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To satisfy the rapid development of energy requirements, power transmission with higher voltage must be adopted. The large improvement in transmission voltage needs more excellent power equipment and better materials to meet its insulation requirement. Polytetrafluoroethylene (PTFE) nozzle used in high voltage circuit breaker faces the issue of breakdown and arc ablation, and thus superior performance...
Trap and polarization greatly affect dielectric breakdown and surface flashover behavior of insulating materials. Trap and polarization may be modified by electron beam irradiation via breaking polymeric molecular chains or triggering cross-linking. Polyethylene terephthalate (PET) with a thickness of 75 μm from DuPont was used to investigate the modifications of trap and polarization by electron...
Spectroscopy is a powerful non-destructive technique that utilizes electromagnetic radiation interaction effect to determine the energy level and structure of atomic or molecular substance. In the last two decades, several researchers attempted to explore new various applications of spectroscopy technology in transformer condition monitoring. These applications include quantifying furan concentration...
The dc breakdown strength of low density polyethylene (LDPE) decreases with an increase in thickness and temperature of the sample. The breakdown strength is influenced by the charge transport and electric field distortion, and is also related to the molecular chain displacement and fracture. This paper investigates mutual relations among the charge transport, molecular chain displacement, and thickness...
Nanodielectrics have been actively investigated in last two decades as they have shown some improved dielectric properties that are important for high voltage insulation applications. One of these improvements is the reduction in space charge when the nanodielectrics are subjected to dc electric fields. The formation of deep trap after introducing nanoparticles in the material has been widely reported...
Two kinds of oxygen/fluorine/nitrogen mixtures with large concentration of oxygen have been used to oxyfluorinate low density polyethylene (LDPE). The O2/F2/N2 volume fraction in the mixtures was 1/1/4 and 2/1/4, respectively. Both the original LDPE and oxyfluorinated samples are plate of 0.25∼0.30 mm in thickness. The space charge characteristics of the original LDPE and the oxyfluorinated samples...
Many papers reported that the effective permittivity of nanodielectrics decreased slightly by incorporating of small amount of nanoparticles, and increased at high nanoparticle loadings. The reduction of permittivity was close related to the molecular chains movements, chemical and physical interactions and polarization effects in interfacial region. This paper simulated the effective permittivity...
Compared with the conventional microcomposites, incorporating nanoparticles into polymeric matrix can better improve breakdown performance. Much works have been done to investigate the electrical properties of nanodielectrics since the first experimental results published. It is acknowledged that the interface between nanoparticle and polymeric matrix play a dominant role in the electric properties...
Compared with breakdown strength of insulating material used in power equipments, insulator employed in power system is easy suffered from surface flashover in vacuum. So, surface flashover has become a mainly restricted factor for developing high voltage and efficiency power equipments in vacuum. Although many works have been done to investigate the characteristics of surface flashover in vacuum,...
Nano alumina particles and nano titanium dioxide particles are incorporated with low density polyethylene to fabricate samples, respectively. The breakdown performance of samples is conducted in the transformer oil. Results indicate that both ac breakdown strength and dc breakdown strength of nanocomposites with appropriate particles concentration have an increase. For example, ac breakdown strength...
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