Method for evaluating icing degradation state of cantilever insulator of overhead line system based on electric field distortion factor

Abstract

The invention provides a contact network cantilever insulator icing degradation state evaluation method based on an electric field distortion factor, and the method is characterized in that a contact network cantilever insulator icing degradation state evaluation platform based on the electric field distortion factor is built, and the actual icing environment condition is simulated; firstly, conditions in an environment simulation test box are adjusted through intelligent environment control equipment; then test voltage is applied to the contact network cantilever insulator, test current under different icing conditions is measured by a current test coil, a theoretical calculation formula of the current is optimized through an optimization algorithm, and finally the icing degradation state of the contact network cantilever insulator is evaluated. The method has the beneficial effects that the method for evaluating the icing degradation state of the cantilever insulator of the contact network based on the electric field distortion factor is provided, the test platform is built, the degradation state of the cantilever insulator of the contact network under the icing condition is accurately evaluated, and an important guarantee is provided for safe and reliable operation of a rail transit system.

Description

Technical Field

[0001] The invention belongs to the field of catenary arm insulator degradation state assessment, and in particular relates to a catenary arm insulator icing degradation state assessment method based on electric field distortion factor. Background Art

[0002] In the rail transit system, the overhead contact arm insulator, as an important part of the high-speed railway power transmission system, bears the dual functions of electrical insulation and mechanical support. The reliability of the performance of the overhead contact arm insulator directly affects the safety and stable operation of rail transit. With the rapid development of high-speed railways, the overhead contact system operates under various climatic conditions, including complex environments such as high cold, humidity, and icing, which puts higher requirements on the performance of insulators. Especially in the cold winter environment, ice is easily formed on the surface of the overhead contact arm insulator, resulting in the degradation of the overhead contact arm insulator performance, affecting the normal operation of the rail transit system, and even causing safety accidents. Therefore, the degradation of the overhead contact arm insulator under icing conditions must be given sufficient attention, and it is necessary to timely evaluate and discover the degradation state of the overhead contact arm insulator and take corresponding protective measures.

[0003] Ice coating will cause changes in the electric field distribution on the surface of the catenary arm insulator, causing electric field distortion, thereby accelerating the deterioration of the insulator. Ice coating not only increases the leakage current on the surface of the insulator, but may also cause partial discharge, further damaging the insulation performance of the catenary arm insulator.

[0004] At present, the evaluation method of the icing degradation state of the arm insulator of the overhead contact network mainly relies on empirical judgment and simple physical detection, and most of them fail to consider the electric field distortion under icing conditions, resulting in limitations in the evaluation of the degradation state of the arm insulator of the overhead contact network under severe cold weather conditions, and it is difficult to provide accurate and timely warnings and maintenance suggestions. Therefore, the present invention builds a platform for evaluating the icing degradation state of the arm insulator of the overhead contact network based on the electric field distortion factor, and proposes a method for evaluating the icing degradation state of the arm insulator of the overhead contact network based on the electric field distortion factor based on this platform, which accurately evaluates the degradation state of the arm insulator of the overhead contact network, and puts forward maintenance suggestions, thereby improving the safety and reliability of the operation of the rail transit system. Summary of the invention

[0005] In order to accurately evaluate the degradation state of the catenary arm insulator under icing conditions, the present invention provides a method for evaluating the icing degradation state of the catenary arm insulator based on the electric field distortion factor. The technical solution for achieving the purpose of the present invention is as follows:

[0006] The first step is to build a platform for evaluating the ice degradation state of the overhead line arm insulator based on the electric field distortion factor, the platform comprising: a host computer (1), a power frequency voltage controller (2), a power frequency voltage generator (3), a power frequency generator grounding electrode (31), a high-voltage coaxial cable (4), a high-voltage switch (51), a grounding switch (52), a high-precision voltage divider (6), an environmental simulation test box (7), a high-voltage test electrode 1 (81), a high-voltage test electrode 2 (82), an overhead line arm insulator test piece (9), and an arm insulator angle adjustment device. device (10), an intelligent angle adjustment control device (11), a current test coil (12), a grounding cable (13), a grounding grid (14), an experimental data acquisition unit (15), a wireless data transmission module 1 (161), a wireless data transmission module 2 (162), a wireless data transmission module (163), an ice thickness measuring instrument (17), an ice ridge length measuring instrument (18), an intelligent ice quantity regulator (19), a fan (20), an adjustable wind direction filter (21), a wind speed integrated control device (22), and an ice maker (23);

