A large hydro-generator partial discharge ultra-high frequency detection sensor arrangement method

Abstract

The present application relates to the technical field of power equipment detection and fault diagnosis, and discloses a large hydro-generator partial discharge ultra-high frequency detection sensor arrangement method, comprising the following steps: arranging candidate points in a preset interval in the area above the outgoing line end of the stator bar of the hydro-generator and the area on the side of the outgoing slot, respectively denoted as a first area and a second area; calculating the core evaluation indexes of each candidate point; normalizing the core evaluation indexes of each candidate point; determining the final dynamic weight of the core evaluation indexes based on the dynamic weight distribution mechanism of the entropy weight method objective weighting method; and weighting and comprehensively scoring each candidate point according to the final dynamic weight, and evaluating the advantages and disadvantages of the partial discharge ultra-high frequency detection applicability of all candidate points in descending order of comprehensive score. The present application aims to solve the technical problem that the existing monitoring method is difficult to comprehensively reflect the anti-interference ability and long-term stability of the sensor under actual working conditions.

Description

Technical Field

[0001] This invention relates to the field of power equipment testing and fault diagnosis technology, specifically to a method for arranging ultra-high frequency detection sensors for partial discharge of a large hydro-generator. Background Technology

[0002] As the core equipment of hydropower systems, large hydro-generators are prone to stator insulation aging under the combined effects of electrical, thermal, and mechanical stresses over long periods. Partial discharge is often an early sign of stator insulation aging. If not detected and addressed in time, partial discharge signals may develop into insulation breakdown, leading to serious accidents. Therefore, online monitoring of partial discharge is a crucial means of ensuring the safe operation of equipment.

[0003] However, in the actual operating environment of large hydro-generators, the complex stator bar structure and strong electromagnetic interference pose significant challenges to the optimized placement of ultra-high frequency (UHF) sensors. On the one hand, sensor installation locations are limited, requiring proximity to partial discharge sources to ensure signal strength while avoiding areas of strong interference to maintain a good signal-to-noise ratio. Simultaneously, accessibility and cost-effectiveness of on-site installation must be considered, making it difficult to quickly and accurately select candidate locations. On the other hand, existing sensor placement schemes rely excessively on engineering experience and lack systematic quantitative evaluation standards. Different personnel provide significantly different and highly subjective placement schemes, making it difficult to establish unified standards and ensuring reliable and consistent detection. Summary of the Invention

[0004] To address the existing problems, this invention aims to provide a method for arranging ultra-high frequency sensors for partial discharge detection in large hydro-generators. This method solves the technical problem that existing monitoring methods rely solely on one or two indicators to evaluate the merits of candidate locations, making it difficult to comprehensively reflect the sensor's anti-interference capability, long-term stability, and evaluation accuracy under actual working conditions. It also avoids the subjectivity of relying solely on engineering experience for point placement.

[0005] To achieve the above objectives, the present invention provides the following technical solution.

[0006] In a first aspect, the present invention provides a method for arranging ultra-high frequency (UHF) sensors for partial discharge detection in a large hydro-generator, comprising the following steps: Candidate points are arranged at preset intervals in the region above the stator conductor output end and the region to the side of the outlet of the hydro-generator, respectively designated as a first region and a second region; time-domain feature analysis, frequency-domain feature analysis, time-frequency joint analysis, spatial field strength uniformity calculation, and attenuation characteristic analysis are performed on the UHF signals received at each candidate point, and core evaluation indicators for each candidate point are calculated; wherein the core evaluation indicators include at least three of the following: pulse rise time, target frequency band energy proportion, wavelet entropy, field strength uniformity, and signal attenuation; the core evaluation indicators for each candidate point are normalized; the final dynamic weights of the core evaluation indicators are determined based on the entropy weight method, objective weighting method, and dynamic weight allocation mechanism; a weighted comprehensive score is applied to each candidate point according to the final dynamic weights, and the applicability of all candidate points for UHF partial discharge detection is evaluated from high to low according to the comprehensive score.

