A method for detecting partial discharge in power transformers based on ultrasonic positioning

Abstract

The present invention relates to the technical field of transformer partial discharge detection technology, and more particularly to a method for detecting partial discharge in power transformers based on ultrasonic positioning. The method comprises: obtaining and analyzing historical partial discharge detection data of the power transformer to obtain historical data analysis results, setting an initial ultrasonic sensor group based on the historical data analysis results and structural characteristics of the power transformer; testing the initial ultrasonic sensor group to obtain test results, adjusting the initial ultrasonic sensor group based on the test results to obtain an adjusted ultrasonic sensor group; testing the power transformer based on the adjusted ultrasonic sensor group, and determining partial discharge locations based on the test results; determining the distribution of multiple partial discharge locations, and calibrating the adjusted ultrasonic sensor group based on the distribution results to obtain a target ultrasonic sensor group. The present invention improves the accuracy of partial discharge detection in power transformers using ultrasonic positioning.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer partial discharge detection, and in particular to a power transformer partial discharge detection method based on ultrasonic positioning. Background Art

[0002] Power transformers are key equipment in power systems, and their operating status directly affects the safety and stability of the power grid. Partial discharge is one of the common faults of transformers. If it is not discovered and handled in time, it may cause damage to the transformer or even lead to more serious power accidents. Ultrasonic positioning technology has been widely used in transformer partial discharge detection due to its non-contact and high sensitivity.

[0003] Chinese Patent Publication No. CN102879714A discloses a method for detecting and locating partial discharge in transformers. The method comprises the following steps: detecting ultrasonic signals generated by partial discharge points of the transformer on the outside of the transformer oil tank using an ultrasonic probe; preprocessing the ultrasonic signals, including analog-to-electrical conversion and analog-to-digital conversion; and determining the location of the partial discharge points based on the ultrasonic signals using a hyperbolic surface positioning method.

[0004] In the prior art, due to the complex structure of the transformer, the ultrasonic signal may be interfered with during the propagation process, resulting in a decrease in positioning accuracy, causing the problem of low accuracy in partial discharge detection of power transformers using ultrasonic positioning. Summary of the Invention

[0005] To this end, the present invention provides a method for detecting partial discharge of power transformers based on ultrasonic positioning, which can solve the problem of low accuracy of partial discharge detection of power transformers based on ultrasonic positioning by adjusting the setting position of the ultrasonic sensor.

[0006] To achieve the above object, the present invention provides a method for detecting partial discharge of a power transformer based on ultrasonic positioning, the method comprising:

[0007] Acquire historical partial discharge detection data of the power transformer, analyze the historical partial discharge detection data, obtain historical data analysis results, and set an initial ultrasonic sensor group based on the historical data analysis results and structural characteristics of the power transformer;

[0008] Testing the initial ultrasonic sensor group to obtain a test result, and adjusting the initial ultrasonic sensor group based on the test result to obtain an adjusted ultrasonic sensor group;

[0009] The power transformer is inspected based on the adjustment of the ultrasonic sensor group, and the partial discharge location is determined according to the inspection results;

[0010] The distribution of a plurality of partial discharge locations is determined, and the adjustment ultrasonic sensor group is calibrated based on the distribution result to obtain a target ultrasonic sensor group.

[0011] Furthermore, the step of analyzing historical partial discharge detection data includes:

[0012] Obtaining a historical partial discharge position of the power transformer and a corresponding historical discharge frequency based on the historical partial discharge detection data;

[0013] A first detection level corresponding to a plurality of the historical partial discharge locations is determined based on the plurality of the historical discharge frequencies.

[0014] Furthermore, the step of setting an initial ultrasonic sensor group based on historical data analysis results and power transformer structural characteristics includes:

[0015] Identifying several key components of the power transformer and their corresponding component locations;

[0016] comparing the locations of the plurality of components with the locations of the plurality of historical partial discharges to obtain a comparison result;

[0017] Determine a non-overlapping position based on the comparison result, obtain historical partial discharge detection data corresponding to the non-overlapping position, and determine a second detection level corresponding to the non-overlapping position based on an analysis result of the historical partial discharge detection data;

[0018] determining a target detection level based on the comparison result, the first detection level, and the second detection level;

[0019] The initial ultrasonic sensor group is set based on the object detection level.

