A method and system for selecting the installation position of a UHF sensor on a transformer

Abstract

The embodiment of this specification discloses a method and system for selecting the installation position of a UHF sensor on a transformer. The scheme includes: constructing a transformer model in simulation software, and dividing the detection point position and the position of the local discharge point inside the transformer according to the transformer model; performing simulation in the simulation software to obtain the UHF signal waveform received by each detection point when local discharge occurs at different positions; extracting the maximum amplitude of the electromagnetic wave signal detected by each sensor at each detection point from the UHF signal waveform, determining a detection point set according to the maximum amplitude, and the maximum amplitude of the detection point in the detection point set is greater than a first preset value; determining a first detection point from the detection point set where the amplitude of the electromagnetic wave signal at multiple local discharge points is greater than a second preset value, and the position corresponding to the first detection point is the position where the UHF sensor is installed.

Description

Technical Field

[0001] The present application relates to the technical field of transformers, and in particular to a method and system for selecting an installation position of a UHF sensor on a transformer. Background Art

[0002] With the continuous advancement of smart grids, a large number of intelligent technologies have begun to be applied to traditional primary equipment. Among them, in order to be able to detect faults in transformers as soon as possible, a large number of online monitoring technologies have begun to merge with transformers, making transformer fault detection more intelligent. Online monitoring of transformers is inseparable from the use of various sensors. The sensor converts the electrical signals, acoustic signals, optical signals, etc. generated by various faults in the transformer into digital signals, and uploads them through optical fibers and other means. Finally, it is processed and analyzed on the server to finally obtain the status and fault conditions of the transformer. Among the many sensors used in transformer online monitoring technology, many have their own configuration plans or are already equipped when the transformer leaves the factory. However, there is currently no unified installation standard for UHF sensors. Summary of the invention

[0003] In view of the shortcomings of the existing method for selecting the location of ultra-high frequency sensor measuring points for transformers, the embodiment of the present application proposes a method for determining the installation location of the ultra-high frequency sensor by comprehensively scoring the detection performance of the ultra-high frequency sensor installation measuring points based on the signal strength of the measuring point location, taking into account the parts inside the transformer where partial discharge is prone to occur.

[0004] To solve the above technical problems, the embodiments of this specification are implemented as follows:

[0005] The embodiment of this specification provides a method for selecting an installation position of a UHF sensor on a transformer, comprising:

[0006] Constructing a transformer model in the simulation software, and dividing the detection point locations and the locations of the local discharge points inside the transformer according to the transformer model;

[0007] Perform simulation in simulation software to obtain the waveform of the UHF signal received by each detection point when partial discharge occurs at different positions;

[0008] Extracting the maximum amplitude of the electromagnetic wave signal detected by each sensor at each detection point from the UHF signal waveform, determining a detection point set according to the maximum amplitude, wherein the maximum amplitude of the detection point in the detection point set is greater than a first preset value;

[0009] A first detection point at which the amplitudes of electromagnetic wave signals at multiple local discharge points are all greater than a second preset value is determined from the detection point set, and the position corresponding to the first detection point is the position where the ultra-high frequency sensor is installed.

[0010] Optionally, the method further includes: normalizing the maximum amplitude data of each detection point, and determining a detection point set according to the normalized value.

[0011] Optionally, the method further includes:

[0012] The value obtained by multiplying the normalized value by 100 is defined as the score of the sensitivity of the detection point in detecting the electromagnetic wave signal when a local discharge occurs at the corresponding local discharge point;

[0013] The total score is obtained by adding up the scores of each detection point corresponding to the occurrence of partial discharge at different partial discharge points;

[0014] The sum totals of the scores of different detection points are compared, and a second detection point whose sum total of the scores is greater than a third preset value is selected.

[0015] Optionally, the method further includes:

[0016] Determine the detection point position where the first detection point and the second detection point overlap as the position where the UHF sensor is installed.