[0007] As a further improvement of the present invention, the time-domain feature analysis includes the following steps: Extract candidate point P i The electric field intensity time-domain sequence U(t) of the received ultra-high frequency signal, with its peak value U peak 10% as the starting point of the rise U 10% With its peak U peak 90% as the endpoint of the rise U 90% Find the starting point U of the ascent. 10% The corresponding time point t 10% and the endpoint of the ascent U 90% The corresponding time point t 90% And calculate the pulse rise time t r :t r =t 90% -t 10% .

[0008] As a further improvement of the present invention, the frequency domain feature analysis includes the following steps: Extract candidate point P i The power spectral density S(f) of the received UHF signal is used to calculate the concentration of UHF signal energy at candidate points within the optimal frequency band of 300MHz to 1.5GHz. : .

[0009] As a further improvement of the present invention, the time-frequency domain joint analysis includes the following steps: Using the db4 wavelet as the basis function, a 5-level wavelet decomposition is performed on the time-domain sequence U(t) of the UHF signal, yielding one low-frequency component cA5 and five high-frequency components cD1-cD5; the energy of each component is then calculated. :

[0010] Where k=0 represents the low-frequency component, and k=1-5 correspond to the high-frequency component; The number of sampling points for the k-th component. This represents the m-th sample value of the k-th component. Calculate the total energy of the six wavelet components. :

[0011] Calculate the energy proportion of each wavelet component :

[0012] And calculate wavelet entropy : .

[0013] As a further improvement of the present invention, the spatial field intensity uniformity calculation includes the following steps: taking the current candidate point P i N sampling points are uniformly selected within a certain radius centered on the target, where i is the candidate point number and N is at least 6; the peak field strength of each sampling point is extracted to obtain the peak field strength sequence. And calculate their arithmetic mean. :

[0014] Calculate the standard deviation of the field strength sequence. Then calculate the field strength uniformity U using the following formula. uni : U uni =1- /

[0015] in, The arithmetic mean of the peak electric field strength is given. The standard deviation is denoted as .

[0016] As a further improvement of the present invention, the attenuation characteristic analysis includes the following steps: Using the midpoint above the line connecting the ends of the two layers of wire rods in the first region and 100mm to the side of the slot outlet of the two slotted wire rods in the second region as reference points, calculate each candidate point P according to the following formula. i Signal attenuation of received UHF signals :

[0017] in, The peak value of the electric field intensity of the UHF signal at the reference point. This represents the peak field strength.

[0018] As a further improvement of the present invention, the step of weighting and comprehensively scoring each candidate point according to the final dynamic weight, and evaluating the applicability of all candidate points for partial discharge UHF detection according to the comprehensive score from high to low, includes the following steps: Calculate the weighted composite score :

[0019] in, The comprehensive score for the i-th candidate point takes a value in the range [0,1]. The final dynamic weight of the j-th core indicator for the i-th candidate point; The normalized value of the j-th indicator for the i-th candidate point; according to the comprehensive score Sort all valid candidate points in descending order to form a candidate point ranking table. These are considered excellent locations and should be prioritized for deployment. These are good locations and will be used as backup deployment locations; These are medium-level locations and are not recommended as primary placement locations. These are the elimination points.

[0020] As a further improvement of the present invention, after weighting and comprehensively scoring each candidate point according to the final dynamic weight, and evaluating the applicability of all candidate points for partial discharge UHF detection from high to low according to the comprehensive score, the method further includes the following steps: re-arranging candidate points at preset intervals in the area above the stator bar output end of the hydro-generator and the area to the side of the outlet, respectively denoted as the first area and the second area, and evaluating the applicability of another set of all candidate points for partial discharge UHF detection.

[0021] In a second aspect, the present invention also discloses a computer-readable storage medium storing instructions that, when executed on an electronic device, cause the electronic device to perform a method for arranging ultra-high frequency partial discharge detection sensors for a large hydro-generator as described in any one of the first aspects.

[0022] Thirdly, the present invention also discloses a computer program product containing instructions that, when the computer program product is run on an electronic device, causes the electronic device to execute a method for arranging ultra-high frequency partial discharge detection sensors for a large hydro-generator as described in any one of the first aspects.