[0007] The input end of the power frequency voltage controller (2) is connected to the host computer (1), the output end of the power frequency voltage controller (2) is connected to the input end of the power frequency voltage generator (3), the output end of the power frequency voltage generator (3) is connected to the left end of the high-voltage switch (51) via the high-voltage coaxial cable (4), the right end of the high-voltage switch (51) is connected to the input end of the high-precision voltage divider (6), the output end of the high-precision voltage divider (6) is connected to the first high-voltage test electrode (81), the first high-voltage test electrode (81) is connected to the upper end of the contact network arm insulator test piece (9), the lower end of the contact network arm insulator test piece (9) is connected to the second high-voltage test electrode (82), the second high-voltage test electrode (82) is fixed on the arm insulator angle adjuster (10), the upper and lower ends of the grounding switch (52) are respectively connected to the second high-voltage test electrode (82) and the grounding cable (13), and the output end of the grounding cable (13) is connected to the grounding grid (14);

[0008] The grounding terminal of the power frequency voltage generator (3) is connected to the power frequency voltage generator grounding electrode (31);

[0009] The current test coil (12) is sleeved on the grounding cable (13), and the output end of the current test coil (12) is connected to the input end of the experimental data acquisition unit (15);

[0010] The output end of the experimental data acquisition unit (15) is connected to the input end of the wireless data transmission module (161), and the wireless data transmission module (161) is wirelessly connected to the host computer (1);

[0011] The input end of the intelligent angle adjustment control device (11) is connected to the host computer (1), and the output end of the intelligent angle adjustment control device (11) is connected to the arm insulator angle adjuster (10); the output ends of the ice thickness measuring instrument (17) and the ice ridge length measuring instrument (18) are connected to the wireless data transmission module 2 (162); the wireless data transmission module 2 (162) is wirelessly connected to the host computer (1);

[0012] The input end of the intelligent ice quantity regulator (19) is connected to the host computer (1), and the output end of the intelligent ice quantity regulator (19) is connected to the ice maker (23); the wind speed integrated control device (22) is respectively connected to the fan (20) and the wireless data transmission module three (163); the wireless data transmission module three (163) is wirelessly connected to the host computer (1);

[0013] The high-voltage test electrode 1 (81), the contact network arm insulator test piece (9), the high-voltage test electrode 2 (82), the arm insulator angle adjuster (10), the ice thickness measuring instrument (17), the ice ridge length measuring instrument (18), the fan (20), the adjustable wind direction filter (21), and the ice maker (23) are fixed inside the environmental simulation test box (7);

[0014] Step 2: Based on a built platform for evaluating the ice degradation status of catenary arm insulators based on electric field distortion factor, a method for evaluating the ice degradation status of catenary arm insulators based on electric field distortion factor is proposed, which includes the following steps:

[0015] S1: Set the installation angle of the contact network arm insulator test piece (9) to θ in the host computer (1). a The upper computer (1) controls the intelligent angle adjustment control device (11) to control the arm insulator angle adjuster (10) to start working, so that the included angle between the contact network arm insulator test piece (9) and the horizontal plane is θ a ;

[0016] S2: In the host computer (1), the amount of ice in the environmental simulation test box (7) is set to H a The host computer (1) controls the intelligent ice quantity regulator (19) to control the ice making amount of the ice making machine (23) to H a ;

[0017] S3: Set the wind speed V in the host computer (1) a, the host computer (1) transmits the wind speed setting signal to the wind speed comprehensive control device (22) through the wireless data transmission module three (163), and controls the rotation speed n of the fan (20) to increase uniformly from 0 through the wind speed comprehensive control device (22); at the same time, the wind speed comprehensive control device (22) measures the wind speed v in the environmental simulation test chamber (7) in real time, and the wireless data transmission module three (163) wirelessly transmits the measurement result of the wind speed comprehensive control device (22) to the host computer (1), and the host computer (1) judges the wind speed v. If |V a - v| < E, the rotation speed n of the fan (20) remains unchanged;

