A performance test method for contaminated composite insulators

Abstract

The present invention provides a performance testing method for contaminated composite insulators. The testing method comprises: selecting a composite insulator and subjecting the composite insulator to an aging treatment using ultraviolet radiation to obtain an aged composite insulator; subjecting the surfaces of the original composite insulator and the aged composite insulator to a contamination treatment to obtain a contaminated composite insulator and a contaminated aged insulator; and independently performing leakage current testing, hydrophobicity testing, surface structure testing, and thermal resistance testing on the original composite insulator, the contaminated composite insulator, the aged composite insulator, and the contaminated aged insulator. The testing method can assess the impact of aging and surface contamination on the performance of composite insulators, thereby predicting the performance of composite insulators currently in use and ensuring the safety of transmission lines.

Description

Technical Field

[0001] The invention belongs to the field of electric power devices and designs a performance testing method for an insulator, in particular to a performance testing method for a contaminated composite insulator. Background Art

[0002] Insulators play a vital role in power systems, withstanding mechanical stress, ensuring safe distances between conductors, preventing current backflow to ground, protecting transmission lines, and isolating them from wire collisions. Compared to porcelain insulators, composite insulators offer superior resistance to contamination and are therefore more widely used. However, due to their long-term exposure to heavily polluted environments, composite insulators suffer from a certain degree of insulation and hydrophobicity. When contaminated, rain or condensation can easily form a layer of water droplets or mist on the surface of the insulator, distorting the electric field and potentially triggering surface discharge and flashover, posing a potential threat to the safe operation of transmission lines. Therefore, performance testing of composite insulators with varying degrees of contamination is of great engineering significance. However, effective methods for testing the insulation and hydrophobicity of contaminated composite insulators are currently lacking, and the underlying factors affecting their performance remain unexplained. Summary of the Invention

[0003] To solve the technical problems existing in the prior art, the present invention provides a performance testing method for contaminated composite insulators. The testing method can evaluate the impact of aging and surface contamination on the performance of composite insulators, thereby predicting the performance of composite insulators in use and providing protection for the safety of transmission lines.

[0004] In order to achieve the above technical effects, the present invention adopts the following technical solutions:

[0005] The present invention provides a performance testing method for a contaminated composite insulator, the testing method comprising:

[0006] Selecting a composite insulator, and performing an aging treatment on the composite insulator using ultraviolet radiation to obtain an aged composite insulator;

[0007] Performing contamination treatment on the surfaces of the original composite insulator and the aged composite insulator to obtain contaminated composite insulators and contaminated aged insulators;

[0008] The original composite insulators, contaminated composite insulators, aged composite insulators and contaminated aged insulators were independently subjected to leakage current test, hydrophobicity test, surface structure test and thermal resistance test.

[0009] In the present invention, the aging of the composite insulator is accurately simulated by ultraviolet radiation, and combined with pollution treatment, the influence of aging and pollution on the surface structure and material of the composite insulator can be accurately reflected. Combined with reasonable methods, the influence of aging and pollution on the performance of the composite insulator can be accurately reflected.

[0010] As a preferred technical solution of the present invention, the time for the ultraviolet radiation to irradiate the composite insulator is not less than 800 hours, such as 800 hours, 805 hours, 810 hours, 815 hours, 820 hours, 825 hours, 850 hours, 900 hours or 1000 hours, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0011] The ultraviolet radiation irradiation is not performed continuously, but is performed for several hours every day until the predetermined irradiation time is reached. The irradiation time each day can be the same or different. The irradiation time and number of days can be specifically selected according to the required aging degree, and are not specifically limited here.

[0012] As a preferred technical solution of the present invention, the contamination treatment is to immerse the original composite insulator and the aged composite insulator in contaminants separately and independently.

[0013] The time for which the original composite insulator and the aged composite insulator are immersed in the pollutants can be specifically selected according to the degree of contamination on the surface of the composite insulator to be studied, and is not specifically limited here.

[0014] As a preferred technical solution of the present invention, the pollutant is an aqueous solution containing salt and kaolin, wherein the salt is preferably sodium chloride.

