A porcelain insulator degradation identification method based on multi-measuring-position axial electric field

Abstract

The application provides a porcelain insulator deterioration identification method based on a multi-measuring-position axial electric field, comprising: acquiring an axial electric field intensity sequence of each porcelain insulator piece at a corresponding measuring position; preprocessing the axial electric field intensity sequence to generate a multi-measuring-position normalized axial electric field intensity sequence; determining a local electric field reconstruction coefficient of each porcelain insulator piece based on the multi-measuring-position normalized axial electric field intensity sequence; determining a candidate deteriorated porcelain insulator piece based on the local electric field reconstruction coefficient; and determining a deteriorated porcelain insulator piece based on the candidate deteriorated porcelain insulator piece. The method provided in the application uses the local electric field redistribution rule generated by the deterioration of a single porcelain insulator piece relative to adjacent pieces for identification, improves the pertinence of abnormal piece position identification, and simultaneously combines the response results of multiple measuring positions on the same piece position for collaborative determination to reduce the misjudgment probability caused by environmental disturbance, measurement deviation or local accidental fluctuation at a single measuring position.

Description

Technical Field

[0001] This application relates to the field of power equipment condition monitoring and fault diagnosis technology, and in particular to a method for identifying the deterioration of porcelain insulators based on multi-position axial electric field. Background Technology

[0002] As a key insulating component in overhead transmission lines, porcelain insulator sheets are subject to various factors such as voltage fluctuations, environmental pollution, temperature and humidity changes, and mechanical stress during long-term operation. This causes their internal insulation performance to gradually deteriorate, resulting in low-value or zero-value insulators. If deteriorated porcelain insulator sheets are not detected and replaced in a timely manner, they can easily lead to flashover, tripping, or even line faults, posing a serious threat to the safe and stable operation of the power system.

[0003] Existing methods for detecting the deterioration of porcelain insulator sheets include manual inspection, infrared imaging, ultraviolet imaging, leakage current detection, and electric field detection. Among these, electric field-based detection methods have been widely studied because they can achieve non-contact detection under energized conditions. These techniques typically measure the spatial electric field strength or electric field distribution characteristics around the insulator and compare the measurement results with preset thresholds to determine whether the porcelain insulator sheet has deteriorated. However, these methods generally have the following shortcomings: they often rely on fixed thresholds or empirical rules for judgment, making it difficult to adapt to different operating conditions, different models, and different installation locations of porcelain insulator sheets; they only utilize a single electric field strength index, failing to fully explore the multi-dimensional characteristic information contained in the electric field data; and they are sensitive to environmental changes and voltage fluctuations, easily leading to misjudgments or missed judgments. Summary of the Invention

[0004] This application provides a method for identifying the degradation of porcelain insulators based on multi-position axial electric field. To solve the above-mentioned technical problems, this application adopts the following technical method:

[0005] This application provides a method for identifying the degradation of porcelain insulators based on multi-position axial electric field, including:

[0006] Obtain the axial electric field intensity sequence of each porcelain insulator sheet at the corresponding measurement position;

[0007] The axial electric field intensity sequence is preprocessed to generate a multi-measurement normalized axial electric field intensity sequence;

[0008] Based on the multi-measurement normalized axial electric field intensity sequence, the local electric field reconstruction coefficient of each ceramic insulator sheet is determined;

[0009] Based on the local electric field reconstruction coefficient, candidate degraded porcelain insulator sheets are determined;

[0010] Based on the candidate deteriorated porcelain insulator pieces, the deteriorated porcelain insulator pieces are determined.

[0011] Optionally, the step of obtaining the axial electric field intensity sequence of each ceramic insulator sheet at the corresponding measurement position includes:

[0012] Under the operating conditions of the transmission line, the axial electric field strength value of each porcelain insulator is collected piece by piece along the axis of the insulator string at at least two different measurement positions on the shed of the porcelain insulator sheet.

[0013] Based on the axial electric field strength values ​​of each porcelain insulator piece, a sequence of axial electric field strengths for each porcelain insulator piece at the corresponding measurement position is constructed.

[0014] Optionally, the preprocessing of the axial electric field intensity sequence to generate a multi-measurement normalized axial electric field intensity sequence includes:

[0015] The axial electric field intensity sequence is cleaned and normalized to generate a multi-measurement normalized axial electric field intensity sequence.