[0017] Optionally, the method further includes: specifying sensor installation schemes with different safety performance requirements according to the sum of the scores of each detection point.

[0018] Optionally, the transformer model is a box structure, including an iron core, a high-voltage winding and a low-voltage winding, the iron core includes a plurality of silicon steel sheets, and the high-voltage winding and the low-voltage winding are equivalent to 10 disks respectively.

[0019] Optionally, the locations of the local discharge points include: between the A-phase high-voltage winding and the A-phase low-voltage winding, between the A-phase low-voltage winding and the iron core, between the A-phase high-voltage winding and the B-phase high-voltage winding, between the B-phase high-voltage winding and the B-phase low-voltage winding, and between the B-phase low-voltage winding and the iron core.

[0020] Optionally, during the simulation process, a Gaussian pulse signal is selected as the discharge signal.

[0021] An embodiment of this specification provides a system for selecting an installation position of a UHF sensor on a transformer, comprising:

[0022] A model building module is used to build a transformer model in the simulation software, and divide the detection point location and the location of the local discharge point inside the transformer according to the transformer model;

[0023] A simulation module is used to perform simulation in the simulation software to obtain the waveform of the ultra-high frequency signal received by each detection point when partial discharge occurs at different positions;

[0024] A detection point set determination module, used to extract the maximum amplitude of the electromagnetic wave signal detected by each sensor at each detection point from the UHF signal waveform, and determine the detection point set according to the maximum amplitude, wherein the maximum amplitude of the detection point in the detection point set is greater than a first preset value;

[0025] The position determination module is used to determine a first detection point from the detection point set where the amplitudes of electromagnetic wave signals at multiple local discharge points are all greater than a second preset value, and the position corresponding to the first detection point is the position where the ultra-high frequency sensor is installed.

[0026] Optionally, the system further includes:

[0027] The normalization module is used to normalize the maximum amplitude data of each detection point.

[0028] At least one of the above technical solutions adopted in the embodiments of this specification can achieve the following beneficial effects:

[0029] This solution scores each measuring point based on the signal strength at the measuring point location, and compares the comprehensive scores of each measuring point at each partial discharge point to determine the installation location of the UHF sensor.

[0030] The sensor installation location selection strategy provided by this solution can evaluate the installation plan of the transformer with the UHF sensor installed, and score the existing installation plan using the scoring system of this patent, so as to make suggestions on whether the installation plan needs to be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0032] Figure 1 A flowchart of a method for selecting an installation position of a UHF sensor on a transformer provided in an embodiment of this specification;

[0033] Figure 2 Three views of the transformer simulation model structure provided in the embodiments of this specification;

[0034] Figure 3 Set up a schematic diagram for the location of the local discharge source;

[0035] Figure 4 This is a schematic diagram of the measurement point location of the UHF sensor;

[0036] Figure 5 The waveform diagram of the partial discharge signal detected at points 1, 5, and 9 within 0-30ns;

[0037] Figure 6 This is the signal amplitude diagram of each detection point when partial discharge occurs at point 1;

[0038] Figure 7 This is a graph showing the total score of each test point. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0040] At present, the research on UHF sensors mainly focuses on the generation mechanism, propagation characteristics and UHF partial discharge positioning methods of UHF signals. These studies cannot provide a theoretical basis for the layout of UHF sensors on transformers. Moreover, the only part of the research on the installation position of UHF sensors on transformers is mainly based on the comparison of signal strength at the measuring points, which is relatively simple and not comprehensive enough. The present invention determines the selection of the sensor installation position by comprehensively scoring the detection performance of the UHF sensor installation measuring points on the basis of comparing the signal strength, and specifically includes the following steps:

[0041] Step 1: Model the transformer in the simulation software, and divide the box detection point area and the location inside the transformer where partial discharge is likely to occur according to the transformer model.

[0042] Step 2: Perform simulation in the software to obtain the waveform of the ultra-high frequency signal received at each detection point on the box when partial discharge occurs at different positions.

