National Repository of Grey Literature 62 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Traction protection
Šüli, Nicolas ; Wasserbauer, Vojtěch (referee) ; Topolánek, David (advisor)
This bachelor’s thesis focuses on methods of protection for AC and DC traction systems. In thesis first deal with current state in traction, next with undesirable conditions and electrical protections. The work describes a draw in the program INKSCAPE two most often used traction power station with protection.
Utilization of SINCAL tool in the field of network protection
Rampák, Dominik ; Wasserbauer, Vojtěch (referee) ; Topolánek, David (advisor)
This bachelor thesis is describing the basics of using program PSS SINCAL for protection of distribution networks. The thesis is divided into 3 parts. The first part is describing basics and functions of the program. The second part is devoted to the moduls, work with moduls described in form of manuals. The last part is describing creation of test network and simulation of single-phase to ground short-circuit to verify selectivity of the protection devices.
Modern protection of distributed energy resources
Bučko, Ondrej ; Kopička, Marek (referee) ; Topolánek, David (advisor)
The aim of this thesis is to describe distributed energy resources (DER) protection system’s main problems and to suggests their possible solutions. The second part is focused on collecting information and description of the new functional principles of protection devices used for protecting distribution network against backwards influences from the DER. The purpose of the thesis is the description of functional principles of the protection devices that are not commonly used in the distribution networks of the Czech Republic. In addition, the schemes of functional blocks of the protection devices that help to configure or project them are also part of this thesis.
Optimization of the 110 kV distribution system in the Přeštice nodal region
Nagy, Pavel ; Křesálek, Petr (referee) ; Topolánek, David (advisor)
This work describes an actual condition of a specific part of a distribution power grid. It is a research of problems based on the computer model in case some power line is in failure or shut down. Simulations are calculated for both currently used load and load expected in future usage. There are partial solutions depicted for each issue found during the simulation. Some of those are used for a final design of a distribution power grid. In the last section, there is a comparison of different types of power lines and their possible usage in the design.
Appropriateness of modelling the actual soil model as a uniform or horizontal two-layer soil model
Kuběna, Michael ; Topolánek, David (referee) ; Vyčítal, Václav (advisor)
The present thesis deals with soil resistivity and especially the suitability of replacing various soil models with a two-layer horizontal model. First, the factors that influence soil resistivity as well as the methodology of its measuring are described, and various soil models are introduced. Then, the Ansys program was used to create several soil models: a vertical model with perpendicular or oblique division, a model with a pronounced inhomogeneity and a three-layer model. In all of these models, a Wenner measurement simulation was performed, followed by a two-layer horizontal replacement model. Then the size of the error that was created by replacing the actual model with a two-layer horizontal model was examined.
Verification of the Vdip method on the physical model of the MV network
Krčál, Vít ; Drápela, Jiří (referee) ; Topolánek, David (advisor)
This Master's thesis is focused on creating of an algorithm which calculates changes of negative-sequence voltages and currents from their instantaneous values. That allows to conduct localization of asymmetrical faults in MV network in line with the Vdip method, which is based on monitoring the changes of negative-sequence components at distribution substations and at a sub-transmission station. The algorithm is being developed in Matlab environment with continuous implementation of partial procedures which are being assessed and compared with each other. A study of phasor estimating methods is carried out with pointing out related problems which are mainly caused by Ripple control and deviation of system frequency from its nominal value. Optimization precautions are designed to mitigate these problems. For elimination of the Ripple control effects a method based on averaging is presented. The deviation of system frequency is dealt with by resampling the original data recordings. The analysis processes are tested by both simulation signals and real measured data. The optimized algorithm enables precise calculation of negative-sequence components changes which is the main contribution of this thesis. The constructed algorithm is used in verification of the Vdip method on physical model of MV network. For these purposes a simple distribution network is created within which ground faults on different places and with different resistances are realised. The results of localization are not convincing which is mainly caused by specific features of laboratory power line models which are constructed with heterogenous parameters.