[0018] S4: Keep the environmental conditions in the environmental simulation test chamber (7) unchanged. After waiting for a time ΔT, measure the maximum ice layer thickness d max , the minimum ice layer thickness d min and the maximum ice ridge length l max , the minimum ice ridge length l min of the catenary cantilever insulator specimen (9) at this time with the ice layer thickness measuring instrument (17) and the ice ridge length measuring instrument (18); the wireless data transmission module two (162) wirelessly transmits the measurement results of the ice layer thickness measuring instrument (17) and the ice ridge length measuring instrument (18) to the host computer (1);

[0019] S5: Send a control signal to the power frequency voltage controller (2) through the host computer (1), so that the power frequency voltage generator (3) performs a constant voltage boost process on the catenary cantilever insulator specimen (9), boosts by ΔU every Δt time, and performs a total of N voltage boosts. After each voltage boost, record the time t and the voltage U1 of the power frequency voltage generator (3) at this time, and then measure the voltage U2 and current I r of the catenary cantilever insulator specimen (9) at this time by the high-precision voltage divider (6) and the current test coil (12), and return them to the host computer (1) through the experimental data acquisition unit (15); disconnect the high-voltage switch (51) and the grounding switch (52);

[0020] S6: Obtain the calculated value I i of the power frequency test current of the catenary cantilever insulator specimen (9) through the following formula:

[0021]

[0022] In formula (1), t is the duration of the simulated environment, k is the weight coefficient, y is the linear error factor, x is the integration variable, and U2 is the voltage measured across the catenary cantilever insulator specimen (9);

[0023] S7: Use an optimization algorithm to optimize the modeling of formula (1) to obtain the value y0 that minimizes the error. The specific steps are as follows:

[0024] 1) Randomly generate the initial solution δ and calculate the objective function:

[0025]

[0026] Formula (2) represents the objective function, I im is the calculated value of the mth power frequency current, I rm is the measured value of the mth power frequency current, and N is the number of tests;

[0027] 2) Generate a new perturbed solution δ' and calculate the objective function Δf = f(δ) - f(δ'); if Δf ≥ 0, accept the new solution; otherwise, obtain the new solution according to the probability acceptance criterion;

[0028] 3) Determine whether the number of iterations has been reached. If so, go to step 3); otherwise, go to step 2;

[0029] 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);

[0030] S8: Substitute y0 obtained in S7 into formula (1) to obtain the optimized power frequency test current I of the overhead contact arm insulator specimen (9) i 'Calculation formula:

[0031]

[0032] S9: Based on the optimized power frequency test current I i 'Calculate the electric field distortion factor σ of the overhead contact arm insulator:

[0033]

[0034] In formula (3), I i ' is the optimized power frequency test current, θ a is the angle between the contact network arm insulator specimen (9) and the horizontal plane, d max is the maximum ice thickness, d min is the minimum ice thickness, l max is the maximum length of the ice ridge, l min is the minimum length of the ice ridge, and N is the number of tests;

[0035] S10: Calculate the icing degradation status assessment factor η of the overhead contact arm insulator:

[0036]

[0037] In formula (5), I i ' is the optimized power frequency test current, σ is the electric field distortion factor, and N is the number of tests;

[0038] S11: Based on the evaluation factor η of the icing degradation state of the contact network arm insulator obtained in the above steps, an evaluation is performed. When η∈(0, 7.49], it indicates that the contact network arm insulator has no degradation; when η∈(7.49, 67.94], it indicates that the contact network arm insulator has slightly degraded; when η∈(67.94, +∞), it indicates that the contact network arm insulator has seriously degraded, and it is recommended to replace the contact network arm insulator.

[0039] The beneficial effects of the present invention are:

[0040] 1) A catenary arm insulator icing degradation status evaluation platform based on electric field distortion factor was built, which can effectively simulate the icing condition of catenary arm insulators under actual environmental conditions;

[0041] 2) Adopting the host computer intelligent control system to simplify the operation process, improve work efficiency and convenience of data management;

[0042] 3) Intelligent environmental control equipment can achieve precise control of test conditions, ensure the stability and repeatability of the test environment, and greatly improve the accuracy of the assessment of the ice degradation status of the overhead line arm insulators;

[0043] 4) Integrate wireless data transmission module to realize real-time remote transmission and monitoring of test data, enhance the accessibility and immediacy of data, and improve the flexibility and efficiency of overall operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of an ice degradation evaluation platform for overhead contact network arm insulators based on electric field distortion factor of the present invention. DETAILED DESCRIPTION