[0023] The present invention has the following beneficial effects: This application proposes a targeted solution by conducting multi-dimensional and comprehensive feature analysis of the UHF signals received at each candidate site. This comprehensive analysis captures the core information of the signals, providing ample evidence for site evaluation. Specifically, the focus is on time-domain feature analysis, frequency-domain feature analysis, joint time-frequency domain analysis, spatial field strength uniformity calculation, and attenuation characteristic analysis. This approach uncovers the essential characteristics of the signals from different dimensions: time-domain feature analysis accurately measures the pulse rise time, clearly reflecting the dynamic changes of the signal within the time domain; frequency-domain feature analysis calculates the energy proportion of the target frequency band, clarifying the energy distribution characteristics of the signal in the frequency domain; and joint time-frequency domain analysis uses wavelet decomposition technology to calculate wavelet entropy, achieving simultaneous consideration of the signal's time-domain and frequency-domain characteristics, and providing a more comprehensive and accurate description of the signal's complexity. Through this multi-dimensional signal analysis, the signal characteristics of each candidate site can be deeply understood, providing rich and reliable support for subsequent site suitability evaluation.

[0024] In terms of the selection of evaluation indicators, this application comprehensively considers multiple aspects such as signal time domain, frequency domain, time-frequency domain, spatial distribution and attenuation characteristics, and selects at least three of the following as core evaluation indicators: pulse rise time, target frequency band energy ratio, wavelet entropy, field strength uniformity and signal attenuation. This completely changes the one-sidedness of the single indicator evaluation in the prior art and can more accurately determine whether the candidate point is suitable for UHF detection requirements.

[0025] To further enhance the scientific rigor and rationality of the assessment and address the pain point of unscientific weight allocation, this application adopts a dynamic weight allocation mechanism based on the entropy weight method and objective weighting method to determine the final dynamic weights of the core evaluation indicators. The organic combination of these two methods ensures the objectivity and scientific nature of the weight allocation and allows for dynamic adjustment of weights according to changes in actual testing conditions, truly reflecting the relative importance of each core indicator in the site evaluation. Simultaneously, the core evaluation indicators for each candidate site are normalized, transforming indicators of different dimensions and magnitudes into dimensionless values ​​with unified standards. This effectively solves the problem of incomparability between different indicators and provides an analytical basis for subsequent weighted comprehensive scoring. Attached Figure Description

[0026] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely schematic to aid in understanding the invention and are not intended to specifically limit the shapes and proportions of the components. In the drawings: Figure 1 This is a flowchart illustrating a method for arranging ultra-high frequency partial discharge detection sensors for a large hydro-generator, as provided in Embodiment 1 of this application. Figure 2 These are time-domain signal waveforms of detection point P1 in Embodiment 1 of this application; Figure 3 These are time-domain signal waveforms of detection point P2 in Embodiment 1 of this application; Figure 4 These are time-domain signal waveforms of detection point P3 in Embodiment 1 of this application; Figure 5 These are time-domain signal waveforms of detection point P4 in Embodiment 1 of this application; Figure 6 These are time-domain signal waveforms of detection point P5 in Embodiment 1 of this application; Figure 7 These are time-domain signal waveforms of detection point P6 in Embodiment 1 of this application; Figure 8 These are time-domain signal waveforms of detection point P7 in Embodiment 1 of this application; Figure 9 These are time-domain signal waveforms of detection point P8 in Embodiment 1 of this application; Figure 10 This is a flowchart illustrating a method for arranging ultra-high frequency sensors for partial discharge detection of a large hydro-generator, as provided in Embodiment 2 of this application. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0028] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is stated to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] Example 1 like Figure 1 As shown, a method for arranging ultra-high frequency sensors for partial discharge detection of a large hydro-generator includes: Step A100: The area above the stator bar output end of the hydro-generator and the area to the side of the outlet are respectively designated as the first area and the second area, and candidate points are arranged at a preset interval.

[0031] In this embodiment, the sampling interval between the first region and the second region is 100mm, generating uniform three-dimensional candidate points. Four candidate points P1-P4 are selected from the first region, and four candidate points P5-P8 are selected from the second region, resulting in an initial set of candidate points. , where n is the number of valid candidate points, and here n=8.