[0043] Step 3: Extract the maximum amplitude of the electromagnetic wave signal detected by the sensor at each measuring point from the simulated UHF signal, then normalize the maximum amplitude data of each detection point, and then select the detection point with the larger amplitude. Finally, compare the detection points with larger amplitudes corresponding to all partial discharge points. The detection points with larger amplitudes at multiple partial discharge points are the recommended locations for installing UHF sensors.

[0044] Step 4: multiply the normalized value in step 3 by 100 to obtain the value obtained as the score of the sensitivity of the detection point to detect electromagnetic wave signals when partial discharge occurs at the corresponding partial discharge point. Add the scores of each detection point when partial discharge occurs at different partial discharge points to obtain the total score, compare the total scores of different measurement points, and select the detection point with the higher total score.

[0045] Step 5: Compare the test points selected in step 3 and step 4. The overlapping test points are the most suitable locations for installing UHF sensors. Sensor installation plans for different safety performance requirements can be formulated based on the scores of the selected test points.

[0046] The technical solutions provided by various embodiments of the present application are described in detail below in conjunction with the accompanying drawings.

[0047] Figure 1 A schematic flow chart of a method for selecting an installation position of a UHF sensor on a transformer provided in an embodiment of this specification.

[0048] like Figure 1 As shown, the process may include the following steps:

[0049] Step 102: constructing a transformer model in simulation software, and dividing the detection point locations and the locations of the local discharge points inside the transformer according to the transformer model;

[0050] Step 104: performing simulation in simulation software to obtain the waveform of the ultra-high frequency signal received by each detection point when partial discharge occurs at different positions;

[0051] Step 106: extracting the maximum amplitude of the electromagnetic wave signal detected by each sensor at each detection point from the UHF signal waveform, and determining a detection point set according to the maximum amplitude, wherein the maximum amplitude of the detection point in the detection point set is greater than a first preset value;

[0052] Step 108: Determine a first detection point from the detection point set where the amplitudes of electromagnetic wave signals at multiple local discharge points are all greater than a second preset value, and the position corresponding to the first detection point is the position where the UHF sensor is installed.

[0053] Optionally, the method further includes: normalizing the maximum amplitude data of each detection point, and determining a detection point set according to the normalized value.

[0054] Optionally, the method further includes:

[0055] The value obtained by multiplying the normalized value by 100 is defined as the score of the sensitivity of the detection point in detecting the electromagnetic wave signal when a local discharge occurs at the corresponding local discharge point;

[0056] The total score is obtained by adding up the scores of each detection point corresponding to the occurrence of partial discharge at different partial discharge points;

[0057] The sum totals of the scores of different detection points are compared, and a second detection point whose sum total of the scores is greater than a third preset value is selected.

[0058] Optionally, the method further includes:

[0059] Determine the detection point position where the first detection point and the second detection point overlap as the position where the UHF sensor is installed.

[0060] Optionally, the method further includes: specifying sensor installation schemes with different safety performance requirements according to the sum of the scores of each detection point.

[0061] Optionally, the transformer model is a box structure, including an iron core, a high-voltage winding and a low-voltage winding, the iron core includes a plurality of silicon steel sheets, and the high-voltage winding and the low-voltage winding are equivalent to 10 disks respectively.

[0062] Optionally, the locations of the local discharge points include: between the A-phase high-voltage winding and the A-phase low-voltage winding, between the A-phase low-voltage winding and the iron core, between the A-phase high-voltage winding and the B-phase high-voltage winding, between the B-phase high-voltage winding and the B-phase low-voltage winding, and between the B-phase low-voltage winding and the iron core.

[0063] Optionally, during the simulation process, a Gaussian pulse signal is selected as the discharge signal.

