Hot spot temperature detection method based on transformer temperature field distribution calculation

Abstract

The present invention discloses a hotspot temperature detection method based on transformer temperature field distribution calculation, which relates to the technical field of transformer detection. The present invention extracts historical operating data of the transformer within a set time window before the current time point, and comprehensively evaluates it with the current operating data to determine the initial temperature distribution. The load rate, ambient temperature, and operating time are converted into a load score, a temperature score, and an operating score respectively. Then, weighted calculation is performed according to a formula, and the initial temperature distribution of the historical data with the lowest similarity index is selected as the current initial temperature distribution, so that the initial temperature is more in line with reality and the subsequent calculation deviation is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer detection, and in particular to a hotspot temperature detection method based on transformer temperature field distribution calculation. Background Art

[0002] As a key equipment in the power system, the operating status of the transformer directly affects the safety and stability of the power system. The hot spot temperature is an important indicator for evaluating the operating status of the transformer. Excessively high hot spot temperature will accelerate insulation aging, shorten the service life of the transformer, and even cause failures.

[0003] At present, the traditional hotspot temperature detection method still has the following shortcomings in practical application:

[0004] The complex physical structure and dynamic operating conditions inside the transformer were not fully considered, and the temperature distribution was determined based on historical data. This resulted in a large discrepancy between the calculated results and the actual hotspot temperature, making it impossible to provide an accurate basis for transformer operation and maintenance.

[0005] In addition, the accuracy of hotspot temperature detection cannot be guaranteed because the winding data, magnetic permeability data, and cooling oil data during the actual operation of the transformer are not combined to adjust and optimize the temperature distribution of each partition.

[0006] Therefore, a hotspot temperature detection method based on transformer temperature field distribution calculation is proposed. Summary of the Invention

[0007] The purpose of the present invention is to solve the problems pointed out in the background technology and to propose a hot spot temperature detection method based on transformer temperature field distribution calculation.

[0008] The object of the present invention can be achieved by the following technical solution: a hot spot temperature detection method based on transformer temperature field distribution calculation, comprising:

[0009] Determine initial conditions: Extract historical operating data of the transformer within a set time window before the current time point; conduct a comprehensive evaluation with the transformer operating data at the current time point to determine the initial temperature distribution of the transformer at the current time point; the operating data includes load rate, ambient temperature, and operating time;

[0010] Evaluation and correction: Based on the initial temperature distribution of the transformer at the current time point, the transformer temperature field is divided into the winding area, the core area and the cooling medium area, and comprehensive evaluations are performed on each area. According to the results of the comprehensive evaluation, the initial temperature distribution of the transformer is adjusted secondary, and the adjusted temperature distribution is used as the final temperature distribution of the corresponding temperature field of the transformer.

[0011] As a preferred embodiment of the present invention, the historical operating data of the transformer within a set time window before the current time point is extracted; and a comprehensive evaluation is performed with the operating data of the transformer at the current time point, specifically:

[0012] Extract the load rate, ambient temperature, and running time of the transformer at the current time point, pre-establish the scoring conversion rules corresponding to the load rate, ambient temperature, and running time, and convert the load rate, ambient temperature, and running time of the transformer at the current time point into a load score, a temperature score, and an operating score, respectively;

[0013] The load score, temperature score and operation score of the transformer at the current time point are marked as At the same time, the historical operation data of the transformer within the set time window before the current time point is extracted, and the load rate, ambient temperature and running time in each group of historical operation data are converted into load score, temperature score and operation score respectively using the same scoring conversion rule. After the conversion, the load score, temperature score and operation score of each group of historical operation data are marked as .

