Pouring curing degree real-time monitoring method for basin-type insulator of ultra / extra-high voltage GIS (Gas Insulated Switchgear)

Abstract

The invention discloses a pouring curing degree real-time monitoring method for an ultra / extra-high voltage GIS basin-type insulator, and the method comprises the following steps: S1, preparing a dumbbell-shaped sample in combination with an actual basin-type insulator epoxy alumina composite material formula and a pouring curing process; s2, calibrating the strain sensitivity coefficient of the Bragg grating by using a dumbbell-shaped sample; s3, calibrating the temperature sensitivity coefficient of the Bragg grating by using the dumbbell-shaped sample; s4, respectively arranging a temperature sensor and the calibrated Bragg grating on the basin-type insulator pouring mold, and testing real-time strain; and S5, according to the real-time strain change, the temperature change and the characteristics of the epoxy alumina composite material, calculating the curing degree of the ultra / extra-high voltage GIS basin-type insulator in real time. According to the method, the blank of real-time monitoring of the pouring curing degree of large epoxy pouring parts such as the extra / ultra-high voltage GIS basin-type insulators in the prior art is filled, and the finished product quality of the basin-type insulators is improved.

Description

Technical Field

[0001] The present invention belongs to the field of quality control of insulating parts of high-voltage switchgear, and in particular relates to a method for real-time monitoring of the casting solidification degree of an ultra-high / ultra-high voltage GIS pot-type insulator. Background Art

[0002] The pot insulator is the core component of the UHV GIS equipment and is widely used on site. The main insulation of the UHV GIS pot insulator adopts an epoxy-alumina composite material system. During the pouring and curing reaction and cooling process, the volume shrinkage will form internal stress, causing insufficient curing reaction, resulting in micro cracks, gaps, and strength reduction in large epoxy castings such as UHV GIS pot insulators. Therefore, real-time monitoring and calculation of the pouring curing degree of epoxy-alumina composite materials is of great significance for evaluating the pouring and curing effect of large epoxy castings such as UHV GIS pot insulators.

[0003] For the pouring curing degree test of epoxy alumina composite materials, DSC is mainly used. However, this test method is mainly for finished samples, and the single test time is long. It is impossible to realize the real-time monitoring of the pouring curing degree of epoxy alumina composite materials, and it is difficult to effectively evaluate the pouring curing effect of large epoxy castings such as ultra-high voltage GIS pot-type insulators in real time. In 2017, the CNKI document "Numerical Simulation of Curing Temperature Field of Hat-Shaped Structure of Resin-Based Composite Materials" and the 2017 Master's thesis of the Civil Aviation Flight Academy of China "Numerical Simulation and Experimental Study of Curing Process of Thermosetting Resin-Based Composite Materials" established the residual strain thermo-chemical model of composite materials and carried out the numerical simulation of the curing process of thermosetting composite materials such as epoxy resin, but the relevant models and simulations mainly remain in the theoretical analysis stage, lacking the real-time feedback of actual monitoring data, and it is difficult to achieve real-time monitoring of the pouring curing degree of large epoxy castings such as ultra-high voltage GIS pot-type insulators. In 2010, the CNKI document “Application of FBG Sensors in Composite Material Curing Monitoring” used Bragg gratings to carry out strain monitoring of composite materials during the curing process, but specifically to the real-time monitoring of the curing degree of large epoxy castings such as ultra-high / ultra-high voltage GIS pot-type insulators.

[0004] In order to fill the gap in the existing methods for real-time monitoring of the casting curing degree of large epoxy castings such as ultra-high voltage GIS pot-type insulators, and to better control the curing process of large epoxy castings, a real-time monitoring method for the casting curing degree of ultra-high voltage GIS pot-type insulators is proposed. However, there is no public report on this method. Summary of the invention

[0005] The purpose of the present invention is to propose a real-time monitoring method for the casting and curing degree of ultra-high voltage GIS pot-type insulators. The method uses Bragg grating strain temperature test to calculate and monitor in real time the casting and curing degree of large epoxy castings such as ultra-high voltage GIS pot-type insulators, which fills the gaps in existing methods.

