Composite insulator wear degree evaluation method and system based on multi-source information weighted fusion

Abstract

The invention discloses a composite insulator wear degree evaluation method and system based on multi-source information weighted fusion, and relates to the technical field of power equipment state monitoring. The method mainly comprises the following steps: acquiring a plurality of mechanical and electrical performance parameters representing the wind-sand erosive wear degree of the composite insulator, calculating a weight coefficient of each performance parameter by adopting an entropy weight method, and calculating a comprehensive wear index by utilizing the weight coefficients. And according to the comprehensive wear index, a wear degree grade is established, and quantitative evaluation of the wear state of the composite insulator is realized. According to the invention, the mechanical and electrical performance degradation condition of the insulator can be comprehensively reflected, and a scientific basis is provided for safe operation and maintenance decision of a power grid.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power equipment state monitoring, and particularly relates to a composite insulator wear degree evaluation method and system based on multi-source information weighted fusion. BACKGROUND

[0002] Composite insulators are widely used in various transmission lines due to their excellent anti-flashover performance. However, in the windy and sandy areas of northwest China, the composite insulators in operation are subjected to severe erosion by sand carried by strong winds for a long time, and the silicone rubber umbrella skirt and sheath material will be severely abraded and aged. This wear not only leads to material loss and surface roughening, but also deeply damages the microstructure of the composite insulator, causing simultaneous deterioration of its mechanical and electrical properties, greatly increasing the risk of mechanical fracture or insulation breakdown of the line, and posing a serious threat to the reliable operation of the power grid.

[0003] At present, the state evaluation of composite insulators after wind-sand wear mainly relies on periodic inspection and single performance test methods. These traditional methods usually include measuring the hardness of the umbrella skirt to judge the material aging degree, performing tensile or tearing tests by sampling inspection to evaluate the mechanical integrity, or testing the hydrophobicity by the water spray grading method. However, these methods have obvious limitations: first, various performance tests are usually carried out independently, and the evaluation conclusions are fragmented, lacking a unified quantitative index that can comprehensively reflect the simultaneous deterioration of mechanical and electrical properties, resulting in one-sided evaluation results that cannot fully represent the overall health status of the insulator; second, the existing evaluation seriously depends on the personal experience of engineering technicians to make subjective judgments on multiple results, lacking an objective and unified quantitative fusion model, resulting in poor consistency and low comparability of the evaluation conclusions; third, this decentralized evaluation cannot effectively predict the remaining life of the insulator, usually only issuing a warning when the performance has already declined seriously, lacking foresight and being not conducive to predictive maintenance. Therefore, developing a new method that can fuse multi-source information and quantitatively and comprehensively evaluate the wear degree of composite insulators has become a technical problem to be solved in the power industry. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art and provide a quantitative, comprehensive and objective composite insulator wear degree evaluation method. This method introduces a weight distribution algorithm to fuse multiple key mechanical and electrical performance test data into a comprehensive wear index, thereby achieving accurate evaluation and graded warning of the overall health status of the composite insulator.

[0005] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0006] The composite insulator wear degree evaluation method based on multi-source information weighted fusion comprises:

[0007] obtain multi-source performance parameter test data of the composite insulator in a sandstorm environment, the multi-source performance parameters including mechanical performance parameters and electrical performance parameters, the mechanical performance parameters at least including Shore hardness, tear strength and tensile strength, and the electrical performance parameters at least including hydrophobicity, dry flashover voltage and pollution flashover voltage;

[0008] perform normalization preprocessing on the original test values of the multi-source performance parameters to eliminate dimensional differences between different parameters, to obtain normalized parameter values;

[0009] objectively calculate weight coefficients of the performance parameters by using an entropy weight method, the entropy weight method assigning weights according to discrete degrees of the parameter test values in sample data, the greater the discrete degree, the higher the weight;

[0010] based on the normalized parameter values and the corresponding weight coefficients, calculate a comprehensive wear index by using a weighted fusion algorithm, to quantitatively represent the overall wear degree of the composite insulator;

[0011] establish a wear degree grade standard according to a numerical range of the comprehensive wear index, and grade the wear state of the composite insulator and predict the service life of the composite insulator according to the standard.