[0032] Step A200: Perform time-domain feature analysis, frequency-domain feature analysis, time-frequency joint analysis, spatial field strength uniformity calculation, and attenuation characteristic analysis on the UHF signals received at each candidate location, and calculate the core evaluation index for each candidate location.

[0033] In this embodiment of the application, the core evaluation indicators include five of the following: pulse rise time, target frequency band energy ratio, wavelet entropy, field strength uniformity, and signal attenuation.

[0034] Figure 2-5 Showing the UHF signals of four candidate points in the first region. Figure 6-9 The UHF signals of four candidate points in the second region are displayed. This embodiment uses point P1 in the first region as an example to evaluate the following five core characteristic indicators: The time-domain feature analysis includes the following steps: Extract candidate point P iThe electric field intensity time-domain sequence U(t) of the received ultra-high frequency signal, with its peak value U peak 10% as the starting point of the rise U 10% With its peak U peak 90% as the endpoint of the rise U 90% Find the starting point U of the ascent. 10% The corresponding time point t 10% and the endpoint of the ascent U 90% The corresponding time point t 90% And calculate the pulse rise time t r :t r =t 90% -t 10% . This indicates the rise rate of the UHF partial discharge pulse, measured in ns. The smaller the value, the faster the pulse rises, the better the sensor's response performance, and the easier it is to capture transient discharge signals.

[0035] In this embodiment of the application, candidate points within the region are extracted. UHF signal electric field intensity time-domain sequence Unit: V / m, time-domain sampling step size is .

[0036] Taking P1 as an example, Figure 2 Show the UHF signal received by P1, and then find the corresponding time point in the time-domain sequence. The corresponding time is , The corresponding time is The calculation formula is:

[0037] The frequency domain feature analysis includes the following steps: extracting candidate points P i The power spectral density S(f) of the received UHF signal is used to calculate the concentration of UHF signal energy at candidate points within the optimal frequency band of 300MHz to 1.5GHz. : .

[0038] in, It represents the degree of concentration of UHF signal energy at the candidate point within the optimal frequency band. It is dimensionless and takes the value [0,1]. The closer it is to 1, the more concentrated the signal energy is, the higher the purity of the signal, and the stronger the anti-interference ability.

[0039] Specifically, extract candidate points UHF signal power spectral density Unit: W / Hz, signal frequency band: 300MHz-3GHz, optimal frequency band: 300MHz-1.5GHz. Calculate the concentration of UHF signal energy at candidate points within the optimal frequency band using the following formula:

[0040] The joint time-frequency domain analysis includes the following steps: extracting candidate points P for each region. i Time-domain series of UHF signals The unit is V / m, and the sampling points are N=10000. The db4 wavelet is selected as the basis function, and a 5-level wavelet decomposition is performed on the time-domain sequence U(t) of the UHF signal to obtain one low-frequency component cA5 and five high-frequency components cD1-cD5; the energy of each component is calculated. :

[0041] Where k=0 represents the low-frequency component, and k=1-5 correspond to the high-frequency component; The number of sampling points for the k-th component. This represents the m-th sample value of the k-th component. Calculate the total energy of the six wavelet components. :

[0042] Calculate the energy proportion of each wavelet component :

[0043]

[0044] And calculate wavelet entropy : .

[0045] in, Wavelet entropy represents the uniformity of energy distribution after wavelet decomposition of a UHF signal, i.e., the complexity of the UHF signal. It takes a value of [0, ln6], is dimensionless, and the smaller the value, the more concentrated the signal energy is in a few wavelet components, the lower the complexity of the UHF signal, and the better the signal fidelity detected by the sensor.

[0046] Specifically, taking P1 as an example, the calculation results are shown in the table below: Table 1. Energy and energy percentage of each wavelet component of candidate point P1

[0047] The total energy, which is the sum of the energies of all wavelet components, is calculated using the following formula: Unit: (V / m) 2 The formula for calculating wavelet entropy is:

[0048] In the formula Wavelet entropy represents the uniformity of energy distribution of a UHF signal after wavelet decomposition, i.e., the complexity of the UHF signal. It takes a value of [0, ln6], ln6≈1.7918, and is dimensionless.