[0006] In one aspect of the present invention, the present invention proposes a method for real-time monitoring of the pouring solidification degree of an ultra-high voltage GIS pot-type insulator. According to an embodiment of the present invention, the method comprises the following steps:

[0007] S1. Combined with the actual formula of epoxy-alumina composite material for pot-type insulator and the pouring and curing process, dumbbell-shaped specimens were prepared;

[0008] S2. Calibrate the strain sensitivity coefficient of the Bragg grating using a dumbbell-shaped specimen;

[0009] S3. Calibrate the temperature sensitivity coefficient of the Bragg grating using a dumbbell-shaped sample;

[0010] S4. Arrange temperature sensors and calibrated Bragg gratings on the pot-type insulator casting mold to test real-time strain;

[0011] S5. Calculate the curing degree of the ultra-high / ultra-high voltage GIS pot-type insulator in real time based on the real-time strain change, temperature change and properties of epoxy-alumina composite materials.

[0012] In addition, the method for real-time monitoring of the pouring solidification degree of an ultra-high voltage GIS pot-type insulator according to the above embodiment of the present invention may also have the following additional technical features:

[0013] In some embodiments of the present invention, in step S1, the epoxy-aluminum oxide composite material formula includes epoxy resin, curing agent, and aluminum oxide filler.

[0014] In some embodiments of the present invention, in step S2, the strain sensitivity coefficient of the Bragg grating is calibrated using the strain value of the dumbbell-shaped specimen at the same temperature and different limit loads and the grating period length.

[0015] In some embodiments of the present invention, step S2 is specifically as follows: a Bragg grating is arranged in the middle of a dumbbell-shaped specimen, and a tensile test is performed on a high and low temperature tensile tester. During the measurement process, the temperature inside the high and low temperature test chamber is kept constant, and an extensometer is used to measure the strain of the grating area under different extreme loads of the dumbbell-shaped tensile specimen, and its grating period length is recorded.

[0016] In some embodiments of the present invention, in step S2, the strain sensitivity coefficient is calibrated according to the following formula:

[0017]

[0018] Where n eff represents the effective refractive index of the Bragg grating used in the test, Λ (i+1) represents the grating period length of the i+1th test, Λ i represents the grating period length of the i-th test, ε i+1 represents the strain of the grating area under the i+1th ultimate load test of the dumbbell-shaped tensile specimen, ε i represents the strain of the grating area under the i-th ultimate load test of the dumbbell tensile specimen, k ε It represents the strain sensitivity coefficient after calibration of the strain sensitivity coefficient of the Bragg grating.

[0019] In some embodiments of the present invention, in step S3, the temperature sensitivity coefficient of the Bragg grating is calibrated using the strain value and grating period length of the dumbbell-shaped specimen at different temperatures and the same limit load.

[0020] In some embodiments of the present invention, step S3 is specifically as follows: keeping the ultimate load of the dumbbell-shaped tensile specimen unchanged, increasing the internal temperature of the high and low temperature test box, measuring the strain at different temperatures respectively, and recording the grating period length.

[0021] In some embodiments of the present invention, in step S3, the temperature sensitivity coefficient is calibrated according to the following formula:

[0022]

[0023] Where n eff represents the effective refractive index of the Bragg grating used in the test, Λ 4-(i+1) represents the length of the grating period of the i+1th time tested in step S3, Λ 4-i represents the length of the grating period of the i-th test in step S3, k T It represents the temperature sensitivity coefficient after the temperature sensitivity coefficient of the Bragg grating is calibrated in step S3.

[0024] In some embodiments of the present invention, in step S4, the test steps are as follows: the inner surface of the mold is cleaned, the mold is put into an oven for preheating, and then the mixture is mixed and poured, and the poured mold is put into the oven again, and solidified according to the process flow, and the temperature value β(t) of the temperature sensor and the Bragg grating period length Λ(t) at different solidification times t are recorded, and the strain ε(t) of the Bragg grating dot position is calculated according to the following formula;

[0025]

[0026] Where n effrepresents the effective refractive index of the Bragg grating used for the test, Λ(t) represents the grating period length at the curing time t, k T represents the temperature sensitivity coefficient of the Bragg grating after the temperature sensitivity coefficient is calibrated in step S3, k ε represents the strain sensitivity coefficient after the strain sensitivity coefficient of the Bragg grating is calibrated in step S2, Λ1 represents the initial value of the grating period length in step S4, and T1 represents the initial value of the temperature in step S4.