[0012] Preferably, the normalization preprocessing on the original test values of the multi-source performance parameters specifically includes the following processing process:

[0013] determine the performance representation direction of the parameters, for parameters whose test values increase to represent performance degradation, perform cost-type index normalization algorithm processing; for parameters whose test values decrease to represent performance degradation, perform benefit-type index normalization algorithm processing;

[0014] through the above processing process, the original test values of all parameters are uniformly mapped to the numerical interval of [0, 1], so as to eliminate the influence of different physical dimensions;

[0015] Preferably, the objective calculation of the weight coefficients of the performance parameters by using the entropy weight method specifically includes:

[0016] construct an original evaluation matrix composed of the performance parameter test values of a plurality of composite insulator samples, and calculate information entropy values corresponding to each column of performance parameter test values in the evaluation matrix;

[0017] further calculate difference coefficients of the parameters according to the calculated information entropy values, wherein the difference coefficients are positively correlated with the finally determined weight coefficients; finally, perform normalization processing on the difference coefficients of all parameters, to finally obtain the objective weight coefficients of the performance parameters.

[0018] Preferably, the comprehensive wear index CWI is equal to the sum of the product of the normalized value of each performance parameter and its corresponding weight coefficient, and the calculation formula is:

[0019]

[0020] Wherein CW is the final calculated comprehensive wear index, W i represents the weight coefficient of the i-th performance parameter, X i represents the value of the i-th performance parameter after normalization.

[0021] Preferably, the establishment of the wear degree grade standard embodiment is: dividing the value range of the comprehensive wear index CWI into four continuous intervals, and the four value intervals correspond to four different wear degree grades of slight wear, moderate wear, severe wear and critical failure respectively. According to the interval range of the calculated CWI value, the corresponding evaluation conclusion and maintenance strategy suggestion are output.

[0022] Preferably, the composite insulator wear degree evaluation system comprises the following functional modules: a data acquisition module specially used for acquiring and storing the multi-source performance parameter test data of the composite insulator; a data processing module responsible for normalizing the original test data; a weight calculation module using entropy weight method to calculate the objective weight coefficient of each performance parameter; a comprehensive evaluation module, the core function of which is to execute a weighted fusion algorithm, calculate a comprehensive wear index and output an evaluation result according to a preset grade standard; and a data output module used for finally displaying the comprehensive wear index, the wear grade and the maintenance suggestion.

[0023] 1. The present application provides a composite insulator wear degree evaluation method based on multi-source information weighted fusion, which introduces an objective weighting model of entropy weight method for calculating the weight coefficient of each mechanical and electrical performance parameter, overcomes the subjective randomness of traditional artificial weight setting, and makes the final comprehensive wear index calculation more scientific and reasonable.

[0024] 2. The present application integrates multiple independent performance parameter test values into a unified comprehensive wear index through a weighted fusion algorithm, realizes the comprehensive quantitative evaluation of the collaborative degradation degree of the mechanical and electrical performance of the composite insulator, effectively solves the fragmentation and one-sidedness of the conclusions of the existing evaluation methods, and provides an intuitive and reliable quantitative basis for operation and maintenance decision-making.

[0025] 3. The grading evaluation model established by the present application can accurately grade the wear state of the insulator according to the specific value of the comprehensive wear index, not only can identify the severe wear that has occurred, but also can give early warning to the early and medium performance degradation, greatly improving the forward-looking and initiative of condition-based maintenance.

[0026] 4. The method and system provided by the application comprehensively key performance parameters of composite insulators after wind and sand abrasion, and overcomes the disadvantages of traditional methods, such as dependence on personal experience, poor evaluation consistency, long test cycle and high cost, by objectively and quantitatively outputting evaluation results, thereby providing an efficient, accurate and economic solution for safe operation and maintenance of power transmission lines.

[0027] The application aims to overcome the deficiencies of the prior art and provide a quantitative, comprehensive and objective composite insulator abrasion degree evaluation method. DETAILED DESCRIPTION

[0028] The detailed description of the various exemplary embodiments of the application should not be considered as limiting the application, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the application.

[0029] The raw materials of the application are not particularly limited in source, and can be purchased on the market or prepared according to conventional methods well known to those skilled in the art.

[0030] As an embodiment of the application, a composite insulator abrasion degree evaluation method based on multi-source information weighted fusion is provided, comprising:

[0031] Step 100: obtaining multi-source performance parameter test data of composite insulators after wind and sand environment, the multi-source performance parameters including mechanical performance parameters and electrical performance parameters, the mechanical performance parameters at least including Shore hardness, tear strength and tensile strength, and the electrical performance parameters at least including hydrophobicity, dry flashover voltage and pollution flashover voltage;

[0032] Step 200: normalizing and preprocessing the original test values of the multi-source performance parameters to eliminate the dimensional differences between different parameters, to obtain normalized parameter values;

[0033] Step 300: objectively calculating the weight coefficients of each performance parameter by using an entropy weight method, the entropy weight method assigning weights according to the dispersion degree of each parameter test value in sample data, the greater the dispersion degree, the higher the weight;

[0034] Step 400: based on the normalized parameter values and corresponding weight coefficients, calculating a comprehensive abrasion index by a weighted fusion algorithm to quantitatively represent the overall abrasion degree of the composite insulator;

[0035] Step 500: establishing abrasion degree grade standards according to the numerical range of the comprehensive abrasion index, and grading the abrasion state of the composite insulator and predicting its service life according to the standards.