[0015] As a preferred technical solution of the present invention, after the pollution treatment, the aged composite insulator and the polluted aged insulator are subjected to a secondary aging treatment using water penetration.

[0016] In the present invention, the function of the water penetration is to further simulate the aging condition of the composite insulator, so that the composite insulator is close to the aging condition in actual application.

[0017] As a preferred technical solution of the present invention, the water penetration treatment includes immersing the composite insulator in a salt solution, wherein the salt is preferably sodium chloride.

[0018] As a preferred technical solution of the present invention, the leakage current testing method includes applying a varying voltage to the composite insulator to be tested, and testing the leakage current at intervals according to the voltage variation.

[0019] In the present invention, the leakage current test specifically involves applying a starting voltage to the composite insulator and continuously increasing the applied voltage. When the voltage reaches a certain value, the corresponding leakage current value is read until the set maximum test voltage value is reached. Preferably, the voltage is increased at a uniform rate or a constant gradient, and the leakage current value is read at the same interval of voltage values.

[0020] As a preferred technical solution of the present invention, the hydrophobicity test method includes a contact angle test.

[0021] As a preferred technical solution of the present invention, the surface structure testing method includes SEM testing and EDX testing.

[0022] In the present invention, the SEM test can characterize the specific morphology of the composite insulator surface, while the EDX test can characterize the element distribution on the composite insulator surface.

[0023] As a preferred technical solution of the present invention, the thermal resistance test method includes thermogravimetric analysis-differential thermal analysis.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] The present invention provides a performance testing method for contaminated composite insulators. The testing method can evaluate the influence of aging and surface contamination on the performance of composite insulators, thereby predicting the performance of composite insulators in use and providing protection for the safety of transmission lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The figure is a flow chart of a performance testing method for a contaminated composite insulator provided in a specific embodiment of the present invention.

[0027] Figure 2 This is a schematic structural diagram of a composite insulator selected in a specific embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of an ultraviolet radiation experiment in a specific embodiment of the present invention;

[0029] Figure 4 This is a graph showing the leakage current test results under pure fog conditions in a specific embodiment of the present invention;

[0030] Figure 5 This is a diagram showing the leakage current test results under salt spray conditions in a specific embodiment of the present invention;

[0031] Figure 6a This is a water drop angle test diagram of the original composite insulator in a specific embodiment of the present invention;

[0032] Figure 6bThis is a water drop angle test diagram of an aged composite insulator in a specific embodiment of the present invention;

[0033] Figure 6c This is a water drop angle test diagram of a contaminated composite insulator in a specific embodiment of the present invention;

[0034] Figure 6d This is a water drop angle test diagram of a polluted and aged composite insulator in a specific embodiment of the present invention;

[0035] Figure 7a and Figure 7b These are SEM test images of the original composite insulator in a specific embodiment of the present invention (scales of 50 μm and 10 μm respectively);

[0036] Figure 7c and Figure 7d These are SEM test images of aged composite insulators in a specific embodiment of the present invention (scales of 50 μm and 10 μm respectively);

[0037] Figure 7e and Figure 7f These are SEM test images of contaminated composite insulators in a specific embodiment of the present invention (scales of 50 μm and 10 μm respectively);

[0038] Figure 7g and Figure 7h These are SEM test images of the polluted and aged composite insulator in a specific embodiment of the present invention (scales of 50 μm and 10 μm respectively);

[0039] Figure 8 It is a TG / DTA curve diagram in a specific embodiment of the present invention.

[0040] The present invention is further described in detail below. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims. DETAILED DESCRIPTION

[0041] To better illustrate the present invention and facilitate understanding of the technical solutions of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0042] In the specific embodiment of the present invention, eight 20kV post composite insulators are selected, and their structure is as follows: Figure 2 Four composite insulators were artificially aged, and the remaining four composite insulators were not treated. The laboratory environment conditions were 90% relative humidity and 30-34°C ambient temperature.

