Improvement of surface flashover in vacuum

Li, Shengtao

doi:10.1049/hve.2020.0021

Cited by 59 publications

(47 citation statements)

References 137 publications

(269 reference statements)

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“…Besides improving wettability, adhesion and chemical stability, direct fluorination is effective approach to modulate the electrical properties for use as an insulating material for transformers, high and extra-high voltage cables, gas-insulated switchgears, inverter-fed motors etc. For the successful use of polymer dielectrics, it is necessary to control the main cause of aging and breakdown -the distribution of space charge in polymer materials [147,148].…”

Section: Electrical Properties Of Polymers After Direct Surface Fluorinationmentioning

confidence: 99%

“…The primary cause of the electric breakdown is the space charge accumulation in polymeric dielectric by charge injection at the electrodes and the field-assisted thermal ionization of internal impurities [55,148,149]. But surface charge accumulation on the insulator causing flashover is a result of a dynamic unbalance between the two contributions: one is the current driven by the normal component of electric field, and another is given by the gradient of the current flowing along the spacer surface, driven by the tangential component of electric field.…”

Section: Electrical Properties Of Polymers After Direct Surface Fluorinationmentioning

confidence: 99%

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Direct Fluorination as Method of Improvement of Operational Properties of Polymeric Materials

et al. 2020

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Direct fluorination of polymers is a widely utilized technique for chemical modification. Such introduction of fluorine into the chemical structure of polymeric materials leads to laminates with highly fluorinated surface layer. The physicochemical properties of this layer are similar to those of perfluorinated polymers that differ by a unique combination of chemical resistance, weak adhesion, low cohesion, and permittivity, often barrier properties, etc. Surface modification by elemental fluorine allows one to avoid laborious synthesis of perfluoropolymers and impart such properties to industrial polymeric materials. The current review is devoted to a detailed consideration of wetting by water, energy characteristics of surfaces, adhesion, mechanical and electrical properties of the polymers, and composites after the direct fluorination.

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Section: Electrical Properties Of Polymers After Direct Surface Fluorinationmentioning

confidence: 99%

Section: Electrical Properties Of Polymers After Direct Surface Fluorinationmentioning

confidence: 99%

Direct Fluorination as Method of Improvement of Operational Properties of Polymeric Materials

et al. 2020

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“…8−10 In large-scale electrical equipment, such as gas-insulated transmission lines (GILs), this problem is particularly significant, and it has become a bottleneck restricting the further development of electrical equipment. 11,12 To solve this problem, many scholars have conducted research and proposed a variety of solutions that can effectively promote the dissipation of the surface charge of a polymer and increase the surface flashover voltage. The mainstream methods include fluorination treatment 13−15 and plasma treatment.…”

Section: ■ Introductionmentioning

confidence: 99%

“…In the safe and stable operation of electrical and electronic equipment, polymer insulating materials have a very important role. The current development trend of the high power and high integration of electrical and electronic equipment has also led to higher requirements for the insulation properties of polymers. , However, during the operation of the electrical equipment, the surface of a polymer easily accumulates a large amount of charge and does not easily dissipate. − This accumulation will cause a local electric field distortion, induce a flashover along the surface, cause insulation failure, and lead to equipment damage. − In large-scale electrical equipment, such as gas-insulated transmission lines (GILs), this problem is particularly significant, and it has become a bottleneck restricting the further development of electrical equipment. , To solve this problem, many scholars have conducted research and proposed a variety of solutions that can effectively promote the dissipation of the surface charge of a polymer and increase the surface flashover voltage. The mainstream methods include fluorination treatment − and plasma treatment. − Although these modification methods have achieved satisfactory results in the laboratory, they have not been applied in industrial practice.…”

Section: Introductionmentioning

confidence: 99%

Oriented Boron Nitride Nanosheet Films for Thermal Management and Electrical Insulation in Electrical and Electronic Equipment

Wang

Zhang

et al. 2021

ACS Appl. Nano Mater.

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Insulation failure and insufficient thermal management in electrical and electronic equipment threaten their safe and stable operation and restrict development toward high power and high integration. Improved insulation or thermal conductivity often sacrifices important physical properties. Moreover, the cost of these methods is high, and the potential for performance improvement is limited. This article reports a thin film of oriented boron nitride nanosheets (BNNSs) that can be obtained by simple self-assembly. The special structure of the film, which provides excellent insulation and thermal conductivity, introduces many shallow traps and promotes the tangential dissipation of charge on the polymer surface while maintaining high normal electrical strength. The maximum flashover voltage increase rate is 30.3%, which greatly improves the insulation level. The film has a low leakage current, dielectric constant, and dielectric loss. Experiments and simulations show that the reasonable heat conduction path in the film provides excellent heat conduction performance and the maximum tangential thermal conductivity of the film is 9.3 W/(m•K), which effectively improves the thermal management capability of the device. The film is utilized in electrical and electronic equipment and exhibits excellent performance; thus, it has an important role in improving the insulation and heat dissipation performance of the equipment.

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“…The insulation failure caused by flashover may lead to serious accidents. In recent years, it has attracted much attention of researchers to improve the surface electrical performances of insulating materials [1][2][3][4][5]. Many methods are developed to avoid the occurrence of surface flashover, an important one of which is the surface fluorination.…”

Section: Introductionmentioning

confidence: 99%

Mechanism on improved surface flashover performances in vacuum of epoxy resin using fluorocarbon plasma treatment

et al. 2021

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To improve the insulation, strength of materials is a permanent topic in the fields of high voltage and insulation, and surface insulation is one of the difficulties. Research shows that the surface fluorination by a non‐equilibrium plasma is a promising method to enhance the surface flashover characteristics of insulating materials. However, the determinants of flashover characteristics are so many that the mechanism is not well known. This paper aims to find out the reasons for the surface insulation improvement and optimise the plasma process parameters. The epoxy resin surfaces are modified by a fluorocarbon plasma, and the flashover voltages in vacuum and secondary electron emission yield are tested experimentally. Combined with the state of the art and the authors' previous work, the mechanism of improved surface flashover performances is investigated in depth from three aspects: the plasma process parameters, the surface physical and chemical properties and the surface electrical performances. A comprehensive understanding of the mechanism is concluded, of which the whole processes from the plasma surface modification of materials to the surface insulation performances are taken into account. It is hopeful to promote the practical applications of plasma fluorination in electrical engineering through the findings of this paper.

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Improvement of surface flashover in vacuum

Cited by 59 publications

References 137 publications

Direct Fluorination as Method of Improvement of Operational Properties of Polymeric Materials

Direct Fluorination as Method of Improvement of Operational Properties of Polymeric Materials

Oriented Boron Nitride Nanosheet Films for Thermal Management and Electrical Insulation in Electrical and Electronic Equipment

Mechanism on improved surface flashover performances in vacuum of epoxy resin using fluorocarbon plasma treatment

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