[0036] The steps of the embodiment are as follows:

[0037] Step one: select a composite insulator of a certain 330 kV power transmission line operated for 8 years in a strong wind-sand environment as a test sample, the product model is FXBW4-330 / 100. When sampling, representative sections should be selected from the middle section of the line, avoiding special locations such as line terminals and corners; the sampling length should contain at least 3 complete pitches to ensure the complete characteristics of the large and small sheds; and secondary damage to the surface of the insulator should be avoided during sampling. At the same time, select unused new insulators of the same batch and same type from the inventory as reference baseline samples.

[0038] Step two: test the mechanical properties of the insulator shed.

[0039] The Shore hardness (HA) test method is: using a Shore hardness tester, 10 measurement points are selected on the upper surface, lower surface and sheath of the shed, totaling 30 measurement points. When measuring, the measurement points should be evenly distributed; avoid obvious defect locations; keep the pressure needle perpendicular to the surface of the sample; measure multiple times and calculate the average value. Finally, take the arithmetic mean of all measurement points as the HA test value.

[0040] The tear strength (TS) test method is: using a universal testing machine, the standard sample specification (straight angle sample without cut, thickness 2 mm) is prepared. Test conditions: tensile speed 500 mm / min, environmental temperature (23±2) °C, relative humidity (50±5) %. Test 5 samples for each sample, and take the arithmetic mean.

[0041] The tensile strength (ULT) test method is: using the same electronic universal testing machine, according to the standard dumbbell sample preparation. Test conditions: tensile speed 500 mm / min, record the maximum tensile load. Test 5 samples for each sample, and take the arithmetic mean.

[0042] Step three: test the electrical properties of the insulator shed.

[0043] The hydrophobicity grade (HC) test method is: using the water spray grading method, using a special water spray bottle, spraying at a distance of 25 cm from the surface of the sample, and the spraying time is about 1 s. After spraying, compare with the standard pattern under standard lighting conditions to determine the grade. Test 3 times for each sample, and take the grade that occurs most frequently.

[0044] The dry flashover voltage (DFV) test is carried out in an artificial climate chamber, and the test conditions are: temperature 20°C, absolute humidity 11 g / m³, and air pressure 101.3 kPa. The applied voltage starts from zero and rises at a constant speed of about 3 kV / s until flashover occurs. Repeat the test 5 times and take the arithmetic mean.

[0045] The SFFV test method is: using solid layer method, the pollution degree is uniformly 0.1 mg / cm² (NaCl) and 0.1 mg / cm² (kaolin) mixed pollution. The wetting method is steam fog method, pre-wetting for 15 min before applying voltage. The test method is the same as dry flash voltage.

[0046] Step four, normalize the obtained test data. Set the maximum value (ideal value) and minimum value (failure threshold) of each performance parameter, wherein the maximum value adopts the test value of new insulator, and the minimum value adopts the failure threshold specified in the industry standard.

[0047] The normalization processing adopts the following formula:

[0048] For benefit-type indicators (the larger the value, the better the performance, such as HA, TS, ULT, DFV, SFFV): normalized value=(measured value-minimum value) / (maximum value-minimum value)

[0049] For cost-type indicators (the larger the value, the worse the performance, such as HC): normalized value=(maximum value-measured value) / (maximum value-minimum value)

[0050] Step five, collect the historical test data of composite insulators with different operating years (1-15 years), construct an original data matrix, and calculate the weight coefficient based on the entropy weight method.

[0051] The specific calculation method is:

[0052] First, standardize the original data matrix, and the calculation method is:

[0053]

[0054] Where x ij is the jth index value of the ith sample, and x ij is the normalized value.

[0055] Then calculate the index information entropy, and the calculation method is:

[0056]

[0057]

[0058] Where pij represents the feature proportion of the ith sample under the jth index; Ej represents the information entropy of the jth index; k=1 / ln(n), n is the number of samples;

[0059] Finally, determine the index weight, and the calculation method is:

[0060]

[0061]

[0062] wherein d j represents the difference coefficient of the jth index, w j represents the weight coefficient of the jth index finally calculated.