[0020] Furthermore, the setting of the initial ultrasonic sensor group based on the target detection level includes:

[0021] Determining the target detection level corresponding to each position to be detected;

[0022] determining the target number of ultrasonic sensors required at each position to be detected based on the target detection level, and setting the ultrasonic sensor group according to the target number;

[0023] The position to be detected is a union of several component positions and several historical partial discharge positions.

[0024] Furthermore, the step of adjusting the initial ultrasonic sensor group based on the test results includes:

[0025] When the power transformer is not in operation, simulating a partial discharge signal, and receiving the simulated signal through the initial ultrasonic sensor group;

[0026] A simulated reception effect of the simulated signal is analyzed, and the initial ultrasonic sensor group is adjusted according to the simulated reception effect to obtain an adjusted ultrasonic sensor group.

[0027] Furthermore, the step of adjusting the initial ultrasonic sensor group according to the simulated reception effect includes:

[0028] Determining an initial ultrasonic sensor corresponding to a poor simulated reception effect, and determining an adjustment strategy for the initial ultrasonic sensor according to the degree of the poor simulated reception effect;

[0029] The initial ultrasonic sensor group is adjusted according to the adjustment strategy to obtain an adjusted ultrasonic sensor group.

[0030] Furthermore, the step of detecting the power transformer based on adjusting the ultrasonic sensor group includes:

[0031] Collecting a number of actual ultrasonic signals, analyzing the number of actual ultrasonic signals, and identifying actual discharge signals based on the analysis results;

[0032] The actual discharge position is determined based on the time difference between the discharge signals received by the adjusted ultrasonic sensor at three known positions.

[0033] Furthermore, the step of determining the actual discharge position by adjusting the time difference of the ultrasonic sensor receiving the discharge signal based on the three known positions includes:

[0034] Calculating respectively the actual time difference of the discharge signal reaching the adjusted ultrasonic sensors at three known positions;

[0035] According to any actual time difference and the corresponding known position, the position coordinates of the actual discharge point are calculated using a triangulation positioning algorithm.

[0036] Furthermore, the step of calibrating the ultrasonic sensor group based on the distribution result includes:

[0037] Drawing a partial discharge position distribution map based on the distribution of the plurality of partial discharge positions;

[0038] The adjustment ultrasonic sensor group is calibrated according to the analysis result of the partial discharge position distribution map to obtain a target ultrasonic sensor group.

[0039] Furthermore, the step of calibrating the ultrasonic sensor group according to the analysis result of the partial discharge position distribution map includes:

[0040] Comparing the partial discharge position distribution map with the setting distribution map of the adjusted ultrasonic sensor group to obtain a comparison result;

[0041] The rationality of the setting of the adjustment ultrasonic sensor group is determined based on the comparison result. If it is unreasonable, the adjustment ultrasonic sensor group is adjusted according to the partial discharge position distribution map.

[0042] Compared with the prior art, the present invention has the following advantages: by analyzing historical partial discharge detection data of power transformers, an in-depth understanding of the laws of discharge phenomena within the transformer is achieved, providing an accurate basis for the design of subsequent sensor groups. An initial ultrasonic sensor group is set in combination with the structural characteristics of the power transformer to ensure that the sensors can efficiently monitor key areas and potential discharge points within the transformer. By actually testing the performance of the initial sensor group, possible blind spots or areas with insufficient detection are promptly discovered and corrected, thereby improving the accuracy and reliability of detection. Adjustments based on test results can further optimize the layout of sensors within the transformer to ensure that every potential discharge point is effectively covered, while reducing unnecessary sensor redundancy. Using the adjusted ultrasonic sensor group to detect power transformers, partial discharge locations can be accurately located in real time, providing an important basis for subsequent fault analysis and processing. The optimized sensor layout and configuration can improve detection efficiency. By determining the distribution of partial discharge locations, the performance and effectiveness of the sensor group can be further analyzed, providing feedback for subsequent calibration work, improving the detection accuracy and coverage of the target ultrasonic sensor group, and thus improving the diagnostic capability of partial discharge faults in power transformers.

