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Differential protection of transformer.
Svoboda, Miloslav ; Paar, Martin (referee) ; Toman, Petr (advisor)
This bachelor thesis is divided into several chapters, which consist of two main parts of the work, theoretical and practical. In the theoretical part the work deals with disorders of electric network, causes and limit of their adverse effects. Further it theoretically analyses the function of electrical protection, requirements for the protection , their basic elements. Then there is described the principle and function of instrument transformers and the differential protection of transformers. The practical part of the work deals with protection for a specific transformer. The proposal involves the calculation of three-phase short-circuit, the selection of differential protection, the proposal of instrument transformers and settings of the protection function.
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Overcurrent protection relay testing using tester TZO3.
Vavreczky, Gábor ; Paar, Martin (referee) ; Toman, Petr (advisor)
The main task of this bachelor’s tesis is testing digital protection 7SA610 from Siemens. Purpose of the project is to take up with overcurrent functions of the protection, and realize it's testing through secondary tester TZO3. For this, the project grants theoretical foundations: deals with basic fault conditions in electrical networks, in detail describes the principle of individual types of overcurrent protections, grants informations about the used tester and about the used protection. In the final section of the thesis suggests applicable laboratory task in teaching at Department of Electrical Power Engineering, based on performed tests.
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Distribution of short circuit currents and voltages in unsymmetrical faults
Kakrda, Michal ; Topolánek, David (referee) ; Haluzík, Evžen (advisor)
The objective of this bachelor thesis is to introduce the calculation of voltage and current ratios in asymmetrical short circuits. The first part of the thesis is focused on delineating the problem of short circuits in general. It describes the causes of short circuit arising, the types of short circuits and their processes. The next part of the thesis shows the ways of calculating particular types of short circuits, namely concentrating on the method of symmetrical components. The last part of the thesis is focused on the application of the discovered findings to calculate the ratios for the particular electric network. The calculation has been made for all the types of short circuits, both symmetrical and asymmetrical. The resulting ratios are recorded into the phasor diagrams for particular types of short circuits. The part of the calculation is also the recalculation of phase currents through a transformer.
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Solder Wave Process Optimization
Procházka, Martin ; Brno, Martin Štěpánek HONEYWELL (referee) ; Starý, Jiří (advisor)
This work describes solder wave process and it‘s optimalization. It informs us about wave soldering and describes it’s fragments. Next it is described partition of fluxes and their properties. In practical part is described researching of defects on PCB’s and analysis of possible reason of defects, measurement of the weight of sprayed flux and measurement of solderable profile.
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Protection of Transformer by Differential Relay
Jára, Jaroslav ; Haluzík, Evžen (referee) ; Toman, Petr (advisor)
This bachelor’s thesis deals with transformer failures and principles of their protection and a design of differential protection of transformers. The first part details with transformer failures, classification of these failures, short-circuit ground faults types, causes of the short-circuit occurrences and consequences of oil-transformer failures. The second part deals with problems of protection in general with the description of protection function, requirements of protection such as selectivity, speed of response, sensitivity and protection classification, methods of protection according to failure type - size of nominal power of transformers. It further describes principle of differential protections. Finally there are previews of historical and modern protections. The third part describes a design of differential protection of transformers. It includes short-circuit ratio calculation, example of three phase short-circuit calculation, CT ratio check, actual setting of protection and setting evaluation.
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The calculation of the short circuits of the given network
Bordovský, Lukáš ; Paar, Martin (referee) ; Toman, Petr (advisor)
The main aim of this Bachelor thesis is to introduce you a calculation of short-circuit rates in compliance with IEC 60909, and a subsequent calculation of a scheduled real network. The thesis itself is divided into two parts : a theory about the short-circuit problems and a simple model example are stated in the first part, in the second part is stated the calculation of the given real network for the case of an occurence of shunt faults at distribution points, namely a three-phase fault, a two-phase isolated fault, a double-phase-to-earth fault and a single phase fault. The work is coupled with a determination of current and voltage rates at points P and K. At the point P is situated distance protection relay and at the point K comes the shunt fault. The calculations are done with a method of successive simplification.
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Distribution of short circuit currents and voltages in unsymmetrical faults
Kakrda, Michal ; Topolánek, David (referee) ; Haluzík, Evžen (advisor)
The objective of this bachelor thesis is to introduce the calculation of voltage and current ratios in asymmetrical short circuits. The first part of the thesis is focused on delineating the problem of short circuits in general. It describes the causes of short circuit arising, the types of short circuits and their processes. The next part of the thesis shows the ways of calculating particular types of short circuits, namely concentrating on the method of symmetrical components. The last part of the thesis is focused on the application of the discovered findings to calculate the ratios for the particular electric network. The calculation has been made for all the types of short circuits, both symmetrical and asymmetrical. The resulting ratios are recorded into the phasor diagrams for particular types of short circuits. The part of the calculation is also the recalculation of phase currents through a transformer.
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The calculation of the short circuits of the given network
Bordovský, Lukáš ; Paar, Martin (referee) ; Toman, Petr (advisor)
The main aim of this Bachelor thesis is to introduce you a calculation of short-circuit rates in compliance with IEC 60909, and a subsequent calculation of a scheduled real network. The thesis itself is divided into two parts : a theory about the short-circuit problems and a simple model example are stated in the first part, in the second part is stated the calculation of the given real network for the case of an occurence of shunt faults at distribution points, namely a three-phase fault, a two-phase isolated fault, a double-phase-to-earth fault and a single phase fault. The work is coupled with a determination of current and voltage rates at points P and K. At the point P is situated distance protection relay and at the point K comes the shunt fault. The calculations are done with a method of successive simplification.
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Overcurrent protection relay testing using tester TZO3.
Vavreczky, Gábor ; Paar, Martin (referee) ; Toman, Petr (advisor)
The main task of this bachelor’s tesis is testing digital protection 7SA610 from Siemens. Purpose of the project is to take up with overcurrent functions of the protection, and realize it's testing through secondary tester TZO3. For this, the project grants theoretical foundations: deals with basic fault conditions in electrical networks, in detail describes the principle of individual types of overcurrent protections, grants informations about the used tester and about the used protection. In the final section of the thesis suggests applicable laboratory task in teaching at Department of Electrical Power Engineering, based on performed tests.
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