Sökning: "transformer"

Visar resultat 31 - 35 av 116 avhandlingar innehållade ordet transformer.

1. 31. Optimal Pin Fin Heat Exchanger Surface

   Författare :Hamid Nabati; Jafar Mahmoudi; Mohsen Assadi; Mälardalens högskola; []
   Nyckelord :Pin Fin; CFD; Numerical Simulation; Power Transformer; TECHNOLOGY; TEKNIKVETENSKAP; Energy- and Environmental Engineering; energi- och miljöteknik;

   Sammanfattning : This research presents the results of numerical study of heat transfer and pressure drop in a heat exchanger that is designed with different shape pin fins. The heat exchanger used for this research consists of a rectangular duct fitted with different shape pin fins, and is heated from the lower plate. LÄS MER

3. 32. On the estrablishment of effective condition monitoring parameters for copper corrosion problems in mineral oil-filled electrical transformers

   Författare :Ramsey Jadim; Mirka Kans; Linnéuniversitetet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; condition monitoring parameters; corrosion problems; sulfur deposits; corrosion reaction mechanisms; transformer failures; CBM.; Maskinteknik; Mechanical Engineering;

   Sammanfattning : The power transformer is a critical equipment in which the protection process is essential for modern societies where continuous electric power supplies are required. Copper corrosion problems due to the formation of sulfur deposits on the copper windings of mineral oil-filled power transformers are considered a major issue that can lead to sudden failures, and in some cases, to costly fire and explosion accidents in the power plants. LÄS MER

4. 33. On Power-system Benefits, Main-circuit Design, and Control of StatComs with Energy Storage

   Författare :Hailian Xie; Hans-Peter Nee; Lennart Ängquist; Timothy Green; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Energy storage; Voltage source converter; VSC; Static synchronous compensation; StatCom; Active power compensation; Phase jump; Voltage dip; Weak network; Flux modulation; Deadbeat current control; Transformer saturation; Dual thyristor converter; dc interface; Electrical engineering; Elektroteknik; Electric power engineering; Elkraftteknik;

   Sammanfattning : Static synchronous compensation (StatCom) is an application that utilizes a voltage source converter (VSC) to provide instantaneous reactive power support to the connected power system. Conventionally, StatComs are employed for reactive power support only. LÄS MER

5. 34. Mechanisms of Electrical Ageing of Oilimpregnated Paper due to Partial Discharges

   Författare :Mohamad Ghaffarian Niasar; Hans Edin; Ernst Gockenback; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; partial discharges; oil-impregnated paper; oil; transformer insulation; dielectric frequency response; breakdown strength; ion mobility; thermal ageing; electrical ageing; moisture in paper; life time; thermal breakdown.; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : In this thesis, partial discharge (PD) phenomenon in oil-impregnated paper (OIP) is investigated under accelerated electrical stress. The thesis is mainly focused on the characteristic of PD activity and the influence it has on the insulation properties of OIP. LÄS MER

7. 35. Aspects on measuring electrical current utilizing magnetic zero-flux technique

   Författare :Maria Hammarqvist; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Current Transformer; AC Current; Frequency Response; Measurement Uncertainty; Traceability; Zero-Flux Measurement Technique; Zero-Flux;

   Sammanfattning : The utilization of high accuracy measurements of electrical quantities is a prerequisite for the development of modern society. Generally, measurements serve different purposes and hence the criteria for the measurement equipment and method are different. LÄS MER