[0043] In particular, by combining the historical discharge frequency with the historical partial discharge location and assigning a first detection level to each location, the severity of the discharge phenomenon at each location can be assessed more precisely, which helps to improve the efficiency of fault prevention and handling. When setting the initial ultrasonic sensor group, the sensor configuration is optimized according to the first detection level of the historical partial discharge location. For areas with high detection levels, the sensor density is increased or higher-sensitivity sensors are used to ensure that the discharge phenomenon in these areas can be monitored in a timely and accurate manner. The determination of the first detection level is based on actual historical discharge data, which more accurately reflects the actual situation of the discharge phenomenon inside the transformer, and helps to improve the accuracy and reliability of detection.

[0044] In particular, by identifying the key components of the power transformer and their locations, monitoring is carried out on those areas that have the greatest impact on the transformer performance, and comparing the component locations with historical partial discharge locations. Key components or potential risk areas with historical discharge records are quickly discovered, and non-overlapping locations are determined and a second detection level is set based on their historical discharge data, ensuring comprehensive coverage of all possible discharge areas inside the transformer. At the same time, the detection priority is set according to the frequency of discharge. Combining the first detection level and the second detection level, a comprehensive assessment of all discharge locations inside the transformer can be achieved, and monitoring priorities for different areas can be set based on the assessment results. The importance and risk level of each location can be determined more accurately. The initial ultrasonic sensor group is set based on the final target detection level, ensuring that sensor resources are reasonably allocated, high-risk areas are monitored in key areas, and unnecessary sensor redundancy is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A schematic flow chart of a method for detecting partial discharge in a power transformer based on ultrasonic positioning according to an embodiment of the present invention;

[0046] Figure 2 A schematic diagram of a process for setting an initial ultrasonic sensor group in a method for detecting partial discharge of a power transformer based on ultrasonic positioning provided by an embodiment of the present invention;

[0047] Figure 3 A schematic diagram of a process for adjusting an initial ultrasonic sensor group in a method for detecting partial discharge of a power transformer based on ultrasonic positioning provided by an embodiment of the present invention;

[0048] Figure 4 A schematic diagram of the process of detecting a power transformer in the method for detecting partial discharge of a power transformer based on ultrasonic positioning provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0050] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0051] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0052] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0053] See also Figure 1 As shown, an embodiment of the present invention provides a method for detecting partial discharge of a power transformer based on ultrasonic positioning, the method comprising:

[0054] Step S100, acquiring historical partial discharge detection data of the power transformer, analyzing the historical partial discharge detection data to obtain historical data analysis results, and setting an initial ultrasonic sensor group based on the historical data analysis results and structural characteristics of the power transformer;

[0055] Step S200, testing the initial ultrasonic sensor group to obtain a test result, and adjusting the initial ultrasonic sensor group based on the test result to obtain an adjusted ultrasonic sensor group;

[0056] Step S300, detecting the power transformer based on adjusting the ultrasonic sensor group, and determining the partial discharge location according to the detection result;

[0057] Step S400 : determining the distribution of a plurality of partial discharge positions, and calibrating the adjustment ultrasonic sensor group based on the distribution result to obtain a target ultrasonic sensor group.

[0058] Specifically, the embodiments of the present invention analyze historical partial discharge detection data of power transformers to gain a deep understanding of the patterns of discharge phenomena within the transformer, providing an accurate basis for the design of subsequent sensor groups. An initial ultrasonic sensor group is set based on the structural characteristics of the power transformer to ensure that the sensors can efficiently monitor key areas and potential discharge points within the transformer. By actually testing the performance of the initial sensor group, potential blind spots or areas with insufficient detection are promptly discovered and corrected, thereby improving detection accuracy and reliability. Adjustments based on test results can further optimize the sensor layout within the transformer to ensure that every potential discharge point is effectively covered while reducing unnecessary sensor redundancy. Using the adjusted ultrasonic sensor group to detect power transformers, the partial discharge position can be accurately and in real time, providing an important basis for subsequent fault analysis and processing. The optimized sensor layout and configuration can improve detection efficiency. By determining the distribution of partial discharge locations, the performance and effectiveness of the sensor group can be further analyzed, providing feedback for subsequent calibration work, improving the detection accuracy and coverage of the target ultrasonic sensor group, and thus enhancing the diagnostic capability for partial discharge faults in power transformers.

