Thesis supervisor: István Kiss
Location of studies (in Hungarian): Department of Electric Power Engineering Abbreviation of location of studies: VET
Description of the research topic:
Power transformers are essential parts of the power system. Their lifetime and environmental friendliness is highly determined by its insulation. Mineral oil as the main insulating and cooling liquid has been successfully replaced by ester liquids in medium-to-low voltage transformers, while its application at high voltage has just been initiated. As there is lack of experience with its use, several open questions have to be answered. The most profound one is the electrical insulating capability. Most electrical tests on pressboard-ester interfaces were performed at room temperature, while the viscosity of esters show a significant change when heated to operation temperature. The effect on lightning impulse flashover needs to be investigated. Ester liquids differ from mineral oils chemically, thus the polarization phenomena is expected to occur differently. Especially the moisture balance is highly different, which changes the evaluation of polarization based diagnostic methods, e.g. the return voltage measurement. The diagnostic measurements on transformers gain more and more importance, as the early detection of failures becomes highly important. Partial discharge measurements can detect local defects. Measuring them in the UHF range allows their localization, but the properties of the propagating path needs to be investigated.
Required language skills: English Number of students who can be accepted: 1
Deadline for application: 2021-09-01
2024. IV. 17. ODT ülés Az ODT következő ülésére 2024. június 14-én, pénteken 10.00 órakor kerül sor a Semmelweis Egyetem Szenátusi termében (Bp. Üllői út 26. I. emelet).
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