[0045] The following is a further description of the specific implementation of the present invention in conjunction with the accompanying drawings. A method for evaluating the ice degradation state of an overhead line arm insulator based on an electric field distortion factor, the specific implementation includes the following steps:

[0046] Step 1: A platform for evaluating the ice degradation state of the overhead contact arm insulator based on the electric field distortion factor is constructed, wherein the platform comprises: a host computer (1), a power frequency voltage controller (2), a power frequency voltage generator (3), a power frequency generator grounding electrode (31), a high-voltage coaxial cable (4), a high-voltage switch (51), a grounding switch (52), a high-precision voltage divider (6), an environmental simulation test chamber (7), a high-voltage test electrode 1 (81), a high-voltage test electrode 2 (82), an overhead contact arm insulator test piece (9), and an angle adjustment device for adjusting the angle of the arm insulator. device (10), an intelligent angle adjustment control device (11), a current test coil (12), a grounding cable (13), a grounding grid (14), an experimental data acquisition unit (15), a wireless data transmission module 1 (161), a wireless data transmission module 2 (162), a wireless data transmission module (163), an ice thickness measuring instrument (17), an ice ridge length measuring instrument (18), an intelligent ice quantity regulator (19), a fan (20), an adjustable wind direction filter (21), a wind speed integrated control device (22), and an ice maker (23);

[0047] The input end of the power frequency voltage controller (2) is connected to the host computer (1), the output end of the power frequency voltage controller (2) is connected to the input end of the power frequency voltage generator (3), the output end of the power frequency voltage generator (3) is connected to the left end of the high-voltage switch (51) via the high-voltage coaxial cable (4), the right end of the high-voltage switch (51) is connected to the input end of the high-precision voltage divider (6), the output end of the high-precision voltage divider (6) is connected to the first high-voltage test electrode (81), the first high-voltage test electrode (81) is connected to the upper end of the contact network arm insulator test piece (9), the lower end of the contact network arm insulator test piece (9) is connected to the second high-voltage test electrode (82), the second high-voltage test electrode (82) is fixed on the arm insulator angle adjuster (10), the upper and lower ends of the grounding switch (52) are respectively connected to the second high-voltage test electrode (82) and the grounding cable (13), and the output end of the grounding cable (13) is connected to the grounding grid (14);

[0048] The grounding terminal of the power frequency voltage generator (3) is connected to the power frequency voltage generator grounding electrode (31);

[0049] The current test coil (12) is sleeved on the grounding cable (13), and the output end of the current test coil (12) is connected to the input end of the experimental data acquisition unit (15);

[0050] The output end of the experimental data acquisition unit (15) is connected to the input end of the wireless data transmission module (161), and the wireless data transmission module (161) is wirelessly connected to the host computer (1);

[0051] The input end of the intelligent angle adjustment control device (11) is connected to the host computer (1), and the output end of the intelligent angle adjustment control device (11) is connected to the arm insulator angle adjuster (10); the output ends of the ice thickness measuring instrument (17) and the ice ridge length measuring instrument (18) are connected to the wireless data transmission module 2 (162); the wireless data transmission module 2 (162) is wirelessly connected to the host computer (1);

[0052] The input end of the intelligent ice quantity regulator (19) is connected to the host computer (1), and the output end of the intelligent ice quantity regulator (19) is connected to the ice maker (23); the wind speed integrated control device (22) is respectively connected to the fan (20) and the wireless data transmission module three (163); the wireless data transmission module three (163) is wirelessly connected to the host computer (1);

[0053] The high-voltage test electrode 1 (81), the contact network arm insulator test piece (9), the high-voltage test electrode 2 (82), the arm insulator angle adjuster (10), the ice thickness measuring instrument (17), the ice ridge length measuring instrument (18), the fan (20), the adjustable wind direction filter (21), and the ice maker (23) are fixed inside the environmental simulation test box (7);

[0054] Step 2: Based on a built platform for evaluating the ice degradation status of the catenary arm insulator based on the electric field distortion factor, a method for evaluating the ice degradation status of the catenary arm insulator based on the electric field distortion factor is proposed, which includes the following steps:

[0055] Step 1: Set the installation angle of the contact network arm insulator test piece (9) to θ in the host computer (1). a The upper computer (1) controls the intelligent angle adjustment control device (11) to control the arm insulator angle adjuster (10) to start working, so that the included angle between the contact network arm insulator test piece (9) and the horizontal plane is θ a ;

[0056] Step 2: Set the ice volume in the environmental simulation test chamber (7) to H in the host computer (1). a The host computer (1) controls the intelligent ice quantity regulator (19) to control the ice making amount of the ice making machine (23) to H a ;

[0057] Step 3: Set the wind speed V in the host computer (1) a, the host computer (1) transmits the wind speed setting signal to the wind speed comprehensive control device (22) through the wireless data transmission module three (163), and controls the rotational speed n of the fan (20) to increase uniformly from 0 through the wind speed comprehensive control device (22); at the same time, the wind speed comprehensive control device (22) measures the wind speed v in the environmental simulation test chamber (7) in real time, and the wireless data transmission module three (163) wirelessly transmits the measurement result of the wind speed comprehensive control device (22) to the host computer (1), and the host computer (1) judges the wind speed v. If |V a - v| < E, then keep the rotational speed n of the fan (20) unchanged;

[0058] Step 4: Keep the environmental conditions in the environmental simulation test chamber (7) unchanged. After waiting for a time ΔT, measure the maximum ice layer thickness d max , the minimum ice layer thickness d min and the maximum ice prism length l max , the minimum ice prism length l min of the catenary wrist arm insulator specimen (9) at this time by the ice layer thickness measuring instrument (17) and the ice prism length measuring instrument (18); the wireless data transmission module two (162) wirelessly transmits the measurement results of the ice layer thickness measuring instrument (17) and the ice prism length measuring instrument (18) to the host computer (1);

[0059] Step 5: Send a control signal to the power frequency voltage controller (2) through the host computer (1) so that the power frequency voltage generator (3) performs a constant voltage boost process on the catenary wrist arm insulator specimen (9), boost ΔU every Δt time, and perform a total of N voltage boosts. After each voltage boost, record the time t at this time and the voltage U1 of the power frequency voltage generator (3), and then measure the voltage U2 and current I r of the catenary wrist arm insulator specimen (9) at this time by the high-precision voltage divider (6) and the current test coil (12), and return them to the host computer (1) through the experimental data acquisition unit (15); disconnect the high-voltage switch (51) and the grounding switch (52);

[0060] Step 3: Obtain the calculated value I of the power frequency test current of the catenary wrist arm insulator specimen (9) through the following formula i :

[0061]

[0062] In formula (1), t is the duration of the simulated environment, k is the weight coefficient, y is the linear error factor, x is the integration variable, and U2 is the voltage measured across the catenary wrist arm insulator specimen (9);

[0063] Step 4: Use an optimization algorithm to optimize and model formula (1) to obtain the value y0 that minimizes the error. The specific steps are as follows:

[0064] Step 1: Randomly generate the initial solution δ and calculate the objective function:

[0065]

[0066] Formula (2) represents the objective function, I im is the calculated value of the mth power frequency current, I rm is the measured value of the mth power frequency current, and N is the number of tests;

[0067] Step 2: Generate a new perturbed solution δ' and calculate the objective function Δf = f(δ) - f(δ'); if Δf ≥ 0, accept the new solution; otherwise, obtain the new solution according to the probability acceptance criterion;

[0068] Step 3: Determine whether the number of iterations has been reached. If so, go to step 3). Otherwise, go to step 2.

[0069] Step 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).

[0070] Step 5: Substitute y0 obtained in S7 into formula (1) to obtain the optimized power frequency test current I of the contact network arm insulator specimen (9) i 'Calculation formula:

[0071]

[0072] Step 5: Based on the optimized power frequency test current I i 'Calculate the electric field distortion factor σ of the overhead contact arm insulator:

[0073]

[0074] In formula (3), I i ' is the optimized power frequency test current, θ a is the angle between the contact network arm insulator specimen (9) and the horizontal plane, d max is the maximum ice thickness, d min is the minimum ice thickness, l max is the maximum length of the ice ridge, l min is the minimum length of the ice ridge, and N is the number of tests;

[0075] Step 6: Calculate the icing degradation status assessment factor η of the overhead contact arm insulator:

[0076]

[0077] In formula (5), I i ' is the optimized power frequency test current, σ is the electric field distortion factor, and N is the number of tests;

[0078] Based on the evaluation factor η of the icing degradation state of the contact network arm insulator obtained in the above steps, when η∈(0,7.49], it indicates that the contact network arm insulator has no degradation; when η∈(7.49,67.94], it indicates that the contact network arm insulator has slightly deteriorated; when η∈(67.94,+∞), it indicates that the contact network arm insulator has seriously deteriorated, and it is recommended to replace the contact network arm insulator.