[0059] Specifically, the step of analyzing historical partial discharge detection data includes:

[0060] Obtaining a historical partial discharge position of the power transformer and a corresponding historical discharge frequency based on the historical partial discharge detection data;

[0061] A first detection level corresponding to a plurality of the historical partial discharge locations is determined based on the plurality of the historical discharge frequencies.

[0062] Specifically, in an embodiment of the present invention, determining the first detection levels corresponding to the plurality of historical partial discharge locations based on the plurality of historical discharge frequencies includes:

[0063] Comparing the plurality of historical discharge frequencies with a preset frequency range to obtain a comparison result;

[0064] When the historical discharge frequency is greater than the preset frequency range, the first detection level is high;

[0065] When the historical discharge frequency is within the preset frequency range, the first detection level is medium;

[0066] When the historical discharge frequency is less than the preset frequency range, the first detection level is low.

[0067] Specifically, the preset frequency range in the embodiment of the present invention is an average value of several historical discharge frequencies ±1.

[0068] Specifically, the embodiment of the present invention combines the historical discharge frequency with the historical partial discharge location and assigns a first detection level to each location, which can more accurately assess the severity of the discharge phenomenon at each location, helping to improve the efficiency of fault prevention and handling. When setting the initial ultrasonic sensor group, the sensor configuration is optimized according to the first detection level of the historical partial discharge location. For areas with high detection levels, the sensor density is increased or sensors with higher sensitivity are used to ensure that the discharge phenomenon in these areas can be monitored in a timely and accurate manner. The determination of the first detection level is based on actual historical discharge data, which more accurately reflects the actual situation of the discharge phenomenon inside the transformer, helping to improve the accuracy and reliability of detection.

[0069] See also Figure 2 As shown, the steps of setting the initial ultrasonic sensor group based on the historical data analysis results and the structural characteristics of the power transformer include:

[0070] Step S110, identifying several key components of the power transformer and their corresponding component positions;

[0071] Step S120, comparing the plurality of component positions with the plurality of historical partial discharge positions to obtain a comparison result;

[0072] Step S130, determining a non-overlapping position based on the comparison result, obtaining historical partial discharge detection data corresponding to the non-overlapping position, and determining a second detection level corresponding to the non-overlapping position based on an analysis result of the historical partial discharge detection data;

[0073] Step S140, determining a target detection level based on the comparison result, the first detection level, and the second detection level;

[0074] Step S150 : setting the initial ultrasonic sensor group based on the target detection level.

[0075] Specifically, the step of determining the second detection level corresponding to the non-overlapping position based on the analysis results of historical partial discharge detection data in the embodiment of the present invention includes:

[0076] Identifying a historical discharge frequency corresponding to the non-overlapping position;

[0077] Comparing the historical discharge frequencies corresponding to the plurality of non-overlapping positions with a preset frequency range to obtain a comparison result;

[0078] When the historical discharge frequency is greater than the preset frequency range, the first detection level is high;

[0079] When the historical discharge frequency is within the preset frequency range, the first detection level is medium;

[0080] When the historical discharge frequency is less than the preset frequency range, the first detection level is low.

[0081] Specifically, the preset frequency range in the embodiment of the present invention is ±1 of the average of the historical discharge frequencies corresponding to the non-overlapping positions.

[0082] Specifically, the step of determining the target detection level based on the comparison result, the first detection level, and the second detection level in the embodiment of the present invention includes:

[0083] Determining an overlapping position based on the comparison result, and determining the target detection level at the overlapping position as high;

[0084] determining a target detection level for non-overlapping locations among the plurality of historical partial discharge locations based on the first detection level;

[0085] determining a target detection level at the non-overlapping position among the plurality of component positions based on the second detection level;

[0086] The final target detection level is determined based on the above results.