[0014] As a preferred embodiment of the present invention, the initial temperature distribution of the transformer at the current time point is determined as follows:

[0015] According to the formula Perform weighted calculation on the transformer's operating data at the current time point and each set of historical operating data to determine the similarity index between the transformer's operating data at the current time point and each set of historical operating data ;in These are the preset weight coefficients corresponding to the load score, temperature score, and operation score;

[0016] Based on the similarity index between the transformer operating data at the current time point and each group of historical operating data , select similar index The lowest historical operating data is used as the similar historical data of the transformer at the current time point, and the initial temperature distribution of the similar historical data is used as the initial temperature distribution of the transformer at the current time point.

[0017] As a preferred embodiment of the present invention, score conversion rules corresponding to the load rate, ambient temperature, and running time are pre-established, specifically:

[0018] The preset load rates correspond to each group of load rate value ranges, and each group of load rate value ranges corresponds to a load score; the preset ambient temperatures correspond to each group of temperature value ranges, and each group of temperature value ranges corresponds to a temperature score; the preset running time corresponds to each group of running time value ranges, and each group of running time value ranges corresponds to an running score.

[0019] As a preferred embodiment of the present invention, the transformer temperature field is divided into the winding area, the core area, and the cooling medium area, and comprehensive evaluation is performed on each area. The specific process of evaluating the cooling medium area is as follows:

[0020] Obtain the cooling oil flow rate and cooling oil temperature data of the transformer within a set time window after the current time point, and set the cooling oil flow rate reference value and temperature reference value when the transformer is operating normally;

[0021] For the cooling oil flow rate and cooling oil temperature within the set time window, the average values are calculated as the flow evaluation value and temperature evaluation value, respectively, and recorded as and ;

[0022] According to the formula The flow evaluation value of the transformer within the set time window after the current time point and temperature evaluation values Perform weighted calculation to obtain the cooling oil evaluation index of the transformer within the set time window after the current time point ;in Respectively represent the flow reference value and temperature reference value; The calculated cooling oil evaluation index is the preset weight coefficient corresponding to the flow evaluation value and temperature evaluation value. Compare it with the corresponding preset cooling oil threshold index. If it is higher than the corresponding preset cooling oil threshold index, calculate the difference between the two and record it as the adjustment difference;

[0023] The preset adjustment differences correspond to the intervals of the difference values of each group, and each adjustment difference corresponds to a temperature increase set, which includes the temperature increase values of each divided area of the transformer.

[0024] As a preferred embodiment of the present invention, the transformer temperature field is divided into the winding area, the core area, and the cooling medium area, and comprehensive evaluation is performed on each area. The specific process of evaluating the winding area is as follows:

[0025] Obtain the winding resistance of the transformer within a set time window after the current time point, and preset a reference resistance value corresponding to the winding resistance; extract the winding resistance at each time point within the set time window as the numerator, and use the reference resistance value as the denominator, and calculate the ratio respectively to obtain the resistance ratio at each time point within the set time window;

[0026] After removing the highest resistance ratio and the lowest resistance ratio, the average value of the remaining resistance ratios is calculated to obtain the resistance evaluation ratio of the transformer within the set time window after the current time point;

[0027] The resistance evaluation ratio within the set time window is compared with the preset resistance threshold ratio. If it is higher than the corresponding preset resistance threshold ratio, the difference between the two is calculated and recorded as the winding difference;

[0028] The intervals of the difference values of each group corresponding to the preset winding difference are each corresponding to a winding temperature increase value.

[0029] As a preferred embodiment of the present invention, the transformer temperature field is divided into the winding area, the core area, and the cooling medium area, and comprehensive evaluation is performed on each area. The specific process of evaluating the core area is as follows:

[0030] Obtain the transformer core magnetic permeability within a set time window after the current time point, and preset a reference magnetic permeability value corresponding to the core magnetic permeability;

[0031] The average value of the core magnetic permeability within the set time window is calculated and recorded as the average magnetic permeability. Then, taking the current set time window as the starting point, the average magnetic permeability of the X time windows before the starting point is extracted; where X>3;

[0032] The average of the permeability averages of X time windows is calculated and recorded as the historical average. The historical average is compared with the permeability average of the current set time window. If the permeability average of the current set time window is less than the historical average, the permeability average of the current set time window is used as the denominator and the historical average is used as the numerator to calculate the ratio. The permeability trend ratio of the transformer in the current set time window is obtained, which is recorded as F.