[0016] Optionally, the multi-measurement normalized axial electric field intensity sequence includes the normalized axial electric field intensity sequence of the current porcelain insulator, the normalized axial electric field intensity sequence of the previous porcelain insulator adjacent to the current porcelain insulator, and the normalized axial electric field intensity sequence of the next porcelain insulator adjacent to the current porcelain insulator; determining the local electric field reconstruction coefficient of each porcelain insulator based on the multi-measurement normalized axial electric field intensity sequence includes:

[0017] Based on the normalized axial electric field intensity sequence of the current porcelain insulator piece, the normalized axial electric field intensity sequence of the previous porcelain insulator piece adjacent to the current porcelain insulator piece, and the normalized axial electric field intensity sequence of the next porcelain insulator piece adjacent to the current porcelain insulator piece, the local electric field reconstruction coefficient of the current porcelain insulator piece is determined.

[0018] Based on the local electric field reconstruction coefficient of the current porcelain insulator sheet, the local electric field reconstruction coefficient of each porcelain insulator sheet is determined.

[0019] Optionally, the step of determining candidate degraded porcelain insulator sheets based on the local electric field reconstruction coefficient includes:

[0020] Obtain the threshold value of the local electric field reconstruction coefficient;

[0021] Determine whether the local electric field reconstruction coefficient is less than the local electric field reconstruction coefficient threshold;

[0022] If so, the current porcelain insulator piece is taken as a candidate deteriorated porcelain insulator piece at the corresponding measurement position.

[0023] Optionally, determining the deteriorated porcelain insulator based on the candidate deteriorated porcelain insulator discs includes:

[0024] Obtain the number of measurement locations and the total number of measurement locations for the current candidate deteriorated porcelain insulator pieces that satisfy the local electric field reconstruction anomaly criterion;

[0025] Based on the number of measurement locations and the total number of measurement locations, calculate the multi-measurement cooperative response coefficient of the current candidate deteriorated porcelain insulator piece;

[0026] Obtain the threshold value of the multi-measurement coordinated response coefficient;

[0027] Determine whether the multi-measurement coordinated response coefficient is less than the multi-measurement coordinated response coefficient threshold;

[0028] If so, the current candidate deteriorated porcelain insulator sheet will be designated as the deteriorated porcelain insulator sheet.

[0029] Optionally, the step of determining deteriorated porcelain insulators based on the candidate deteriorated porcelain insulators includes the following:

[0030] Based on the mapping relationship between axial electric field strength and distributed voltage of porcelain insulator, the axial electric field strength value of the current deteriorated porcelain insulator piece is converted into the estimated value of the distributed voltage at the corresponding piece position.

[0031] Obtain the reference distributed voltage;

[0032] Based on the estimated distributed voltage and the reference distributed voltage, the degradation level index of the current deteriorated porcelain insulator is determined.

[0033] This application has the following beneficial effects:

[0034] The method proposed in this application utilizes the local electric field redistribution law generated by a single porcelain insulator relative to adjacent pieces after its deterioration to improve the targeting of abnormal piece identification. At the same time, it combines the response results of multiple measurement positions to the same piece position for collaborative judgment, reducing the probability of misjudgment caused by environmental disturbances, measurement deviations or local random fluctuations under a single measurement position. Attached Figure Description

[0035] Figure 1 A flowchart illustrating a method for identifying the degradation of porcelain insulators based on multi-position axial electric field, provided for an embodiment of this application;

[0036] Figure 2 This is a schematic diagram of multi-position axial electric field strength acquisition for porcelain insulator strings of transmission lines provided in an embodiment of this application;

[0037] Figure 3 A schematic diagram of the normalized axial electric field distribution curve provided in the embodiments of this application. Detailed Implementation

[0038] To facilitate understanding by those skilled in the art, the present application will be further described below in conjunction with embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present application.

[0039] To solve the above technical problems, such as Figure 1 As shown, this application proposes a method for identifying the degradation of porcelain insulators based on multi-position axial electric fields, including:

[0040] Step S101: Obtain the axial electric field intensity sequence of each porcelain insulator sheet at the corresponding measurement position;

[0041] Using a non-contact electric field measurement device, under the operating conditions of the transmission line, the axial electric field intensity values ​​of each porcelain insulator sheet are collected sequentially along the insulator string axis at at least two different measurement positions on the sheds of the porcelain insulator sheet. The collected axial electric field intensity values ​​are as follows: Figure 2 As shown. The measurement positions here include two or three of the following: the bottom end of the shed, the outermost edge of the shed, and the top end of the shed. Then, according to the spatial order of the porcelain insulator discs in the insulator string, and based on the axial electric field strength value of each porcelain insulator disc, an axial electric field strength sequence Ep(i) can be constructed for each porcelain insulator disc at the corresponding measurement position, where p represents the measurement position number and i represents the porcelain insulator disc number.