[0087] Specifically, the embodiment of the present invention identifies the key components of the power transformer and their locations, monitors those areas that have the greatest impact on the transformer performance, compares the component locations with historical partial discharge locations, and quickly discovers those key components or potential risk areas with historical discharge records. It determines the non-overlapping positions and sets the second detection level based on their historical discharge data, ensuring comprehensive coverage of all possible discharge areas inside the transformer. At the same time, the detection priority is set according to the discharge frequency. Combined with the first detection level and the second detection level, a comprehensive assessment of all discharge positions inside the transformer can be achieved, and the monitoring priority of different areas can be set according to the assessment results. The importance and risk level of each position can be determined more accurately. The initial ultrasonic sensor group is set based on the final target detection level, ensuring that sensor resources are reasonably allocated, high-risk areas are monitored in key areas, and unnecessary sensor redundancy is reduced.

[0088] Specifically, setting the initial ultrasonic sensor group based on the target detection level includes:

[0089] Determining the target detection level corresponding to each position to be detected;

[0090] determining the target number of ultrasonic sensors required at each position to be detected based on the target detection level, and setting the ultrasonic sensor group according to the target number;

[0091] The position to be detected is a union of several component positions and several historical partial discharge positions.

[0092] Specifically, the step of determining the target number of ultrasonic sensors required at each to-be-detected position based on the target detection level in the embodiment of the present invention includes:

[0093] Determining the area to be detected corresponding to each position to be detected based on the target detection level;

[0094] determining a target detection range of the ultrasonic sensor;

[0095] The number of targets required at any position to be detected is determined based on any area to be detected and the target detection range.

[0096] Specifically, the step of determining the to-be-detected area corresponding to each to-be-detected position based on the target detection level in the embodiment of the present invention includes:

[0097] Determine a number of straight-line distances between any position to be detected and other positions to be detected;

[0098] Selecting a straight-line distance based on the target detection level to further determine the range radius;

[0099] The target detection range is determined with any position to be detected as the center and the range radius as the radius.

[0100] Specifically, the step of selecting the straight-line distance according to the target detection level in the embodiment of the present invention includes:

[0101] When the target detection level is high, the maximum value among several straight-line distances is selected;

[0102] When the target detection level is medium, the average of several straight-line distances is selected;

[0103] When the target detection level is low, the minimum value among several straight-line distances is selected.

[0104] Specifically, an embodiment of the present invention also includes identifying several target detection ranges, determining whether there is an undetected area of the transformer, identifying the area of the undetected area, and comparing it with the target detection range. When the area of the undetected area is smaller than the target detection range, an ultrasonic sensor is set at the center of the undetected area. When the area of the undetected area is greater than or equal to the target detection range, multiple ultrasonic sensors are set in the undetected area so that their detection range covers the undetected area.

[0105] Specifically, the embodiment of the present invention compares the area of the undetected area with the target detection range to determine the number of ultrasonic sensors that need to be set. If the area of the undetected area is smaller than the target detection range, one ultrasonic sensor is set at the center of the area. If the area of the undetected area is greater than or equal to the target detection range, multiple ultrasonic sensors are set within the area to ensure that their detection range can cover the entire undetected area. In this way, every part of the transformer is properly monitored, thereby improving overall detection efficiency and accuracy.

[0106] See also Figure 3 As shown, the step of adjusting the initial ultrasonic sensor group based on the test results includes:

[0107] Step S210, simulating a partial discharge signal when the power transformer is not in operation, and receiving the simulated signal through the initial ultrasonic sensor group;

[0108] Step S220 , analyzing the simulated reception effect of the simulated signal, and adjusting the initial ultrasonic sensor group according to the simulated reception effect to obtain an adjusted ultrasonic sensor group.

[0109] Specifically, the step of analyzing the analog reception effect of the analog signal in the embodiment of the present invention includes:

[0110] Identifying the similarity between the analog signal and a preset discharge signal;

[0111] The simulated reception effect is determined based on a comparison result of the similarity and a preset similarity threshold.

[0112] Specifically, the real-time example similarity of the present invention can be calculated by cosine similarity;

[0113] The similarity threshold is 90%.

