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DC arc extinguishing in low voltage switching devices for critical currents
Fencl, Martin ; Šimek, David (referee) ; Píška, Jakub (advisor)
This bachelor’s thesis deals with DC arc extinguishing for critical currents. The first, theoretical part describes and defines an arc, a DC arc and methods of its extinguishing. The second, theoretical part concerns spectral analysis – specifically, the emission method. Methods of research of extinguishing critical currents are also presented. The practical part consists of two measurements. The first measurement consists of spectrum measuring in time, in conjunction with voltage and current measurements. In the second measurement, the goal was to measure the dependence of arc burning time on voltage and current. The thesis concludes with summary of the results of each individual measurement and their presentation in the wider context.
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Low level DC voltage measurement
Obšilová, Lucie ; Nováková Zachovalová, Věra (referee) ; Havlíková, Marie (advisor)
This thesis deals with low level DC voltage measurement by three methods. First part of this thesis describes each method. It is about potentiometric method, reference step method and direct method. This thesis also describes Josephson voltage standard which was used for calibration nanovoltmeter and Zener reference. The theoretical part of this thesis also deals with the evaluation of key comparison data. The main goal of this thesis is the comparison of methods used to measure low level DC voltage. The practical part of the thesis deals with the implementation of measurement with all methods in cooperation with Czech metrology institute. The measured values are processed including uncertainty evaluations. The final part of this thesis focuses on comparison of measurement methods. The key comparison reference value and the degree of equivalence of the measurement of each method are determined. Next part of comparison consisted of graphic comparison of methods. The end of the thesis contains evaluation of the achieved results.
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Electric networks with DC voltage up to 1000 V
Fiala, Martin ; Kopička, Marek (referee) ; Ptáček, Michal (advisor)
This master´s thesis deals with the proposal of DC low voltage network at a voltage level of 1000 V DC in Praskolesy u Mrakotina village. Direct distribution will be realized only at the terminal, which will power the village. Next part of this thesis is theoretical and its main focus is description of both DC and AC distribution systems. The proposed DC grid will use existing distribution grid. The thesis further describes the problems of long terminals in low voltage distribution systems and electrical installation in buildings. The result of this work is a comparison of the losses between AC and the proposed DC system. The last part deals with economical evaluation and technical solution for the proposed network variant, including their advantages and disadvantages.
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The Model of HVDC Line for Laboratory
Mička, Dominik ; Paar, Martin (referee) ; Krbal, Michal (advisor)
The objective of this bachelor thesis is to provide comprehensive information of HDVC transmission and to create laboratory model of HVDC connection. The first part of the thesis presents its pros and cons and provides basic description of individual parts related to the transmission of electrical energy. The thesis also shows proposed design model of HVDC connection, used as a guidance for work in lab environment. Provided are calculated parameters and operational options of working prototype model. Subsequently, the prototype is created and measured test results are compared against calculated and simulated values.
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Meaurement process automatization of Zener reference
Bábek, Tomáš ; Nováková Zachovalová, Věra (referee) ; Havlíková, Marie (advisor)
This thesis deals with metrology specialized to DC voltage. In the begining of thesis is explanation of technical terms from metrology, summarization of units from International System and explanation of the standards and its kinds in the context of metrology. Primary standards of DC voltage based on Zener diodes and Josephson effect are described as well. In cooperation with Czech metrology institute in Brno this work is focused on automatization of measuring Zener reference standards (ZRS). Goal of this project is to automatize the measuring of Zener reference standards and its relationship with Josephson voltage system using scanner. To do this, there is a need to find out offsets, that can develop on scanner's channels. There is a theoretical analysis of measuring made on the scanner and their uncertainties. Aim of the solution is computation of scanner channels offsets using everyday automatic measuring the system of Zener reference standards (ZRS). For measuring the LabView was used and for computing the data from measured values the Matlab was used. This thesis should short the time needed when measuring DC voltage references, measure values of DC voltage standards and set the scanner channels offsets. In the end there is a summarization of offsets measured on individual scanner channels.
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Short Circuit Currents in DC Systems
Kolařík, Robin ; Geschwinder, Lukáš (referee) ; Paar, Martin (advisor)
The bachelor thesis deals with the analysis of short-circuit currents in DC systems. The thesis introduces the possibility of application of low voltage DC distribution in commercial and industrial buildings. The second part is focused to high voltage direct current transmission. The practical part deals with the calculation of short-circuit currents of individual elements and subsequently with short-circuit conditions in the DC network. At the end of the work are evaluated advantages and disadvantages between AC and DC voltage and suitability of use in given areas.
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DC arc extinguishing in low voltage switching devices for critical currents
Fencl, Martin ; Šimek, David (referee) ; Píška, Jakub (advisor)
This bachelor’s thesis deals with DC arc extinguishing for critical currents. The first, theoretical part describes and defines an arc, a DC arc and methods of its extinguishing. The second, theoretical part concerns spectral analysis – specifically, the emission method. Methods of research of extinguishing critical currents are also presented. The practical part consists of two measurements. The first measurement consists of spectrum measuring in time, in conjunction with voltage and current measurements. In the second measurement, the goal was to measure the dependence of arc burning time on voltage and current. The thesis concludes with summary of the results of each individual measurement and their presentation in the wider context.
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Short Circuit Currents in DC Systems
Kolařík, Robin ; Geschwinder, Lukáš (referee) ; Paar, Martin (advisor)
The bachelor thesis deals with the analysis of short-circuit currents in DC systems. The thesis introduces the possibility of application of low voltage DC distribution in commercial and industrial buildings. The second part is focused to high voltage direct current transmission. The practical part deals with the calculation of short-circuit currents of individual elements and subsequently with short-circuit conditions in the DC network. At the end of the work are evaluated advantages and disadvantages between AC and DC voltage and suitability of use in given areas.
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The Model of HVDC Line for Laboratory
Mička, Dominik ; Paar, Martin (referee) ; Krbal, Michal (advisor)
The objective of this bachelor thesis is to provide comprehensive information of HDVC transmission and to create laboratory model of HVDC connection. The first part of the thesis presents its pros and cons and provides basic description of individual parts related to the transmission of electrical energy. The thesis also shows proposed design model of HVDC connection, used as a guidance for work in lab environment. Provided are calculated parameters and operational options of working prototype model. Subsequently, the prototype is created and measured test results are compared against calculated and simulated values.
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Electric networks with DC voltage up to 1000 V
Fiala, Martin ; Kopička, Marek (referee) ; Ptáček, Michal (advisor)
This master´s thesis deals with the proposal of DC low voltage network at a voltage level of 1000 V DC in Praskolesy u Mrakotina village. Direct distribution will be realized only at the terminal, which will power the village. Next part of this thesis is theoretical and its main focus is description of both DC and AC distribution systems. The proposed DC grid will use existing distribution grid. The thesis further describes the problems of long terminals in low voltage distribution systems and electrical installation in buildings. The result of this work is a comparison of the losses between AC and the proposed DC system. The last part deals with economical evaluation and technical solution for the proposed network variant, including their advantages and disadvantages.
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