[0042] Step S102: Preprocess the axial electric field intensity sequence to generate a multi-measurement normalized axial electric field intensity sequence;

[0043] The axial electric field intensity sequences collected at each measurement location were cleaned and normalized to eliminate the influence of different operating voltages and measurement conditions on the electric field amplitude, thus obtaining a multi-measurement normalized axial electric field intensity sequence.

[0044] The formula for the above normalization process is shown below:

[0045] (1)

[0046] in, Let n be the measured electric field strength of the i-th porcelain insulator at the p-th measurement location, and n be the total number of porcelain insulators. This is a sequence of normalized axial electric field intensities from multiple measurement sites.

[0047] The above-mentioned multi-measurement normalized axial electric field intensity sequence is arranged according to the porcelain insulator piece number, and can be plotted as axial electric field distribution curves at the corresponding measurement positions to assist in observing the changes in the axial electric field distribution of the porcelain insulator string. Figure 3As shown, under normal conditions, the axial electric field distribution exhibits a relatively smooth trend. When a porcelain insulator deteriorates, the axial electric field intensity at its corresponding position will decrease significantly relative to that of the adjacent porcelain insulator, thus forming obvious local troughs or abrupt changes in the normalized axial electric field distribution curve.

[0048] Step S103: Based on the multi-measurement normalized axial electric field intensity sequence, determine the local electric field reconstruction coefficient of each ceramic insulator sheet;

[0049] Based on the multi-measurement normalized axial electric field intensity sequence, the local electric field reconstruction coefficient is calculated for the i-th porcelain insulator at each measurement location. This coefficient characterizes the degree of abnormal deviation of the axial electric field intensity of this insulator relative to the average axial electric field intensity of adjacent porcelain insulators. The calculation process is as follows:

[0050] The multi-measurement normalized axial electric field intensity sequence includes the normalized axial electric field intensity sequence of the current porcelain insulator sheet. The normalized axial electric field intensity sequence of the previous porcelain insulator adjacent to the current porcelain insulator. And the normalized axial electric field intensity sequence of the next porcelain insulator adjacent to the current porcelain insulator. Therefore, the local electric field reconstruction coefficient of the i-th ceramic insulator at the p-th measurement position can be calculated as follows:

[0051] (2)

[0052] in, Let be the local electric field reconstruction coefficient of the i-th porcelain insulator at the p-th measurement position.

[0053] Then the local electric field reconstruction coefficients of each current porcelain insulator piece can be combined to obtain the local electric field reconstruction coefficient of each porcelain insulator piece.

[0054] Step S104: Based on the local electric field reconstruction coefficient, determine the candidate deteriorated porcelain insulator pieces;

[0055] At this point, a threshold for the local electric field reconstruction coefficient is obtained. This threshold can be set based on different voltage levels, the number of insulator discs in the string, and historical test data or simulation analysis results. Alternatively, it can be obtained statistically based on sample data under normal conditions. For normal porcelain insulator strings with the same voltage level, the same number of insulator discs, and the same measurement location, the local electric field reconstruction coefficient for each porcelain insulator disc is calculated, resulting in a sample set of local electric field reconstruction coefficients under normal conditions. The mean of this sample set is then further calculated. and standard deviation The threshold for the local electric field reconstruction coefficient is set as follows:

[0056] (3)

[0057] in, The threshold for the local electric field reconstruction coefficient. The mean of the normal state sample set. Let k be the standard deviation of the normal state sample set, and k be the threshold adjustment coefficient used to adjust the sensitivity of the local electric field reconstruction anomaly criterion. The value of k can be set according to historical experimental data, simulation analysis results, or target false positive rate requirements. For example, k can be 1 to 3 to balance the anomaly detection rate and false positive rate. The larger the value of k, the lower the threshold and the more stringent the anomaly judgment; the smaller the value of k, the higher the threshold and the more sensitive the anomaly judgment.