[0114] Specifically, in the embodiment of the present invention, when the similarity is less than the similarity threshold, the simulation reception effect is poor.

[0115] Specifically, the embodiment of the present invention simulates partial discharge signals when the power transformer is not in operation and tests the performance of the ultrasonic sensor group separately without being interfered with by the complex electromagnetic environment and other noise sources in actual operation. This helps to accurately evaluate the sensor's responsiveness and sensitivity to discharge signals. By analyzing the reception effect of the simulated signal, blind spots or weak detection areas in the sensor group are identified, and the sensor position is adjusted accordingly. This helps to improve the accuracy and reliability of the entire detection system, ensure that partial discharge phenomena inside the transformer can be accurately captured, and adjust the sensor group according to the simulated reception effect to further optimize the layout and configuration of the sensors and improve the overall performance of the system.

[0116] Specifically, the step of adjusting the initial ultrasonic sensor group according to the simulated reception effect includes:

[0117] Determining an initial ultrasonic sensor corresponding to a poor simulated reception effect, and determining an adjustment strategy for the initial ultrasonic sensor according to the degree of the poor simulated reception effect;

[0118] The initial ultrasonic sensor group is adjusted according to the adjustment strategy to obtain an adjusted ultrasonic sensor group.

[0119] Specifically, the step of determining the adjustment strategy for the initial ultrasonic sensor according to the degree of poor simulated reception effect in the embodiment of the present invention includes:

[0120] Comparing the similarity with a preset similarity range, and determining the degree of poor simulation effect based on the comparison result;

[0121] When the similarity is greater than the similarity range, the degree of poor simulation effect is low;

[0122] When the similarity is within the similarity range, the degree of poor simulation effect is medium;

[0123] When the similarity is less than the similarity range, the degree of poor simulation effect is high;

[0124] When the degree of poor simulation effect is low, repairing and adjusting the initial ultrasonic sensor;

[0125] When the degree of poor simulation effect is medium, the initial ultrasonic sensor is replaced and adjusted;

[0126] When the degree of poor simulation effect is high, the initial ultrasonic sensor is replaced and an ultrasonic sensor at the position is added.

[0127] See also Figure 4 As shown, the step of detecting the power transformer based on adjusting the ultrasonic sensor group includes:

[0128] Step S310, collecting a number of actual ultrasonic signals, analyzing the number of actual ultrasonic signals, and identifying an actual discharge signal based on the analysis results;

[0129] Step S320 , determining the actual discharge position based on the time difference between the discharge signal received by the adjusted ultrasonic sensor at the three known positions.

[0130] Specifically, the step of identifying the actual discharge signal according to the analysis result in the embodiment of the present invention includes:

[0131] Compare the actual ultrasonic signal with the preset discharge signal for similarity;

[0132] When the similarity result is greater than the preset similarity, it is determined to be an actual discharge signal.

[0133] Specifically, the preset similarity in the embodiment of the present invention is 95%.

[0134] Specifically, the step of determining the actual discharge position by adjusting the time difference of the ultrasonic sensor receiving the discharge signal based on the three known positions includes:

[0135] Calculating respectively the actual time difference of the discharge signal reaching the adjusted ultrasonic sensors at three known positions;

[0136] According to any actual time difference and the corresponding known position, the position coordinates of the actual discharge point are calculated using a triangulation positioning algorithm.

[0137] Specifically, the embodiment of the present invention assumes that partial discharge detection is performed inside a power transformer. Three ultrasonic sensors A, B, and C are installed at different positions of the transformer. Their coordinates are A(0,0,0), B(3,0,0), and C(1.5,2.6,0) (unit: meter). The propagation speed of ultrasonic waves in transformer oil is assumed to be 1500 meters per second.

[0138] Time difference record:

[0139] The time when sensor A receives the discharge signal is t1.

[0140] The time when sensor B receives the discharge signal is t2, and the time difference with A is Δt_AB=t2-t1.

[0141] The time when sensor C receives the discharge signal is t3, the time difference with A is Δt_AC=t3-t1, and the time difference with B is Δt_BC=t3-t2 (but Δt_AB and Δt_AC are usually used for calculation).