[0043] Table 1

[0044] Rated voltage Operating voltage Section length (H) Creepage distance Arcing distance (H) Lightning impulse withstand voltage 24kV 20kV 305±5mm 730±10mm 230±10mm 170kV

[0045] Example 1

[0046] This embodiment provides a performance test method for contaminated composite insulators. The process is as follows: Figure 1 As shown, the test method includes:

[0047] (1) Select a composite insulator and perform an aging treatment on the composite insulator using ultraviolet radiation, such as Figure 3 As shown, an aged composite insulator is obtained;

[0048] Among them, ultraviolet radiation was carried out for 825 hours, 11 hours per day;

[0049] (2) performing contamination treatment on the surfaces of the original composite insulator and the aged composite insulator to obtain a contaminated composite insulator and a contaminated aged insulator;

[0050] The filth was an aqueous solution of NaCl (12 gr / L) and kaolin (40 gr / L);

[0051] (3) After the pollution treatment, the aged composite insulator and the polluted aged insulator are subjected to secondary aging treatment by water penetration;

[0052] The water infiltration treatment uses a sodium chloride solution with a mass concentration of 0.1%, and the soaking time is 825 hours, 11 hours per day.

[0053] (4) Conduct leakage current tests on original composite insulators, contaminated composite insulators, aged composite insulators, and contaminated aged insulators independently;

[0054] The test conditions are: increasing the source voltage from 11.6kV to 50kV with an interval of 5kV, and measuring the leakage current of the insulator;

[0055] ① Under pure fog conditions, conduct leakage current test, the results are as follows Figure 4 As shown. Figure 4 It can be found that with the increase of test voltage, the leakage current of insulators in original state and aged state has a small increasing trend, while the presence of dirt destroys the hydrophobic recovery process of the insulator surface, resulting in a decrease in its hydrophobic performance and a sharp increase in leakage current.

[0056] ② Under salt spray conditions, conduct leakage current test, the results are as follows Figure 5 As shown. Figure 5As can be seen in the figure, because the conductivity of salt fog (20 S / m) is much higher than that of clean fog (2 S / m), the leakage current of composite insulators exposed to salt fog also increases. Compared to clean fog, the leakage current of aged insulators exposed to salt fog is more severe. Contaminated insulators, on the other hand, are less affected by salt fog, with leakage current levels roughly the same as those in clean fog. Contaminated and aged insulators, however, do not experience a significant increase in leakage current due to the effects of salt fog.

[0057] (5) Conduct hydrophobicity tests on original composite insulators, contaminated composite insulators, aged composite insulators, and contaminated aged insulators independently;

[0058] Specifically, according to the IEC62073 classification standard, the hydrophobicity of the sample is graded by measuring the angle of water droplets on the surface of the insulator. The test structure is as follows: Figure 6a -d as shown;

[0059] Through analysis Figure 6a -d shows that both aging and contamination lead to a decrease in the hydrophobicity of composite insulators, with aged insulators containing contaminants achieving the lowest hydrophobicity rating. While the composite insulators' drainage and pollution resistance abilities have been reduced due to aging and contamination, their hydrophobicity remains within the first category. This further demonstrates the excellent hydrophobicity of composite insulators.

[0060] (6) Conduct surface structural tests on original composite insulators, contaminated composite insulators, aged composite insulators, and contaminated aged insulators independently;

[0061] Specifically, the specific morphology of the composite insulator surface is characterized by SEM testing, and the element distribution on the composite insulator surface is characterized by EDX testing.

[0062] The test conditions of SEM and EDX are as follows: Hitachi SU 3500 was used to perform SEM-EDX test under the conditions of voltage 10kV, magnification 1000 (50μm), and magnification 5000 (10μm). The test results of SEM are shown in the figure. Figure 7a -h, and the EDX test results are shown in Table 2.

[0063] Through analysis Figure 7a -h shows that the surface of the original sample is smoother and the contaminants are lighter. In contrast, the surface of the aged sample is rougher and the contaminant concentration is higher, indicating that the hydrophobicity and anti-contamination ability of the insulator decrease after aging.

[0064] Naturally aged composite insulators undergo two chemical reactions: one is compound softening, breaking long chemical bonds into short ones; the other is cross-linking between compounds, forming new compounds. To investigate the effects of aging and contamination on the composition of insulator materials, EDX experiments were conducted on samples. The EDX test results are shown in Table 2.

