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Analysis of Ferroresonance Overvoltage in Electrical Net
Bátora, Branislav ; Eleschová,, Žaneta (referee) ; Krejčí, Petr (referee) ; Toman, Petr (advisor)
This thesis deals with the ferroresonance phenomenon and ferroresonance overvoltage in electric networks. That’s why the introduction part explains the theoretical basis of ferroresonance and its consequences in the power system. The work then focuses on the power system as a non-linear dynamic system and describes various analytical methods for solving these systems. These methods are further applied to diagnose specific systems. There are a number of various power system configurations susceptible to ferroresonance. The most frequent one is theoretically analyzed in this thesis and a number of recommendations are offered for reducing the ferroresonance phenomenon. The thesis further deals with the selection of suitable software for this computationally chal-lenging task. A number of different tools are considered and efficiently reduced to Matlab Sim-ulink and PSCAD software. Matlab Simulink and its SimPowerSystem Toolbox are used to ana-lyze the effect of hysteresis of the magnetic core of the transformer on the emergence and course of the ferroresonance phenomenon. Using PSCAD, various configurations of the power systems are compared in terms of possible emergence and course of ferroresonance and also to find the limiting conditions that increase the probability of this phenomenon. The possibility of using arti-ficial neural networks for ferroresonance diagnosis is also mentioned in this thesis. The final part provides a number of recommendations for design and operation of both new and existing power systems.
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Tilt sensors
Hájek, Tomáš ; Caha, Luděk (referee) ; Beneš, Petr (advisor)
The topic of the Bachelor's thesis are MEMS sensors of inclination, which find their use inside integrated circuits, equipment of aerospace and automobile industry, but also in ordinary electrical appliance. The work serves the reader to build a grasp over production, usage, basic principles. Finally, it offers an overview of sensors to ease the orientation on the market. The design of the physical model, which can be used to prevent the sensor from apperance of mathematical errors, is tested in the practical part.
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Stray losses in magnetic material in the end of stator packet
Kopecký, Ivo ; Skalka, Miroslav (referee) ; Ondrůšek, Čestmír (advisor)
This thesis examines the magnetic field and magnetic flow at the end of the stator synchronous machine. This problem is solid using nonlinear magnetic resistive network, which is simulating by PSpice software. A simple model of stator, consisting of stator plates, air gaps and the two-thumbs, which hold the stator together. All of this is replace magnetic nonlinear resistive network, which is then divided into elements. According to these element is a simplified model solid and analyzed.
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Hysteresis of regional unemployment: the case of Greece and Spain
Bradáčová, Lucie ; Slaný, Martin (advisor) ; Tříska, Dušan (referee)
The substantial increase in the unemployment rate after the crisis in the year 2008, its persistence and slow gradual decreasing in European countries is the reason that makes us think about if the theory of hysteresis is applicable to European labour markets. The main objective of this work is to verify the hypothesis of hysteresis in labour markets at regional level in Greece and Spain. The unit root tests were used on the time series of unemployment rate between 2001-2015 for Greek regions and 2002-2016 for the Spanish regions. The result is that the theory of hysteresis in unemployment is applicable on all the regions in both countries. When the data series of employment are used, the results are different. In Greece only Crete and in Spain regions Andalusia, Balearic Islands, Canary Islands, Kastilie la Mancha, Catalonia, Valencia, Murcia and Ceuta exhibit the hysteresis in employment. There are also differences between rates of men and women in Spanish regions. When unemployment rates are considered, only three region have different results. But when employments rates are used most of women's time series can't be described as non-stationary in contrast of those of the men's.
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Determinism, Path-depedence and Uncertainty: A Post-Keynesian Perspective
Máslo, Lukáš ; Chytil, Zdeněk (advisor) ; Janíčko, Martin (referee) ; Pastoráková, Erika (referee)
The thesis deals with analysis of conceptual-methodological issues examined in the framework of post-keynesian economics. The author´s goal is to supply a solution to the problem of a definition of determinism/non-determinism for both deterministic and stochastic systems and also to the problem of the prevailing confusion which surrounds the notion of reversibility/irreversibility in both path-dependent and traditional-equilibrist systems. The author regards the determinism/non-determinism problem as essentially linked to the problem of a definition of fundamental uncertainty. The key issues are being identified in the "problem of a generator of endogenous shocks" and the "selection - creation problem". Finding solutions to these enables us to take a stand on the validity/invalidity of the classical dichotomy, in the eyes of the author. Davidson´s interpretation of ergodicity and O´Donnell´s critique of this are being presented and, drawing on the latter, along with Álvarez-Ehnts´ critique, the author rejects a simplifying pattern of Davidson´s, according to which neoclassical economics is based on the ergodic axiom. The author suggests a solution to the "selection - creation problem" consisting in distinguishing epistemological determinism from ontological determinism on the one hand, and epistemological determinism from epistemological non-determinism on the other hand. While selection is a characteristic feature of epistemological determinism and, in effect, the realm of "fundamental certainty", creation is referred to by the author as a characteristic feature of epistemological non-determinism, i. e., in effect, the realm of fundamental uncertainty. The author regards the "problem of a generator of endogenous shocks" a self-contradictory notion, based on the principle of causality and the law of non-contradiction, and suggests a solution to the problem consisting in rejection of the concept of shock endogeneity. At the same time, the author rejects Davidson´s "fundamental neoclassical article of faith" rhetoric, based on the first cause argument implied by the principle of causality. In opposition to Davidson, the author regards fundamental uncertainty being of a basically epistemological nature, consisting in our ignorance of the "ultimate law of change", the "Devine formula". Unlike O´Donnell, however, who puts stress on the element of epistemological uncertainty in his epistemological approach to uncertainty, the author also puts stress on the element of ontological certainty, consisting in our knowledge of the existence of the "Devine formula", apart from our epistemological uncertainty.
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Natural rate of unemployment or hysteresis? The case of the Czech Republic
Bechný, Jakub ; Potužák, Pavel (advisor) ; Kadeřábková, Božena (referee)
The aim of this thesis is to empirically investigate, using stationarity and unit root tests, whether is the labor market of the Czech Republic developing accordingly to the natural rate of unemployment theory, or the hysteresis theory. Taking into consideration a structural break in the second half of the nineties I conclude, that the hysteresis at the national level works only in unemployment. Employment data, on the other hand, do not indicate the hysteresis. Unemployment tests on the regional level then suggest, that transitory shocks have permanent effects only in half of the regions.
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Moderní přístupy k trhu práce: přirozená míra nezaměstnanosti a hystereze
Slaný, Martin ; Holman, Robert (advisor) ; Chalupníček, Pavel (referee)
Diplomová práce se věnuje přirozené míře nezaměstnanosti a hysterezi nezaměstnanosti. V kapitolách věnovaných přirozené míře rozebírá dynamický model, Phillipsovu křivku a koncept NAIRU. Práce porovnává hypotézu přirozené míry a NAIRU. Analýza hystereze nezaměstnanosti představuje jádro práce. Po úvodním vymezení se práce soustředí zejména příčinám ? modelu insider-outsider, roli dlouhodobě nezaměstnaných a efektu poklesu kapitálové zásoby a investic. Vyústěním hystereze jsou hospodářsko politické implikace s důrazem na měnovou politiku. Závěr práce se věnuje evropské nezaměstnanosti a snahou je zasadit do praktického kontextu probírané teoretické koncepty. Práce vyúsťuje do domněnky, že jedním z hlavních důvodů pomalého růstu evropské ekonomiky může být hystereze.
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