Method for determining failure characteristics of silicone rubber insulators based on the proportion of surface hydrophobicity loss area

Abstract

The present invention provides a method for determining the failure characteristics of silicone rubber insulators based on the proportion of the surface hydrophobicity loss area, which can accurately predict the proportion of the hydrophobicity loss area of ​​the silicone rubber insulator in combination with the electrical state of the insulator, and provide a new judgment standard for determining whether the silicone rubber insulator will fail, thereby providing accurate data support for the operation and maintenance measures of the insulator, ensuring the safe and stable operation of the power grid.

Description

Technical Field

[0001] The present invention relates to a method for determining failure characteristics of a silicone rubber insulator, and in particular to a method for determining failure characteristics of a silicone rubber insulator based on a proportion of a surface hydrophobicity loss area. Background Art

[0002] Composite insulators made of silicone rubber composite materials have excellent pollution flashover resistance due to their good hydrophobicity and hydrophobic migration, and have been widely used in power grids.

[0003] In harsh outdoor environments, the performance of the silicone rubber surface will deteriorate after long-term operation, and in severe cases, the insulation may even fail, causing power grid operation failures. In the prior art, the failure of silicone rubber insulators is often judged based solely on the leakage current of the insulator. However, when the hydrophobic area of ​​the silicone rubber insulator is damaged, the silicone rubber insulator is actually failed. However, there is no technology in the prior art to characterize the failure of the insulator based on the proportion of the hydrophobicity loss area, which reduces the accuracy of the judgment of the failure of the silicone rubber insulator.

[0004] Therefore, in order to solve the above technical problems, it is urgent to propose a new technical means. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a method for determining the failure characteristics of silicone rubber insulators based on the proportion of surface hydrophobicity loss areas, which can accurately predict the proportion of hydrophobicity loss areas of silicone rubber insulators in combination with the electrical state of the insulator, and provide a new judgment standard for determining whether the silicone rubber insulator will fail, thereby providing accurate data support for the operation and maintenance measures of the insulators, and ensuring the safe and stable operation of the power grid.

[0006] The present invention provides a method for determining failure characteristics of a silicone rubber insulator based on the proportion of a surface hydrophobicity loss area, comprising the following steps:

[0007] S1. Simulate different corrosion environments of silicone rubber insulators in the laboratory, and perform aging experiments on silicone rubber insulators in different corrosion environments, and record the parameters of silicone rubber insulators, including 50% flashover voltage U f , the voltage value of the i-th flashover U i And the ratio k of the water film area on the insulator surface to the area of ​​the entire insulator at different times;

[0008] S2. Determine the 99.87% tolerance gradient E of silicone rubber insulators under different working conditions 0.13 , and fitting silicone rubber insulator 99.87% withstand gradient E 0.13 Curves of variation with time and curves of leakage current variation with time;

[0009] S3. Fitting the curve of the ratio k of the water film area on the insulator surface to the area of ​​the entire insulator over time;

[0010] S4. Based on silicone rubber insulator 99.87% tolerance gradient E 0.13 The curves of the change with time and the curves of the change with time of the leakage current determine the 99.87% tolerance gradient E of the silicone rubber insulator in the actual operating environment. 0.13 The time t required to reach the failure threshold;

[0011] S5. Determine the predicted value of the ratio of the water film area on the surface of the silicone rubber insulator to the area of ​​the entire insulator in the actual operating environment from the curve of the ratio k of the water film area on the surface of the insulator to the area of ​​the entire insulator changing with time according to time t; and use the predicted value as the basis for judging the failure of the silicone rubber insulator in actual operation.

[0012] Further, in step S2, the silicone rubber insulator 99.87% withstands the gradient E 0.13 The curves changing with time and the expressions of the curves changing with time of leakage current are:

[0013] E 0.13 (t) = a·t -b ;

[0014] Where: a and b are constants related to the environmental parameters of silicone rubber insulators.

[0015] Further, in step S3, the curve expression of the ratio k of the water film area on the insulator surface to the area of ​​the entire insulator changing with time is:

[0016] Among them, α is the scale factor and β is the shape factor of the silicone rubber insulator.