[0033] The permeability evaluation factor W is calculated using the formula W=KK×(F-1), where K represents the average permeability of the current set time window. The permeability evaluation factor W is compared with the reference permeability value. If the permeability evaluation factor is lower than the reference permeability value, the difference between the two is calculated and recorded as the core difference.

[0034] The intervals of each group of difference values corresponding to the preset core differences are each corresponding to an increase in core temperature.

[0035] As a preferred embodiment of the present invention, the initial temperature distribution of the transformer is adjusted secondary according to the results of the comprehensive evaluation, specifically:

[0036] Based on the calculated adjustment difference, on the basis of the initial temperature distribution, the temperature of each divided area of the transformer is adjusted to the corresponding temperature increase value; after the temperature of each divided area of the transformer is adjusted to the corresponding temperature increase value, the winding area after the adjustment is adjusted to the corresponding winding temperature increase value; after the temperature of each divided area of the transformer is adjusted to the corresponding temperature increase value, the core area after the adjustment is adjusted to the corresponding core temperature increase value; after the adjustment is completed, the final temperature distribution of the corresponding temperature field of the transformer is used.

[0037] As a preferred embodiment of the present invention, it also includes:

[0038] Real-time update: according to the preset adjustment time interval, the initial temperature distribution and the final temperature distribution are re-determined after the preset adjustment time interval is reached;

[0039] Verification and optimization: The final temperature distribution is applied to the pre-built transformer temperature field calculation model and compared with the temperature measurement data during actual transformer operation. If the comparison result shows that the difference between the calculated temperature and the measured temperature in a certain partition is higher than the corresponding preset allowable value, a deviation signal is triggered and sent to the technician.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The present invention extracts historical operating data within a set time window before the current time point of the transformer and comprehensively evaluates it with the current operating data to determine the initial temperature distribution. The load rate, ambient temperature, and operating time are converted into load scores, temperature scores, and operating scores respectively. Then, weighted calculations are performed according to the formula, and the initial temperature distribution of the historical data with the lowest similarity index is selected as the current initial temperature distribution, making the initial temperature more realistic and reducing subsequent calculation deviations.

[0042] The present invention divides the transformer temperature field into the winding area, the core area, and the cooling medium area for separate evaluation. In the cooling medium area, the cooling oil flow and temperature data are obtained to calculate the evaluation index, which is then compared with the threshold to adjust the temperature of each zone. The winding area adjusts the temperature by calculating the resistance evaluation ratio and comparing it with the threshold. The core area adjusts the temperature by calculating the magnetic permeability evaluation ratio based on the change in magnetic permeability and comparing it with the reference value. This method comprehensively considers multiple factors in multiple areas, fully reflects the actual operating status of the transformer, corrects the initial temperature distribution, and improves the accuracy of hot spot temperature detection.

[0043] The present invention ensures that the temperature field distribution can reflect the changes in the transformer operating status in real time by redetermining the initial and final temperature distributions according to preset adjustment time intervals. The final temperature distribution is applied to the calculation model and compared with the actual measurement data. If there is any deviation, a signal is triggered to the technicians, who will evaluate and adjust to make the temperature field distribution more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] To facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0045] Figure 1 Flowchart of the present invention. DETAILED DESCRIPTION

[0046] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0047] See also Figure 1 As shown, the hotspot temperature detection method based on transformer temperature field distribution calculation includes:

[0048] Determine initial conditions: Extract historical operating data of the transformer within a set time window before the current time point. Obtain historical operating data from the transformer's operation and maintenance management system, monitoring equipment logs, and past maintenance reports. This data covers records from different time periods, seasons, and operating conditions to ensure data comprehensiveness and diversity. A comprehensive evaluation is then conducted with the transformer's operating data at the current time point to determine the transformer's initial temperature distribution at the current time point. Operating data includes load factor, ambient temperature, and elapsed operating time.

