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Modelling and Simulations of Electromechanical Transients is Electrical Power Systems
Gromotovič, Ivan ; Bátora, Branislav (referee) ; Koudelka, Jan (advisor)
This work deals with the issue of evaluating transient stability in the simulation program PSCAD. Factors affecting transient stability were analyzed on a single-machine SMIB model. The results of this analysis confirmed the theoretical assumption that for more accurate results of the analysis of transient stability, it is necessary to consider the mentioned factors. A short circuit was simulated on the IEEE9 test model and subsequently the load angles of the generators were monitored using various methods. The method of reference of the largest generator in the system proved to be a more suitable method for the assessment of relative load angles from the results of the analysis.
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HV grid model in PSCAD
Tomšů, Vojtěch ; Ptáček, Michal (referee) ; Kopička, Marek (advisor)
This thesis deals with the issue of computer modelling and electroenergetic calculations. The first part focuses on the description of the PSCAD program and selected competitive software. There are listed main characteristics, usage and subsequently the overall comparison of the programs with potential use in electroenergetic industry. It also lists the basics of PSCAD and description of its working environment. Another section deals with the calculation of parameters of overhead lines, transmision lines substitute with pi-section and the process of pi-section phasor diagram construction. In the next part, there is a model of HV grid in the form of pi-section. As reference values for simulation were used values from exercise of the subject Distribution of electric energy. Output values obtained from the simulation in PSCAD were used to create a phasor diagram in Matlab. The last part focuses on the issue of calculating the natural power, cascade and parallel sections sorting and a simple case of three-phase fault.
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Model of Stirling Engine in PSCAD
Gallo, Michal ; Kopička, Marek (referee) ; Radil, Lukáš (advisor)
This dissertation about the Stirling engine deals with the history and formation of the heat engine. At the beginning of this work, fundamental parts and their functions are described, elucidating the principle of operation explained by the thermodynamic cycle and subsequently comparing the ideal and the real Stirling cycle and last but not least provides various modifications whilst describing their differences. The mathematical model of the Stirling engine is processed by Schmidth’s theoretical analysis and thereafter is created in PScad v46. The process of creating a model is shown in one of the chapters of this dissertation. The results were taken into account in the design of 3D models in Inventor Professional by Autodesk. The work concludes with the evaluation of the computational model and its functionality as well as the documentation of the 3D model.
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Autonomous and dispatching control of distributed power generating plants operated in the HV distribution system
Dvořáček, Jiří ; Jurík, Michal (referee) ; Drápela, Jiří (advisor)
Theses focuses on the evaluation of the possible means of active and reactive power control of generating units connected to medium voltage. First part summarizes analysis of Czech Republic medium voltage distribution grid. It summarizes means of autonomous and dispatcher control of generating units with respect to European Comission directive RfG, standard ČSN EN 50549-2 and national implementation PPDS. Following parts provide description of generating unit and distribution grid models used for simulation in PSCAD. Last part focuses on evaluation of results obtained via simulating steady-state scenarios as well as continuous simulation.
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Modeling and simulation of a hybrid micro grid in PSCAD environment
Moravčík, Martin ; Mastný, Petr (referee) ; Drápela, Jiří (advisor)
In the opening part of this master´s thesis there is given concept, description, usage and advantages of micro hybrid grids in comparison to micro grids and there are evolution steps towards hybrid grid. There is also a mention about economics of operation of these grids. In the second part of this thesis there are descriptions of devices that are suitable for usage in micro hybrid grids with emphasis on generators and accumulation possibilities. In the next part of this thesis there is given an approach and description for modeling of various components of hybrid grids in PSCAD environment. In the next part of this thesis there are given simulation results that were conducted on created model. Especially power balance in 24 hour operation of the grid with method for determining suitable size of accumulation and installed capacity of photovoltaics. And next there are showed responses from change of power from photovoltaics, next there is a transition to islanded mode and last there is showed the behavior of converter when the limits of accumulation are reached. In the final part of this thesis there are conclusions, fulfillment of goals of this thesis and possibilities of further study.
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Power Cables Parameters
Váša, Lukáš ; Jurák, Viktor (referee) ; Orságová, Jaroslava (advisor)
In recent years, the development trend of power grids character shows increased demand for using cables of both current overhead and newly constructed lines. In order to preserve reliable operation and to predict the maintenance requirements, it is crucial to regard not only the parameters certified by manufacturers, but also externalities induced by real environment and incorporate these externalities into cable models in simulation software. The diploma thesis deals with determining of characteristic parameters of single core cables in real environment, which are affected by real grounding methods of metal shielding. The emphasis is put on analysis of current cable models in simulation software PSCAD and its evaluation using two-step experiment 1) measurement of shunt parameters in laboratory using electronic bridge model and 2) on field measurement of cable series parameters in real environment.
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Deficiencies and inaccuracies in measurement of MV distribution network laboratory model
Němec, Jiří ; Vyčítal, Václav (referee) ; Ptáček, Michal (advisor)
The paper analyzes the deficiencies and inaccuracies in measurement of medium voltage distribution network laboratory model. The aim is to propose solution to these problems. In the second chapter, basics of the theory of medium voltage network and the operating parameters of distribution grids are described. The theoretical part is mainly based on the Czech technical standards. The third chapter focuses on description of the laboratory model and it contains its label values. The fourth chapter deals with executed measurements and mathematical models created in the program PSCad. Comparison of the measurements and the computer simulations is included. Description of the measurements contains its purpose, the measured parameters and results of the measurements. Input parameters for creating computer simulations are listed and their results are processed. In response to measurements, yet unknown parameters of the laboratory model and its behavior in various operational states are clarified. On the basis of the findings, which this paper brings, it is possible to modify the laboratory exercise and thus reach more accurate results.
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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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Analysis of Frequency Measurement and RoCoF in Simulation Programs
Koudelka, Jan ; Máslo, Karel (referee) ; Orságová, Jaroslava (advisor)
The thesis deals with the issue of measurement of frequency and its derivative (RoCoF) in simulation software. The aim of the thesis was to compare results obtained in three different pieces of software (PSS/E, PSCAD, MODES). 2 disturbances were simulated in a grid model IEEE 39 bus system and values of frequency and generator speed were assessed. The results obtained in different software are diverse. This is influenced by method of modelling of synchronous generator and algorithm of calculation of frequency. Findings are important for future investigation of power system transients in simulation software and also point to potencial incorrect assassement of frequency in protective relays.
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