Claims

1. A method for evaluating the ice degradation state of overhead contact arm insulators based on electric field distortion factor, characterized in that: The steps include: The first step is to build a platform for evaluating the ice degradation state of the overhead line arm insulator based on the electric field distortion factor, the platform comprising: a host computer (1), a power frequency voltage controller (2), a power frequency voltage generator (3), a power frequency generator grounding electrode (31), a high-voltage coaxial cable (4), a high-voltage switch (51), a grounding switch (52), a high-precision voltage divider (6), an environmental simulation test box (7), a high-voltage test electrode 1 (81), a high-voltage test electrode 2 (82), an overhead line arm insulator test piece (9), and an arm insulator angle adjustment device. device (10), an intelligent angle adjustment control device (11), a current test coil (12), a grounding cable (13), a grounding grid (14), an experimental data acquisition unit (15), a wireless data transmission module 1 (161), a wireless data transmission module 2 (162), a wireless data transmission module (163), an ice thickness measuring instrument (17), an ice ridge length measuring instrument (18), an intelligent ice quantity regulator (19), a fan (20), an adjustable wind direction filter (21), a wind speed integrated control device (22), and an ice maker (23); The input end of the power frequency voltage controller (2) is connected to the host computer (1), the output end of the power frequency voltage controller (2) is connected to the input end of the power frequency voltage generator (3), the output end of the power frequency voltage generator (3) is connected to the left end of the high-voltage switch (51) via the high-voltage coaxial cable (4), the right end of the high-voltage switch (51) is connected to the input end of the high-precision voltage divider (6), the output end of the high-precision voltage divider (6) is connected to the first high-voltage test electrode (81), the first high-voltage test electrode (81) is connected to the upper end of the contact network arm insulator test piece (9), the lower end of the contact network arm insulator test piece (9) is connected to the second high-voltage test electrode (82), the second high-voltage test electrode (82) is fixed on the arm insulator angle adjuster (10), the upper and lower ends of the grounding switch (52) are respectively connected to the second high-voltage test electrode (82) and the grounding cable (13), and the output end of the grounding cable (13) is connected to the grounding grid (14); The grounding terminal of the power frequency voltage generator (3) is connected to the power frequency voltage generator grounding electrode (31); The current test coil (12) is sleeved on the grounding cable (13), and the output end of the current test coil (12) is connected to the input end of the experimental data acquisition unit (15); The output end of the experimental data acquisition unit (15) is connected to the input end of the wireless data transmission module (161), and the wireless data transmission module (161) is wirelessly connected to the host computer (1); The input end of the intelligent angle adjustment control device (11) is connected to the host computer (1), and the output end of the intelligent angle adjustment control device (11) is connected to the arm insulator angle adjuster (10); the output ends of the ice thickness measuring instrument (17) and the ice ridge length measuring instrument (18) are connected to the wireless data transmission module 2 (162); the wireless data transmission module 2 (162) is wirelessly connected to the host computer (1); The input end of the intelligent ice quantity regulator (19) is connected to the host computer (1), and the output end of the intelligent ice quantity regulator (19) is connected to the ice maker (23); the wind speed integrated control device (22) is respectively connected to the fan (20) and the wireless data transmission module three (163); the wireless data transmission module three (163) is wirelessly connected to the host computer (1); The high-voltage test electrode 1 (81), the contact network arm insulator test piece (9), the high-voltage test electrode 2 (82), the arm insulator angle adjuster (10), the ice thickness measuring instrument (17), the ice ridge length measuring instrument (18), the fan (20), the adjustable wind direction filter (21), and the ice maker (23) are fixed inside the environmental simulation test box (7); Step 2: Based on a built platform for evaluating the ice degradation status of catenary arm insulators based on electric field distortion factor, a method for evaluating the ice degradation status of catenary arm insulators based on electric field distortion factor is proposed, which includes the following steps: S1: Set the installation angle of the contact network arm insulator test piece (9) to θ in the host computer (1). a The upper computer (1) controls the intelligent angle adjustment control device (11) to control the arm insulator angle adjuster (10) to start