With its unique features, photoconductive semiconductor switch (PCSS) is generally recognized today as a promising power electronic device. However, a major limitation of PCSS is its surprisingly low voltage threshold...With its unique features, photoconductive semiconductor switch (PCSS) is generally recognized today as a promising power electronic device. However, a major limitation of PCSS is its surprisingly low voltage threshold of surface flashover (SF). In this paper, an experimental study of surface flashover of a back-triggered PCSS is presented. The PCSSs with electrode gap of 18 mm are fabricated from liquid encapsulated czochralski (LEC) semi-insulating gallium arsenide (SI-GaAs), and they are either un-coated, or partly coated, or en- tirely coated PCSSs with high-strength transparent insulation. The SF fields of the PCSSs are measured and discussed. According to the experimental results, the high-dielectric-strength coating is efficient in both reducing the gas desorption from semiconductor and increasing the SF field: a well-designed PCSS can resist a voltage up to 20 kV under the repetition frequency of 30 Hz. The physical mechanism of the PCSS SF is analyzed, and the conclusion is made that having a channel structure, the SF is the breakdown of the contaminated dielectric layer at the semiconductor-ambient dielectric interface. The non-uniform distribution of the surface field and the gas desorption due to thermal effects of semiconductor surface currents are key factors causing the SF field reduction.展开更多
Biomimetic superhydrophobic(SH)coatings have emerged as a promising alternative to traditional room temperature vulcanizing(RTV)silicone rubber coatings for improving the flashover strength of insulators.However,organ...Biomimetic superhydrophobic(SH)coatings have emerged as a promising alternative to traditional room temperature vulcanizing(RTV)silicone rubber coatings for improving the flashover strength of insulators.However,organic contamination occurs in outdoor applications and thus a superamphiphobic(SAP)surface is more desirable but not yet reported for improving flashover performance.Herein,we developed a novel anti-flashover technique by fabricating robust SAP coating with unique gradient and micro-nanoscale hierarchical architecture.The SAP coating was fabricated by sequentially spray-depositing a resin-based primer and a silica-based topcoat on substrates(i.e.,glass slides and insulators).The primer not only functions as an adhesive offering strong adhesion to the substrate but also offers a micromastoid-like structure facilitating the subsequent formation of hierarchical micro-nanostructure.The appropriate spraying pressure leads to a diffusion of the fluorocarbon-modified silica nanoparticles into the primer to form a unique gradient structure,by analogy to inserting bullets into a wood.These features render the SAP coating excellent robustness with strong abrasive resistance,excellent ultraviolet(UV)resistance,and excellent chemical and thermal stability.Pollution flashover property of the SAP coating was explored and compared with that of SH and RTV specimens,from which a novel organic-contamination model to evaluate the flashover performance was proposed.The coated SAP glass insulator demonstrated 42.9%pollution flashover voltage improvement than RTV-coated insulator.These stated unique features reveal the convincing potential of the present SAP coatings to be applied for not only outdoor transmission line insulators for antiflashover but also other fields for self-cleaning,anti-fouling,and anti-icing.展开更多
为分析高湿气候下室温硫化硅橡胶(room temperature vulcanized silicone rubber,RTV)防污闪涂料的运行特性,对广东地区使用多年的RTV绝缘子进行了试验研究,包括外观状态、附着力、憎水性、污秽度等以及污秽闪络试验,并与山西地区RTV绝...为分析高湿气候下室温硫化硅橡胶(room temperature vulcanized silicone rubber,RTV)防污闪涂料的运行特性,对广东地区使用多年的RTV绝缘子进行了试验研究,包括外观状态、附着力、憎水性、污秽度等以及污秽闪络试验,并与山西地区RTV绝缘子的运行特性进行对比分析,在此基础上,提出了高湿气候下RTV涂料运行特性的特殊劣化特征及相关原因,并通过实验室模拟试验研究了这种劣化特征对绝缘子耐污闪性能的影响。结果表明,高湿气候下,广东RTV绝缘子的外观状态、附着力、憎水性都劣化得更为严重,悬垂串绝缘子与耐张串绝缘子表面的RTV涂层劣化特征不同,高湿多雨环境对RTV涂层的粘结性能有影响。试验结果及结论为高湿气候地区RTV涂料的使用和推广提供一定的试验依据。展开更多
基金Project supported by National Natural Science Foundation of China （50837005, 5110 7099）, Foundation of the State Key Laboratory of Electrical Insulation for Power Equip- ment （EIPE09203）.
