A method for evaluating the insulation state of an epoxy resin through-wall bushing in a switch cabinet in a hot and humid environment

Abstract

The application provides a kind of wet heat environment under switchgear in epoxy resin bushing insulation state evaluation method, including building test platform, change the environmental temperature and humidity in test box, then the voltage of epoxy resin bushing inner conductive busbar both ends is raised to test voltage, the working current of epoxy resin bushing under different environmental humidity and temperature is measured by working current tester, and the theoretical calculation formula of epoxy resin bushing working current is optimized by optimization algorithm, finally the insulation state of epoxy resin bushing is evaluated;The beneficial effect of the application lies in providing a kind of wet heat environment under epoxy resin bushing insulation state evaluation method, and builds test platform, can realize the evaluation of epoxy resin bushing insulation state under different environmental temperature and humidity, provides important guarantee for the reliable operation of switchgear.

Description

Technical Field

[0001] This invention belongs to the field of switchgear insulation technology, and in particular, it is a method for evaluating the insulation status of epoxy resin through-wall bushings in switchgear under humid and hot conditions. Background Technology

[0002] With the increase in electricity load, users have placed higher demands on the reliable operation of the power system. As a key piece of equipment in the distribution network, the operating status of switchgear seriously affects the safe operation of the power system. Epoxy resin wall bushings are one of the core components of switchgear insulation, and their insulation condition significantly affects the overall operating status of the switchgear. Furthermore, as the switchgear operates for longer periods, internal defects in the epoxy resin wall bushings accumulate and develop, greatly increasing the probability of insulation failure and causing severe disruptions to people's lives.

[0003] Currently, there is little research on the damage to the insulation performance of epoxy resin wall bushings under humid and hot conditions. Therefore, this invention establishes a test platform for evaluating the insulation status of epoxy resin wall bushings in switchgear under humid and hot conditions, and proposes a method for evaluating the insulation status of epoxy resin wall bushings in switchgear under humid and hot conditions based on this platform. This method can accurately evaluate the insulation status of epoxy resin wall bushings in switchgear, further ensuring the reliability of power supply in the power system. Summary of the Invention

[0004] The purpose of this invention is to provide a method for evaluating the insulation status of epoxy resin through-wall bushings in switchgear under humid and hot conditions. The technical solution to achieve this purpose is as follows:

[0005] An evaluation platform for the insulation status of epoxy resin through-wall bushings in switchgear under humid and hot conditions is provided. The platform includes: a host computer, a test voltage controller, a test voltage generator, a test chamber, epoxy resin through-wall bushings, conductive busbars, test electrodes, a cavity, grounding device one, grounding device two, a working current tester, a grounding grid, a data acquisition device, intelligent humidity control equipment, a humidity regulator, humidity sensor one, humidity sensor two, a new temperature control device, a temperature regulation system, and temperature sensor one and temperature sensor two.

[0006] The control terminal of the intelligent humidity control device is connected to the humidity regulator, the feedback terminal of the intelligent humidity control device is connected to humidity sensor one and humidity sensor two, and the data output terminal of the intelligent humidity control device is connected to the host computer.

[0007] The control terminal of the novel temperature control device is connected to the temperature regulation system, the feedback terminal of the novel temperature control device is connected to temperature sensor one and temperature sensor two, and the data output terminal of the novel temperature control device is connected to the host computer.

[0008] The grounding terminal of the test voltage generator is connected to grounding device one, the signal input terminal of the test voltage generator is connected to the control terminal of the test voltage controller, the output terminal of the test voltage generator is connected to the left end of the conductive busbar, the right end of the conductive busbar is connected to grounding device two, and the input terminal of the test voltage controller is connected to the host computer.

[0009] The epoxy resin through-wall bushing contains a cavity and a conductive busbar. The test electrode of the epoxy resin through-wall bushing is connected to the current input terminal IB of the working current tester. The grounding terminal E of the working current tester is connected to the grounding grid. The signal output terminal O of the working current tester is connected to the data acquisition unit. The data acquisition unit is connected to the host computer.

