National Repository of Grey Literature 104 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Probabilistic Approach for Assessment of Earthing System Design
Vyčítal, Václav ; Gurecký, Jiří (referee) ; Procházka, Karel (referee) ; Toman, Petr (advisor)
This dissertation thesis deals with application of probabilistic approach to assessment of earthing system safety in distribution networks, especially for cases with common earthing of high and low voltage side of distribution transformers HV/LV. In these cases, the increased potential during fault might be transferred from high voltage to low voltage network and thus the individuals from public can be exposed to increased risk. Thus, for these cases were in this thesis defined expectable touch scenarios together with the resulting risk imposed on individuals from the public. Based on the results it seems that adoption of probabilistic approach for these cases of earthing systems might be more suitable compared to the conventional deterministic worst case approach. In accordance to the aims of the thesis, a thorough analysis of currently adopted probabilistic approaches was carried out as well and it was pointed out to some new possible simplifications in the adopted probabilistic based methodologies. For example, it seems that appropriate modelling of human body resistance by the full lognormal distribution is not completely necessary and similar results can be obtained when only the resistance for 50 % of population together with c3 and c4 fibrillation curves are used. Much of the work was also devoted to the determination of possible uncertainty of calculated risk of evaluated earthing system, especially due to inappropriate modelling of earthing system. The appropriateness of different earthing system modelling methods together with other parameters on the value of calculated risk was investigated through conducting sensitivity analysis. Based on the analysis results it seems, that due to using more, or less simplified modelling method, a possible underrating in the resulting risk of about 40 % (about half an order/decade) is expectable. On the other hand, the change of parameters related directly to calculation of fibrillation probability seems to exhibit greater change in calculated risk by up to units of orders/decades.
Distance Protection Design Using Digital Input Data
Wannous, Kinan Hasan Wafaa ; Müller,, Zdeněk (referee) ; Braciník, Peter (referee) ; Toman, Petr (advisor)
Standard IEC 61850-9-2 definuje přenos vzorkovaných měřených hodnot (sampled measured values, SMV) prostřednictvím sítě Ethernet a využití SMV získaných ze slučovacích jednotek nebo přístrojových transformátorů. Implementace IEC 61850-9-2 závisí na vlastnostech datového souboru, jakými jsou časová synchronizace, počet vzorků a časový interval. Dizertační práce je zaměřena na algoritmy chránění a analýzu vlivu standardu IEC61850-9-2LE na fyzická zařízení ochran s analogově/digitálními vstupními daty o proudu a napětí. S ohledem na narůstající míru interakce mezi fyzickými zařízeními a komunikačními prvky byl navržen test pro analýzu komunikace pro rozvodnu využívající konvenční metody (analogové vstupy) a metody digitální založené na standardu IEC 61850-9-2. Práce dále popisuje funkci slučovací jednotky využívající standard IEC61850-9-2LE. Navržená metoda definuje zdroj SMV a analyzuje přenos dat. V rámci práce byl za využití softwaru Matlab naprogramován algoritmus ochrany. Vytvořený model je schopen vyhodnotit vliv harmonického zkreslení na funkci digitálních ochran a vliv přesycení proudového transformátoru na distanční ochranu. V práci jsou zhodnoceny i možnosti zrychlení testování systémů chránění s využitím neuronové sítě. Závěrečná kapitola se zabývá aplikacemi v reálném čase, využívajícími data z rozvodny v blízkosti Vysokého učení technického v Brně. K přenosu dat z rozvodny do univerzitní laboratoře je zde využíváno SMV přenášených optickým kabelem o délce 16 km. Aplikace je vytvořena v programu Matlab a je schopna číst data z ethernetového portu, dekódovat je, převést z formátu ASCII do desítkové soustavy a poté vykreslit průběhy proudu a napětí. Mezi vlastnosti aplikace se řadí jednoduchost použití, schopnost implementace funkcí distanční ochrany, výpočet RMS hodnot proudu a napětí a harmonického zkreslení, harmonická analýza prostřednictvím rychlé Fourierovy transformace a výpočet impedance poruchové smyčky. Všechny výpočty běží v reálném čase a provedena je i citlivostní analýza modelu.
