pressure history data of the oil-immersed transformer;

[0040] The determination module is used to determine that the oil-immersed transformer has oil leakage if the current insulating oil temperature and the current internal pressure of the box do not conform to the temperature-pressure variation law, or the current oil level drop distance and the current internal pressure of the box do not conform to the oil level pressure variation law.

[0041] The present invention first determines whether the insulating oil level has dropped, and based on the oil level drop, determines whether there is an oil leakage according to the current oil temperature and the current pressure in the box combined with the oil temperature and pressure variation law, fully considering the false oil leakage caused by the natural change of the oil temperature and the pressure in the box, thereby improving the monitoring accuracy; in addition, based on the oil level drop, determines whether there is an oil leakage according to the current oil level drop distance and the current pressure in the box combined with the oil level pressure variation law, fully considering the false oil leakage caused only by the natural change of the pressure in the box, thereby improving the monitoring accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1It is a flow chart of a method for monitoring oil leakage of an oil-immersed transformer provided by an embodiment of the present invention;

[0043] Figure 2 It is another flow chart of the oil-immersed transformer oil leakage monitoring method provided by the embodiment of the present invention;

[0044] Figure 3 It is another flow chart of the oil-immersed transformer oil leakage monitoring method provided by the embodiment of the present invention;

[0045] Figure 4 It is another flow chart of the oil-immersed transformer oil leakage monitoring method provided by the embodiment of the present invention;

[0046] Figure 5 It is a structural schematic diagram of an oil-immersed transformer oil leakage monitoring device provided by an embodiment of the present invention; DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Embodiment 1

[0049] Please refer to Figure 1 1 is a flow chart of a method for monitoring oil leakage of an oil-immersed transformer provided by an embodiment of the present invention, which mainly includes steps 101 to 103, which are specifically as follows:

[0050] Step 101: monitor the current insulating oil level of the oil-immersed transformer, and determine whether the insulating oil level has dropped according to the insulating oil level.

[0051] In this embodiment, the insulating oil level of the oil-immersed transformer can be collected in a preset periodic manner, and then the initial insulating oil level is subtracted from the insulating oil level collected later to check whether the difference is greater than 0; if the difference is greater than 0, it indicates that the insulating oil level has dropped and there is a possibility of oil leakage; if the difference is equal to 0, it indicates that the insulating oil level remains unchanged.

[0052] Step 102: If it is determined that the insulating oil level drops, monitor the current insulating oil temperature and the internal pressure of the oil-immersed transformer, and determine whether the current insulating oil temperature and the current internal pressure of the oil-immersed transformer conform to the temperature-pressure variation law, and calculate the current oil level drop distance according to the current insulating oil level, and determine whether the current oil level drop distance and the current internal pressure of the oil-immersed transformer conform to the oil level pressure variation law; wherein the temperature-pressure variation law is fitted based on the temperature historical data and the internal pressure historical data of the oil-immersed transformer; the oil level pressure variation law is fitted based on the oil level drop distance historical data and the internal pressure historical data of the oil-immersed transformer.

[0053] In this embodiment, by fitting the temperature historical data, the box internal pressure historical data and the oil level drop distance historical data, the temperature-pressure variation law and the oil level pressure variation law are obtained; the temperature-pressure variation law represents the relationship between the insulating oil temperature and the box internal pressure, and the oil level pressure variation law represents the variation relationship between the insulating oil level drop distance and the box internal pressure; if it is found through judgment that various factors in the box meet the above two variation laws, it indicates that a false oil leakage has occurred in the insulating oil.

[0054] In this embodiment, the temperature-pressure variation law is fitted based on the temperature history data and the internal pressure history data of the oil-immersed transformer, specifically: a plurality of data pairs are established based on the temperature history data and the internal pressure history data of the box; each data pair includes the insulating oil temperature and the internal pressure of the box at the same time; fitting calculation is performed based on the plurality of data pairs to obtain the temperature-pressure variation relationship.

