A method for evaluating epoxy resin degradation status in a dirty environment

Abstract

The present invention provides a method for evaluating the degradation state of epoxy resin under a polluted environment, including building a test platform, firstly performing a pollutant coating treatment on the epoxy resin sample by a pollutant spraying device, increasing the voltage at both ends of the epoxy resin sample at a pressure rate of Δv until the epoxy resin sample breaks down along the surface, measuring and collecting the voltage value at this time, changing the pollutant concentration in the test box and repeating the above steps to obtain the surface breakdown voltage value of the epoxy resin sample of group τ; then calculating the theoretical value of the surface breakdown voltage of the epoxy resin sample and optimizing it through an optimization algorithm, and finally calculating the epoxy resin degradation state evaluation factor and evaluating the degradation state of the epoxy resin sample. The present invention is committed to providing a method for evaluating the degradation state of epoxy resin under a polluted environment, accurately evaluating the degradation state of epoxy resin insulating materials, thereby ensuring the safe operation of electrical equipment.

Description

Technical Field

[0001] The invention belongs to the field of epoxy resin insulation performance evaluation, in particular to a method for evaluating the degradation state of epoxy resin in a dirty environment. Background Art

[0002] Epoxy resin materials have good electrical insulation properties and have been widely used in the casting of insulating components in electrical equipment such as motors and transformers, and in contact boxes and supporting insulators in high-voltage switchgear. Insulating materials will deteriorate in insulation after long-term operation. Pollution in the environment will affect the insulation properties of epoxy resin materials, accelerate the deterioration of epoxy resin materials, and seriously affect the safe operation of electrical equipment and the power supply reliability of the power system.

[0003] At present, there is little research on the degradation state of epoxy resin materials in dirty environments. Therefore, the present invention builds a test platform for evaluating the degradation state of epoxy resin in dirty environments, and proposes a method for evaluating the degradation state of epoxy resin in dirty environments. The degradation state of epoxy resin insulating materials can be accurately evaluated, thereby ensuring the safe operation of electrical equipment and further ensuring the safe and stable operation of the power system. Summary of the invention

[0004] The purpose of the present invention is to provide a method for evaluating the degradation state of epoxy resin under a dirty environment. The technical solution for achieving the purpose of the present invention is as follows:

[0005] A method for evaluating the degradation state of epoxy resin under a contaminated environment, characterized in that it specifically includes: a host computer, a power frequency voltage controller, a power frequency voltage generator, a voltage divider, a power frequency voltage data collector, a grounding device 1, a grounding device 2, a test box, an epoxy resin sample, a high voltage test electrode, a low voltage test electrode, a grounding grid, a pollution spraying device, a contamination measurement analyzer, a contamination adjustment control device, a contamination control switch, contamination liquid, a contamination input conduit, and a contamination output conduit;

[0006] The lower end of the dirt control switch is connected to the dirt liquid via the dirt input conduit, and the upper end is connected to the dirt spraying device via the dirt output conduit;

[0007] The pollution regulating and controlling device is respectively connected to the pollution measuring and analyzing instrument, the pollution control switch and the upper computer;

[0008] The high-voltage test electrode of the epoxy resin sample is connected to a voltage divider and a power frequency voltage generator, the grounding end of the power frequency voltage generator is connected to a grounding device, the signal input end of the power frequency voltage generator is connected to a power frequency voltage controller, the signal input end of the power frequency voltage controller is connected to a host computer, and the low-voltage test electrode of the epoxy resin sample is connected to a grounding grid;

[0009] The two ends of the power frequency voltage data collector are respectively connected to the voltage divider and the host computer, and the ground end of the voltage divider is connected to the second grounding device;

[0010] The method for evaluating the degradation state of epoxy resin in a dirty environment is characterized by comprising the following steps:

[0011] S1: A pollution setting signal is sent to the pollution regulating and controlling device through the upper computer. The pollution regulating and controlling device turns on the pollution control switch. The pollution liquid flows to the pollution spraying device through the pollution input conduit, the pollution control switch and the pollution output conduit. The pollution spraying device sprays the pollution liquid into the test chamber to coat the epoxy resin sample with pollution. The pollution measuring and analyzing instrument measures the pollution concentration in the test chamber after the epoxy resin sample is coated with pollution every Δt, transmits the data to the pollution regulating and controlling device to calculate the average pollution concentration, and transmits the pollution concentration c to the upper computer for storage.

