National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
The Conversion Efficiency of Different Kinds of Energy into Electrical Energy and the Possibility of its Accumulation
Ostruška, Jan ; Bartošík, Tomáš (referee) ; Macháček, Jan (advisor)
The thesis deals with the issues of the conversion efficiency of different kinds of energy into electric energy. Firstly, the thesis presents a brief introduction into types of energy sources and their capacity. Then, conversion efficiency of particular direct and indirect conversion is scrutinized, pointing to factors which affect conversion efficiency. The next chapter deals with the possibilities of accumulating electric energy. These are analysed as far as conversion efficiency is concerned as well and the end of the chapter concludes with comparison of these particular possibilities. Booth parts of the process – power generation and its accumulation – are connected in comprehensive scheme of energy conversions. The thesis develops on this scheme by mathematic description of its components and by designing a simulation programme, which would show the flow of energy in the scheme.
Earth Faults Protections
Ostruška, Jan ; Topolánek, David (referee) ; Orságová, Jaroslava (advisor)
The thesis deals with wattmetric and conductance principle of faulted feeder detection in medium voltage compensated distribution networks. These principles are analysed and tested with particular emphasis on high impedance earth faults. The first part of testing utilizes data about state of the system with earth fault, which was determined by designed static model of earth fault. The testing in the second part utilizes real records of high impedance earth faults. In both parts the wattmetric and conductance protections was presented on protective relays ABB REF 615, ABB REM 543 and Protection&Consulting RYo by means of unit OMICRON CMC 256plus. As a major result of performed tests are records of detection of particular earth faults. Based on these records it could be concluded, that functionality of protections is substantially dependent on magnitude of zero sequence voltage. Furthermore the wattmetric protections are dependent on fault resistance as well.

Interested in being notified about new results for this query?
Subscribe to the RSS feed.