Voltage profile regulation in LV distribution systems by means of OLTC equipped distribution transformer and series transformers based on distributed monitoring data
Hála, Tomáš ; Topolánek, David (referee) ; Drápela, Jiří (advisor)
This diploma thesis discusses two major topics. The first one is the control size of the voltage in LV networks in regard to the increase in distributed generation concered to renewable energy sources. The study contains a review focused on the current state of low voltagegrid followed by a proposal for the solution of the oncoming state. The solution is identified as a deploying OLTC distribution transformer. In the case of more complex topology is deployed a series voltage transformer. Both methods are part of the Smart Grid. The thesis also analyzes the issue of the data measurement and data transmission. The second part of the thesis consists of the description of selected control strategies and their simulations. The design of individual system elements in the PSCAD is described. From these elements, a test network was constructed and tested the individual simulation scenarios.
Development of the tool for application of the method for localization of unsymmetrical faults
Pospíšil, Tomáš ; Vyčítal, Václav (referee) ; Topolánek, David (advisor)
In resonant earthed distribution systems, the capacitive current of the system is compensated by grounding via a arc suppression coil. The level of fault current is then very small and independent on the fault location which greatly complicates the rapid finding of the fault site. At this moment there is no method to be used to directly locate the site of a single-phase fault in the distribution network, new methods and solutions are being constantly sought to address the shortcomings of the existent localization methods. The diploma thesis deals with the design of a universal software tool that allows to apply a new method of locating an asymmetric fault in the distribution network. The tool is created in a MATLAB environment and utilizes the negative sequence voltage measured on the low-voltage sides of the distribution transformers and the negative sequence current measured behind the power transformer. By using the proposed tool, it is possible to read the parameters of any part of the distribution system that the user enters together with the measured values of the voltage and current into the initialization file. After the specified network parameters are loaded, a numerical model is created, which is then used for the method. In the work is described in detail the way of entering the parameters of the network into the initialization file, the method of automatic assembling of the numerical model based on the entered data and the possibility of customizing the calculation parameters. At the end of the thesis, the functionality of the proposed software tool is verified on data from simulation of the test network.
Coordination of operation of PST transformers in the interconnected region
Tesař, Jan ; Topolánek, David (referee) ; Bátora, Branislav (advisor)
This master’s thesis deals with phase-shifting transformers (PST) and coordination of electrically close devices in an interconnected region. Theoretical research is performed in the work, describing methods of power control, function and design of PST, as well as actual methods of PST coordination in the rest of the world. Based on the research there is an optimalisation algorithm designed in MATLAB, which computes recommended tap petting of PST based on the network configuration. In the second part of this thesis there are described components of this algorithm and also presented the results of three demonstrative scenarios. Algorithm is able to solve minor problems in the network; more complex problems are beyond its solving ability. For an improved functionality there is a necessity to further expand this algorithm by a network redispatch solving algorithm.
Measurement of electrical soil resistivity
Matyska, Stanislav ; Topolánek, David (referee) ; Vyčítal, Václav (advisor)
This master’s thesis deals with the measurement of the electrical soil resistivity. In the theoretical part there are described the methods by which the soil resistivity is measured – especially the Wenner’s method, which was used for the practical measurements. Then there is also described the one-layered and the two-layered model of this method. Furthermore, there is described the procedure for the measurement of soil resistivity using the OMICRON CPC 100 and PU 193 instruments used in the measurement. To verify the modeling of a two-layered soil model, the theoretical part of the thesis describes the soil modeling process using the program Ansys. As for the practical part of the thesis, the measurements were carried out in three localities: Brno – Královo Pole; Hrušovany nad Jevišovkou – Pravice; Hustopeče nad Bečvou – Vysoká. The measured values were processed using the Matlab’s graphical user interface (GUI) that was developed within this thesis. From these values, at least one two-layered soil model was created for each location and both meters – a total of 12 models were created. For these models, measurements were simulated in Ansys. The results of the simulations were then compared with the measured values. The aim of this thesis is to compare the measured data with the data obtained by the simulations and subsequently to describe the suitability / unsuitability of the substitution of the one-layered soil model for the two-layered one for given measurements.

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