[0049] Specifically:

[0050] S1: Extract the load rate, ambient temperature, and running time of the transformer at the current time point, pre-establish the scoring conversion rules corresponding to the load rate, ambient temperature, and running time, and convert the load rate, ambient temperature, and running time of the transformer at the current time point into a load score, a temperature score, and an operating score, respectively;

[0051] S1-1: The load rate value ranges for each group of preset load rates correspond to a load score. The load score range is set to 1-10 and is a positive integer. The higher the load rate of the transformer, the higher the corresponding load score.

[0052] The preset ambient temperature corresponds to each group of temperature value ranges, and each group of temperature value ranges corresponds to a temperature score; the temperature score range is set to 1-10 and is a positive integer. The higher the ambient temperature of the transformer, the higher the corresponding matching temperature score;

[0053] The preset operating time value ranges for each group correspond to the running time, and each group of running time value ranges corresponds to an operating score; the operating score range is set to 1-10 and is a positive integer. The higher the running time of the transformer, the higher the corresponding matching operating score;

[0054] Taking load factor as an example,

[0055] The value range corresponds to the score:

[0056] 0-20% load rate: the corresponding load score is 1;

[0057] 20-40% load rate: load score is 3;

[0058] 40-60% load rate: load score is 5;

[0059] 60-80% load rate: load score is 7;

[0060] 80-100% load rate: load score is 10;

[0061] S2: Mark the load score, temperature score and operation score of the transformer at the current time as At the same time, the historical operation data of the transformer within the set time window before the current time point is extracted, and the load rate, ambient temperature and running time in each group of historical operation data are converted into load score, temperature score and operation score respectively using the same scoring conversion rule. After the conversion, the load score, temperature score and operation score of each group of historical operation data are marked as ;

[0062] S3: According to the formula Perform weighted calculation on the transformer's operating data at the current time point and each set of historical operating data to determine the similarity index between the transformer's operating data at the current time point and each set of historical operating data ;in These are the preset weight coefficients corresponding to the load score, temperature score, and operation score, and their values are set to 1.138, 1.094, and 1.073 respectively;

[0063] S4: Based on the similarity index between the transformer operating data at the current time point and each group of historical operating data , select similar index The lowest historical operating data is used as the similar historical data of the transformer at the current time point, and the initial temperature distribution of the similar historical data is used as the initial temperature distribution of the transformer at the current time point;

[0064] It should be noted that by comparing the current operating data with the historical data, using weighted calculation to obtain a similar index, and selecting the initial temperature distribution of similar historical data, it can be more in line with the actual initial operating state of the transformer. Compared with simply assuming the initial temperature, the accuracy of determining the initial temperature distribution is greatly improved; this is crucial for the reliability of subsequent hot spot temperature detection based on temperature field distribution calculations, can reduce calculation deviations caused by inaccurate initial conditions, and more accurately evaluate the operating state of the transformer.

[0065] For example, suppose the current time point is 10:00 on July 15, 2022, and the initial temperature distribution of a transformer at this time is to be determined;

[0066] According to monitoring, the current transformer load rate is 65%. According to the scoring conversion rules, it is in the 60-80% load rate range, and the corresponding load score is 7;

[0067] The ambient temperature is 32°C, which is within the 30-40°C ambient temperature range, and the temperature score is 7;

[0068] The running time is 9 hours, which is in the 7-10 hours running time range, and the running score is 7;

[0069] Set the time window to the past year; extract historical operating data for that period from the operation and maintenance management system, monitoring equipment logs, and past maintenance reports. For example, one set of historical data shows that at 2:00 PM on August 20, 2024, the load factor was 62% (load score 7), the ambient temperature was 30°C (temperature score 6), and the operating time was 8 hours (operation score 7).