working, so that the included angle between the contact network arm insulator test piece (9) and the horizontal plane is θ a ; S2: In the host computer (1), the amount of ice in the environmental simulation test box (7) is set to H a The host computer (1) controls the intelligent ice quantity regulator (19) to control the ice making amount of the ice making machine (23) to H a ; S3: Set the wind speed V in the host computer (1). a , the host computer (1) transmits the wind speed setting signal to the wind speed comprehensive control device (22) through the wireless data transmission module three (163), and controls the rotation speed n of the fan (20) to increase uniformly from 0 through the wind speed comprehensive control device (22); at the same time, the wind speed comprehensive control device (22) measures the wind speed v in the environmental simulation test chamber (7) in real time, and the wireless data transmission module three (163) wirelessly transmits the measurement result of the wind speed comprehensive control device (22) to the host computer (1), and the host computer (1) judges the wind speed v. If |V a - v| < E, then keep the rotation speed n of the fan (20) unchanged; S4: Keep the environmental conditions in the environmental simulation test box (7) unchanged, wait for a period of time ΔT, and measure the maximum ice thickness d of the contact network arm insulator test piece (9) by using an ice thickness measuring instrument (17) and an ice ridge length measuring instrument (18). max , minimum ice thickness d min and the maximum length of the ice ridge l max , minimum length of ice ridge l min The wireless data transmission module 2 (162) wirelessly transmits the measurement results of the ice thickness measuring instrument (17) and the ice ridge length measuring instrument (18) to the host computer (1); S5: The upper computer (1) sends a control signal to the power frequency voltage controller (2), so that the power frequency voltage generator (3) performs a constant voltage boost process on the contact network arm insulator test piece (9), and the voltage is boosted by ΔU every time Δt, and a total of N times of boosting is performed. After each boosting, the time t and the voltage U1 of the power frequency voltage generator (3) are recorded at that time, and then the voltage U2 and the current I1 of the contact network arm insulator test piece (9) at that time are measured by the high-precision voltage divider (6) and the current test coil (12). r and returns to the host computer (1) through the experimental data acquisition unit (15), disconnecting the high-voltage switch (51) and the grounding switch (52); S6: The calculated value of the power frequency test current I of the contact network arm insulator specimen (9) is obtained by the following formula: i : In formula (1), t is the duration of the simulated environment, k is the weight coefficient, y is the linear error factor, x is the integral variable, and U2 is the measured voltage across the contact network arm insulator specimen (9); S7: Use the optimization algorithm to optimize the formula (1) and obtain the value y0 that minimizes the error. The specific steps are: 1) Randomly generate the initial solution δ and calculate the objective function: Formula (2) represents the objective function, I im is the calculated value of the mth power frequency current, I rm is the measured value of the mth power frequency current, and N is the number of tests; 2) Generate a new perturbed solution δ' and calculate the objective function Δf = f(δ) - f(δ'); 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 3); 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); S8: Substitute y0 obtained in S7 into formula (1) to obtain the optimized power frequency test current I of the overhead contact arm insulator specimen (9) i 'Calculation formula: S9: Based on the optimized power frequency test current I i 'Calculate the electric field distortion factor σ of the overhead contact arm insulator: In formula (3), I i ' is the optimized power frequency test current, θ a is the angle between the contact network arm insulator specimen (9) and the horizontal plane, d max is the maximum ice thickness, d min is the minimum ice thickness, l max is the maximum length of the ice ridge, l min is the minimum length of the ice ridge, and N is the number of tests; S10: Calculate the icing degradation status assessment factor η of the overhead contact arm insulator: In formula (5), I i ' is the optimized power frequency test current, σ is the electric field distortion factor; S11: Based on the evaluation factor η of the icing degradation state of the contact network arm insulator obtained in the above steps, an evaluation is performed. When η∈(0, 7.49], it indicates that the contact network arm insulator has no degradation; when η∈(7.49, 67.94], it indicates that the contact network arm insulator has slightly degraded; when η∈(67.94, +∞), it indicates that the contact network arm insulator has seriously degraded, and it is recommended to replace the contact network arm insulator.

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