[0065] Table 2

[0066]

[0067] Analysis of Table 2 shows that after aging, the silicon content of composite insulators decreases, while the oxygen and carbon contents increase. The silicon and oxygen on the composite insulator surface are both present in compound chains (Si-O) and kaolin contaminants (Al₂O₃, 2SiO₂, 2H₂O). Oxygen is also present in the aluminum hydroxide filler, while Al originates both from the composite insulator's aluminum hydroxide filler and from the contaminants. For contaminated insulators, the oxygen content increases due to oxidation caused by UV radiation and corona activity.

[0068] (7) Conduct thermal resistance tests on original composite insulators, contaminated composite insulators, aged composite insulators, and contaminated aged insulators independently;

[0069] Specifically, the thermogravimetric analysis-differential thermal analysis method was used, and the temperature rise rate was 10℃ / min. In the experiment, the temperature rise rate of each sample was 10℃ / min, and the TG curve and DTG curve were recorded, such as Figure 8 shown.

[0070] In order to obtain the temperature information of the insulator material, the two slopes of the TG curve are qualitatively analyzed, and the results are shown in Table 3.

[0071] Table 3

[0072]

[0073] Through analysis Figure 8 As shown in Table 3, there was no significant change in mass between the original and aged samples, and the changes in both slopes were similar. In the first slope, the mass loss of the composite insulator was caused by the volatilization of volatile components (such as water and low-molecular-weight solvents). The mass change in the second slope was caused by the thermal decomposition of the composite insulator's filler, Al(OH)3, into aluminum compounds and water. This experiment also indirectly demonstrated that the composite insulator maintained excellent thermal stability and degradation resistance even after UV radiation, water penetration testing, and contaminant coating.

[0074] Research using the embodiments of the present invention has shown that aging and contamination significantly impact the performance of composite insulators. The presence of contaminants creates a rough surface texture on the composite insulator, reducing its hydrophobicity, which in turn increases leakage current and the probability of flashover. Furthermore, aging of the insulating material reduces the silicon content and increases the oxygen and carbon contents, further reducing the hydrophobicity and insulation performance of the composite insulator.

[0075] The applicant declares that the present invention is intended to illustrate the detailed structural features of the present invention through the above-described embodiments, but the present invention is not limited to the above-described detailed structural features. This does not mean that the present invention must rely on the above-described detailed structural features in order to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for selected components, additions of auxiliary components, and selection of specific embodiments, etc., fall within the scope of protection and disclosure of the present invention.

[0076] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0077] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0078] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A performance testing method for contaminated composite insulators, characterized in that: The test method includes: Selecting a composite insulator, and performing an aging treatment on the composite insulator using ultraviolet radiation to obtain an aged composite insulator; The surfaces of the original composite insulator and the aged composite insulator are subjected to contamination treatment to obtain contaminated composite insulators and contaminated aged insulators; after the contamination treatment, the aged composite insulator and the contaminated aged insulator are subjected to secondary aging treatment using water penetration; the water penetration method comprises immersing the composite insulator in a salt solution; The original composite insulators, contaminated composite insulators, aged composite insulators and contaminated aged insulators were independently subjected to leakage current test, hydrophobicity test, surface structure test and thermal resistance test.

2. The performance testing method according to claim 1, wherein: The ultraviolet radiation irradiates the composite insulator for no less than 800 hours.

3. The performance testing method according to claim 1, characterized in that: The contamination treatment is to immerse the original composite insulator and the aged composite insulator in contamination respectively and independently.

4. The performance testing method according to claim 3, characterized in that: The filth is an aqueous solution containing salt and kaolin.

5. The performance testing method according to claim 1, wherein: The leakage current test method includes applying a varying voltage to the composite insulator to be tested, and testing the leakage current at intervals according to the voltage variation.

6. The performance testing method according to claim 1, wherein: The hydrophobicity test method includes a contact angle test.

7. The performance testing method according to claim 1, characterized in that: The surface structure testing method includes SEM testing and EDX testing.

8. The performance testing method according to claim 1, characterized in that: The thermal resistance test method includes thermogravimetric analysis-differential thermal analysis.

Images