[0070] All historical operating data are processed according to the scoring conversion rules to obtain the load score, temperature score and operating score corresponding to each set of data;

[0071] A similar index calculation is performed on all historical operation data groups. After calculation, it is found that the similar index of the above-mentioned historical operation data group is the lowest among all historical data groups.

[0072] Therefore, the initial temperature distribution corresponding to this set of similar historical data is used as the initial temperature distribution of the transformer at 10:00 on July 15, 2022, for subsequent calculation of hot spot temperature detection and other related analyses based on the transformer temperature field distribution;

[0073] Evaluation and correction: Based on the initial temperature distribution of the transformer at the current time point, the transformer temperature field is divided into the winding area, the core area, and the cooling medium area, and comprehensive evaluation is performed on each area. Based on the results of the comprehensive evaluation, the initial temperature distribution of the transformer is adjusted twice, and the adjusted temperature distribution is used as the final temperature distribution of the corresponding temperature field of the transformer;

[0074] Specifically:

[0075] Cooling medium area: obtains the cooling oil flow and cooling oil temperature data of the transformer within the set time window after the current time point, and sets the cooling oil flow reference value and temperature reference value when the transformer is operating normally;

[0076] For the cooling oil flow rate and cooling oil temperature within the set time window, the average values are calculated as the flow evaluation value and temperature evaluation value, respectively, and recorded as and ;

[0077] According to the formula The flow evaluation value of the transformer within the set time window after the current time point and temperature evaluation values Perform weighted calculation to obtain the cooling oil evaluation index of the transformer within the set time window after the current time point ;in Respectively represent the flow reference value and temperature reference value; are the preset weight coefficients corresponding to the flow evaluation value and temperature evaluation value, and their values are 1.082 and 1.079 respectively;

[0078] The calculated cooling oil evaluation index Compare it with the corresponding preset cooling oil threshold index. If it is higher than the corresponding preset cooling oil threshold index, calculate the difference between the two and record it as the adjustment difference;

[0079] The intervals of each group of difference values corresponding to the preset adjustment differences are each corresponding to a temperature increase set, which includes the temperature increase values of each partition of the transformer. Based on the calculated adjustment differences and the initial temperature distribution, the temperature of each partition of the transformer is adjusted to the corresponding temperature increase value;

[0080] The temperature of each part of the transformer is raised as a whole. The extent of the increase is determined by the intensity of heat exchange between different parts and the cooling medium. For example, the parts with close heat exchange between the winding and the cooling oil will have a larger increase, up to 6-8°C, while the parts far away from the cooling oil circulation path will have a smaller increase, about 4-6°C.

[0081] It should be noted that when the cooling oil flow rate is reduced by 20%, according to the principles of heat transfer, the cooling oil's ability to remove heat decreases, and it is estimated that the overall temperature of the transformer will increase by 5-8°C. Therefore, based on the initial temperature distribution, the temperature of each part of the transformer is increased as a whole. The increase is determined by the heat exchange intensity between different parts and the cooling medium.

[0082] Winding area: Obtain the winding resistance of the transformer within a set time window after the current time point, and preset the reference resistance value corresponding to the winding resistance; that is, the winding resistance when it is newly put into operation; extract the winding resistance at each time point in the set time window as the numerator, and use the reference resistance value as the denominator to calculate the ratio respectively, and obtain the resistance ratio at each time point in the set time window;

[0083] After removing the highest resistance ratio and the lowest resistance ratio, the average value of the remaining resistance ratios is calculated to obtain the resistance evaluation ratio of the transformer within the set time window after the current time point;

[0084] The resistance evaluation ratio within the set time window is compared with the preset resistance threshold ratio. If it is higher than the corresponding preset resistance threshold ratio, the difference between the two is calculated and recorded as the winding difference;