[0063] Step six, the comprehensive wear index (CWI) is calculated by using the weighted summation method:

[0064]

[0065] wherein x j ' is the normalized value of the jth index.

[0066] The above-described embodiments are only used to describe the preferred modes of the present application, and are not used to limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements of the technical solutions of the present application made by those skilled in the art shall fall within the protection scope defined by the claims of the present application.

Claims

1. A composite insulator wear degree evaluation method based on multi-source information weighted fusion, characterized in that, The method comprises the following steps: obtaining multi-source performance parameter test data of composite insulators in a sandstorm environment, the multi-source performance parameters including mechanical performance parameters and electrical performance parameters, the mechanical performance parameters at least including Shore hardness, tear strength and tensile strength, and the electrical performance parameters at least including hydrophobicity, dry flashover voltage and pollution flashover voltage; normalizing the original test values of the multi-source performance parameters to eliminate the dimensional differences between different parameters, to obtain normalized parameter values; objectively calculating weight coefficients of the performance parameters by using an entropy weight method, the entropy weight method assigning weights according to the discrete degrees of the parameter test values in sample data, the greater the discrete degree, the higher the weight; calculating a comprehensive wear index by using a weighted fusion algorithm based on the normalized parameter values and the corresponding weight coefficients, to quantitatively represent the overall wear degree of the composite insulator; establishing a wear degree grade standard according to the numerical range of the comprehensive wear index, and grading the wear state of the composite insulator according to the standard to make a life prediction.

2. The composite insulator wear degree evaluation method based on multi-source information weighted fusion according to claim 1, characterized in that, The step of normalizing the original test values of the multi-source performance parameters specifically comprises the following processing procedures: judging the performance representation direction of the parameters, for parameters whose performance representation direction is that the test value increases with the deterioration of the performance, a cost-type index normalization algorithm is used for processing; for parameters whose performance representation direction is that the test value decreases with the deterioration of the performance, a benefit-type index normalization algorithm is used for processing; through the above processing procedures, the original test values of all parameters are uniformly mapped to the numerical interval [0, 1], so as to eliminate the influence of different physical dimensions.

3. The composite insulator wear degree evaluation method based on multi-source information weighted fusion according to claim 1, characterized in that, The step of objectively calculating the weight coefficients of the performance parameters by using the entropy weight method specifically comprises: constructing an original evaluation matrix composed of the performance parameter test values of a plurality of composite insulator samples, and calculating the information entropy values corresponding to each column of performance parameter test values based on the evaluation matrix; further calculating the difference coefficients of the parameters according to the calculated information entropy values, wherein the difference coefficients are positively correlated with the finally determined weight coefficients; finally, the difference coefficients of all parameters are normalized to finally obtain the objective weight coefficients of the performance parameters.

4. The composite insulator wear degree evaluation method based on multi-source information weighted fusion according to claim 1, characterized in that, The comprehensive wear index CWI is equal to the sum of the products of the normalized values of the performance parameters and their corresponding weight coefficients, and the calculation formula is:

5. wherein CW is the final calculated comprehensive wear index, W i Xi represents the weight coefficient of the i-th performance parameter, X i Xi represents the value of the i-th performance parameter after normalization.

6. The composite insulator wear degree evaluation method based on multi-source information weighted fusion according to claim 1, characterized in that, The specific implementation of establishing the wear degree grade standard is that the numerical range of the comprehensive wear index CWI is divided into four continuous intervals, and the four numerical intervals correspond to four different wear degree grades of slight wear, moderate wear, severe wear and critical failure respectively, and the corresponding evaluation conclusion and maintenance strategy suggestion are output according to the interval range in which the calculated CWI value falls.

7. A system for implementing the composite insulator wear-out assessment method based on multi-source information weighted fusion according to any one of claims 1-6, characterized in that, The system comprises the following functional modules: a data acquisition module specially used for obtaining and storing the multi-source performance parameter test data of the composite insulator; a data processing module responsible for normalizing the original test data; a weight calculation module for calculating the objective weight coefficients of the performance parameters by using the entropy weight method; and a comprehensive wear index calculation module for calculating the comprehensive wear index of the composite insulator by using a weighted fusion algorithm. The core function of the comprehensive evaluation module is to execute a weighted fusion algorithm, calculate a comprehensive wear index, and output an evaluation result according to a preset grade standard; and the data output module is used for finally displaying the comprehensive wear index, a wear grade, and a maintenance suggestion.

Images