A method for evaluating the insulation health of epoxy resin in high and low temperature environments

Abstract

The present invention provides an insulation health assessment method for epoxy resin considering high and low temperature environments, characterized in that an insulation health status test platform for epoxy resin considering high and low temperature environments is built, and the assessment steps are as follows: epoxy resin and three electrodes are placed in a test box, the temperature in the test box is set by adjusting a temperature regulator, a DC voltage is applied to the epoxy resin by a high resistance meter, and a volume resistivity health parameter is measured, and at the same time, a current flowing through the epoxy resin in a high and low temperature environment is measured by a high-precision Rogowski coil, and the volume resistivity health parameter value of the epoxy resin in the high and low temperature environment is calculated, and then the volume resistivity health parameter calculation formula is optimized by an iterative algorithm to obtain the optimized volume resistivity health parameter value, and then the surface health factor of the epoxy resin sample at different temperatures is calculated, and finally the insulation health assessment comprehensive factor of the epoxy resin in the high and low temperature environment is calculated and the epoxy resin health status is evaluated. The present invention is committed to providing an insulation health assessment method for epoxy resin considering high and low temperature environments, providing a reference for the safe and stable operation of power systems.

Description

Technical Field

[0001] The invention relates to the field of epoxy resin health assessment, in particular to an epoxy resin insulation health assessment method considering high and low temperature environments. Background Art

[0002] Insulating resin is widely used in the field of electrical insulation due to its excellent electrical insulation performance, mechanical properties, corrosion resistance and mature technology. For example, bushings, contact boxes, post insulators, and insulating sleeves can be used as packaging materials to effectively isolate electrical components from the complex external environment and improve the insulation performance of equipment. However, with the continuous increase in the capacity of the power system, epoxy resin faces the phenomenon of declining insulation health in high or low temperature working environments. The decline in its own health status restricts the reliability and service life of equipment operation. Once the health status of the insulating material declines, it is easy to cause electrical breakdown and scarring and ablation, causing electrical equipment and components to fail and damage. The failure rate of power equipment caused by the decline in insulation health is very high. The insulation health status of epoxy resin affects the safe and stable operation of the power system.

[0003] Existing research results show that the rise in ambient temperature will lead to a decrease in the health of epoxy resin and more serious insulation degradation, but there is currently a lack of evaluation methods for the health of epoxy resin to determine the health of epoxy resin in high and low temperature environments. Therefore, it is urgent to study the insulation health evaluation method of epoxy resin considering high and low temperature environments, which can provide an important reference for understanding the insulation health of epoxy resin. Summary of the invention

[0004] In order to accurately evaluate the insulation health status of epoxy resin, the present invention provides an insulation health evaluation method of epoxy resin considering high and low temperature environments.

[0005] The technical solution for achieving the purpose of the present invention is as follows, comprising the following steps:

[0006] The first step is to build an insulation health status test platform for epoxy resin under high and low temperature environments. The platform specifically includes: a host computer (1), a temperature integrated control device (2), a temperature regulator (3), a temperature sensor 1 (41), a temperature sensor 2 (42), a temperature sensor 3 (43), a test box (5), an epoxy resin test piece (6), a high voltage electrode (7), a grounding electrode (8), a shielding electrode (9), a high resistance meter (10), a grounding device (11), a data acquisition device (12), a high-precision Rogowski coil (13), a temperature control bus (14), and a data transmission line (15);

[0007] The host computer is connected to a temperature integrated control device (2) and a data acquisition device (12); the temperature integrated control device (2) is connected to a temperature regulator (3) via a temperature control bus (14); and the data acquisition device (12) is connected to a high-precision Rogowski coil (13) via a data transmission line (15);

[0008] The temperature integrated control device (2) is connected to the temperature sensor 1 (41), the temperature sensor 2 (42), and the temperature sensor 3 (43); the temperature regulator (3), the temperature sensor 1 (41), the temperature sensor 2 (42), and the temperature sensor 3 (43) are all arranged inside the test box (5);

[0009] The data acquisition device (12) is connected to the high resistance meter (10), the high resistance meter (10) is connected to the high voltage electrode (7), the grounding electrode (8), the shielding electrode (9), and the grounding device (11), and the epoxy resin test piece (6) is connected to the high voltage electrode (7), the grounding electrode (8), and the shielding electrode (9);