[0017] Furthermore, 99.87% of silicone rubber insulators can withstand the gradient E 0.13 Determined by:

[0018] E 0.13 =(1-3σ%)(1-σ%)E f ; Where: σ is the standard deviation of the 50% average flashover voltage, E f is the flashover gradient.

[0019] Furthermore, the flashover gradient E f Determined by the following formula:

[0020] Among them, U f is the 50% average flashover voltage of the insulator, and H is the height of the silicone rubber insulator.

[0021] Furthermore, the average flashover voltage U of the insulator at 50% f Determined by the following formula:

[0022] Where m is the total number of flashovers of the silicone rubber insulator in the simulation test.

[0023] Further, σ is determined as the standard deviation of the 50% mean flashover voltage by:

[0024]

[0025] The beneficial effects of the present invention are as follows: Through the present invention, the proportion of the hydrophobicity loss area of ​​the silicone rubber insulator can be accurately predicted in combination with the electrical state of the insulator, providing a new judgment standard for whether the silicone rubber insulator will fail, thereby providing accurate data support for the operation and maintenance measures of the insulator, and ensuring the safe and stable operation of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0027] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below:

[0029] The present invention provides a method for determining failure characteristics of a silicone rubber insulator based on the proportion of a surface hydrophobicity loss area, comprising the following steps:

[0030] S1. Simulate different corrosion environments of silicone rubber insulators in the laboratory, that is, simulate different solute components, water mist conductivity and different charged voltages of silicone rubber insulators in the test environment; and perform aging tests on silicone rubber insulators in different corrosion environments, and record the parameters of silicone rubber insulators, including 50% flashover voltage U f , the voltage value of the i-th flashover U i And the ratio k of the water film area on the insulator surface to the area of ​​the entire insulator at different times;

[0031] S2. Determine the 99.87% tolerance gradient E of silicone rubber insulators under different working conditions 0.13 , and fitting silicone rubber insulator 99.87% withstand gradient E 0.13 The curves of the leakage current over time and the curves of the leakage current over time; specifically:

[0032] Silicone rubber insulator 99.87% tolerance gradient E 0.13 The curves changing with time and the expressions of the curves changing with time of leakage current are:

[0033] E 0.13 (t) = a·t -b ; Where: a and b are constants related to the environmental parameters of silicone rubber insulators;

[0034] S3. Fit the curve of the ratio k of the water film area on the insulator surface to the area of ​​the entire insulator over time; the curve expression of the ratio k of the water film area on the insulator surface to the area of ​​the entire insulator over time is:

[0035] Among them, α is the scale factor and β is the shape factor of the silicone rubber insulator.

[0036] The coefficients of the expressions of the above two curves are different in different corrosion environments. The coefficients of the above expressions are set according to the actual situation. The above two curves are obtained by fitting the discrete values ​​obtained in the experiment through the existing fitting algorithm. The fitting algorithm belongs to the prior art and will not be described in detail here.

[0037] S4. Based on silicone rubber insulator 99.87% tolerance gradient E 0.13 The curves of the change with time and the curves of the change with time of the leakage current determine the 99.87% tolerance gradient E of the silicone rubber insulator in the actual operating environment. 0.13 The time t required to reach the failure threshold;

[0038] S5. Determine the predicted value of the ratio of the water film area on the surface of the silicone rubber insulator to the area of ​​the entire insulator in the actual operating environment from the curve of the ratio k of the water film area on the surface of the insulator to the area of ​​the entire insulator changing with time according to time t; use the predicted value as the basis for judging the failure of the silicone rubber insulator in actual operation, for example, to judge the failure, perform a difference operation between the set threshold and the predicted value, when the difference is less than the set value, it indicates that the hydrophobicity of the insulator is about to fail, that is, the surface hydrophobicity loss area of ​​the silicone rubber insulator exceeds the threshold of the safe operation of the insulator, and operation and maintenance are required. The above process is to substitute the t value determined in step S4 into the curve expression of the ratio k of the water film area on the surface of the insulator to the area of ​​the entire insulator changing with time to obtain the predicted value k. Through the above method, the proportion of the hydrophobicity loss area of ​​the silicone rubber insulator can be accurately predicted in combination with the electrical state of the insulator, providing a new judgment standard for judging whether the silicone rubber insulator will fail, thereby providing accurate data support for the operation and maintenance measures of the insulator, and ensuring the safe and stable operation of the power grid.