[0027] In some embodiments of the present invention, in step S5, the calculation formula for the casting solidification degree of the ultra-high voltage / ultra-high voltage GIS pot-type insulator is as follows:

[0028]

[0029] Where V r represents the volume fraction of epoxy resin in epoxy-aluminum oxide composite materials for ultra-high voltage GIS pot insulators, ε(t) represents the strain change of Bragg grating distribution position at curing time t, β(t) represents the temperature value of the temperature sensor at curing time t, α m (t) represents the linear thermal expansion coefficient of the epoxy-aluminum oxide composite material for ultra-high voltage GIS pot-type insulator at the curing time t, and t0 represents the starting time of curing.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The present invention solves the gap in existing methods for real-time monitoring of the casting curing degree of large epoxy castings such as ultra-high / ultra-high voltage GIS pot-type insulators.

[0032] (2) The present invention uses Bragg grating strain temperature test to calibrate the strain sensitivity coefficient and temperature sensitivity coefficient of the Bragg grating using small-sized specimens. Combined with real-time temperature and strain tests and the properties of epoxy-aluminum oxide composite materials, real-time monitoring of the casting curing degree of large epoxy castings such as ultra-high / ultra-high voltage GIS pot-type insulators can be achieved.

[0033] (3) The present invention fills the gap in the existing methods for real-time monitoring of the casting curing degree of large epoxy castings such as ultra-high voltage GIS pot-type insulators, and can better control the curing process of large epoxy castings and improve the finished product quality of pot-type insulators, which is of great significance for improving the operating reliability of ultra-high voltage GIS.

[0034] (4) The present invention can timely discover and solve problems in the curing process by real-time monitoring of the curing degree of large epoxy castings, thereby improving product quality, which is of great significance for improving the operating reliability of ultra-high / ultra-high voltage GIS equipment.

[0035] (5) The real-time monitoring method proposed in the present invention can be widely used in the curing degree monitoring of other large epoxy castings, providing a new technical solution for related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The Bragg grating used for monitoring the curing degree of the epoxy-aluminum oxide composite material in the embodiment of the present invention;

[0037] Figure 2 It is a flow chart of a method for real-time monitoring of the pouring and curing degree of an ultra-high voltage / ultra-high voltage GIS pot-type insulator in an embodiment of the present invention;

[0038] Figure 3 The test curve of temperature and strain of the epoxy-aluminum oxide composite material in step S5 in the embodiment of the present invention;

[0039] Figure 4 Schematic diagram of the sample pouring process in step S4 in an embodiment of the present invention;

[0040] Figure 5 Schematic diagram of the sample curing process in step S4 in an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] like Figure 2 As shown, a method for real-time monitoring of the pouring and curing degree of an ultra-high voltage / ultra-high voltage GIS pot-type insulator comprises the following steps:

[0043] S1. Based on the actual formula of epoxy-alumina composite material for pot-type insulator and the casting and curing process, dumbbell-shaped specimens were prepared.

[0044] The composite sample material is an epoxy resin system for UHV basin insulators: CT5531Cl (solid at room temperature, solvent-free bisphenol A epoxy resin) and HT903Cl (carboxylic acid anhydride curing agent), with a mass ratio of 1:0.38. The filler used is α-type electrical alumina filler produced by China Aluminum Corporation. According to the actual application of UHV basin insulator process, the sample epoxy resin and alumina filler are degassed after being fully mixed, and then the preheated curing agent is added to the mixture and stirred, and finally the final mixture is injected into the mold. The mold is cleaned with ethanol and coated with a release agent in advance. The mold is preheated at 100°C for more than 5 hours before pouring. After pouring, the sample is sent to the oven for curing, and the residual strain is monitored at the same time.

[0045] like Figure 1 As shown, the Bragg grating used in the measurement is made on a common quartz optical fiber for communication. The fiber diameter is 125μm, the grating length is 12mm, the central wavelength is 1550nm and 1555nm, and the reflectivity is greater than 99%. A 30mm optical fiber is left at the end of the grating to fix it at the end cover opening of the mold. The sample is a cylindrical sample with a length of 70mm and a diameter of 80mm. The container for the reaction is an aluminum mold with a central opening on both sides of the end cover so that the optical fiber can be buried along the central axis of the sample, and the grating is arranged in the middle of the sample.

