Pollution morphology characteristics on a superhydrophobic surface and its pollution flashover voltage in DC electric field

With the accelerating construction of strong smart grid, and the grid voltage level rising, performance requirements for the electrical insulation of electrical equipment also continue to increase. In terms of the advantages of RTV on antifouling, RTV-based paints coated insulator coating capacity of its flash tolerance can significantly increase, mainly due to RTV coating hydrophobic hydrophobicity and migration. But when the hydrophobic surface is in the fully wet, many small drops of water in the surface will be gathered into big drops of water, and these large droplets will distort the surface electric field of the medium. So the flashover voltage of the hydrophobic surface’s separated water droplets under DC electric field are analyzed comparatively in this paper, while some influencing factors such as different medias and volume of water drops, are introduced in specific experiments, and their effects on the flashover voltage are analyzed; under DC electric field experiment on the surface of hydrophobic and hydrophilic surface flashover voltage drops separation characteristics were studied.

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Pollution Flashover Characteristics of Coated Insulators under Different Profiles of Coating Damage

Coatings ◽

10.3390/coatings11101194 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1194

Author(s):

Ali Ahmed Salem ◽

Kwan Yiew Lau ◽

Wan Rahiman ◽

Samir A. Al-Gailani ◽

Zulkurnain Abdul-Malek ◽

...

Keyword(s):

Electric Field ◽

Room Temperature ◽

Electrical Characteristics ◽

The Finite Element Method ◽

Damage Distribution ◽

Analysis Techniques ◽

Significant Difference ◽

Pollution Flashover ◽

Flashover Voltage ◽

Layer Resistance

Based on experiments and numerical analysis techniques, this paper aims to investigate the influence of the four different coating damage profiles on the performance of coated 33 kV porcelain insulator strings under polluted and clean surface conditions. The performance of the insulators coated with room temperature vulcanizing (RTV) under partial coating damage and undamaged coating was evaluated. The influence of humidity on pollution flashover was taken into consideration. The ring-shaped, fan-shaped, and random-shaped coating was applied following coating damage. The results showed that the flashover characteristic of the RTV-coated insulators had a significant difference as compared to the normal insulators. Electrical characteristics such as the flashover voltage, critical current, and surface resistance were significantly affected by coating damage distribution and humidity level on the insulators’ surface. The electric field and potential difference were analyzed as well using the finite element method (FEM). The initiation of the arc was observed to appear at the area of insulators where the electric field was the highest. It was also observed that different coating distributions of pollution and humidity levels resulted in a change in the surface pollution layer resistance and an uneven distribution of the electric field. This indicates that the coated insulators’ parameters are directly related to the coating damage distribution on the insulator surface, particularly in the presence of humidity.

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