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The shortcomings of oil-immersed transformer solid insulation like low high-temperature resistance of the insulation paper and the uneven distribution of electric field caused by the large difference of dielectric constants between insulation paper and transformer oil, restricted the development of transformer with smaller size and larger capacity. In view of this situation and the transformer’s demand...
The dielectric constant and the high temperature resistant performance of solid insulation used in oil-immersed transformer would limit the capacity and size of an oil-immersed transformer. In this paper, kraft paper and polycarbonate has been aged under 90 °C, 110 °C and 130 °C up to 300 days, simultaneously an electric pre-stressing of 3kV/mm is performed. The dielectric spectroscopy (here refer...
The poor thermo stability and electrical properties of insulation paper used in an oil-immersed transformer would limit the performance and size of the transformer. In order to substitute insulation paper, we chose polyphenylene sulfide (PPS) as the object of study to make research on its electro-thermal aging characteristics. We tested PPS's dielectrical, physical, chemical and mechanical properties...
Traditionally, oil-filled transformers have utilized cellulose paper as primary insulation. However, cellulose insulation is a relatively low temperature material and thermal degradation due to overload conditions and long-term aging can lead to transformer failures, Therefore, it restraints the development of high density power transformers. What's more, since the transformer oil has a relative dielectric...
Material's micromechanism determines its property, therefore we should research on polymer material's micromechanism so as to further explain its insulation characteristic. From material's infrared spectrum, main function groups can be found through the wave numbers of absorption peaks. In the experiment five kinds of polymer materials, which are kraft paper, PC, PET, PTFE and PPS, are aged in the...
In the online monitoring on partial discharge of high voltage XLPE cable, severity of insulation electrical tree can be early warned through its partial discharge. This is an important measure to prevent sudden accident in high voltage cable and to ensure the normal operation of power system. This paper will apply the equivalent time-frequency analysis technology classified with PD pulses into the...
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