[0085] The intervals of the difference values of each group corresponding to the winding difference are preset, and each group of winding difference corresponds to a winding temperature increase value. After adjusting the temperature of each divided area of the transformer according to the corresponding temperature increase value, the adjusted winding area is adjusted according to the corresponding winding temperature increase value;

[0086] It should be noted that if winding aging causes increased resistance, Joule's law indicates that heat generation will increase at the same load current. Assuming a 5% increase in winding resistance results in an 8% increase in winding heat generation, the initial temperature distribution should be adjusted to increase the winding temperature appropriately, for example, by 3-5°C. The specific value should be determined based on the overall thermal balance of the transformer.

[0087] Core area: Obtains the transformer core magnetic permeability within a set time window after the current time point, and presets the reference magnetic permeability value corresponding to the core magnetic permeability; this is determined based on the standard characteristics of the core material and the design specifications of the transformer;

[0088] The average value of the core magnetic permeability within the set time window is calculated and recorded as the average magnetic permeability. Then, taking the current set time window as the starting point, the average magnetic permeability of the X time windows before the starting point is extracted; where X>3, the specific value is set by the technician;

[0089] The average of the permeability averages of X time windows is calculated and recorded as the historical average. The historical average is compared with the permeability average of the current set time window. If the permeability average of the current set time window is less than the historical average, it indicates that the permeability of the transformer core is on a downward trend during this period. The permeability average of the current set time window is used as the denominator and the historical average is used as the numerator to calculate the ratio. The permeability trend ratio of the transformer in the current set time window is obtained, which is recorded as F.

[0090] The permeability evaluation rate W is calculated using the formula W=KK×(F-1); where K represents the average permeability of the current set time window. This is then compared with the reference permeability value. If the average permeability of the current set time window is greater than the historical average permeability, the average permeability of the current set time window is directly compared with the reference permeability value. If the permeability evaluation rate is lower than the reference permeability value, the difference between the two is calculated and recorded as the core difference.

[0091] The intervals of each group of difference values corresponding to the preset core difference are each corresponding to a core temperature increase value. After the temperature of each divided area of the transformer is adjusted to the corresponding temperature increase value, the adjusted core area is adjusted to the corresponding core temperature increase value;

[0092] It should be noted that, when analyzing the changes in the magnetic permeability of the core silicon steel sheets, a decrease in magnetic permeability will lead to an increase in core loss, thereby generating more heat.

[0093] During the aforementioned secondary adjustment process, existing technologies may only consider the temperature field distribution to calculate the hotspot temperature. However, this method divides the transformer temperature field into the winding area, the core area, and the cooling medium area for comprehensive evaluation. This evaluation not only considers the flow rate and temperature of the cooling medium, the changes in the winding resistance, but also the changes in the core magnetic permeability and other factors. This can more comprehensively reflect the actual operating status of the transformer, thereby more accurately determining the temperature changes in each area and making the temperature adjustment more realistic.

[0094] Targeted temperature adjustments are made to each zone of the transformer based on the heat exchange intensity between different zones and the cooling medium, as well as the special conditions of each zone (such as winding aging and changes in core magnetic permeability). For example, the temperature increase is larger for areas where the winding has close heat exchange with the cooling oil, while it is smaller for areas away from the cooling oil circulation path. Furthermore, corresponding temperature increase values are set for situations such as increased winding resistance and changes in core magnetic permeability. This makes the temperature distribution adjustment more precise, better reflects the actual heating conditions of various parts of the transformer, helps to more accurately detect hot spot temperatures, and improves the safety and reliability of transformer operation.

[0095] Real-time update: according to the preset adjustment time interval, the initial temperature distribution and the final temperature distribution are re-determined after the preset adjustment time interval is reached;

[0096] Verification and Optimization: The final temperature distribution is applied to a pre-built transformer temperature field calculation model and compared with the temperature measurement data during actual transformer operation. For example, thermocouples, fiber optic sensors, and other devices installed at key locations on the transformer are used to measure the winding hotspot temperature, top oil temperature, and core temperature in real time. The calculated temperature values are compared with the measured values to calculate the error. If the comparison results show that the difference between the calculated and measured temperatures in a certain area is higher than the corresponding preset allowable value, a deviation signal is triggered and sent to the technician.