[0142] Distance difference calculation:

[0143] d_AB=1500×Δt_AB

[0144] d_AC=1500×Δt_AC

[0145] Triangulation:

[0146] With A as the origin and B and C as two known points, the hyperbola positioning method is used (because the distance differences d_AB and d_AC determine two hyperbolas with A, B and A, C as foci respectively).

[0147] Solving the intersection of these two hyperbolas gives the position coordinates (x, y, z) of the discharge point.

[0148] Specifically, the step of calibrating and adjusting the ultrasonic sensor group based on the distribution result includes:

[0149] Drawing a partial discharge position distribution map based on the distribution of the plurality of partial discharge positions;

[0150] The adjustment ultrasonic sensor group is calibrated according to the analysis result of the partial discharge position distribution map to obtain a target ultrasonic sensor group.

[0151] Specifically, the step of calibrating the ultrasonic sensor group according to the analysis result of the partial discharge position distribution map includes:

[0152] Comparing the partial discharge position distribution map with the setting distribution map of the adjusted ultrasonic sensor group to obtain a comparison result;

[0153] The rationality of the setting of the adjustment ultrasonic sensor group is determined based on the comparison result. If it is unreasonable, the adjustment ultrasonic sensor group is adjusted according to the partial discharge position distribution map.

[0154] Specifically, the step of determining the rationality of adjusting the settings of the ultrasonic sensor group based on the comparison results in the embodiment of the present invention includes:

[0155] Determining a first density in the partial discharge position distribution map and a second density of the adjustment ultrasonic sensor group;

[0156] When the difference between the first density and the second density is greater than a preset difference, it is determined to be unreasonable.

[0157] Specifically, in this embodiment of the present invention, adjusting the ultrasonic sensor group based on the partial discharge location distribution map includes adjusting the ultrasonic sensor group so that the difference between the first density and the second density is less than or equal to a preset difference. Adjustment strategies include, but are not limited to, increasing or decreasing the number of sensors, changing sensor positions, or rearranging the sensor group to optimize detection results. This ensures that the layout of the ultrasonic sensors more accurately reflects the actual partial discharge situation in the power transformer, thereby improving detection accuracy and efficiency.

[0158] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

[0159] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for detecting partial discharge of a power transformer based on ultrasonic positioning, characterized in that: include: Acquire historical partial discharge detection data of the power transformer, analyze the historical partial discharge detection data, obtain historical data analysis results, and set an initial ultrasonic sensor group based on the historical data analysis results and structural characteristics of the power transformer; Testing the initial ultrasonic sensor group to obtain a test result, and adjusting the initial ultrasonic sensor group based on the test result to obtain an adjusted ultrasonic sensor group; The power transformer is inspected based on the adjustment of the ultrasonic sensor group, and the partial discharge location is determined according to the inspection results; determining a distribution of a plurality of partial discharge locations, and calibrating an adjustment ultrasonic sensor group based on the distribution results to obtain a target ultrasonic sensor group; The step of analyzing historical partial discharge detection data includes: Obtaining a historical partial discharge position of the power transformer and a corresponding historical discharge frequency based on the historical partial discharge detection data; determining first detection levels corresponding to a plurality of the historical partial discharge locations based on the plurality of the historical discharge frequencies; The step of setting an initial ultrasonic sensor group based on historical data analysis results and power transformer structural characteristics includes: Identifying several key components of the power transformer and their corresponding component locations; comparing the locations of the plurality of components with the locations of the plurality of historical partial discharges to obtain a comparison result; Determine a non-overlapping position based on the comparison result, obtain historical partial discharge detection data corresponding to the non-overlapping position, and determine a second detection level corresponding to the non-overlapping position based on an analysis result of the historical partial discharge detection data; determining a target detection level based on the comparison result, the first detection level, and the second detection level; setting the initial ultrasonic sensor group based on the target detection level; The setting of the initial ultrasonic sensor group based on the target detection level includes: Determining the target detection level corresponding to each position to be detected; determining the target number of ultrasonic sensors required at each position to be detected based on the target detection level, and setting the ultrasonic sensor group according to the target number; Wherein, the position to be detected is the union of several of the component positions and several of the historical partial discharge positions; The step of determining a target detection level based on the comparison result, the first detection level, and the second detection level includes: Determining an overlapping position based on the comparison result, and determining the target detection level at the overlapping position as high; determining a target detection level for non-overlapping locations among the plurality of historical partial discharge locations based on the first detection level; determining a target detection level at the non-overlapping position among the plurality of component positions based on the second detection level; Determine the final target detection level based on the above results; The step of determining the target number of ultrasonic sensors required at each to-be-detected position based on the target detection level includes: Determining the area to be detected corresponding to each position to be detected based on the target detection level; determining a target detection range of the ultrasonic sensor; Determine the number of targets required at any position to be detected based on any area to be detected and the target detection range; The step of determining the to-be-detected area corresponding to each to-be-detected position based on the target detection level includes: Determine a number of straight-line distances between any position to be detected and other positions to be detected; Selecting a straight-line distance based on the target detection level to further determine the range radius; Determine the target detection range with any position to be detected as the center and the range radius as the radius; The step of selecting the straight-line distance according to the target detection level includes: When the target detection level is high, the maximum value among several straight-line distances is selected; When the target detection level is medium, the average of several straight-line distances is selected; When the target detection level is low, the minimum value among several straight-line distances is selected.