[0064] Based on the above method, an embodiment of this specification provides a system for selecting an installation position of a UHF sensor on a transformer, including:

[0065] A model building module is used to build a transformer model in the simulation software, and divide the detection point location and the location of the local discharge point inside the transformer according to the transformer model;

[0066] A simulation module is used to perform simulation in the simulation software to obtain the waveform of the ultra-high frequency signal received by each detection point when partial discharge occurs at different positions;

[0067] A detection point set determination module, used to extract the maximum amplitude of the electromagnetic wave signal detected by each sensor at each detection point from the UHF signal waveform, and determine the detection point set according to the maximum amplitude, wherein the maximum amplitude of the detection point in the detection point set is greater than a first preset value;

[0068] The position determination module is used to determine a first detection point from the detection point set where the amplitudes of electromagnetic wave signals at multiple local discharge points are all greater than a second preset value, and the position corresponding to the first detection point is the position where the ultra-high frequency sensor is installed.

[0069] Optionally, the system further includes:

[0070] The normalization module is used to normalize the maximum amplitude data of each detection point.

[0071] based on Figure 1 The method, the embodiments of this specification also provide some specific implementation methods of the method, which are described below.

[0072] 1. Modeling:

[0073] This solution models a 110kV / 35kV three-phase transformer. In order to balance the simulation calculation time and calculation accuracy, the transformer model is simplified as follows:

[0074] (1) Simplify the box structure and make it equivalent to a rectangular parallelepiped.

[0075] (2) Ignore the influence of insulating paper. Insulating paper has little effect on the propagation of electromagnetic waves, but it will greatly increase the complexity of the calculation.

[0076] (3) Simplify the winding structure. In the transformer, the winding is composed of flat copper wire. Considering that electromagnetic waves cannot propagate through metal, in the simulation model, the winding is simplified to a ring with the same size as the transformer.

[0077] (4) Ignore small structures such as tap changers and leads.

[0078] Finally, this patent constructed a three-phase transformer model with a size of 310cm×148cm×210cm, which includes an iron core, a high-voltage winding, and a low-voltage winding. The iron core is composed of multiple silicon steel sheets, and considering the gaps between the windings, the high-voltage winding and the low-voltage winding are equivalent to 10 discs. The schematic diagram of the transformer simulation model is as follows Figure 2 shown.

[0079] 2. Setting of the location of the local discharge source and the location of the UHF sensor measurement point:

[0080] Figure 3 The schematic diagram of the local discharge source location is shown in Figure 1. Considering the symmetrical structure of the transformer, the local discharge source locations are selected as follows: (a) between the high-voltage and low-voltage windings of phase A (points 1, 2, and 3); (b) between the low-voltage winding of phase A and the iron core (points 4, 5, and 6); (c) between the high-voltage windings of phase A and phase B (point 7); (d) between the high-voltage and low-voltage windings of phase B (points 8 and 9); (e) between the low-voltage winding of phase B and the iron core (points 10 and 11). In addition, these eleven locations are divided into two upper and lower locations in the vertical space, totaling 22 local discharge locations.

[0081] In order to obtain the influence of the sensor installation position on the detection signal sensitivity during the propagation of UHF signals under different discharge source positions, a Gaussian pulse signal was selected as the discharge signal during the simulation process. 44 signal detection points were set on the front, back, two sides and top of the transformer, and the UHF signal waveform and signal amplitude at each detection point that changed with time were compared and analyzed. The specific distribution of the UHF sensor measurement points is as follows: Figure 4 shown.

[0082] 3. Signal strength simulation at measuring point

[0083] Inside the transformer, the insulating oil, insulating cardboard and other structures do not affect the propagation of electromagnetic wave signals, but the iron core and winding coils are made of metal materials, and the ultra-high frequency electromagnetic waves generated by partial discharge often have to go through multiple refractions and reflections before reaching the sensor installed on the box wall. In this process, high-frequency electromagnetic waves with complex frequency components are formed, and the electromagnetic wave energy and electromagnetic field amplitude at various locations in the transformer are different.