文摘With its unique features, photoconductive semiconductor switch (PCSS) is generally recognized today as a promising power electronic device. However, a major limitation of PCSS is its surprisingly low voltage threshold of surface flashover (SF). In this paper, an experimental study of surface flashover of a back-triggered PCSS is presented. The PCSSs with electrode gap of 18 mm are fabricated from liquid encapsulated czochralski (LEC) semi-insulating gallium arsenide (SI-GaAs), and they are either un-coated, or partly coated, or en- tirely coated PCSSs with high-strength transparent insulation. The SF fields of the PCSSs are measured and discussed. According to the experimental results, the high-dielectric-strength coating is efficient in both reducing the gas desorption from semiconductor and increasing the SF field: a well-designed PCSS can resist a voltage up to 20 kV under the repetition frequency of 30 Hz. The physical mechanism of the PCSS SF is analyzed, and the conclusion is made that having a channel structure, the SF is the breakdown of the contaminated dielectric layer at the semiconductor-ambient dielectric interface. The non-uniform distribution of the surface field and the gas desorption due to thermal effects of semiconductor surface currents are key factors causing the SF field reduction.
基金the project“Synthesis and Application of Superhydrophobic Self-cleaning Materials for Electric Engineering”(No.6111901321)Overseas Expertise Introduction Project(111 project)for Discipline Innovation of China(No.B18038)the State Key Laboratory of Silicate Materials for Architectures(Wuhan University of Technology)Open Foundation(No.SYSJJ2021-02).
文摘Biomimetic superhydrophobic(SH)coatings have emerged as a promising alternative to traditional room temperature vulcanizing(RTV)silicone rubber coatings for improving the flashover strength of insulators.However,organic contamination occurs in outdoor applications and thus a superamphiphobic(SAP)surface is more desirable but not yet reported for improving flashover performance.Herein,we developed a novel anti-flashover technique by fabricating robust SAP coating with unique gradient and micro-nanoscale hierarchical architecture.The SAP coating was fabricated by sequentially spray-depositing a resin-based primer and a silica-based topcoat on substrates(i.e.,glass slides and insulators).The primer not only functions as an adhesive offering strong adhesion to the substrate but also offers a micromastoid-like structure facilitating the subsequent formation of hierarchical micro-nanostructure.The appropriate spraying pressure leads to a diffusion of the fluorocarbon-modified silica nanoparticles into the primer to form a unique gradient structure,by analogy to inserting bullets into a wood.These features render the SAP coating excellent robustness with strong abrasive resistance,excellent ultraviolet(UV)resistance,and excellent chemical and thermal stability.Pollution flashover property of the SAP coating was explored and compared with that of SH and RTV specimens,from which a novel organic-contamination model to evaluate the flashover performance was proposed.The coated SAP glass insulator demonstrated 42.9%pollution flashover voltage improvement than RTV-coated insulator.These stated unique features reveal the convincing potential of the present SAP coatings to be applied for not only outdoor transmission line insulators for antiflashover but also other fields for self-cleaning,anti-fouling,and anti-icing.
文摘为分析高湿气候下室温硫化硅橡胶(room temperature vulcanized silicone rubber,RTV)防污闪涂料的运行特性,对广东地区使用多年的RTV绝缘子进行了试验研究,包括外观状态、附着力、憎水性、污秽度等以及污秽闪络试验,并与山西地区RTV绝缘子的运行特性进行对比分析,在此基础上,提出了高湿气候下RTV涂料运行特性的特殊劣化特征及相关原因,并通过实验室模拟试验研究了这种劣化特征对绝缘子耐污闪性能的影响。结果表明,高湿气候下,广东RTV绝缘子的外观状态、附着力、憎水性都劣化得更为严重,悬垂串绝缘子与耐张串绝缘子表面的RTV涂层劣化特征不同,高湿多雨环境对RTV涂层的粘结性能有影响。试验结果及结论为高湿气候地区RTV涂料的使用和推广提供一定的试验依据。