[0055] In this embodiment, before the internal pressure of the box body is stable, several data pairs can be expressed as the following table:

[0056] temperature pressure temperature pressure temperature pressure temperature pressure 30 100.53 50 103.62 70 106.89 90 110.64 31 100.69 51 103.79 71 107.2 91 110.93 32 100.85 52 103.98 72 107.28 92 110.99 33 101.01 53 104.16 73 107.49 93 111.26 34 101.18 54 104.38 74 107.75 94 111.43 35 101.34 55 104.46 75 107.86 95 111.64 36 101.47 56 104.73 76 108.02 96 111.83 37 101.61 57 104.81 77 108.32 97 112.08 38 101.8 58 104.97 78 108.42 98 112.26 39 101.94 59 105.1 79 108.69 99 112.44 40 102.06 60 105.29 80 108.85 100 112.63 41 102.17 61 105.42 81 109.02 101 112.74 42 102.44 62 105.57 82 109.16 102 112.86 43 102.56 63 105.65 83 109.44 103 113.16 44 102.68 64 105.85 84 109.62 104 113.24 45 102.84 65 106.13 85 109.76 105 113.51 46 103.03 66 106.22 86 109.94 106 113.9 47 103.16 67 106.42 87 110.12 107 114.05 48 103.32 68 106.56 88 110.28 108 114.42 49 103.51 69 106.75 89 110.5 109 114.58

[0057] Among them, temperature is the insulating oil temperature, in ℃; pressure is the internal pressure of the box, in kPa; when the oil-immersed transformer changes with the temperature during operation, when the internal pressure of the box is higher than 25kPa, the pressure will be released. After the pressure release is completed, the data of the transformer will meet the records in the above table. When the transformer reaches a stable state after several temperature changes, when the temperature is 30℃, the pressure of the transformer is 93.21kPa. After further testing, the data of the oil-immersed transformer after stable operation is recorded as follows:

[0058] temperature pressure temperature pressure temperature pressure temperature pressure 30 93.30 50 96.37 70 99.77 90 103.50 31 93.44 51 96.53 71 99.94 91 103.70 32 93.59 52 96.69 72 100.12 92 103.89 33 93.74 53 96.85 73 100.30 93 104.09 34 93.88 54 97.02 74 100.49 94 104.29 35 94.03 55 97.18 75 100.67 95 104.49 36 94.18 56 97.35 76 100.85 96 104.69 37 94.33 57 97.52 77 101.03 97 104.89 38 94.49 58 97.69 78 101.22 98 105.09 39 94.64 59 97.85 79 101.40 99 105.29 40 94.79 60 98.02 80 101.59 100 105.50 41 94.94 61 98.19 81 101.78 101 105.70 42 95.10 62 98.37 82 101.97 102 105.91 43 95.25 63 98.54 83 102.16 103 106.11 44 95.41 64 98.71 84 102.35 104 106.32 45 95.57 65 98.88 85 102.54 105 106.53 46 95.73 66 99.06 86 102.73 106 106.74 47 95.88 67 99.23 87 102.92 107 106.95 48 96.04 68 99.41 88 103.11 108 107.16 49 96.20 69 99.59 89 103.31 109 107.37

[0059] Corresponding to the two states of the pressure inside the box before and after stabilization, the fitted temperature-pressure change relationship also has two relationship equations before and after stabilization. The temperature-pressure change relationship before stabilization is:

[0060] Y=0.0000007T 3 +0.0003T 2 +0.128T+96.465;

[0061] After stabilization, the temperature-pressure change relationship is:

[0062] Y=0.0000001T 3 +0.0004T 2 +0.1209T+89.306;

[0063] Where, Y is the internal pressure of the box, in kPa; T is the insulating oil temperature, in °C.

[0064] In this embodiment, the oil level pressure variation law is fitted based on the historical data of the oil level drop distance and the historical data of the internal pressure of the oil-immersed transformer, specifically: a number of data pairs are established based on the historical data of the oil level drop distance and the historical data of the internal pressure of the tank; each data pair includes the oil level drop distance and the internal pressure of the tank at the same time; fitting calculation is performed based on the several data pairs to obtain the oil level pressure variation relationship.