[0097] Technicians evaluate the causes of the deviation and make adjustments. For example, it may be due to inaccurate assessment of aging and heat dissipation system performance, or unreasonable optimization adjustment range. Based on the analysis results, they re-evaluate the transformer aging degree and heat dissipation system performance, adjust the optimization direction and range, and perform secondary optimization adjustments again until the error between the calculated temperature and the measured temperature is within an acceptable range, ensuring that the adjusted initial temperature distribution can more accurately reflect the actual initial operating status of the transformer;

[0098] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A hotspot temperature detection method based on transformer temperature field distribution calculation is characterized in that: include: Determine the initial conditions: extract the historical operating data of the transformer within the set time window before the current time point; A comprehensive evaluation is then performed with the transformer's operating data at the current time point to determine the transformer's initial temperature distribution at the current time point; the operating data includes load rate, ambient temperature, and operating time; Get the historical operating data of the transformer within the set time window before the current time point; and make a comprehensive evaluation with the operating data of the transformer at the current time point, specifically: Extract the load rate, ambient temperature, and running time of the transformer at the current time point, pre-establish the scoring conversion rules corresponding to the load rate, ambient temperature, and running time, and convert the load rate, ambient temperature, and running time of the transformer at the current time point into a load score, a temperature score, and an operating score, respectively; The load score, temperature score and operation score of the transformer at the current time point are marked as At the same time, the historical operation data of the transformer within the set time window before the current time point is extracted, and the load rate, ambient temperature and running time in each group of historical operation data are converted into load score, temperature score and operation score respectively using the same scoring conversion rule. After the conversion, the load score, temperature score and operation score of each group of historical operation data are marked as ; Determine the initial temperature distribution of the transformer at the current time point, specifically: According to the formula Perform weighted calculation on the transformer's operating data at the current time point and each set of historical operating data to determine the similarity index between the transformer's operating data at the current time point and each set of historical operating data ;in These are the preset weight coefficients corresponding to the load score, temperature score, and operation score; Based on the similarity index between the transformer operating data at the current time point and each group of historical operating data , select similar index The lowest historical operating data is used as the similar historical data of the transformer at the current time point, and the initial temperature distribution of the similar historical data is used as the initial temperature distribution of the transformer at the current time point; Evaluation and correction: Based on the initial temperature distribution of the transformer at the current time point, the transformer temperature field is divided into the winding area, the core area, and the cooling medium area, and comprehensive evaluation is performed on each area. Based on the results of the comprehensive evaluation, the initial temperature distribution of the transformer is adjusted twice, and the adjusted temperature distribution is used as the final temperature distribution of the corresponding temperature field of the transformer; The specific process of evaluating the cooling medium area is as follows: Obtain the cooling oil flow rate and cooling oil temperature data of the transformer within a set time window after the current time point, and set the cooling oil flow rate reference value and temperature reference value when the transformer is operating normally; For the cooling oil flow rate and cooling oil temperature within the set time window, the average values are calculated as the flow evaluation value and temperature evaluation value, respectively, and recorded as and ; According to the formula The flow evaluation value of the transformer within the set time window after the current time point and temperature evaluation values Perform weighted calculation to obtain the cooling oil evaluation index of the transformer within the set time window after the current time point ;in Respectively represent the flow reference value and temperature reference value; The calculated cooling oil evaluation index is the preset weight coefficient corresponding to the flow evaluation value and temperature evaluation value. Compare it with the corresponding preset cooling oil threshold index. If it is higher than the corresponding preset cooling oil threshold index, calculate the difference between the two and record it as the adjustment difference; The intervals of each group of difference values corresponding to the preset adjustment difference, each group of adjustment difference corresponds to a temperature increase set, and the temperature increase set includes the temperature