[0010] The epoxy resin through-wall sleeve, conductive busbar, test electrode, humidity regulator, humidity sensor 1, humidity sensor 2, temperature control system, temperature sensor 1, and temperature sensor 2 are all fixed inside the test chamber.

[0011] The method for evaluating the insulation status of epoxy resin through-wall bushings in switchgear under humid and hot conditions is characterized by comprising the following steps:

[0012] S1: The host computer sends a test temperature setting signal to the new temperature control equipment. The new temperature control equipment controls the temperature regulation system to set the ambient temperature inside the test chamber to T℃. Temperature sensor 1 and temperature sensor 2 provide real-time feedback of the ambient temperature T inside the test chamber. r From ℃ to new temperature control equipment, until TT r ≤ΔT B ;

[0013] S2: The host computer sends a test humidity setting signal to the intelligent humidity control device. The intelligent humidity control device controls the humidity regulator to set the environmental humidity percentage inside the test chamber to w%RH. Humidity sensor 1 and humidity sensor 2 provide real-time feedback on the environmental humidity percentage w inside the test chamber. r From %RH to intelligent humidity control equipment, up to ww r ≤Δw B ;

[0014] S3: Turn on the test voltage generator and send a test voltage setting signal to the test voltage controller through the host computer. The test voltage controller controls the test voltage generator to quickly raise the voltage across the conductive busbar in the epoxy resin through-wall bushing to the test voltage value U. The working current tester measures the working current I of the epoxy resin through-wall bushing at this time. The data acquisition unit collects the working current I of the epoxy resin through-wall bushing and transmits the data to the host computer for storage.

[0015] S4: The temperature regulation system is controlled by a new type of temperature control equipment to change the ambient temperature inside the test chamber at intervals of ΔT℃, and then at each ambient temperature T j The humidity is controlled by an intelligent humidity control device to change the ambient humidity in the test chamber by a humidity percentage of Δw%RH at each interval, and step S3 is repeated for N tests.

[0016] S5: Calculate the working current value I of the epoxy resin through-wall bushing. i :

[0017]

[0018] In the formula, w is the percentage of ambient humidity, y is the linear error factor, λ is the integral variable, k is the influence coefficient of ambient temperature, and T j T represents the ambient temperature inside the chamber during the j-th test. s The reference ambient temperature;

[0019] S6: The optimization algorithm is used to optimize and model formula (1) to obtain the value of y' that minimizes the error. The specific steps are as follows:

[0020] 1) Randomly generate an initial solution ζ and calculate the objective function f(ζ):

[0021]

[0022] In equation (2), f(ζ) represents the objective function, I ij I is the calculated value of the working current of the epoxy resin through-wall bushing for the j-th time. cj , where is the measured value of the working current of the epoxy resin through-wall bushing in the j-th test, and N is the total number of tests;

[0023] 2) Generate a new perturbation solution ζ', and calculate the objective function Δf = f(ζ) - f(ζ'); if Δf ≥ 0, accept the new solution; otherwise, obtain the new solution according to the probability acceptance criterion.

[0024] 3) Determine if the number of iterations has been reached. If it has, proceed to step 4); otherwise, proceed to step 2.

[0025] 4) Determine if the termination condition is met. If it is, the operation ends and the optimal solution is output. Otherwise, reset the iteration count and go to step 2).

[0026] S7: Substitute the minimum error value y' obtained in step S6 into formula (1) to obtain the optimized epoxy resin through-wall bushing working current I. i Calculation formula:

[0027]

[0028] S7: Calculate the insulation status assessment factor ε of epoxy resin through-wall bushing;

[0029]

[0030] In the formula, I i 'To optimize the operating current of the epoxy resin through-wall bushing, I' s This is the reference value for the working current of the epoxy resin through-wall bushing.

[0031] S8: When ε∈(0,5.56], it indicates that the epoxy resin through-wall bushing insulation performance has failed; when ε∈[5.56,+∞), it indicates that the epoxy resin through-wall bushing insulation performance is normal.

[0032] The beneficial effects of this invention are as follows:

[0033] 1) An experimental platform for evaluating the insulation status of epoxy resin through-wall bushings in switchgear under humid and hot conditions was built, which can effectively simulate the temperature and humidity conditions of epoxy resin through-wall bushings under actual working conditions.