Development of methodology and supporting tool for evaluation of measured values of high voltage poles grounding systems according standard PNE 33 3300-1
Kováč, Frederik ; Basík, Josef (referee) ; Toman, Petr (advisor)
Diploma thesis is oriented on measuring and evaluation of grounding conditions of HV pylons. In theoretical part is described theory of grounding including related legislation, impact of electric current on human body, methods of measuring earth resistance, soil resitivity and description of available measurers. Practical part is focused on measuring earth resistance of selected pylons and measuring procedures followed by evaluation of measurements according to person's safety from dangerous touch voltage and impact of lightings. For evauluation of measured data is created supporting tool in MS Excel. In the last part of thesis are described recommendations for cutting-down touch voltages.
R290 heat pump
Toman, Petr ; Pospíšil, Jiří (referee) ; Hejčík, Jiří (advisor)
This diploma thesis deals with design of air-water heat pump which uses natural refrigerant, propane. In the thesis there are mentioned various types of devices using the source of low-potential heat for heating. The main part of the thesis is the design of the heat pump cooling circuit. In this section, individual components are designed, the calculation and comparison of the heating factor for different operating parameters is performed. Finally, the construction of the coolant circuit and the air exchanger is designed.
Design of Protection Relays for MV Distribution Grid
Sochor, Tomáš ; Bukvišová, Zuzana (referee) ; Toman, Petr (advisor)
The master´s thesis deals with the design of medium voltage power line protection and the calculation of reliability indicators. First, it deals with the possibilities of power system operation. Subsequently, it divides the networks according to the grounding of the transformer node and the switching elements and devices occurring in the MV distribution network are mentioned. It presents the basic classification of power line protection and its use, especially it focuses on overhead and cable MV power lines. It also discusses the reliability of the power supply and lists the basic reliability indicators and their possible calculation. The practical part describes the changes in the considered area of the distribution network, where the reconstruction of the power line VN872 and a new way of powering the village Drnholec will take place. The impact of this change on the reliability of the supplied energy is also calculated. Furthermore, the protection of the power line is designed and the correctness of its setting is then verified on the model in the PSS Sincal software.
Telemetry and Dispatch Control of Low Voltage Grid
Gála, Michal ; Vaculík, Petr (referee) ; Toman, Petr (advisor)
The contents of this thesis are the introduction to mesh grids, the method of dispatch control of these grids and the description of technology used in mesh grids distribution nodes in the city of Brno. This thesis also describes low voltage switchgears used in these types of grids. The development of dispatch control in ECD company is also mentioned. The development describes the grid dispatch control methods prior to implementing the OMS system and the changes which followed after the implementation. The process improvements of the new system resulting from this thesis can be found in this thesis as well. The improvements are incorporated in the OMS system and are used for more efficient dispatch control of the low voltage mesh grids. There is a more detailed analysis of the mesh grid Brno – Bohunice in the practical part of this thesis. The practical part contains analyses of mesh grids stabilized conditions measurements and analyses of mesh grids fault conditions measurements. The analyses assess the power load in transformers, minimal and maximal phase current and maximal power load at the time they were observed. The analysis of the measured data is accompanied by the assessment of differences in current phase measurements and differences in voltage phase and combined measurements. The result, based on the analysis and collection of the data, is a proposition of adding switchgears for the support of the dispatch control of the mesh grid Brno – Bohunice. In the summary of the thesis there is a comparison of the result of the factual and theoretical analysis. An experimental model of the mesh grid Brno – Bohunice was created in PS CAD software as a part of the theoretical analysis.