[0010] The epoxy resin test piece (6), the high voltage electrode (7), the grounding electrode (8), and the shielding electrode (9) are all placed inside the test box (5); the signal output end of the high resistance meter (10) is connected to the data acquisition device (12);

[0011] The experimental method of the above experimental platform includes the following steps:

[0012] S1: Set the temperature of the test chamber (5) to T in the host computer (1). i The upper computer (1) sends a temperature setting signal to the temperature integrated control device (2), and the temperature integrated control device (2) controls the temperature regulator (3) to adjust the ambient temperature in the test box (5) through the temperature control bus (14); the temperature sensor 1 (41), the temperature sensor 2 (42), and the temperature sensor 3 (43) measure the temperature in the test box (5), and transmit the measurement results to the temperature integrated control device (2), and the temperature integrated control device (2) calculates the average value T of the three temperature measurement values avi , if T avi With T i The absolute error is less than T c , then T avi The information is transmitted back to the host computer (1), otherwise the temperature integrated control device (2) continues to control the temperature regulator (3) to adjust the temperature in the test chamber (5);

[0013] S2: Turn on the high resistance meter (10) and apply a DC voltage of U = 1000 V to the epoxy resin sample (6). After 60 seconds, obtain the epoxy resin sample (6) at the ambient temperature T i The current size I i ;

[0014] S3: turning off the high resistance meter (10), setting the temperature in the test box (5) by adjusting the temperature integrated control device (2) so that the temperature in the test box (5) is within the range of 5°C to 95°C, performing a set of tests with a gradient of 2.5°C, and repeating steps S1 and S2, using the high resistance meter (10) to measure the actual measured value of the volume resistivity health parameter under each set of temperature conditions;

[0015] S4: Calculate the healthy parameter reference value of volume resistivity of epoxy resin samples at different ambient temperatures T:

[0016]

[0017] In formula (1), λ A is the healthy parameter reference value of volume resistivity of epoxy resin samples under different ambient temperatures T, T is the ambient temperature, the unit of T is ℃, U is the epoxy resin test voltage, I i is the test current of epoxy resin under the test voltage, I i The unit of is A, σ is the error coefficient, and y is the integral variable.

[0018] S5: Optimize the volume resistivity health parameter of the epoxy resin sample to obtain the σ value that minimizes the error between the theoretical benchmark and the experimental measured value of the volume resistivity health parameter of the epoxy resin sample. The specific steps are:

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

[0020]

[0021] In the formula, f(x) represents the objective function, λ Bi is the reference value of the volume resistivity health parameter under the ith temperature condition, λ Si is the measured value of the volume resistivity health parameter under the i-th temperature condition, and n is the number of measured value data sets;

[0022] 2) Generate a new perturbed solution σ' and calculate the objective function Δf = f(σ) - f(σ'); 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 returned. Otherwise, the number of iterations is reset and the second step is performed.

[0025] S6: Substitute the σ obtained in S5 0 Substitute into formula (1) to obtain the optimized calculation formula:

[0026]

[0027] In formula (2), λ Ao is the optimized volume resistivity health parameter, T is the ambient temperature, U is the epoxy resin test voltage, I i It is the test current of epoxy resin under the test voltage.

[0028] S8: Calculate the surface health factor of epoxy resin samples at different temperatures:

[0029]

[0030] In formula (4), λ Bo is the surface health factor of epoxy resin samples at different temperatures, T is the ambient temperature, the unit of T is ℃, U is the epoxy resin test voltage, I i is the test current of epoxy resin under the test voltage, I i The unit is A.

[0031] S9: Calculate the comprehensive factor λ for insulation health assessment of epoxy resin under high and low temperature environments C :

[0032]

[0033] In formula (5), α 1 , α 2 is a weight factor and satisfies α 1 +α 2 =1.

[0034] The comprehensive factor λ of the insulation health assessment of epoxy resin under high and low temperature environment obtained based on the above steps C When λ∈(+∞, 5], the epoxy resin insulation is considered to be in good health; when λ∈(5, 3.5], the epoxy resin insulation is considered to be in general health and should be paid more attention to; when λ∈(3.5, 0], the epoxy resin is in poor health and should not be used to ensure insulation safety.