[0034] 2) Related equipment can be intelligently controlled via a host computer, making operation convenient.

[0035] 3) Intelligent humidity control equipment and new temperature control equipment can achieve precise control of the humidity and temperature in the test chamber, which greatly improves the accuracy of the evaluation of the insulation performance of epoxy resin through-wall bushings. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of the present invention; Detailed Implementation

[0037] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, including the following steps:

[0038] like Figure 1 As shown, a test platform for evaluating the insulation status of epoxy resin through-wall bushings in switchgear under humid and hot conditions is constructed. The platform includes: host computer (1), test voltage controller (2), test voltage generator (3), test chamber (4), epoxy resin through-wall bushing (5), conductive busbar (6), test electrode (7), cavity (15), grounding device one (161), grounding device two (162), working current tester (8), grounding grid (9), data acquisition device (10), intelligent humidity control device (11), humidity regulator (12), humidity sensor one (171), humidity sensor two (172), new temperature control device (13), temperature control system (14), temperature sensor one (181), temperature sensor two (182);

[0039] The control terminal of the intelligent humidity control device (11) is connected to the humidity regulator (12), the feedback terminal of the intelligent humidity control device (11) is connected to the humidity sensor one (171) and the humidity sensor two (172), and the data output terminal of the intelligent humidity control device (11) is connected to the host computer (1).

[0040] The control terminal of the novel temperature control device (13) is connected to the temperature regulation system (14), the feedback terminal of the novel temperature control device (13) is connected to temperature sensor one (181) and temperature sensor two (182), and the data output terminal of the novel temperature control device (13) is connected to the host computer (1).

[0041] The grounding terminal of the test voltage generator (3) is connected to the grounding device one (161), the signal input terminal of the test voltage generator (3) is connected to the control terminal of the test voltage controller (2), the output terminal of the test voltage generator (3) is connected to the left end of the conductive busbar (6), the right end of the conductive busbar (6) is connected to the grounding device two (162), and the input terminal of the test voltage controller (2) is connected to the host computer (1).

[0042] The epoxy resin through-wall bushing (5) contains a cavity (15) and a conductive busbar (6). The test electrode (7) of the epoxy resin through-wall bushing (5) is connected to the current input terminal IB of the working current tester (8). The grounding terminal E of the working current tester (8) is connected to the grounding grid (9). The signal output terminal O of the working current tester (8) is connected to the data acquisition unit (10). The data acquisition unit (10) is connected to the host computer (1).

[0043] The epoxy resin through-wall sleeve (5), conductive busbar (6), test electrode (7), humidity regulator (12), humidity sensor one (171), humidity sensor two (172), temperature regulation system (14), temperature sensor one (181), and temperature sensor two (182) are all fixed inside the test chamber (4).

[0044] The method for evaluating the insulation status of epoxy resin through-wall bushings in switchgear under humid and hot conditions is characterized by comprising the following steps:

[0045] S1: The host computer (1) sends a test temperature setting signal to the new temperature control device (13). The new temperature control device (13) controls the temperature adjustment system (14) to set the ambient temperature inside the test chamber (4) to T℃. Temperature sensor 1 (181) and temperature sensor 2 (182) provide real-time feedback on the ambient temperature T inside the test chamber (4). r ℃ to new temperature control equipment (13), until TT r ≤ΔT B ;

[0046] S2: The host computer (1) sends a test humidity setting signal to the intelligent humidity control device (11). The intelligent humidity control device (11) controls the humidity regulator (12) to set the environmental humidity percentage in the test chamber (4) to w%RH. Humidity sensor 1 (171) and humidity sensor 2 (172) provide real-time feedback on the environmental humidity percentage w% in the test chamber (4). r %RH to intelligent humidity control equipment (11), until ww r ≤Δw B ;

[0047] S3: Turn on the test voltage generator (3), and send a test voltage setting signal to the test voltage controller (2) through the host computer (1). The test voltage controller (2) controls the test voltage generator (3) to quickly raise the voltage across the conductive busbar (6) in the epoxy resin through-wall bushing (5) to the test voltage value U. The working current tester (8) measures the working current I of the epoxy resin through-wall bushing (5) at this time. The data acquisition device (10) collects the working current I of the epoxy resin through-wall bushing (5) and transmits the data to the host computer (1) for storage.