increase values of each divided area of the transformer; The specific process of evaluating the winding area is as follows: Obtain the winding resistance of the transformer within a set time window after the current time point, and preset a reference resistance value corresponding to the winding resistance; extract the winding resistance at each time point within the set time window as the numerator, and use the reference resistance value as the denominator, and calculate the ratio respectively to obtain the resistance ratio at each time point within the set time window; After removing the highest resistance ratio and the lowest resistance ratio, the average value of the remaining resistance ratios is calculated to obtain the resistance evaluation ratio of the transformer within the set time window after the current time point; The resistance evaluation ratio within the set time window is compared with the preset resistance threshold ratio. If it is higher than the corresponding preset resistance threshold ratio, the difference between the two is calculated and recorded as the winding difference; The intervals of the difference values of each group corresponding to the preset winding difference are located, and each group of winding difference corresponds to a winding temperature increase value; The specific process of evaluating the core area is as follows: Obtain the transformer core magnetic permeability within a set time window after the current time point, and preset a reference magnetic permeability value corresponding to the core magnetic permeability; The average value of the core magnetic permeability within the set time window is calculated and recorded as the average magnetic permeability. Then, taking the current set time window as the starting point, the average magnetic permeability of the X time windows before the starting point is extracted; where X>3; The average of the permeability averages of X time windows is calculated and recorded as the historical average. The historical average is compared with the permeability average of the current set time window. If the permeability average of the current set time window is less than the historical average, the permeability average of the current set time window is used as the denominator and the historical average is used as the numerator to calculate the ratio. The permeability trend ratio of the transformer in the current set time window is obtained, which is recorded as F. The permeability evaluation factor W is calculated using the formula W=KK×(F-1), where K represents the average permeability of the current set time window. The permeability evaluation factor W is compared with the reference permeability value. If the permeability evaluation factor is lower than the reference permeability value, the difference between the two is calculated and recorded as the core difference. The intervals of each group of difference values corresponding to the preset core difference are located, and each group of core difference corresponds to an increase value of the core temperature; Based on the results of the comprehensive evaluation, the initial temperature distribution of the transformer is adjusted twice, specifically: Based on the calculated adjustment difference, on the basis of the initial temperature distribution, the temperature of each divided area of the transformer is adjusted to the corresponding temperature increase value; after the temperature of each divided area of the transformer is adjusted to the corresponding temperature increase value, the winding area after the adjustment is adjusted to the corresponding winding temperature increase value; after the temperature of each divided area of the transformer is adjusted to the corresponding temperature increase value, the core area after the adjustment is adjusted to the corresponding core temperature increase value; after the adjustment is completed, the final temperature distribution of the corresponding temperature field of the transformer is used.

2. The hotspot temperature detection method based on transformer temperature field distribution calculation according to claim 1 is characterized in that: The scoring conversion rules corresponding to the load rate, ambient temperature, and running time are pre-established, specifically: The preset load rates correspond to the respective load rate value ranges, and each load rate value range corresponds to a load score; the preset ambient temperatures correspond to the respective temperature value ranges, and each temperature value range corresponds to a temperature score; The preset running time value ranges correspond to the running time, and each running time value range corresponds to a running score.

3. The hotspot temperature detection method based on transformer temperature field distribution calculation according to claim 2 is characterized in that: Also includes: Real-time update: according to the preset adjustment time interval, the initial temperature distribution and the final temperature distribution are re-determined after the preset adjustment time interval is reached; Verification and optimization: The final temperature distribution is applied to the pre-built transformer temperature field calculation model and compared with the temperature measurement data during actual transformer operation. If the comparison result shows that the difference between the calculated temperature and the measured temperature in a certain partition is higher than the corresponding preset allowable value, a deviation signal is triggered and sent to the technician.

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