[0058] The local electric field reconstruction coefficient of the current porcelain insulator is compared with the local electric field reconstruction coefficient threshold. If the local electric field reconstruction coefficient of the current porcelain insulator is less than the local electric field reconstruction coefficient threshold, it indicates that the axial electric field of the piece has collapsed significantly relative to the average level of the neighborhood. It can be judged as a local electric field reconstruction anomaly. The current porcelain insulator is preliminarily judged as a candidate deteriorated porcelain insulator at the corresponding measurement position.

[0059] Step S105: Based on the candidate deteriorated porcelain insulator pieces, determine the deteriorated porcelain insulator pieces.

[0060] Based on the above-mentioned candidate deteriorated porcelain insulator discs, the corresponding multi-measurement coordinated response coefficients were calculated at different measurement positions of the porcelain insulator disc skirts. The multi-measurement coordinated response coefficients are used to characterize the consistency of the abnormal response of the same porcelain insulator disc at different measurement positions. The calculation process is as follows:

[0061] Obtain the number of measurement locations of the current candidate deteriorated porcelain insulator pieces that satisfy the local electric field reconstruction anomaly criterion. And the total number of measurement locations M, and then based on the number of measurement locations Given the total number of measurement locations M, calculate the multi-measurement coordinated response coefficient of the current candidate deteriorated porcelain insulator disc, as shown in the following formula:

[0062] (4)

[0063] in, Let be the multi-position coordinated response coefficient of the i-th porcelain insulator piece.

[0064] At this point, the threshold for the multi-measurement cooperative response coefficient is obtained. This threshold can be set according to the total number of measurement locations and the error rate requirements of the engineering application. When the total number of measurement locations is large, the threshold can be appropriately increased based on historical experimental data, simulation analysis results, or target error rate requirements to enhance the reliability of identifying degraded locations. For the case where the total number of measurement locations is M, when the number of measurement locations that meet the local electric field reconstruction anomaly criterion is not less than 2, the threshold for the multi-measurement cooperative response coefficient can be... Set as:

[0065] (5)

[0066] The threshold of the multi-measurement coordinated response coefficient is compared with the multi-measurement coordinated response coefficient. When the multi-measurement coordinated response coefficient of the current candidate deteriorated porcelain insulator is... ≥ This indicates that the abnormal position of the insulator is not a single, occasional fluctuation, but a collective response caused by the deterioration of the porcelain insulator. The current candidate deteriorated porcelain insulator is then identified as a deteriorated porcelain insulator.

[0067] After identifying the aforementioned deteriorated porcelain insulator segments, the pre-established mapping relationship between axial electric field strength and distributed voltage of the porcelain insulator is invoked to convert the axial electric field strength value of the current deteriorated porcelain insulator segment into an estimated distributed voltage value for the corresponding segment location. Therefore, the estimated value of the distributed voltage Reference distributed voltage at the same voltage level and chip position under normal conditions By comparison, the degradation degree index of the current deteriorated porcelain insulator discs can be obtained. :

[0068] (6)

[0069] The parameter K ranges from [0,1]. When K is closer to 0, it indicates that the insulator is more severely degraded; when K is closer to 1, it indicates that the insulator is closer to normal.

[0070] After calculating all the above results, the deterioration status, deterioration piece number, and corresponding deterioration degree index of the porcelain insulator can be output.

[0071] In summary, the method proposed in this application utilizes the local electric field redistribution pattern generated by a single porcelain insulator after deterioration relative to adjacent pieces for identification, thereby improving the targeting of abnormal piece location identification. At the same time, it combines the response results of multiple measurement positions to the same piece location for collaborative judgment, reducing the probability of misjudgment caused by environmental disturbances, measurement deviations, or local random fluctuations under single measurement positions. Furthermore, based on the identification of deteriorated piece locations, it further realizes the quantitative assessment of the degree of deterioration based on the electric field-voltage mapping relationship, and can simultaneously obtain information on the deterioration state, deteriorated piece number, and degree of deterioration.

[0072] In some embodiments, this application also provides a computer system including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0073] This application also provides a computer-readable storage medium for storing a computer program. This computer-readable storage medium can be applied to a computer device, and the computer program causes the computer device to execute the corresponding processes in the methods described above in the embodiments of this application; for brevity, further details are omitted here.

[0074] The above embodiments are preferred implementations of this application. In addition, this application can be implemented in other ways. Any obvious substitutions without departing from the concept of this technical solution are within the protection scope of this application.