[0049] The calculation of the spatial field intensity uniformity includes the following steps: determining the current candidate point P. i Using this candidate point as the center, 20 sampling points are uniformly selected within a radius of 50 mm. The peak field strength of each sampling point is extracted to obtain the peak field strength sequence. And calculate their arithmetic mean. :

[0050] in, The arithmetic mean of the peak electric field strength is given. The standard deviation is denoted as .

[0051] Calculate the standard deviation of the field strength sequence. Then calculate the field strength uniformity U using the following formula. uni : U uni =1- /

[0052] in, This represents the uniformity of the field strength distribution of the candidate point within the region. It takes a value of [0,1] and is dimensionless. The closer it is to 1, the more uniform it is, indicating that the detection accuracy of the candidate point is better.

[0053] Specifically, determine the current candidate point P1, and take this candidate point as the center. Within a radius of 50 mm, select 20 sampling points evenly, i.e., N=20. Extract the field strength peak value of each sampling point to obtain the field strength peak value sequence (0.013988, 0.013794, 0.013963, 0.014169, 0.013913, 0.013840, 0.014086, 0.013938, 0.013829, 0.013918, 0.013801, 0.013807, 0.014063, 0.014083, 0.013862, 0.014143, 0.013868, 0.014062, 0.013994, 0.014167).

[0054] Calculate their arithmetic mean:

[0055] Calculate the standard deviation of this field strength sequence:

[0056] Substitute into the formula for calculating field strength uniformity:

[0057] The attenuation characteristic analysis includes the following steps: taking the midpoint above the line connecting the ends of the two layers of wire rods in the first region and 100mm to the side of the slot outlet of the two slotted wire rods in the second region as reference points, respectively, the candidate points P are calculated according to the following formula. i Signal attenuation of received UHF signals :

[0058] in, and These are the reference point and P, respectively. i The peak value of the electric field intensity of the ultra-high frequency signal, in V / m; Signal attenuation, measured in dB (decibels), represents the transmission loss of the signal from the reference point to the current candidate point. The smaller the value, the less signal attenuation, and the better the placement of the candidate point.

[0059] Specifically, the peak value U1 of the UHF signal electric field intensity at candidate point P1 is calculated relative to the reference point U. base The attenuation amount is calculated using the following formula: dB Step A300: Normalize the core evaluation indicators for each candidate point.

[0060] In this embodiment of the application, the original data of the core indicators are normalized to eliminate the dimensions of different indicators and map all indicators uniformly to the range of [0,1] to ensure that all indicators are in a unified evaluation dimension.

[0061] Positive indicator: Energy share of the target frequency band and field strength uniformity The larger the value, the better the performance. The normalized formula for the positive index is:

[0062] In the formula, The value of the j-th positive index for the i-th candidate point is normalized and takes the value [0,1]. This is the original calculated value of the indicator; The minimum value of this index for all candidate points; The maximum value of this indicator for all candidate points.

[0063] Contrarian indicator: Pulse rise time Signal attenuation index and wavelet entropy The smaller the value, the better the performance. The formula for the normalized calculation of the inverse indicator is: , In the formula, each letter represents the same meaning as the positive index. Through reverse mapping, it is ensured that the larger the normalized value, the better the performance of the corresponding original index.

[0064] Specifically, the evaluation index for the normalization of candidate point P1 is calculated as follows: Table 2. Normalized inverse indices for candidate point P1

[0065] Step A400: Determine the final dynamic weights of the core evaluation indicators based on the dynamic weight allocation mechanism of the objective weighting method and the entropy weight method.

[0066] The entropy weighting method, an objective weighting method, includes: constructing a data matrix X (n×5 matrix) based on normalized index data, where n is the number of valid candidate points, and the element in the i-th row and j-th column of X is... This represents the normalized value of the j-th indicator for the i-th candidate point, and the indicator weight is calculated. (The weight of the j-th indicator at the i-th candidate point), the formula is:

[0067] To avoid the denominator being 0, if ,but .

[0068] Specifically, , , , , .