The Application of an Innovative Methodology for Transmission System Development Planning
Vrábel, Radek ; Pistora, Martin (referee) ; Toman, Petr (advisor)
This master thesis deals with new approach to development planning in transmission system. As an introduction to the topic the current ways of planning the development of the transmission system are presented in the beginning of the theoretical part of the thesis. The following section analyze the projected scenarios of the development of energy sector from three different sources. The theoretical part is followed by modelling of the electricity market with an explanation of its use for planning the development of the transmission system. The next chapter deals with the use of market modelling results in the network calculation of steady state with and without contingency. The last part of the master thesis analyzes the results of the simulations and proposes appropriate steps and new projects.
Utilization of Knowledge Systems and Bases for Selection and Evaluation of Domestic Electrical Installations.
Haluza, Miroslav ; Martínek, Zbyněk (referee) ; Gurecký, Jiří (referee) ; Toman, Petr (advisor)
My doctoral thesis deals with use of the sophisticated methods for the selection of technical and economic solution of electrical wiring. This solution is based not only on a price but also on many other criteria such as a comfort, service, durability etc. The focus of the work is a treatise on wiring systems from a global perspective, where it is impossible to use a conventional approach for objective evaluation and selection of the appropriate electrical wiring system (because of the complexity of such systems and their interdependencies). In the four chapter are given information of an energy consumption (the total consumption and household consumption). In this chapter is given also a consumption prediction – especially for households. Following is an overview of possible measures for reducing electricity consumption in households. In the next part of this thesis are solved the knowledge, respectively expert systems for use in an electrical engineering – especially for a suitable tool for the selection and evaluation of households wiring electrical system. The result of this work provides a possible solution for a selection of wiring electrical system for households (focusing on the intelligent wiring) – from a technical and economic point of view and with using an innovative approach. The main contribution of this work is a proposal of the main part of the knowledge base. This base could be as a basis for knowledge, respectively for an evaluating technical and economical solution of an electrical wiring system – the expert system includes also a feedback function of an effectiveness solution, use value, price etc., which would also serve as a knowledge base.
VAT in developing countries
Chadimová, Denisa ; Zídková, Hana (advisor) ; Toman, Petr (referee)
This thesis is focused on the Value Added Tax in developing countries. The main goals of this thesis are to describe and compare tax systems from developing countries, and to conduct a broad overview of the basic elements of the VAT consumption tax in these countries. The Value Added Tax is one of the most applied consumption taxes because of its benefits compared the other consumption taxes. This thesis describes the application and the basic elements of the Value Added Tax in developing countries. In the end of this thesis is the analysis and the comparison of these basic elements.
A Reconstruction of the Crucifixion of Jesus of Nazareth from the Archeological Evidence and Ancient Literary Sources
Toman, Petr ; Brož, Jaroslav (advisor) ; Ryšková, Mireia (referee)
The thesis A Reconstruction of the Crucifixion of Jesus of Nazareth from the Archeological Evidence and Ancient Literary Sources deals in nine chapters with the crucifixion phenomenon. Due to its dual approach it is divided into two major parts - general and specific. General part firstly presents the latest scientific treatises dedicated to this phenomenon (1), afterwards introduces the only archaeological evidence of crucifixion (2), analyzes semantical span of terms related to crucifixion (3) and ultimately defines the crucifion penalty (4). Specific part deals with the events of Jesus of Nazareth's case following the pronouncement of judgement. Attention is firstly paid to the flogging penalty (5) and afterwards to the analysis of the royal mockery game (6). Further it focuses on the transition scene, mainly on search for topography of the Way of the Cross (7). The Golgota chapters initially pay attention to the psychological abuse, perception of the crucifixion punishment, resemblance of Jesus' cross (8) and afterwards to the physical abuse and the search for causes of Jesus' death from the medical point of view (9). Keywords Jesus, crucifixion, cross, capital punishment, passion narratives, archaeology, antiquity

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