pollution flashover
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IEEE Access ◽  
2022 ◽  
pp. 1-1
Author(s):  
Ali Ahmed Salem ◽  
Kwan Yiew Lau ◽  
Wan Rahiman ◽  
Zulkurnain Abdul-Malek ◽  
Samir A. Al-Gailani ◽  
...  

2021 ◽  
Vol 9 ◽  
Author(s):  
Chunhua Fang ◽  
Yuning Tao ◽  
Jianguo Wang ◽  
Haixin You ◽  
Yan Cui ◽  
...  

The surface discharge development processes of polluted porcelain insulators for power transmission lines are tightly related with the development of leakage current (LC), the characteristics of LC, the insulating condition, and discharge intensity of the insulator surface have an important significance for revealing the contamination discharge state of insulators. In order to analyze the LC characteristics of porcelain insulators in the process of pollution flashover, artificial pollution flashover tests on porcelain insulators were conducted in the artificial fog cabinet, and the characteristics of LC waveforms in time-domain and frequency-domain were simultaneously measured and analyzed during the tests. The results indicated that the amplitude of LC, fundamental harmonic, the third harmonic, and fifth harmonic had a strong correlation, the maximum of LC(Im), the rate of total harmonics (THD), and the phase difference of fundamental harmonic (θ) were used for the representation of the characteristics of the LC waveform. The LC has the characteristics of high amplitude, low proportion harmonic, and small phase difference between the fundamental harmonic and voltage before the flashover occurrence. The test results provide effective reference for porcelain insulators in pollution flashover forecasting.


Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3784
Author(s):  
Xiaobo Meng ◽  
Liming Wang ◽  
Hongwei Mei ◽  
Chuyan Zhang

A pollution flashover along an insulation surface—a catastrophic accident in electrical power system—threatens the safe and reliable operation of a power grid. Silicone rubber coatings are applied to the surfaces of other insulation materials in order to improve the pollution flashover voltage of the insulation structure. It is generally believed that the hydrophobicity of the silicone rubber coating is key to blocking the physical process of pollution flashover, which prevents the formation of continuously wet pollution areas. However, it is unclear whether silicone rubber coating can suppress the generation of pre-discharges such as corona discharge and streamer discharge. In this research, the influence of silicone rubber coating on the characteristics of surface streamer discharge was researched in-depth. The streamer ‘stability’ propagation fields of the polymer are lower than that of the polymer with silicone rubber coating. The velocities of the streamer propagation along the polymer are higher than those along the polymer with silicone rubber coating. This indicates that the surface properties of the polymer with the silicone rubber coating are less favorable for streamer propagation than those of the polymer.


Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6491
Author(s):  
Jing Nan ◽  
Hua Li ◽  
Xiaodong Wan ◽  
Feng Huo ◽  
Fuchang Lin

The composite crossarm insulator differs greatly from the suspension insulator in structure and arrangement. This study aims to determine the pollution flashover characteristics of composite crossarm insulators under different voltage grades. Four types of AC composite crossarm insulators with diameters ranging from 100 mm to 450 mm are subjected to artificial pollution test, and then the effects of the surface hydrophobicity state of silicone rubber, core diameter, umbrella structure, arrangement, and insulation distance on the pollution flashover voltage of the composite crossarm insulators are analyzed. Under the pollution grade 0.2/1.0 mg/cm2 and voltage grade from 66 kV to 1000 kV, if the silicone rubber surface changes from HC5 to HC6, the pollution flashover voltage of the composite crossarm insulator will increase by 13.5% to 21.0% compared with the hydrophilic surface. If the core diameter changes from 100 mm to 300 mm, the pollution flashover voltage gradient decreases with the increase in core diameter; if the core diameter changes from 300 mm to 450 mm, the pollution flashover voltage gradient increases with core diameter. Under the same insulation height and core diameter, the umbrella structure will have a certain impact on pollution flashover voltage by up to 1.7% to 5.4%. Under the horizontal arrangement, the pollution flashover voltage can increase by 10.5% to 12.1% compared with that under the vertical arrangement. Under the hydrophilic surface and weak hydrophobicity state, the pollution flashover voltage has a linear relationship with the insulation distance. The above results can provide a reference for the structural design and optimization of the composite crossarm insulator.


Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1194
Author(s):  
Ali Ahmed Salem ◽  
Kwan Yiew Lau ◽  
Wan Rahiman ◽  
Samir A. Al-Gailani ◽  
Zulkurnain Abdul-Malek ◽  
...  

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.


2021 ◽  
Author(s):  
Bansi L Kaul

Abstract This paper is not just about the benefits of the smart plastics, but also about the potential remedies of the environmental concerns of their use. It is also a discussion about a potential pathway to an efficient use of fossil (combustion) fuels and the reduction of the emissions caused due to their use, in general. Morpholino-poly (piperazinyl-morpholinyl-triazin) imparts sustainable fire-safety and subdued incineration behaviour to plastics combined with weight reduction, and facilitates their melt processing. Additionally, it enables their ultimate environmentally friendly disposal as waste, after the ultimate use, coupled with simultaneous generation of usable energy. The knowledge & experience thus gained from energy extraction of waste plastics provide guidelines for future research to increase the efficiency of energy extraction and the reduction of emissions from combustion fuels in general. The technology is also intended to safeguard against open burning of plastics that leads to air-pollution flashover and forest fires. The various aspects of the experimental data generated are presented and plausible mechanisms of the technology are discussed.


Author(s):  
Li Jin ◽  
Li Ran ◽  
Wang Jilai ◽  
Zhang Zhijin ◽  
Jiang Xingliang

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