[0046] S2. Use dumbbell-shaped specimens to calibrate the strain sensitivity coefficient of the Bragg grating.

[0047] The Bragg grating was arranged in the middle of the dumbbell-shaped tensile specimen, and a tensile test was carried out on a high and low temperature tensile tester. During the measurement, the internal temperature of the high and low temperature test box was maintained at 20°C. An extensometer was used to measure the strains ε1, ε2, ε3, and ε4 of the grating area at 10%, 20%, 30%, and 40% of the ultimate loads of dumbbell-shaped tensile specimens 1, 2, 3, and 4, and the grating period lengths Λ1, Λ2, Λ3, and Λ4 were recorded. The strain sensitivity coefficient k of the Bragg grating was calibrated using the strain values ​​and grating period lengths at the same temperature and different ultimate loads. ε , the results are shown in Table 1.

[0048] Table 1 Strain values ​​and grating period lengths of samples at the same temperature and different limit loads

[0049]

[0050] Strain sensitivity coefficient k of Bragg grating ε The calculation formula is as follows:

[0051]

[0052] Where n effrepresents the effective refractive index of the Bragg grating used in the test, Λ (i+1) represents the grating period length of the i+1th test, Λ i represents the grating period length of the i-th test, ε i+1 represents the strain of the grating area under the i+1th ultimate load test of the dumbbell-shaped tensile specimen, ε i represents the strain of the grating area under the i-th ultimate load test of the dumbbell tensile specimen, k ε It represents the strain sensitivity coefficient after calibration of the strain sensitivity coefficient of the Bragg grating.

[0053] After calculation, k ε The value is 924.388.

[0054] S3. Use a dumbbell-shaped sample to calibrate the temperature sensitivity coefficient of the Bragg grating.

[0055] Keep the dumbbell-shaped tensile specimen at 40% of the ultimate load, increase the temperature inside the high and low temperature test chamber, and measure the strain ε of specimens 4-1, 4-2, 4-3, 4-4, 4-5, 4-6, 4-7, and 4-8 at 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, and 100°C respectively. 4-1 , ε 4-2 , ε 4-3 , ε 4-4 , ε 4-5 , ε 4-6 , ε 4-7 , ε 4-8 , and record its grating period length Λ 4-1 ,Λ 4-2 ,Λ 4-3 ,Λ 4-4 ,Λ 4-5 ,Λ 4-6 ,Λ 4-7 ,Λ 4-8 The temperature sensitivity coefficient k of the Bragg grating is calibrated using the strain value and grating period length at different temperatures and the same limit load. T , the results are shown in Table 2;

[0056] Table 2 Strain values ​​and grating period lengths of the samples at different temperatures and the same limit load in step S3

[0057]

[0058] The temperature sensitivity coefficient is calibrated according to the following formula:

[0059]

[0060] Where n eff represents the effective refractive index of the Bragg grating used in the test, Λ4-(i+1) represents the length of the grating period of the i+1th time tested in step S3, Λ 4-i represents the length of the grating period of the i-th test in step S3, k T It represents the temperature sensitivity coefficient after the temperature sensitivity coefficient of the Bragg grating is calibrated in step S3.

[0061] After calculation, k T The value is 1045.501.

[0062] S4. Arrange temperature sensors and calibrated Bragg gratings on the pot-type insulator casting mold to test real-time strain.

[0063] Clean the inner surface of the mold, put the mold into the oven for preheating, and then mix and pour. The pouring time and temperature are as follows: Figure 4 Then the cast mold is put into the oven again and cured according to the process flow. The curing time and temperature are as shown in Figure 5 The temperature value β(t) of the temperature sensor and the period length Λ(t) of the Bragg grating were recorded at different curing times t, and the strain ε(t) of the Bragg grating distribution position was calculated according to the following formula. The results are shown in Table 3.

[0064]

[0065] Where n eff represents the effective refractive index of the Bragg grating used for the test, Λ(t) represents the grating period length at the curing time t, k T represents the temperature sensitivity coefficient of the Bragg grating after the temperature sensitivity coefficient is calibrated in step S3, k ε represents the strain sensitivity coefficient after the strain sensitivity coefficient of the Bragg grating is calibrated in step S2, Λ1 represents the initial value of the grating period length in step S4, and T1 represents the initial value of the temperature in step S4.