[0035] The beneficial effects of the present invention are:

[0036] 1) A test platform for the insulation health status of epoxy resin under high and low temperature environments was built. This platform can effectively simulate the health status of epoxy resin under high and low temperature environments;

[0037] 2) Based on the test platform, the comprehensive factors of insulation health assessment of epoxy resin under high and low temperature environments can be accurately obtained, and suggestions can be made through the comprehensive factors of insulation health assessment of epoxy resin under high and low temperature environments to further improve the insulation of the power system;

[0038] 3) The present invention is mainly completed through a host computer, and is easy to operate and safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of an insulation health status test platform for epoxy resin in high and low temperature environments shown in this application; DETAILED DESCRIPTION

[0040] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings. A specific implementation of an epoxy resin insulation health assessment method under high and low temperature environments includes the following steps:

[0041] Step 1: First, a test platform for the insulation health status of epoxy resin under high and low temperature environments is constructed, the platform comprising: a host computer (1), a temperature integrated control device (2), a temperature regulator (3), a temperature sensor 1 (41), a temperature sensor 2 (42), a temperature sensor 3 (43), a test box (5), an epoxy resin test piece (6), a high voltage electrode (7), a grounding electrode (8), a shielding electrode (9), a high resistance meter (10), a grounding device (11), a data acquisition device (12), a high-precision Rogowski coil (13), a temperature control bus (14), and a data transmission line (15);

[0042] The host computer is connected to a temperature integrated control device (2) and a data acquisition device (12); the temperature integrated control device (2) is connected to a temperature regulator (3) via a temperature control bus (14); and the data acquisition device (12) is connected to a high-precision Rogowski coil (13) via a data transmission line (15);

[0043] The temperature integrated control device (2) is connected to the temperature sensor 1 (41), the temperature sensor 2 (42), and the temperature sensor 3 (43); the temperature regulator (3), the temperature sensor 1 (41), the temperature sensor 2 (42), and the temperature sensor 3 (43) are all arranged inside the test box (5);

[0044] The data acquisition device (12) is connected to the high resistance meter (10), the high resistance meter (10) is connected to the high voltage electrode (7), the grounding electrode (8), the shielding electrode (9), and the grounding device (11), and the epoxy resin test piece (6) is connected to the high voltage electrode (7), the grounding electrode (8), and the shielding electrode (9);

[0045] The epoxy resin test piece (6), the high voltage electrode (7), the grounding electrode (8), and the shielding electrode (9) are all placed inside the test box (5); the signal output end of the high resistance meter (10) is connected to the data acquisition device (12);

[0046] The experimental method of the above experimental platform includes the following steps:

[0047] S1: Set the temperature of the test chamber (5) to T in the host computer (1). i The upper computer (1) sends a temperature setting signal to the temperature integrated control device (2), and the temperature integrated control device (2) controls the temperature regulator (3) to adjust the ambient temperature in the test box (5) through the temperature control bus (14); the temperature sensor 1 (41), the temperature sensor 2 (42), and the temperature sensor 3 (43) measure the temperature in the test box (5), and transmit the measurement results to the temperature integrated control device (2), and the temperature integrated control device (2) calculates the average value T of the three temperature measurement values avi , if T avi With T i The absolute error is less than T c , then T avi The information is transmitted back to the host computer (1), otherwise the temperature integrated control device (2) continues to control the temperature regulator (3) to adjust the temperature in the test chamber (5);

[0048] S2: Turn on the high resistance meter (10) and apply a DC voltage of U = 1000 V to the epoxy resin sample (6). After 60 seconds, obtain the epoxy resin sample (6) at the ambient temperature T i The current size I i ;

[0049] S3: turning off the high resistance meter (10), setting the temperature in the test box (5) by adjusting the temperature integrated control device (2) so that the temperature in the test box (5) is within the range of 5°C to 95°C, performing a set of tests with a gradient of 2.5°C, and repeating steps S1 and S2, using the high resistance meter (10) to measure the actual measured value of the volume resistivity health parameter under each set of temperature conditions;

[0050] S4: Calculate the healthy parameter reference value of volume resistivity of epoxy resin samples at different ambient temperatures T:

[0051]

[0052] In formula (1), λ A is the healthy parameter reference value of volume resistivity of epoxy resin samples under different ambient temperatures T, T is the ambient temperature, the unit of T is ℃, U is the epoxy resin test voltage, I i is the test current of epoxy resin under the test voltage, I i The unit of is A, σ is the error coefficient, and y is the integral variable.