[0065] In this embodiment, corresponding to the two situations before and after the internal pressure of the tank is stabilized, a number of data pairs established by the historical data of the oil level drop distance and the historical data of the internal pressure of the tank are also divided into two situations; before the internal pressure of the tank is stabilized, the data pair can be expressed as:

[0066] Oil level drop distance (mm) 0 1 2 3 Internal pressure of the box (kPa) 101.55 105.06 108.25 113.56

[0067] Correspondingly, the oil level pressure change relationship obtained by fitting is:

[0068] Y=0.71L 2 +1.76L+101.89;

[0069] Among them, Y is the internal pressure of the box, in kPa; L is the distance the oil level drops, in mm. After the internal pressure of the box stabilizes, the data pair is expressed as:

[0070] Oil level drop distance (mm) 4 3 2 1 0 1 2 3 Internal pressure of the box (kPa) 93.41 94.2 96.15 98.26 100.98 103.87 107.99 113.31

[0071] After the internal pressure of the box is stable, according to the data pairs, the oil level drop distance and the internal pressure of the box present two laws. When the internal pressure of the box is less than or equal to the standard atmospheric pressure, the fitted oil level pressure change relationship is:

[0072] Y=0.0458L 3 +0.0121L 2 -2.6744L+100.96;

[0073] When the internal pressure of the box is greater than or equal to the standard atmospheric pressure, the fitted oil level pressure change relationship is:

[0074] Y=-0.005L 3 +0.63L 2 -2.265L+100.98;

[0075] Among them, Y is the internal pressure of the box, in kPa; L is the distance the oil level drops, in mm.

[0076] Step 103: If the current insulating oil temperature and the current internal pressure of the box do not conform to the temperature-pressure variation law, or the current oil level drop distance and the current internal pressure of the box do not conform to the oil level-pressure variation law, it is determined that the oil-immersed transformer has an oil leak.

[0077] In this embodiment, when the current oil level drop distance and the current internal pressure of the tank do not conform to the oil level pressure change law, it is determined that the oil-immersed transformer has an oil leak. Specifically, when the current oil level drop distance and the current internal pressure of the tank do not conform to the oil level pressure change law, and the current oil level drop distance is greater than or equal to a preset distance, it is determined that the oil-immersed transformer has an oil leak.

[0078] In this embodiment, the situation that does not conform to the oil temperature and pressure variation law can be represented by the following oil leakage simulation data:

[0079]

[0080] When an oil-immersed transformer leaks oil, the internal pressure of the box will eventually approach the external pressure, so the temperature-pressure variation law that the internal pressure of the box is in direct proportion to the temperature of the insulating oil is not satisfied.

[0081] The present invention first determines whether the insulating oil level has dropped, and on the basis of the oil level drop, determines whether there is an oil leak according to the current oil temperature and the current pressure in the box combined with the oil temperature and pressure variation law, fully considering the false oil leak caused by the natural change of the oil temperature and the pressure in the box, thereby improving the monitoring accuracy; in addition, on the basis of the oil level drop, determines whether there is an oil leak according to the current oil level drop distance and the current pressure in the box combined with the oil level pressure variation law, fully considering the false oil leak caused only by the natural change of the pressure in the box, thereby improving the monitoring accuracy. In addition, by additionally judging whether the oil level drop distance reaches a preset value, the error caused by the measurement can be further reduced, thereby improving the monitoring accuracy.

[0082] Please refer to Figure 2 2 is another flow chart of the oil-immersed transformer oil leakage monitoring method provided by the embodiment of the present invention, which mainly includes steps 201 to 204, which are as follows:

[0083] Step 201: Monitor the current insulating oil temperature and internal pressure of the oil-immersed transformer.

[0084] Step 2021: Substitute the insulating oil temperature and the internal pressure of the box into the temperature-pressure change relationship.

[0085] Step 2022: Determine whether the temperature-pressure change relationship is established; when the temperature-pressure change relationship is established, execute step 203; when the temperature-pressure change relationship is not established, execute step 204.

[0086] Step 203: Determine whether the current insulating oil temperature and the current internal pressure of the box conform to the temperature-pressure variation law.

[0087] Step 204: Determine that the current insulating oil temperature and the current internal pressure of the box do not conform to the temperature-pressure variation law.

[0088] The present invention fits a temperature-pressure expression that accurately reflects the temperature-pressure variation law based on the transformer environment historical data, and determines whether the expression is valid by substituting the current insulating oil temperature and the current internal pressure of the box into the temperature-pressure expression. It can accurately judge whether the current insulating oil temperature and the current internal pressure of the box conform to the temperature-pressure variation law, thereby improving the accuracy of monitoring.

