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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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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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