[0053] S5: Optimize the volume resistivity health parameter of the epoxy resin sample to obtain the σ value that minimizes the error between the theoretical benchmark and the experimental measured value of the volume resistivity health parameter of the epoxy resin sample. The specific steps are:

[0054] 2) Randomly generate an initial solution σ and calculate the objective function f(σ):

[0055]

[0056] In the formula, f(x) represents the objective function, λ Bi is the reference value of the volume resistivity health parameter under the ith temperature condition, λ Si is the measured value of the volume resistivity health parameter under the i-th temperature condition, and n is the number of measured value data sets;

[0057] 2) Generate a new perturbed solution σ' and calculate the objective function Δf = f(σ) - f(σ'); if Δf ≥ 0, accept the new solution; otherwise, obtain the new solution according to the probability acceptance criterion;

[0058] 3) Determine whether the number of iterations has been reached. If so, go to step 4; otherwise, go to step 2.

[0059] 4) Determine whether the termination condition is met. If so, the operation ends and the optimal solution is returned. Otherwise, the number of iterations is reset and the second step is performed.

[0060] S6: Substitute the σ obtained in S5 0 Substitute into formula (1) to obtain the optimized calculation formula:

[0061]

[0062] In formula (2), λ Ao is the optimized volume resistivity health parameter, T is the ambient temperature, U is the epoxy resin test voltage, I i It is the test current of epoxy resin under the test voltage.

[0063] S8: Calculate the surface health factor of epoxy resin samples at different temperatures:

[0064]

[0065] In formula (4), λ Bo is the surface health factor of epoxy resin samples at different temperatures, T is the ambient temperature, the unit of T is ℃, U is the epoxy resin test voltage, I i is the test current of epoxy resin under the test voltage, I i The unit is A.

[0066] S9: Calculate the comprehensive factor λ for insulation health assessment of epoxy resin under high and low temperature environments C :

[0067]

[0068] In formula (5), α 1 , α2 is a weight factor and satisfies α 1 +α 2 =1.

[0069] The comprehensive factor λ of the insulation health assessment of epoxy resin under high and low temperature environment obtained based on the above steps C When λ∈(+∞, 5], the epoxy resin insulation is considered to be in good health; when λ∈(5, 3.5], the epoxy resin insulation is considered to be in general health and should be paid more attention to; when λ∈(3.5, 0], the epoxy resin is in poor health and should not be used to ensure insulation safety.