[0084] By performing simulation calculations in the simulation software, it is possible to obtain the signal strength detected by each of the 44 detection points when partial discharge occurs at the 22 partial discharge points. Figure 5 The figure shows the change of electric field strength over time at detection points 1, 5 and 9 when partial discharge occurs at point 1, and the detection results are normalized with the maximum value of the detected signal as the standard. It can be seen from the figure that the partial discharge signal is detected at points 1 and 5 at about 3ns, and the signal amplitude is strong. The partial discharge signal is detected at point 9 at 7ns, and the signal amplitude is low.

[0085] The partial discharge source is set at point 1 between the high-voltage winding and the low-voltage winding of the A-phase winding, and the maximum amplitude of the electromagnetic wave signal detected by the sensor at each measuring point is extracted and normalized, and the following can be obtained: Figure 6 The results are shown. Figure 6 It can be seen that when the release occurred at point No. 1, the signal amplitudes detected by detection points in areas No. 1, 2, 5, 13, 17, 18, 25, 26, 27, 28, 37, and 41 were above 60% after normalization, which was higher than that of other detection points.

[0086] The partial discharge sources are placed at the other 21 positions respectively, and the corresponding data are processed according to the above steps, and finally the detection points with normalized signal amplitudes above 60% when partial discharge occurs at different positions can be obtained as shown in Table 1. In addition, it can be seen from Table 1 that the normalized values ​​of the five detection points No. 2, No. 5, No. 6, No. 9, and No. 10 at more than ten partial discharge point positions exceed 60%, that is, these five detection points are more suitable for installing UHF sensors.

[0087] Table 1 Detection points with higher amplitude under partial discharge sources at different locations

[0088]

[0089] IV. Comprehensive score of each testing point

[0090] The partial discharge source is set at a position. At this time, the maximum amplitude of the electromagnetic wave signal detected at each detection point is normalized (i.e., the normalized value in step 3) and multiplied by 100 to obtain the value obtained as the sensitivity score of the electromagnetic wave signal detected by the detection point when partial discharge occurs at the corresponding partial discharge point. The comprehensive score of each detection point can be obtained by adding up the scores of each detection point at each partial discharge point, such as Figure 7 As shown. Figure 7 It can be seen that the testing points in areas 2, 5, 6, 10, 18, 29 and 30 have higher scores.

[0091] In step 3, five positions are obtained, namely, No. 2, No. 5, No. 6, No. 9, and No. 10. In step 4, seven positions are obtained, namely, No. 2, No. 5, No. 6, No. 10, No. 18, No. 29, and No. 30. In general, it is easier to detect UHF signals by installing sensors at the four positions No. 2, No. 5, No. 6, and No. 10 on the front of the transformer. Moreover, it can be seen from steps 3 and 4 that No. 6 has a higher sensitivity than the other three positions. At the same time, it should also be considered that the positions of the 22 partial discharge sources are concentrated in the lower left of the XY plane of the transformer, and no partial discharge sources are set at other positions, and the transformer is symmetrical. Therefore, installing UHF sensors in the No. 2, No. 3, No. 5, No. 6, No. 7, No. 8, No. 10, No. 11, No. 14, No. 15, No. 17, No. 18, No. 19, No. 20, No. 22, and No. 23 areas of the transformer has a higher sensitivity for partial discharge detection, among which the sensitivity of the four areas No. 6, No. 7, No. 18, and No. 19 is the highest. Therefore, for this transformer, it is recommended to install the UHF sensor at positions 6, 7, 18, and 19.

[0092] V. Conclusion

[0093] This solution uses a 110kV / 35kV three-phase transformer as an example to analyze and obtain a reasonable sensor installation position, proving that the UHF sensor installation position selection strategy provided by this patent can effectively guide the selection of the actual transformer UHF sensor installation position. In addition, in addition to providing installation suggestions for transformers that do not have UHF sensors installed, the installation position selection strategy of this patent can also evaluate the installation plan of transformers that have already installed UHF sensors, and use the scoring system of this patent to score the existing installation plan, so as to make suggestions on whether the installation plan needs to be improved.