[0069] Calculate the information entropy of the j-th indicator for the i-th candidate point. The formula is: , Calculate the difference coefficient of the j-th indicator for the i-th candidate point. The formula is: The larger the difference coefficient, the higher the distinguishability of the indicator, and the greater its weight.

[0070] Specifically, , , , , , , , , , .

[0071] Then, calculate the objective weight vector: , in, The total weight is 1.

[0072] Specifically, .

[0073] Step A500: Calculate a weighted comprehensive score for each candidate point based on the final dynamic weight, and evaluate the applicability of all candidate points for partial discharge UHF detection in descending order of comprehensive score.

[0074] In this embodiment of the application, a weighted comprehensive score is calculated. This includes the following steps:

[0075] in, The comprehensive score for the i-th candidate point takes a value in the range [0,1]. The final dynamic weight of the j-th core indicator for the i-th candidate point; is the normalized value of the j-th indicator for the i-th candidate point; the higher the comprehensive score, the more suitable the candidate point is as a sensor placement location. For P1, It is 0.915. The remaining P2-P8 are as follows: It is 0.804. It is 0.775. It is 0.713. It is 0.861. It is 0.806. It is 0.767. It is 0.694.

[0076] According to the overall score Sort all valid candidate points in descending order to form a candidate point ranking table. P1 is an excellent location and should be prioritized for deployment. P2, P5, and P6 are good locations and will be used as backup deployment locations. P3, P4, and P7 are medium-level locations and are not recommended as primary placement locations. P8 is the elimination point.

[0077] Optionally, after weighting and comprehensively scoring each candidate point according to the final dynamic weight, and evaluating the applicability of all candidate points for partial discharge UHF detection from high to low according to the comprehensive score, the method further includes: re-arranging candidate points at preset intervals in the area above the stator bar output end and the area to the side of the slot outlet of the hydro-generator, respectively denoted as the first area and the second area, and evaluating the applicability of another set of all candidate points for partial discharge UHF detection.

[0078] Example 2 This application provides a method for arranging ultra-high frequency sensors for partial discharge detection in large hydro-generators, such as... Figure 10 As shown, unlike Embodiment 1, a three-dimensional mesh is generated in the area above the stator bar output end and the area to the side of the outlet of the hydro-generator. Candidate points are selected in the three-dimensional mesh, and reference points can be set in different areas. The signal attenuation is calculated based on the reference points of each area, thereby achieving the selection of candidate points that are compatible with the structure.

[0079] Example 3 This application provides a computer-readable storage medium storing instructions. The instructions, when executed on an electronic device, cause the electronic device to perform a method for arranging ultra-high frequency partial discharge detection sensors for a large hydroelectric generator as described in Embodiment 1. The computer-readable storage medium includes, but is not limited to, USB flash drives, hard drives, portable hard drives, cloud storage under cloud technology, and even web pages (here, a web page specifically refers to a web page capable of recording the aforementioned computer program).

[0080] Example 4 This application provides a computer program product containing instructions, characterized in that, when the computer program product is run on an electronic device, the electronic device executes a method for arranging ultra-high frequency partial discharge detection sensors for a large hydro-generator as described in Embodiment 1.

[0081] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0082] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0083] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0084] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variations thereof is intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes said element.

