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Polymer‐based dielectrics are essential components in electrical and power electronic systems for high power density storage and conversion. A mounting challenge for polymer dielectrics is how to maintain their electrical insulation at not only high electric fields but also elevated temperatures, in order to meet the growing needs for renewable energies and grand electrifications. Here, a sandwiched...
In this study, the effect of organically modified clay on the orientation enhancement in Nylon 11 in melt casting was investigated. Nylon 11 was mixed with 1 and 3 wt% Cloisite 20A using twin screw extrusion and they were cast into films with varying take‐up speeds. The addition of clay in Nylon 11 helped increase orientation levels substantially in melt cast films, both as a function of clay concentration...
In this study, the effect of processing on the structural and dielectric properties of Nylon 11 melt cast film was studied. Capacitor grade thin films were cast using a film extruder and stretched uniaxially and real‐time mechano‐optical data were acquired at temperatures ranging from solid state all the way to partially molten state. These studies were supplemented with offline WAXS, SAXS, and DSC...
The DC conduction of transformer oil and transformer oil-based nanofluids were investigated with increasing electric field strength in this paper. The results show that entire process of conduction can be divided into three stages, including resistance stage, tunneling stage and space-charge limited stage. Further analysis indicate that the generation and movement mechanism of carriers are different...
Oil impregnated paper is an important solid insulation dielectric in power transformers. Thus it is very significant to understand the dielectric properties of the oil impregnated paper. In this paper, a conductivity measuring system was built to explore the conduction mechanism of oil impregnated paper. This measuring system is able to measure the conduction current in the samples. Based on the system,...
Gas Insulted Switcher (GIS) is one of the most important equipments in power system. Partial discharges (PDs) detection has the vital significance to the condition diagnosis of GIS. In this paper, a multispectral optical PD detection system based on three photomultipliers (PMs) with corresponding light filters in the front is built to detect PD under power frequency voltage. The variations of the...
Metal enclosed switchgears, which have been widely used, play an important role in power distribution network. PD detection is an effective way to identify potential faults and inspect insulation defects for high-voltage switchgear. Occurring inside a switchgear, PD would emit electromagnetic (EM) wave that propagates and leaks to the outside, and it also excites the surface current on the metal wall...
In order to explore the relationship between microstructure and macroscopic performance of transformer oil-based nanofluids, the transformer oil modified by silicon dioxide nanoparticles were prepared whose stability and moisture content were measured. Then the dielectric spectroscopy of the pure oil and transformer oil-based nanofluids were measured and the influence of nanoparticle concentration...
The conduction mechanism under high field has a close relationship with the pre-breakdown process of dielectrics. In this paper, a conduction measuring system was built to explore the conduction mechanism of oil-paper insulation under high field. Based on the established system, the conduction current of transformer oil, kraft paper and oil impregnated paper were investigated under various applied...
In order to obtain the nanosecond partial discharge pulse current signal of needle-plate electrode, a new measurement method of wideband PD pulse current has been proposed in this paper. By the numerical calculation of current parameters, the optimized needle-plate electrode structure and the accurate finite element simulation, the experimental platform of the fast PD pulse current detection was set...
The transformer oil-based nanofluids have significant improvements in their thermal conductivity and dielectric strength than traditional transformer oil, so they have a wide prospect of application. In order to explore the mechanism of the thermal dissipation enhancement of transformer oil-based nanofluids, the flow field distribution of them under the DC voltage were measured by particle image velocimetry...
In order to obtain the nanosecond partial discharge pulse current signal of needle-plate electrode, a new measurement method of wideband PD pulse current is proposed in this paper. By the numerical calculation of current parameters, the optimized needle-plate electrode structure and the accurate finite element simulation, the experimental platform of the fast PD pulse current detection is set up and...
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