[0089] Please refer to Figure 3 3 is another flow chart of the oil-immersed transformer oil leakage monitoring method provided by the embodiment of the present invention, which mainly includes steps 301 to 304, which are as follows:

[0090] Step 301: subtract the current insulating oil level from the initial insulating oil level to obtain the current oil level drop distance.

[0091] Step 3021: Substitute the oil level drop distance and the internal pressure of the tank into the oil level pressure change relationship.

[0092] Step 2022: Determine whether the oil level pressure change relationship is established; when the oil level pressure change relationship is established, execute step 303; when the oil level pressure change relationship is not established, execute step 304.

[0093] Step 203: Determine whether the current oil level drop distance and the current internal pressure of the tank conform to the oil level pressure variation law.

[0094] Step 204: Determine that the current oil level drop distance and the current internal pressure of the tank do not conform to the oil level pressure variation law.

[0095] The present invention fits an oil level pressure expression that accurately reflects the law of oil level pressure change based on the oil level historical data and the transformer environment historical data. By substituting the current insulating oil temperature and the current internal pressure of the box into the oil level pressure expression to determine whether the expression is established, it is possible to accurately judge whether the current oil level drop distance and the current internal pressure of the box conform to the law of oil level pressure change, thereby improving the accuracy of monitoring. In addition, by substituting the currently detected data into the relationship formed by the insulating oil temperature and the internal pressure of the box, or the relationship formed by the oil level drop distance and the internal pressure of the box to judge whether the corresponding relationship is established, this judgment method is more accurate and quicker than the AI ​​camera observing through images. In addition, by additionally judging whether the oil level drop distance reaches the preset value, the error caused by the measurement can be further reduced, and the accuracy of monitoring can be improved.

[0096] In this embodiment, the temperature history data, the box internal pressure history data and the oil level drop distance history data are obtained through multiple monitorings, specifically: the insulating oil temperature, the box internal pressure and the insulating oil level of the oil-immersed transformer are monitored and recorded according to a preset period, and a number of insulating oil temperatures and a number of box internal pressures are obtained, and a number of insulating oil levels are obtained; wherein the insulating oil level must meet a preset accuracy; the insulating oil level at the initial moment is subtracted from the several insulating oil levels, respectively, to obtain a number of oil level drop distances; according to the several insulating oil temperatures and the preset period, the temperature history data is established; according to the several box internal pressures and the preset period, the box internal pressure history data is established; according to the several oil level drop distances and the preset period, the oil level drop distance history data is established.

[0097] The present invention collects various data of the oil-immersed transformer in a preset period, and collects the oil level drop distance according to a preset accuracy, taking into account the change speed of various factors of the transformer and the monitoring accuracy of the oil level position; by establishing transformer historical data and oil level drop distance historical data, various historical data are saved and the changes of various data are accurately recorded.

[0098] Please refer to Figure 4 This is another flow chart of the oil leakage monitoring method for oil-immersed transformers provided in an embodiment of the present invention. Figure 4 and Figure 1 The main difference is that Figure 4 The step 401 is also included, which is as follows:

[0099] In this embodiment, step 401 occurs after step 103 .

[0100] Step 401: Start the oil leak alarm.

[0101] In this embodiment, as long as the insulating oil level drops, the insulating oil temperature and the internal pressure of the box do not satisfy the temperature-pressure change relationship, or the right drop distance and the internal pressure of the box do not satisfy the oil level pressure change relationship, an oil leakage alarm is triggered, and the staff notices the abnormal oil level, so that the staff can perform manual inspection or maintenance on the oil-immersed transformer in time.

[0102] In this embodiment, if the current insulating oil temperature and the current internal pressure of the box do not conform to the temperature-pressure variation law, and the current oil level drop distance and the current internal pressure of the box do not conform to the oil level pressure variation law, and the oil leakage alarm has been activated, it is determined that a serious oil leakage accident has occurred in the oil-immersed transformer, and oil leakage protection is activated; the oil leakage protection is to notify the maintenance department so that the maintenance department can repair the oil-immersed transformer and repair the leakage.

[0103] In this embodiment, the required data inside the box can be collected by pressure sensors, temperature sensors, liquid level sensors, and insulating oil resistance sensors, and the collected data can be recorded, calculated, processed, and proofread by the main control chip. The analog signal collected and output by the sensor is processed into a digital signal that can be recognized by the main control chip according to the analog-to-digital converter.