[0075] To facilitate understanding by those skilled in the art of the improvements made by this application compared to the prior art, some of the accompanying drawings and descriptions have been simplified, and for clarity, some other elements have been omitted from this application. Those skilled in the art should realize that these omitted elements may also constitute the content of this application.

Claims

1. A method for identifying the degradation of porcelain insulators based on multi-position axial electric field, characterized in that, include: Obtain the axial electric field intensity sequence of each porcelain insulator sheet at the corresponding measurement position; the corresponding measurement position includes two or three of the following: the bottom end position of the porcelain insulator sheet skirt, the outermost edge position of the skirt, and the top end position of the skirt; The axial electric field intensity sequence is preprocessed to generate a multi-measurement normalized axial electric field intensity sequence; the multi-measurement normalized axial electric field intensity sequence includes the normalized axial electric field intensity sequence of the current porcelain insulator, the normalized axial electric field intensity sequence of the previous porcelain insulator adjacent to the current porcelain insulator, and the normalized axial electric field intensity sequence of the next porcelain insulator adjacent to the current porcelain insulator. Based on the normalized axial electric field intensity sequence of the current porcelain insulator piece, the normalized axial electric field intensity sequence of the previous porcelain insulator piece adjacent to the current porcelain insulator piece, and the normalized axial electric field intensity sequence of the next porcelain insulator piece adjacent to the current porcelain insulator piece, the local electric field reconstruction coefficient of the current porcelain insulator piece is determined: ； In the formula, Let be the local electric field reconstruction coefficient of the i-th ceramic insulator at the p-th measurement position. The normalized axial electric field intensity sequence of the current porcelain insulator sheet, This is the normalized axial electric field intensity sequence of the previous porcelain insulator adjacent to the current porcelain insulator. This is the normalized axial electric field intensity sequence of the next porcelain insulator adjacent to the current porcelain insulator. Based on the local electric field reconstruction coefficient of the current porcelain insulator sheet, the local electric field reconstruction coefficient of each porcelain insulator sheet is determined. Based on the local electric field reconstruction coefficient, candidate degraded porcelain insulator sheets are determined; Obtain the number of measurement locations and the total number of measurement locations for the current candidate deteriorated porcelain insulator pieces that satisfy the local electric field reconstruction anomaly criterion; Based on the number of measurement locations and the total number of measurement locations, calculate the multi-measurement cooperative response coefficient of the current candidate deteriorated porcelain insulator piece; Obtain the threshold value of the multi-measurement coordinated response coefficient; Determine whether the multi-measurement coordinated response coefficient is less than the multi-measurement coordinated response coefficient threshold; If so, the current candidate deteriorated porcelain insulator sheet will be designated as the deteriorated porcelain insulator sheet.

2. The method according to claim 1, characterized in that, Prior to the step of obtaining the axial electric field intensity sequence of each ceramic insulator sheet at the corresponding measurement position, the following steps are included: Under the operating conditions of the transmission line, the axial electric field strength value of each porcelain insulator is collected piece by piece along the axis of the insulator string at at least two different measurement positions on the shed of the porcelain insulator sheet. Based on the axial electric field strength values ​​of each porcelain insulator piece, a sequence of axial electric field strengths for each porcelain insulator piece at the corresponding measurement position is constructed.

3. The method according to claim 2, characterized in that, The preprocessing of the axial electric field intensity sequence to generate a multi-measurement normalized axial electric field intensity sequence includes: The axial electric field intensity sequence is cleaned and normalized to generate a multi-measurement normalized axial electric field intensity sequence.

4. The method according to claim 3, characterized in that, The step of determining candidate degraded porcelain insulator sheets based on the local electric field reconstruction coefficient includes: Obtain the threshold value of the local electric field reconstruction coefficient; Determine whether the local electric field reconstruction coefficient is less than the local electric field reconstruction coefficient threshold; If so, the current porcelain insulator piece is taken as a candidate deteriorated porcelain insulator piece at the corresponding measurement position.

5. The method according to claim 1, characterized in that, The step of determining the deteriorated porcelain insulator based on the candidate deteriorated porcelain insulator discs includes: Based on the mapping relationship between axial electric field strength and distributed voltage of porcelain insulator, the axial electric field strength value of the current deteriorated porcelain insulator piece is converted into the estimated value of the distributed voltage at the corresponding piece position. Obtain the reference distributed voltage; Based on the estimated distributed voltage and the reference distributed voltage, the degradation level index of the current deteriorated porcelain insulator is determined.

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