[0094] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0095] The present application may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules may be located in local and remote computer storage media, including storage devices.

[0096] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0097] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for selecting an installation position of a UHF sensor on a transformer, characterized in that: include: Constructing a transformer model in the simulation software, and dividing the detection point locations and the locations of the local discharge points inside the transformer according to the transformer model; Perform simulation in simulation software to obtain the waveform of the UHF signal received by each detection point when partial discharge occurs at different positions; Extracting the maximum amplitude of the electromagnetic wave signal detected by each sensor at each detection point from the UHF signal waveform, determining a detection point set according to the maximum amplitude, wherein the maximum amplitude of the detection point in the detection point set is greater than a first preset value; Determine, from the detection point set, a first detection point at which the amplitudes of electromagnetic wave signals at multiple local discharge points are all greater than a second preset value, wherein the position corresponding to the first detection point is the position at which the UHF sensor is installed; Normalize the maximum amplitude data of each detection point, and determine the detection point set according to the normalized value; The value obtained by multiplying the normalized value by 100 is defined as the score of the sensitivity of the detection point in detecting the electromagnetic wave signal when a local discharge occurs at the corresponding local discharge point; The total score is obtained by adding up the scores of each detection point corresponding to the occurrence of partial discharge at different partial discharge points; Compare the sum of the scores of different detection points, and select a second detection point whose sum of the scores is greater than a third preset value; Determine the detection point position where the first detection point and the second detection point overlap as the position where the UHF sensor is installed.

2. The method according to claim 1, characterized in that The method further comprises: specifying sensor installation schemes with different safety performance requirements according to the sum of the scores of each detection point.

3. The method according to claim 1, characterized in that The transformer model is a box structure, including an iron core, a high-voltage winding and a low-voltage winding. The iron core includes a plurality of silicon steel sheets, and the high-voltage winding and the low-voltage winding are equivalent to 10 disks respectively.

4. The method according to claim 1, characterized in that The locations of the local discharge points include: between the A-phase high-voltage winding and the A-phase low-voltage winding, between the A-phase low-voltage winding and the iron core, between the A-phase high-voltage winding and the B-phase high-voltage winding, between the B-phase high-voltage winding and the B-phase low-voltage winding, and between the B-phase low-voltage winding and the iron core.

5. The method according to claim 1, characterized in that During the simulation, a Gaussian pulse signal is selected as the discharge signal.

6. A system for selecting an installation position of a UHF sensor on a transformer, characterized in that: include: A model building module is used to build a transformer model in the simulation software, and divide the detection point location and the location of the local discharge point inside the transformer according to the transformer model; A simulation module is used to perform simulation in the simulation software to obtain the waveform of the ultra-high frequency signal received by each detection point when partial discharge occurs at different positions; A detection point set determination module, used to extract the maximum amplitude of the electromagnetic wave signal detected by each sensor at each detection point from the UHF signal waveform, and determine the detection point set according to the maximum amplitude, wherein the maximum amplitude of the detection point in the detection point set is greater than a first preset value; A position determination module, used to determine, from the detection point set, a first detection point at which the amplitudes of electromagnetic wave signals at multiple local discharge points are all greater than a second preset value, wherein the position corresponding to the first detection point is a position at which a UHF sensor is installed; A normalization module is used to normalize the maximum amplitude data of each detection point, and determine a detection point set according to the normalized value, multiply the normalized value by 100 to obtain a value as the score of the detection point's sensitivity to detecting electromagnetic wave signals when local discharge occurs at the corresponding local discharge point, add the scores of each detection point when local discharge occurs at different local discharge points to obtain a total score, compare the total scores of different detection points, select a second detection point whose total score is greater than a third preset value, and determine that the detection point position where the first detection point and the second detection point overlap is the position where the ultra-high frequency sensor is installed.

Images