[0104] After determining that the oil level drop distance does not conform to the oil level pressure change law, the present invention further determines whether the oil level drop distance reaches a preset value, thereby further improving the monitoring accuracy. After determining that the oil-immersed transformer has leaked oil, the oil leakage alarm prompt is activated to remind the staff to pay attention to the abnormal oil level of the transformer; in addition, according to the temperature and pressure change law, the oil level pressure change law and the oil leakage alarm prompt, it is judged whether the oil-immersed transformer has a serious oil leakage accident, and the oil level, oil temperature and whether the alarm prompt has been issued are comprehensively considered. The judgment of serious oil leakage is more strict, and the monitoring accuracy is improved.

[0105] Please refer to Figure 5 It is a flow chart of an oil-immersed transformer oil leakage monitoring device provided by an embodiment of the present invention, which mainly includes: a monitoring module 501, a judgment module 502 and a determination module 503.

[0106] In this embodiment, the monitoring module 501 is used to monitor the current insulating oil level of the oil-immersed transformer, and determine whether the insulating oil level has dropped according to the insulating oil level.

[0107] The judgment module 502 is used to monitor the current insulating oil temperature and the internal pressure of the oil-immersed transformer when the monitoring module 501 determines that the insulating oil level has dropped, and to judge whether the current insulating oil temperature and the current internal pressure of the box conform to the temperature-pressure variation law, and to calculate the current oil level drop distance according to the current insulating oil level, and to judge whether the current oil level drop distance and the current internal pressure of the box conform to the oil level pressure variation law; wherein the temperature-pressure variation law is fitted based on the temperature historical data and the internal pressure historical data of the oil-immersed transformer; the oil level pressure variation law is fitted based on the oil level drop distance historical data and the internal pressure historical data of the oil-immersed transformer.

[0108] The determination module 503 is used to determine that the oil-immersed transformer has oil leakage when the judgment module 502 determines that the current insulating oil temperature and the current internal pressure of the box do not conform to the temperature-pressure variation law, or the current oil level drop distance and the current internal pressure of the box do not conform to the oil level-pressure variation law.

[0109] In this embodiment, the oil-immersed transformer oil leakage monitoring device further includes: an alarm module; the alarm module is used to start an oil leakage alarm prompt after the determination module 503 determines that the oil-immersed transformer has oil leakage.

[0110] In this embodiment, the judgment module 502 includes: a first monitoring unit, a first judgment unit and a first determination unit; the first monitoring unit is used to monitor the current insulating oil temperature and the internal pressure of the box of the oil-immersed transformer; the first judgment unit is used to substitute the insulating oil temperature and the internal pressure of the box into the temperature-pressure change relationship after the first monitoring unit monitors the current insulating oil temperature and the internal pressure of the box of the oil-immersed transformer, and judge whether the temperature-pressure change relationship holds; the first determination unit is used to determine that the current insulating oil temperature and the current internal pressure of the box conform to the temperature-pressure change law when the first judgment unit judges that the temperature-pressure change relationship holds, and to determine that the current insulating oil temperature and the current internal pressure of the box do not conform to the temperature-pressure change law when the first judgment unit judges that the temperature-pressure change relationship does not hold.

[0111] In this embodiment, the judgment module 502 also includes: a second monitoring unit, a second judgment unit and a second determination unit; the second monitoring unit is used to subtract the current insulating oil level from the insulating oil level at the initial moment to obtain the current oil level drop distance; the second judgment unit is used to substitute the oil level drop distance and the internal pressure of the tank into the oil level pressure change relationship after the second monitoring unit obtains the current oil level drop distance, to determine whether the oil level pressure change relationship holds; the second determination unit is used to determine that the current oil level drop distance and the current internal pressure of the tank conform to the oil level pressure change law when the second judgment unit determines that the oil level pressure change relationship holds, and to determine that the current oil level drop distance and the current internal pressure of the tank do not conform to the oil level pressure change law when the second judgment unit determines that the oil level pressure change relationship does not hold.