[0012] S2: Turn on the power frequency voltage generator, and send a test voltage setting signal to the power frequency voltage controller through the host computer. The power frequency voltage controller controls the power frequency voltage generator to increase the voltage at both ends of the epoxy resin sample at a voltage increase rate of Δv until the epoxy resin sample breaks down along the surface;

[0013] S3: Measure the surface breakdown voltage U at both ends of the epoxy resin sample when it breaks down along the surface through a voltage divider. The power frequency voltage data collector collects the surface breakdown voltage U and transmits the data to the host computer for storage.

[0014] S4: Adjust the power frequency voltage controller to disconnect the power frequency voltage generator, clean the surface of the epoxy resin sample, change the contamination concentration of the contamination liquid, repeat the above steps S1-S3, and conduct τ tests;

[0015] S5: Calculate the surface breakdown voltage U of the epoxy resin sample i ;

[0016]

[0017] In the formula, c is the pollution concentration, x is the linear error factor, and λ is the integral variable

[0018] S6: Use the optimization algorithm to optimize the formula (1) and obtain the x' value that minimizes the error. The specific steps are:

[0019] 1) Randomly generate an initial solution η and calculate the objective function f(η):

[0020]

[0021] In formula (2), f(η) represents the objective function, U ij is the calculated value of the surface breakdown voltage of the jth epoxy resin sample, Usj is the measured value of the surface breakdown voltage of the jth epoxy resin sample, and τ is the total number of tests;

[0022] 2) Generate a new perturbed solution η' and calculate the objective function Δf = f(η) - f(η'); if Δf ≥ 0, accept the new solution; otherwise, obtain the new solution according to the probability acceptance criterion;

[0023] 3) Determine whether the number of iterations has been reached. If so, go to step 4); otherwise, go to step 2);

[0024] 4) Determine whether the termination condition is met. If so, the operation ends and the optimal solution is output. Otherwise, reset the number of iterations and go to step 2);

[0025] S7: Substitute the minimum error x' value obtained in step S6 into formula (1) to obtain the optimized epoxy resin sample surface breakdown voltage U i 'Calculation formula:

[0026]

[0027] S8: Calculate the epoxy resin degradation state assessment factor ε;

[0028]

[0029] Where U i ' is the surface breakdown voltage of the optimized epoxy resin sample, U B is the reference value of the surface breakdown voltage of the epoxy resin sample;

[0030] S9: When ε∈(0,8.4], it indicates that the insulation of the epoxy resin sample has not deteriorated; when ε∈[8.4,+∞), it indicates that the insulation of the epoxy resin sample has deteriorated.

[0031] The beneficial effects of the present invention are:

[0032] 1) The present invention builds a test platform for evaluating the degradation state of epoxy resin in a contaminated environment, which can accurately measure the surface breakdown voltage values ​​of epoxy resin samples under different contamination levels.

[0033] 2) The test device of the present invention is easy to operate, is mainly controlled by a host computer, and is intelligent.

[0034] 3) The evaluation method proposed in the present invention can obtain the degradation state of the epoxy resin sample in a dirty environment and evaluate the insulation performance of the epoxy resin sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the structure of the present invention; DETAILED DESCRIPTION

[0036] The specific implementation of the present invention is described in detail below with reference to the accompanying drawings, including the following steps:

[0037] like Figure 1 As shown, a test platform for evaluating the degradation state of epoxy resin under a polluted environment is constructed, the platform comprising: a host computer (1), a power frequency voltage controller (2), a power frequency voltage generator (3), a voltage divider (4), a power frequency voltage data collector (5), a grounding device 1 (131), a grounding device 2 (132), a test box (6), an epoxy resin sample (7), a high voltage test electrode (8), a low voltage test electrode (9), a grounding grid (10), a pollution spraying device (11), a pollution measurement analyzer (12), a pollution regulating control device (13), a pollution control switch (14), a pollution liquid (15), a pollution input conduit (191), and a pollution output conduit (192);

[0038] The lower end of the dirt control switch (14) is connected to the dirt liquid (15) via the dirt input conduit (191), and the upper end is connected to the dirt spraying device (11) via the dirt output conduit (192);

[0039] The pollution regulating and controlling device (13) is respectively connected to the pollution measuring and analyzing instrument (12), the pollution control switch (14), and the upper computer (1);

[0040] The high-voltage test electrode (8) of the epoxy resin sample (7) is connected to the voltage divider (4) and the power frequency voltage generator (3), the grounding end of the power frequency voltage generator (3) is connected to the grounding device (131), the signal input end of the power frequency voltage generator (3) is connected to the power frequency voltage controller (2), the signal input end of the power frequency voltage controller (2) is connected to the host computer (1), and the low-voltage test electrode (9) of the epoxy resin sample (7) is connected to the grounding grid (10);