[0048] S4: The temperature regulation system (14) is controlled by a new type of temperature control device (13) to change the ambient temperature inside the test chamber (4) at intervals of ΔT℃, and then at each ambient temperature T j The humidity is controlled by the intelligent humidity control device (11) to change the humidity in the test chamber (4) by the humidity regulator (12) at intervals of Δw%RH, and step S3 is repeated for N tests.

[0049] S5: Calculate the working current value I of the epoxy resin through-wall bushing. i :

[0050]

[0051] In the formula, w is the percentage of ambient humidity, y is the linear error factor, λ is the integral variable, k is the influence coefficient of ambient temperature, and T j T represents the ambient temperature inside the chamber during the j-th test. s The reference ambient temperature;

[0052] S6: The optimization algorithm is used to optimize and model formula (1) to obtain the value of y' that minimizes the error. The specific steps are as follows:

[0053] 1) Randomly generate an initial solution ζ and calculate the objective function f(ζ):

[0054]

[0055] In equation (2), f(ζ) represents the objective function, I ijI is the calculated value of the working current of the epoxy resin through-wall bushing for the j-th time. cj , where is the measured value of the working current of the epoxy resin through-wall bushing in the j-th test, and N is the total number of tests;

[0056] 2) Generate a new perturbation solution ζ', and calculate the objective function Δf = f(ζ) - f(ζ'); if Δf ≥ 0, accept the new solution; otherwise, obtain the new solution according to the probability acceptance criterion.

[0057] 3) Determine if the number of iterations has been reached. If it has, proceed to step 4); otherwise, proceed to step 2.

[0058] 4) Determine if the termination condition is met. If it is, the operation ends and the optimal solution is output. Otherwise, reset the iteration count and go to step 2).

[0059] S7: Substitute the minimum error value y' obtained in step S6 into formula (1) to obtain the optimized epoxy resin through-wall bushing working current I. i Calculation formula:

[0060]

[0061] S7: Calculate the insulation status assessment factor ε of epoxy resin through-wall bushing;

[0062]

[0063] In the formula, I i 'To optimize the operating current of the epoxy resin through-wall bushing, I' s This is the reference value for the working current of the epoxy resin through-wall bushing.

[0064] S8: When ε∈(0,5.56], it indicates that the epoxy resin through-wall bushing insulation performance has failed; when ε∈[5.56,+∞), it indicates that the epoxy resin through-wall bushing insulation performance is normal.