Claims

1. A method for evaluating the insulation health of epoxy resin in high and low temperature environments. It is characterized in that Firstly, a test platform for the insulation health status of epoxy resin under high and low temperature environments is built, which includes: a host computer (1), a temperature integrated control device (2), a temperature regulator (3), a temperature sensor 1 (41), a temperature sensor 2 (42), a temperature sensor 3 (43), a test box (5), an epoxy resin test piece (6), a high voltage electrode (7), a grounding electrode (8), a shielding electrode (9), a high resistance meter (10), a grounding device (11), a data acquisition device (12), a high-precision Rogowski coil (13), a temperature control bus (14), and a data transmission line (15); The host computer is connected to a temperature integrated control device (2) and a data acquisition device (12); the temperature integrated control device (2) is connected to a temperature regulator (3) via a temperature control bus (14); and the data acquisition device (12) is connected to a high-precision Rogowski coil (13) via a data transmission line (15); The temperature integrated control device (2) is connected to the temperature sensor 1 (41), the temperature sensor 2 (42), and the temperature sensor 3 (43); the temperature regulator (3), the temperature sensor 1 (41), the temperature sensor 2 (42), and the temperature sensor 3 (43) are all arranged inside the test box (5); The data acquisition device (12) is connected to the high resistance meter (10), the high resistance meter (10) is connected to the high voltage electrode (7), the grounding electrode (8), the shielding electrode (9), and the grounding device (11), and the epoxy resin test piece (6) is connected to the high voltage electrode (7), the grounding electrode (8), and the shielding electrode (9); The epoxy resin test piece (6), the high voltage electrode (7), the grounding electrode (8), and the shielding electrode (9) are all placed inside the test box (5); the signal output end of the high resistance meter (10) is connected to the data acquisition device (12); The experimental method of the above test platform includes the following steps: S1: Set the temperature of the test chamber (5) to T in the host computer (1). i The upper computer (1) sends a temperature setting signal to the temperature integrated control device (2), and the temperature integrated control device (2) controls the temperature regulator (3) to adjust the ambient temperature in the test box (5) through the temperature control bus (14); the temperature sensor 1 (41), the temperature sensor 2 (42), and the temperature sensor 3 (43) measure the temperature in the test box (5), and transmit the measurement results to the temperature integrated control device (2), and the temperature integrated control device (2) calculates the average value T of the three temperature measurement values avi , if T avi With T i The absolute error is less than T c , then T avi The information is transmitted back to the host computer (1), otherwise the temperature integrated control device (2) continues to control the temperature regulator (3) to adjust the temperature in the test chamber (5); S2: Turn on the high resistance meter (10) and apply a DC voltage of U = 1000 V to the epoxy resin sample (6). After 60 seconds, obtain the epoxy resin sample (6) at the ambient temperature T i The current size I i ; S3: turning off the high resistance meter (10), setting the temperature in the test box (5) by adjusting the temperature integrated control device (2) so that the temperature in the test box (5) is within the range of 5°C to 95°C, performing a set of tests with a gradient of 2.5°C, and repeating steps S1 and S2, using the high resistance meter (10) to measure the actual measured value of the volume resistivity health parameter under each set of temperature conditions; S4: Calculate the healthy parameter reference value of volume resistivity of epoxy resin samples at different ambient temperatures T: In formula (1), λ A is the healthy parameter reference value of volume resistivity of epoxy resin samples under different ambient temperatures T, T is the ambient temperature, the unit of T is ℃, U is the epoxy resin test voltage, I i is the test current of epoxy resin under the test voltage, I i The unit of is A, σ is the error coefficient, and y is the integral variable; S5: Optimize the volume resistivity health parameter of the epoxy resin sample to obtain the σ value that minimizes the error between the theoretical benchmark and the experimental measured value of the volume resistivity health parameter of the epoxy resin sample. The specific steps are: 1) Randomly generate an initial solution σ and calculate the objective function f(σ): In the formula, f(x) represents the objective function, λ Bi is the reference value of the volume resistivity health parameter under the ith temperature condition, λ Si is the measured value of the volume resistivity health parameter under the i-th temperature condition, and n is the number of measured value data sets; 2) Generate a new perturbed solution σ' and calculate the objective function Δf = f(σ) - f(σ'); 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 returned. Otherwise, the number of iterations is reset and the second step is performed. S6: Substitute the σ obtained in S5 0 Substitute into formula (1) to obtain the optimized calculation formula: In formula (2), λ Ao is the optimized volume resistivity health parameter, T is the ambient temperature, U is the epoxy resin test voltage, I i is the test current of epoxy resin under the test voltage; S8: Calculate the surface health factor of epoxy resin samples at different temperatures: In formula (4), λ Bo is the surface health factor of epoxy resin samples at different temperatures, T is the ambient temperature, the unit of T is ℃, U is the epoxy resin test voltage, I i is the test current of epoxy resin under the test voltage, I i The unit is A; S9: Calculate the comprehensive factor λ for insulation health assessment of epoxy resin under high and low temperature environments C : In formula (5), α 1 , α 2 is a weight factor and satisfies α 1 +α 2 =1; The comprehensive factor λ of the insulation health assessment of epoxy resin under high and low temperature environment obtained based on the above steps C When λ∈(+∞, 5], the epoxy resin insulation is considered to be in good health; when λ∈(5, 3.5], the epoxy resin insulation is considered to be in general health and should be paid more attention to; when λ∈(3.5, 0], the epoxy resin is in poor health and should not be used to ensure insulation safety.

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