[0041] The two ends of the power frequency voltage data collector (5) are respectively connected to the voltage divider (4) and the host computer (1), and the grounding end of the voltage divider (4) is connected to the second grounding device (132);

[0042] The method for evaluating the degradation state of epoxy resin in a dirty environment is characterized by comprising the following steps:

[0043] S1: A pollution setting signal is sent to the pollution regulating and controlling device (13) through the upper computer (1), and the pollution regulating and controlling device (13) turns on the pollution control switch (14), and the pollution liquid (15) flows to the pollution spraying device (11) through the pollution input conduit (191), the pollution control switch (14), and the pollution output conduit (192). The pollution spraying device (11) sprays the pollution liquid (15) into the interior of the test box (6) to perform a pollution coating treatment on the epoxy resin sample (7); the pollution measuring and analyzing instrument (12) measures the pollution concentration in the test box (6) after the epoxy resin sample (7) is coated with pollution every Δt, transmits the data to the pollution regulating and controlling device (13), calculates the pollution concentration average value, and transmits the pollution concentration c to the upper computer (1) for storage;

[0044] S2: Turn on the power frequency voltage generator (3), and send a test voltage setting signal to the power frequency voltage controller (2) through the host computer (1). The power frequency voltage controller (2) controls the power frequency voltage generator (3) to increase the voltage at both ends of the epoxy resin sample (7) at a voltage increase rate of Δv until the epoxy resin sample (7) breaks down along the surface;

[0045] S3: measuring the surface breakdown voltage U at both ends of the epoxy resin sample (7) when the surface is broken down by a voltage divider (4), and collecting the surface breakdown voltage value U by a power frequency voltage data collector (5), and transmitting the data to a host computer (1) for storage;

[0046] S4: adjusting the power frequency voltage controller (2) to disconnect the power frequency voltage generator (3), cleaning the surface of the epoxy resin sample (7), changing the contamination concentration of the contamination liquid (15), repeating the above steps S1-S3, and conducting τ tests;

[0047] S5: Calculate the surface breakdown voltage U of the epoxy resin sample i ;

[0048]

[0049] In the formula, c is the pollution concentration, x is the linear error factor, and λ is the integral variable

[0050] S6: Use the optimization algorithm to optimize the formula (1) and obtain the x' value that minimizes the error. The specific steps are:

[0051] 1) Randomly generate an initial solution η and calculate the objective function f(η):

[0052]

[0053] In formula (2), f(η) represents the objective function, U ij is the calculated value of the surface breakdown voltage of the jth epoxy resin sample, U sjis the measured value of the surface breakdown voltage of the jth epoxy resin sample, and τ is the total number of tests;

[0054] 2) Generate a new perturbed solution η' and calculate the objective function Δf = f(η) - f(η'); if Δf ≥ 0, accept the new solution; otherwise, obtain the new solution according to the probability acceptance criterion;

[0055] 3) Determine whether the number of iterations has been reached. If so, go to step 4); otherwise, go to step 2);

[0056] 4) Determine whether the termination condition is met. If so, the operation ends and the optimal solution is output. Otherwise, reset the number of iterations and go to step 2);

[0057] S7: Substitute the minimum error x' value obtained in step S6 into formula (1) to obtain the optimized epoxy resin sample surface breakdown voltage U i 'Calculation formula:

[0058]

[0059] S8: Calculate the epoxy resin degradation state assessment factor ε;

[0060]

[0061] Where U i ' is the surface breakdown voltage of the optimized epoxy resin sample, U B is the reference value of the surface breakdown voltage of the epoxy resin sample;

[0062] S9: When ε∈(0,8.4], it indicates that the insulation of the epoxy resin sample has not deteriorated; when ε∈[8.4,+∞), it indicates that the insulation of the epoxy resin sample has deteriorated.