Claims

1. A method for evaluating the insulation state of an epoxy resin bushing in a switchgear under a wet heat environment, characterized by, Specifically includes: host computer (1), test voltage controller (2), test voltage generator (3), test box (4), epoxy resin wall bushing (5), conductive busbar (6), test electrode (7), cavity (15), grounding device one (161), grounding device two (162), working current tester (8), grounding grid (9), data collector (10), intelligent humidity control equipment (11), humidity regulator (12), humidity sensor one (171), humidity sensor two (172), new temperature control equipment (13), temperature regulation system (14), temperature sensor one (181), temperature sensor two (182); The control end of the intelligent humidity control equipment (11) is connected with the humidity regulator (12), the feedback end of the intelligent humidity control equipment (11) is connected with the humidity sensor one (171) and the humidity sensor two (172), and the data output end of the intelligent humidity control equipment (11) is connected with the host computer (1); The control end of the new temperature control equipment (13) is connected with the temperature regulation system (14), the feedback end of the new temperature control equipment (13) is connected with the temperature sensor one (181) and the temperature sensor two (182), and the data output end of the new temperature control equipment (13) is connected with the host computer (1); The grounding end of the test voltage generator (3) is connected with the grounding device one (161), the signal input end of the test voltage generator (3) is connected with the control end of the test voltage controller (2), the output end of the test voltage generator (3) is connected with the left end of the conductive busbar (6), the right end of the conductive busbar (6) is connected with the grounding device two (162), and the input end of the test voltage controller (2) is connected with the host computer (1); The epoxy resin wall bushing (5) contains the cavity (15) and the conductive busbar (6) inside, the test electrode (7) of the epoxy resin wall bushing (5) is connected with the current input terminal IB of the working current tester (8), the grounding terminal E of the working current tester (8) is connected with the grounding grid (9), the signal output terminal O of the working current tester (8) is connected with the data collector (10), and the data collector (10) is connected with the host computer (1); The epoxy resin wall bushing (5), the conductive busbar (6), the test electrode (7), the humidity regulator (12), the humidity sensor one (171), the humidity sensor two (172), the temperature regulation system (14), the temperature sensor one (181) and the temperature sensor two (182) are fixed inside the test box (4); The switch cabinet epoxy resin wall bushing insulation state evaluation method under the humid heat environment, characterized in that, comprising the following steps: S1: send a test temperature setting signal to the new temperature control device (13) through the host computer (1), and the new temperature control device (13) controls the temperature adjusting system (14) to set the environment temperature in the test box (4) to T ℃, and the temperature sensor one (181) and the temperature sensor two (182) feedback the environment temperature T in the test box (4) in real time to the new temperature control device (13) r ℃ until T-T r ≤ΔT B ; S2: The host computer (1) sends a test humidity setting signal to the intelligent humidity control device (11). The intelligent humidity control device (11) controls the humidity regulator (12) to set the environmental humidity percentage in the test chamber (4) to w%RH. Humidity sensor 1 (171) and humidity sensor 2 (172) provide real-time feedback on the environmental humidity percentage w% in the test chamber (4). r %RH to intelligent humidity control equipment (11), until ww r ≤Δw B ; S3: Turn on the test voltage generator (3), send the test voltage setting signal to the test voltage controller (2) through the host computer (1), and control the test voltage generator (3) to quickly rise the voltage at both ends of the conductive busbar (6) in the epoxy resin bushing (5) to the test voltage value U, and the working current tester (8) measures the working current I of the epoxy resin bushing (5) at this time. The data collector (10) collects the working current I of the epoxy resin bushing (5) and transmits the data to the host computer (1) for storage; S4: control the temperature adjustment system (14) by the new temperature control device (13) to change the environmental temperature in the test chamber (4) every interval AT °C, and then at each environmental temperature T j Next, control the humidity adjustment instrument (12) by the intelligent humidity control device (11) to change the environmental humidity in the test chamber (4) every interval Aw%RH of the humidity percentage, and repeat step S3 to conduct N tests. S5: Calculate the working current value I of the epoxy resin bushing i : where w is the ambient humidity percentage, y is a linear error factor, λ is an integration variable, k is an ambient temperature influence coefficient, T j Tj is the ambient temperature in the test chamber for the jth test s Tref is the reference ambient temperature S6: The formula (1) is optimized by using an optimization algorithm to obtain the value of y' that minimizes the error. The specific steps are as follows: 1) Randomly generate an initial solution ζ and calculate the objective function f(ζ): f(ζ) in formula (2) represents an objective function, I ij Ij is the calculated value of the working current of the jth epoxy resin bushing, I cj Ij is the measured value of the working current of the jth epoxy resin bushing, N is the total number of tests; 2) Generate a perturbed new solution ζ' and calculate the objective function Δf = f(ζ)-f(ζ'); 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 it has, go to step 4), otherwise, go to step 2); 4) Determine whether the termination condition is met. If it is met, the operation is ended, and the optimal solution is output, otherwise, reset the number of iterations and go to step 2); S7: The minimum error y' value obtained in step S6 is substituted into formula (1) to obtain the optimized working current I of the epoxy resin bushing i The calculation formula is: S7: Calculate the insulation state evaluation factor ε of the epoxy resin bushing; In the formula, I i I is the working current of the optimized epoxy bushing s I is the working current of the epoxy bushing S8: When ε ∈ (0, 5.56], it represents the failure of the insulation performance of the epoxy resin bushing; when ε ∈ [5.56, +∞), it represents the normal insulation performance of the epoxy resin bushing.

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