[0112] In this embodiment, the oil-immersed transformer oil leakage monitoring device also includes: a protection module; the protection module is used to determine that a serious oil leakage accident has occurred in the oil-immersed transformer and start oil leakage protection when the judgment module 502 determines that the current insulating oil temperature and the current internal pressure of the box do not conform to the temperature-pressure change law, and the current oil level drop distance and the current internal pressure of the box do not conform to the oil level pressure change law, and the alarm module starts the oil leakage alarm prompt; the oil leakage protection is to notify the maintenance department so that the maintenance department can repair the oil-immersed transformer.

[0113] The present invention first determines whether the insulating oil level has dropped, and based on the oil level drop, determines whether there is an oil leakage according to the current oil temperature and the current pressure in the box combined with the oil temperature and pressure variation law, fully considering the false oil leakage caused by the natural change of the oil temperature and the pressure in the box, thereby improving the monitoring accuracy; in addition, based on the oil level drop, determines whether there is an oil leakage according to the current oil level drop distance and the current pressure in the box combined with the oil level pressure variation law, fully considering the false oil leakage caused only by the natural change of the pressure in the box, thereby improving the monitoring accuracy.

[0114] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for monitoring oil leakage of oil-immersed transformers. It is characterized in that include: Monitoring the current insulating oil level of the oil-immersed transformer and judging whether the insulating oil level has dropped according to the insulating oil level; If it is determined that the insulating oil level drops, the current insulating oil temperature and the internal pressure of the oil-immersed transformer are monitored, and it is determined whether the current insulating oil temperature and the current internal pressure of the box conform to the temperature-pressure variation law, and the current oil level drop distance is calculated according to the current insulating oil level, and it is determined whether the current oil level drop distance and the current internal pressure of the box conform to the oil level pressure variation law; wherein the temperature-pressure variation law is fitted according to the temperature history data and the internal pressure history data of the oil-immersed transformer, specifically: according to the temperature history data and the internal pressure history data of the box, establish Several data pairs; wherein each data pair includes the insulating oil temperature and the internal pressure of the box at the same time; fitting calculation is performed based on the several data pairs to obtain the temperature-pressure change relationship; the oil level pressure change law is obtained by fitting based on the historical data of the oil level drop distance of the oil-immersed transformer and the historical data of the internal pressure of the box, specifically: according to the historical data of the oil level drop distance and the historical data of the internal pressure of the box, several data pairs are established; wherein each data pair includes the oil level drop distance and the internal pressure of the box at the same time; fitting calculation is performed based on the several data pairs to obtain the oil level pressure change relationship; If the current insulating oil temperature and the current internal pressure of the box do not conform to the temperature-pressure variation law, or the current oil level drop distance and the current internal pressure of the box do not conform to the oil level-pressure variation law, it is determined that the oil-immersed transformer has oil leakage; When the current oil level drop distance and the current internal pressure of the box do not conform to the oil level pressure change law, it is determined that the oil-immersed transformer has oil leakage, specifically: When the current oil level drop distance and the current internal pressure of the box do not conform to the oil level pressure variation law, and the current oil level drop distance is greater than or equal to the preset distance, it is determined that the oil-immersed transformer has oil leakage.

2. A method for monitoring oil leakage of an oil-immersed transformer as claimed in claim 1, It is characterized in that The monitoring of the current insulating oil temperature and the internal pressure of the oil-immersed transformer to determine whether the current insulating oil temperature and the current internal pressure of the box conform to the temperature and pressure variation law is specifically as follows: Monitor the current insulating oil temperature and internal pressure of the oil-immersed transformer; Substituting the insulating oil temperature and the internal pressure of the box into the temperature-pressure change relationship equation to determine whether the temperature-pressure change relationship equation holds; When the temperature-pressure variation relationship is established, it is determined that the current insulating oil temperature and the current internal pressure of the box body conform to the temperature-pressure variation law; When the temperature-pressure variation relationship does not hold, it is determined that the current insulating oil temperature and the current internal pressure of the box body do not conform to the temperature-pressure variation law.

3. A method for monitoring oil leakage of an oil-immersed transformer as claimed in claim 1, It is characterized in that The current oil level drop distance is calculated according to the current insulating oil level, and it is determined whether the current oil level drop distance and the current internal pressure of the box conform to the oil level pressure change law, specifically: Subtract the current insulating oil level from the initial insulating oil level to obtain the current oil level drop distance; Substituting the oil level drop distance and the internal pressure of the box into the oil level pressure change relationship equation to determine whether the oil level pressure change relationship equation is established; When the oil level pressure change relationship is established, it is determined that the current oil level drop distance and the current internal pressure of the tank conform to the oil level pressure change law; When the oil level pressure variation relationship does not hold, it is determined that the current oil level drop distance and the current internal pressure of the tank do not conform to the oil level pressure variation law.