[0085] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for arranging ultra-high frequency sensors for partial discharge detection in a large hydro-generator, characterized in that, Includes the following steps: The area above the stator bar output end of the hydro-generator and the area to the side of the outlet are respectively designated as the first area and the second area, and candidate points are arranged at a preset interval. The UHF signals received at each candidate point are subjected to time-domain feature analysis, frequency-domain feature analysis, joint time-frequency domain analysis, spatial field strength uniformity calculation, and attenuation characteristic analysis, and the core evaluation indicators for each candidate point are calculated. The core evaluation indicators include at least three of the following: pulse rise time, target frequency band energy proportion, wavelet entropy, field strength uniformity, and signal attenuation. The spatial field strength uniformity calculation includes the following steps: With the current candidate point P i N sampling points are uniformly selected within a certain radius centered on the target, where i is the candidate point number and N is at least 6; the peak field strength of each sampling point is extracted to obtain the peak field strength sequence. And calculate its arithmetic mean mean(U): Calculate the standard deviation of the peak field strength sequence, and then calculate the field strength uniformity U using the following formula. uni : U uni =1- / in, The arithmetic mean of the peak electric field strength is given. Standard deviation; The attenuation characteristic analysis includes the following steps: Using the midpoint above the line connecting the ends of the two layers of wire rods in the first region and 100mm to the side of the slot outlet of the two slotted wire rods in the second region as reference points, calculate each candidate point P according to the following formula. i Signal attenuation of received UHF signals : in, The peak value of the electric field intensity of the UHF signal at the reference point. This represents the peak field strength. The core evaluation indicators for each candidate point are normalized. Based on the entropy weight method, objective weighting method, and dynamic weight allocation mechanism, the final dynamic weights of the core evaluation indicators are determined. The candidate points are weighted and comprehensively scored according to the final dynamic weights, and the applicability of all candidate points to UHF partial discharge detection is evaluated from high to low according to the comprehensive scores. The process of weighting and comprehensively scoring each candidate point according to the final dynamic weights and evaluating the applicability of all candidate points to UHF partial discharge detection from high to low according to the comprehensive scores includes the following steps: Calculate the weighted composite score : in, The comprehensive score for the i-th candidate point takes a value in the range [0,1]. The final dynamic weight of the j-th core indicator for the i-th candidate point; Let be the normalized value of the j-th indicator for the i-th candidate point; According to the overall score Sort all valid candidate points in descending order to form a candidate point ranking table. These are considered excellent locations and should be prioritized for deployment. These are good locations and will be used as backup deployment locations; These are medium-level locations and are not recommended as primary placement locations. These are the elimination points; The joint time-frequency domain analysis includes the following steps: The db4 wavelet is selected as the basis function, and the time-domain sequence U(t) of the UHF signal is decomposed into 5-level wavelet decomposition to obtain one low-frequency component cA5 and five high-frequency components cD1-cD5. Calculate the energy of each component : Where k=0 represents the low-frequency component, and k=1-5 correspond to the high-frequency component; The number of sampling points for the k-th component. This represents the m-th sample value of the k-th component. Calculate the sum of the energy of the six wavelet components: : Calculate the energy proportion of each wavelet component : And calculate wavelet entropy : ； The time-domain feature analysis includes the following steps: Extract candidate point P i The electric field intensity time-domain sequence U(t) of the received ultra-high frequency signal, with its peak value U peak 10% as the starting point of the rise U 10% With its peak U peak 90% as the endpoint of the rise U 90% Find the starting point U of the ascent. 10% The corresponding time point t 10% and the endpoint of the ascent U 90% The corresponding time point t 90% And calculate the pulse rise time t r : t r =t 90% -t 10% 。 2. The method for arranging ultra-high frequency partial discharge detection sensors for a large hydro-generator according to claim 1, characterized in that, The frequency domain feature analysis includes the following steps: Extract candidate point P i The power spectral density S(f) of the received UHF signal is used to calculate the concentration of UHF signal energy at candidate points within the optimal frequency band of 300MHz to 1.5GHz. : 。 3. The method for arranging ultra-high frequency partial discharge detection sensors for a large hydro-generator according to claim 1, characterized in that, After weighting and comprehensively scoring each candidate point according to the final dynamic weight, and evaluating the applicability of all candidate points for partial discharge UHF detection from high to low according to the comprehensive score, the method further includes the following steps: re-arranging candidate points at preset intervals in the area above the stator bar output end of the hydro-generator and the area to the side of the outlet, respectively denoted as the first area and the second area, and evaluating the applicability of another set of all candidate points for partial discharge UHF detection.

4. A computer-readable storage medium storing instructions, characterized in that, When the instruction is executed on the electronic device, the electronic device performs a method for arranging ultra-high frequency partial discharge detection sensors for a large hydro-generator as described in any one of claims 1-3.

5. A computer program product containing instructions, characterized in that, When the computer program product runs on the electronic device, it causes the electronic device to perform a method for arranging ultra-high frequency partial discharge detection sensors for a large hydro-generator as described in any one of claims 1-3.

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