Claims

1. A method for evaluating the degradation state of epoxy resin under a dirty environment, characterized in that: Specifically comprising: a host computer (1), a power frequency voltage controller (2), a power frequency voltage generator (3), a voltage divider (4), a power frequency voltage data collector (5), a grounding device 1 (131), a grounding device 2 (132), a test box (6), an epoxy resin sample (7), a high voltage test electrode (8), a low voltage test electrode (9), a grounding grid (10), a pollution spraying device (11), a pollution measurement and analysis instrument (12), a pollution adjustment and control device (13), a pollution control switch (14), a pollution liquid (15), a pollution input conduit (191), and a pollution output conduit (192); The lower end of the dirt control switch (14) is connected to the dirt liquid (15) via the dirt input conduit (191), and the upper end is connected to the dirt spraying device (11) via the dirt output conduit (192); The pollution regulating and controlling device (13) is respectively connected to the pollution measuring and analyzing instrument (12), the pollution control switch (14), and the upper computer (1); The high-voltage test electrode (8) of the epoxy resin sample (7) is connected to the voltage divider (4) and the power frequency voltage generator (3), the grounding end of the power frequency voltage generator (3) is connected to the grounding device (131), the signal input end of the power frequency voltage generator (3) is connected to the power frequency voltage controller (2), the signal input end of the power frequency voltage controller (2) is connected to the host computer (1), and the low-voltage test electrode (9) of the epoxy resin sample (7) is connected to the grounding grid (10); The two ends of the power frequency voltage data collector (5) are respectively connected to the voltage divider (4) and the host computer (1), and the grounding end of the voltage divider (4) is connected to the second grounding device (132); The method for evaluating the degradation state of epoxy resin in a dirty environment is characterized by comprising the following steps: S1: A pollution setting signal is sent to the pollution regulating and controlling device (13) through the upper computer (1), and the pollution regulating and controlling device (13) turns on the pollution control switch (14), and the pollution liquid (15) flows to the pollution spraying device (11) through the pollution input conduit (191), the pollution control switch (14), and the pollution output conduit (192). The pollution spraying device (11) sprays the pollution liquid (15) into the interior of the test box (6) to perform a pollution coating treatment on the epoxy resin sample (7); the pollution measuring and analyzing instrument (12) measures the pollution concentration in the test box (6) after the epoxy resin sample (7) is coated with pollution every Δt, transmits the data to the pollution regulating and controlling device (13), calculates the pollution concentration average value, and transmits the pollution concentration c to the upper computer (1) for storage; S2: Turn on the power frequency voltage generator (3), and send a test voltage setting signal to the power frequency voltage controller (2) through the host computer (1). The power frequency voltage controller (2) controls the power frequency voltage generator (3) to increase the voltage at both ends of the epoxy resin sample (7) at a voltage increase rate of Δv until the epoxy resin sample (7) breaks down along the surface; S3: measuring the surface breakdown voltage U at both ends of the epoxy resin sample (7) when the surface is broken down by a voltage divider (4), and collecting the surface breakdown voltage value U by a power frequency voltage data collector (5), and transmitting the data to a host computer (1) for storage; S4: adjusting the power frequency voltage controller (2) to disconnect the power frequency voltage generator (3), cleaning the surface of the epoxy resin sample (7), changing the contamination concentration of the contamination liquid (15), repeating the above steps S1-S3, and conducting τ tests; S5: Calculate the surface breakdown voltage U of the epoxy resin sample i ; In the formula, c is the pollution concentration, x is the linear error factor, and λ is the integral variable S6: Use the optimization algorithm to optimize the formula (1) and obtain the x' value that minimizes the error. The specific steps are: 1) Randomly generate an initial solution η and calculate the objective function f(η): In formula (2), f(η) represents the objective function, U ij is the calculated value of the surface breakdown voltage of the jth epoxy resin sample, U sj is the measured value of the surface breakdown voltage of the jth epoxy resin sample, and τ is the total number of tests; 2) Generate a new perturbed solution η' and calculate the objective function Δf = f(η) - f(η'); if Δf ≥ 0, accept the new solution; otherwise, obtain the new solution according to the probability acceptance criterion; 3) Determine whether the number of iterations has been reached. If so, go to step 4); otherwise, go to step 2); 4) Determine whether the termination condition is met. If so, the operation ends and the optimal solution is output. Otherwise, reset the number of iterations and go to step 2); S7: Substitute the minimum error x' value obtained in step S6 into formula (1) to obtain the optimized epoxy resin sample surface breakdown voltage U i 'Calculation formula: S8: Calculate the epoxy resin degradation state assessment factor ε; Where U i ' is the surface breakdown voltage of the optimized epoxy resin sample, U B is the reference value of the surface breakdown voltage of the epoxy resin sample; S9: When ε∈(0,8.4], it indicates that the insulation of the epoxy resin sample has not deteriorated; when ε∈[8.4,+∞), it indicates that the insulation of the epoxy resin sample has deteriorated.

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