[0066] Table 3 β(t), Λ(t), ε(t) values ​​of pot-type insulators at different curing times t in step S4

[0067]

[0068] S5. According to the real-time strain change ε(t), the temperature value β(t) of the temperature sensor and the properties of the epoxy-alumina composite material, the casting curing degree of the ultra-high / ultra-high voltage GIS pot-type insulator is calculated in real time. The results are shown in Table 4.

[0069] The curing degree calculation formula is as follows:

[0070]

[0071] Where Vr represents the volume fraction of epoxy resin in epoxy-aluminum oxide composite materials for ultra-high voltage GIS pot insulators, ε(t) represents the strain change of Bragg grating distribution position at curing time t, β(t) represents the temperature value of the temperature sensor at curing time t, α m (t) represents the linear thermal expansion coefficient of the epoxy-aluminum oxide composite material for ultra-high voltage GIS pot-type insulator at the curing time t, and t0 represents the starting time of curing.

[0072] Table 4 Casting solidification value of super / UHV GIS pot insulator in step S5

[0073]

[0074] like Figure 5 As shown in the figure, in the stage before point A, the system is still in liquid state, and the contraction strain monitored by the grating remains at 0. After point A, the strain curve decreases linearly with time. Since the contraction strain monitored by the grating sensor at this time is caused by the curing reaction, it means that the curing reaction is carried out at a uniform speed with time during this period. Then, when the temperature just starts to rise, the sample curve moves upward with the temperature, indicating that the Bragg grating sensor has detected the tensile strain at this time. When the sample temperature is about to reach 130℃, the curve turns around and continues to move downward, forming the peak shown in area B. After analysis, this is the result of the combined effect of two factors: thermal expansion caused by temperature rise and contraction caused by curing reaction. The two have opposite effects. The former makes the strain curve move upward, and the latter makes the strain curve move downward. After the peak in area B, the strain curve continues to decrease with the reaction. When it reaches the position of area C, there will be a step. After analysis, it is believed that this is caused by the demoulding process: the axial contraction strain decreases after demoulding, and because the demoulding process is very short, it appears as a steep jump on the strain curve. After curing, the temperature in the oven was cooled from 130°C to room temperature at a rate of 10°C / h. As the temperature dropped at a uniform rate, the strain curve began to drop at a uniform rate. When it dropped to a certain temperature range, the slope of the curve changed, forming an inflection point D. After analysis, the change in the slope before and after point D was because the sample underwent a glass transition near this temperature, and the thermal expansion coefficient of the material changed.

[0075] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A method for real-time monitoring of the pouring and curing degree of an ultra-high voltage (UHV) GIS pot-type insulator, characterized in that: The following steps are involved: S1. Combined with the actual formula of epoxy-alumina composite material for pot-type insulator and the pouring and curing process, dumbbell-shaped specimens were prepared; S2. Calibrate the strain sensitivity coefficient of the Bragg grating using a dumbbell-shaped specimen; S3. Calibrate the temperature sensitivity coefficient of the Bragg grating using a dumbbell-shaped sample; S4. Arrange temperature sensors and calibrated Bragg gratings on the pot-type insulator casting mold to test real-time strain; S5. Calculate the curing degree of the ultra-high / ultra-high voltage GIS pot-type insulator in real time based on the real-time strain change, temperature change and properties of epoxy-alumina composite materials.

2. A method for real-time monitoring of casting curing degree of ultra-high voltage / ultra-high voltage GIS pot-type insulator according to claim 1, characterized in that: In the step S1, the formula of the epoxy-alumina composite material includes epoxy resin, curing agent, and alumina filler.

3. The method for real-time monitoring of casting curing degree of ultra-high voltage / ultra-high voltage GIS pot-type insulator according to claim 1 is characterized in that: In the step S2, the strain sensitivity coefficient of the Bragg grating is calibrated using the strain value of the dumbbell-shaped sample at the same temperature and different limit loads and the grating period length.