2. The method for detecting partial discharge of a power transformer based on ultrasonic positioning according to claim 1, characterized in that: The step of adjusting the initial ultrasonic sensor group based on the test results includes: When the power transformer is not in operation, simulating a partial discharge signal, and receiving the simulated signal through the initial ultrasonic sensor group; A simulated reception effect of the simulated signal is analyzed, and the initial ultrasonic sensor group is adjusted according to the simulated reception effect to obtain an adjusted ultrasonic sensor group.

3. The method for detecting partial discharge of a power transformer based on ultrasonic positioning according to claim 2, characterized in that: The step of adjusting the initial ultrasonic sensor group according to the simulated receiving effect includes: Determining an initial ultrasonic sensor corresponding to a poor simulated reception effect, and determining an adjustment strategy for the initial ultrasonic sensor according to the degree of the poor simulated reception effect; The initial ultrasonic sensor group is adjusted according to the adjustment strategy to obtain an adjusted ultrasonic sensor group.

4. The method for detecting partial discharge of a power transformer based on ultrasonic positioning according to claim 3, characterized in that: The step of detecting the power transformer based on adjusting the ultrasonic sensor group includes: Collecting a number of actual ultrasonic signals, analyzing the number of actual ultrasonic signals, and identifying actual discharge signals based on the analysis results; The actual discharge position is determined based on the time difference between the discharge signals received by the adjusted ultrasonic sensor at three known positions.

5. The method for detecting partial discharge of a power transformer based on ultrasonic positioning according to claim 4, characterized in that: The step of determining the actual discharge position by adjusting the time difference of the ultrasonic sensor receiving the discharge signal based on the three known positions includes: Calculating respectively the actual time difference of the discharge signal reaching the adjusted ultrasonic sensors at three known positions; According to any actual time difference and the corresponding known position, the position coordinates of the actual discharge point are calculated using a triangulation positioning algorithm.

6. The method for detecting partial discharge of a power transformer based on ultrasonic positioning according to claim 5, characterized in that: The step of calibrating and adjusting the ultrasonic sensor group based on the distribution result includes: Drawing a partial discharge position distribution map based on the distribution of the plurality of partial discharge positions; The adjustment ultrasonic sensor group is calibrated according to the analysis result of the partial discharge position distribution map to obtain a target ultrasonic sensor group.

7. The method for detecting partial discharge of a power transformer based on ultrasonic positioning according to claim 6, characterized in that: The step of calibrating the ultrasonic sensor group according to the analysis result of the partial discharge position distribution map includes: Comparing the partial discharge position distribution map with the setting distribution map of the adjusted ultrasonic sensor group to obtain a comparison result; The rationality of the setting of the adjustment ultrasonic sensor group is determined based on the comparison result. If it is unreasonable, the adjustment ultrasonic sensor group is adjusted according to the partial discharge position distribution map.

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