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The world of diagnostics has to keep up with the needs and possibilities today's world requires and offers. Everyone want to have the information they desire at the moment and, of course, at minimal cost. The world of diagnostics is no different. One tool that offers that is the online diagnostics. It has many benefits that allow, with proper usage of tools like CBM (condition based maintenance),...
This paper deals with the effect of inorganic micro/nanofillers and nanofabric on electrical tree growth in high voltage insulation. Experiments were conducted at a constant AC voltage of 20 kHz, 50 Hz epoxy samples without any fillers as well as epoxy nanocomposites with hydrophobic nanosilica or hydrophilic microsilica or polyamide nanofabric. The time to breakdown tree was observed and the transparency...
Natural esters are candidate fluids for transformer insulation system. Recently the most common insulation system in power transformers is paper-oil system. Oil generally mean petroleum based insulating fluid. As there are efforts to preserve sustainable development, crude oil products should be eliminated and replaced by natural products, which are easily biodegradable. In past it was shown that...
Until now not much attention was paid to behavior of insulating materials under different voltage stresses. For decades, the applied research was done generally under AC voltage. As power electronics was involved in drives and dominated instead of DC drives, new troubles with lifetime occurred. The great influence of higher harmonics does not affect operating parameters only but also it limits the...
Natural esters are candidate element of transformer insulation system. Recently most common insulation in power transformers is composed of mineral oil and transformer paper. As there are efforts to preserve sustainable development, crude oil products should be eliminated and replaced by natural products, which are easily biodegradable. In past, it was shown, that natural esters may reach qualities...
Partial discharges proved to be important diagnostic parameter during technical lifetime of operated electrical machines. Until now PD phenomena was well described and understood in technical society, especially for characteristic arrangement, e.g. corona, tip to plane, sphere to plane, and others. Most of the studies were done under AC voltage. However as DC transmission is concerned, more attention...
Insulating liquids are used as electrical insulation and cooling medium for power transformers. The most commonly used insulation liquid is mineral oil. Mineral oil is characterized by its high flammability and poor biodegradability. On the other hand, this oil has very good electrical properties. The future development of biodegradable oil is most focused on vegetable oils. The disadvantage of this...
The paper presents a methodology for processing experimental data related to the issue of the electrical insulation system endurance, using the method of accelerated laboratory aging. Several possible approaches are proposed. Traditionally used is the phenomenological approach combined with mathematical regression of measured data. This method is complemented by confidence intervals to ensure statistical...
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