4. A method for real-time monitoring of casting curing degree of ultra-high voltage / ultra-high voltage GIS pot-type insulator according to claim 3, characterized in that: The step S2 is specifically as follows: a Bragg grating is arranged in the middle of a dumbbell-shaped specimen, and a tensile test is performed on a high and low temperature tensile tester. During the measurement process, the temperature inside the high and low temperature test chamber is kept constant, and an extensometer is used to measure the strain of the grating area under different extreme loads of the dumbbell-shaped tensile specimen, and its grating period length is recorded.

5. A method for real-time monitoring of casting solidification degree of ultra-high voltage / ultra-high voltage GIS pot-type insulator according to claim 4, characterized in that: In step S2, the strain sensitivity coefficient is calibrated according to the following formula: Where n eff represents the effective refractive index of the Bragg grating used in the test, Λ (i+1) represents the grating period length of the i+1th test, Λ i represents the grating period length of the i-th test, ε i+1 represents the strain of the grating area under the i+1th ultimate load test of the dumbbell-shaped tensile specimen, ε i represents the strain of the grating area under the i-th ultimate load test of the dumbbell tensile specimen, k ε It represents the strain sensitivity coefficient after calibration of the strain sensitivity coefficient of the Bragg grating.

6. A method for real-time monitoring of casting curing degree of ultra-high voltage / ultra-high voltage GIS pot-type insulator according to claim 1, characterized in that: In step S3, the temperature sensitivity coefficient of the Bragg grating is calibrated using the strain value and grating period length of the dumbbell-shaped specimen at different temperatures and the same limit load.

7. A method for real-time monitoring of casting curing degree of ultra-high voltage / ultra-high voltage GIS pot-type insulator according to claim 6, characterized in that: The step S3 is specifically as follows: keeping the ultimate load of the dumbbell-shaped tensile specimen unchanged, raising the internal temperature of the high and low temperature test box, measuring the strain at different temperatures respectively, and recording the grating period length.

8. A method for real-time monitoring of casting curing degree of ultra-high voltage / ultra-high voltage GIS pot-type insulator according to claim 7, characterized in that: In step S3, the temperature sensitivity coefficient is calibrated according to the following formula: Where n eff represents the effective refractive index of the Bragg grating used in the test, Λ 4-(i+1) represents the length of the grating period of the i+1th time tested in step S3, Λ 4-i represents the length of the grating period of the i-th test in step S3, k T It represents the temperature sensitivity coefficient after the temperature sensitivity coefficient of the Bragg grating is calibrated in step S3.

9. A method for real-time monitoring of casting curing degree of ultra-high voltage / ultra-high voltage GIS pot-type insulator according to claim 1, characterized in that: In step S4, the test steps are as follows: the inner surface of the mold is cleaned, the mold is put into an oven for preheating, and then the mixture is mixed and poured, and the poured mold is put into the oven again, and solidified according to the process flow, and the temperature value β(t) of the temperature sensor and the Bragg grating period length Λ(t) at different solidification times t are recorded, and the strain ε(t) of the Bragg grating dot position is calculated according to the following formula; Where n eff represents the effective refractive index of the Bragg grating used for the test, Λ(t) represents the grating period length at the curing time t, k T represents the temperature sensitivity coefficient of the Bragg grating after the temperature sensitivity coefficient is calibrated in step S3, k ε represents the strain sensitivity coefficient after the strain sensitivity coefficient of the Bragg grating is calibrated in step S2, Λ1 represents the initial value of the grating period length in step S4, and T1 represents the initial value of the temperature in step S4.

10. A method for real-time monitoring of casting curing degree of ultra-high voltage / ultra-high voltage GIS pot-type insulator according to claim 1, characterized in that: In step S5, the formula for calculating the casting solidification degree of the ultra-high voltage / ultra-high voltage GIS pot-type insulator is as follows: Where V r represents the volume fraction of epoxy resin in epoxy-aluminum oxide composite materials for ultra-high voltage GIS pot insulators, ε(t) represents the strain change of Bragg grating distribution position at curing time t, β(t) represents the temperature value of the temperature sensor at curing time t, α m (t) represents the linear thermal expansion coefficient of the epoxy-aluminum oxide composite material for ultra-high voltage GIS pot-type insulator at the curing time t, and t0 represents the starting time of curing.

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