[0039] In this embodiment, the silicone rubber insulator has a 99.87% tolerance gradient E 0.13 Determined by:

[0040] E 0.13=(1-3σ%)(1-σ%)E f ; Where: σ is the standard deviation of the 50% average flashover voltage, E f is the flashover gradient.

[0041] Flashover gradient E f Determined by the following formula:

[0042] Among them, U f is the 50% average flashover voltage of the insulator, and H is the height of the silicone rubber insulator.

[0043] Insulator 50% average flashover voltage U f Determined by the following formula:

[0044] Where m is the total number of flashovers of the silicone rubber insulator in the simulation test.

[0045] σ is the standard deviation of the 50% mean flashover voltage determined as follows:

[0046] Through the above method, the corresponding E can be accurately obtained based on the electrical parameters of the operation of the silicone rubber insulator. 0.13 It provides accurate data support for subsequent curve fitting.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for determining the failure characteristics of silicone rubber insulators based on the proportion of surface hydrophobicity loss area, characterized in that: The following steps are involved: S1. Simulate different corrosion environments of silicone rubber insulators in the laboratory, and perform aging experiments on silicone rubber insulators in different corrosion environments, and record the parameters of silicone rubber insulators, including the 50% average flashover voltage U of the insulator. f , the voltage value of the i-th flashover U i And the ratio k of the water film area on the insulator surface to the area of ​​the entire insulator at different times; S2. Determine the 99.87% tolerance gradient E of silicone rubber insulators under different working conditions 0.13 , and fitting silicone rubber insulator 99.87% withstand gradient E 0.13 Curves that change over time; S3. Fitting the curve of the ratio k of the water film area on the insulator surface to the area of ​​the entire insulator over time; S4. Based on silicone rubber insulator 99.87% tolerance gradient E 0.13 The time-varying curve determines the 99.87% tolerance gradient E of silicone rubber insulators in actual operating environment. 0.13 The time t required to reach the failure threshold; S5. Determine the predicted value of the ratio of the water film area on the surface of the silicone rubber insulator to the area of ​​the entire insulator in the actual operating environment from the curve of the ratio k of the water film area on the surface of the insulator to the area of ​​the entire insulator according to time t; The predicted value is used as the basis for judging the failure of silicone rubber insulators in actual operation.

2. The method for determining the failure characteristics of silicone rubber insulators based on the proportion of surface hydrophobicity loss area according to claim 1 is characterized in that: In step S2, the silicone rubber insulator 99.87% withstands the gradient E 0.13 The curve expression of time change is: E 0.13 (t)=a·t -b ; Where: a and b are constants related to the environmental parameters of silicone rubber insulators.

3. The method for determining the failure characteristics of silicone rubber insulators based on the proportion of surface hydrophobicity loss area according to claim 1 is characterized in that: In step S3, the curve expression of the ratio k of the water film area on the insulator surface to the area of ​​the entire insulator changing with time is: k(t)=1-e -(t / α)β ; Among them, α is the scale coefficient and β is the shape coefficient of the silicone rubber insulator.

4. The method for determining the failure characteristics of silicone rubber insulators based on the proportion of surface hydrophobicity loss area according to claim 1 is characterized in that: Silicone rubber insulator 99.87% tolerance gradient E 0.13 Determined by: E 0.13 =(1-3σ%)(1-σ%)E f ; Where: σ is the standard deviation of the 50% average flashover voltage of the insulator, E f is the flashover gradient.

5. The method for determining the failure characteristics of silicone rubber insulators based on the proportion of surface hydrophobicity loss area according to claim 4 is characterized in that: Flashover gradient E f Determined by the following formula: Among them, U f is the 50% average flashover voltage of the insulator, and H is the height of the silicone rubber insulator.

6. The method for determining failure characteristics of silicone rubber insulators based on the proportion of surface hydrophobicity loss area according to claim 4 is characterized in that: Insulator 50% average flashover voltage U f Determined by the following formula: Where m is the total number of flashovers of the silicone rubber insulator in the simulation test.

7. The method for determining the failure characteristics of silicone rubber insulators based on the proportion of surface hydrophobicity loss area according to claim 6 is characterized in that: σ is the standard deviation of the 50% mean flashover voltage of the insulator determined as follows:

Images