4. A method for monitoring oil leakage of an oil-immersed transformer as claimed in any one of claims 1 to 3, It is characterized in that The temperature historical data, the box internal pressure historical data and the oil level drop distance historical data are obtained through multiple monitoring, specifically: Monitor and record the insulating oil temperature, the internal pressure of the box and the insulating oil level of the oil-immersed transformer according to a preset period, obtain a number of insulating oil temperatures and a number of internal pressures of the box, and obtain a number of insulating oil levels; wherein the insulating oil level must meet a preset accuracy; Subtracting the insulating oil level at the initial moment from the several insulating oil levels respectively to obtain several oil level drop distances; According to the several insulating oil temperatures and the preset cycles, temperature history data is established; according to the several box internal pressures and the preset cycles, box internal pressure history data is established; according to the several oil level drop distances and the preset cycles, the oil level drop distance history data is established.

5. A method for monitoring oil leakage of an oil-immersed transformer as claimed in any one of claims 1 to 3, It is characterized in that After determining that the oil-immersed transformer has oil leakage, an oil leakage alarm prompt is initiated.

6. A method for monitoring oil leakage of an oil-immersed transformer as claimed in claim 5, It is characterized in that Also includes: If the current insulating oil temperature and the current internal pressure of the box do not conform to the temperature-pressure variation law, and the current oil level drop distance and the current internal pressure of the box do not conform to the oil level pressure variation law, and the oil leakage alarm has been activated, it is determined that a serious oil leakage accident has occurred in the oil-immersed transformer, and oil leakage protection is activated; the oil leakage protection is to notify the maintenance department so that the maintenance department can repair the oil-immersed transformer and repair the leakage.

7. An oil-immersed transformer oil leakage monitoring device, include: Monitoring module, judgment module and determination module; The monitoring module is used to monitor the current insulating oil level of the oil-immersed transformer and determine whether the insulating oil level has dropped according to the insulating oil level; The judging module is used to monitor the current insulating oil temperature and the internal pressure of the oil-immersed transformer if it is determined that the insulating oil level has dropped, and to judge whether the current insulating oil temperature and the current internal pressure of the box conform to the temperature-pressure variation law, and to calculate the current oil level drop distance according to the current insulating oil level, and to judge whether the current oil level drop distance and the current internal pressure of the box conform to the oil level-pressure variation law; wherein the temperature-pressure variation law is fitted according to the temperature history data and the internal pressure history data of the oil-immersed transformer, specifically: according to the temperature history data and the internal pressure history data of the box, the temperature-pressure variation law is fitted according to the temperature history data and the internal pressure history data of the oil-immersed transformer. According to the historical data of the oil level drop distance and the historical data of the internal pressure of the box, several data pairs are established; each data pair includes the insulating oil temperature and the internal pressure of the box at the same time; fitting calculation is performed according to the several data pairs to obtain the temperature-pressure change relationship; the oil level pressure change law is obtained by fitting according to the historical data of the oil level drop distance of the oil-immersed transformer and the historical data of the internal pressure of the box, specifically: according to the historical data of the oil level drop distance and the historical data of the internal pressure of the box, several data pairs are established; each data pair includes the oil level drop distance and the internal pressure of the box at the same time; fitting calculation is performed according to the several data pairs to obtain the oil level pressure change relationship; The determination module is used to determine that the oil-immersed transformer has oil leakage if the current insulating oil temperature and the current internal pressure of the box do not conform to the temperature-pressure variation law, or the current oil level drop distance and the current internal pressure of the box do not conform to the oil level-pressure variation law; When the current oil level drop distance and the current internal pressure of the box do not conform to the oil level pressure change law, it is determined that the oil-immersed transformer has oil leakage, specifically: When the current oil level drop distance and the current internal pressure of the box do not conform to the oil level pressure variation law, and the current oil level drop distance is greater than or equal to the preset distance, it is determined that the oil-immersed transformer has oil leakage.

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