National Repository of Grey Literature 64 records found  previous11 - 20nextend  jump to record: Search took 0.01 seconds. 
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.
Short Circuit Calculation and Generator Protections Settings for Hydro Plant Lipno I
Guliš, Tomáš ; Topolánek, David (referee) ; Orságová, Jaroslava (advisor)
This Master 's thesis deals with the topic of protection of generators in case of faults, short circuits and their calculation according to the valid standard ČSN EN 60909-0 ed.2. The practical part includes the calculation of the minimum and maximum short-circuit currents of the Lipno I hydroelectric power plant at various locations using the NetCalc calculation program and for comparison of program funcionality provides the manual calculation. Next chapter deals with the calculation of settings of each protection function of the SIEMENS Siprotec 7UM622 protection relay, which is used to protect main generators of this hydropower plant.
Verification of the outputs opteined from the new developed three-phase numarical model of the network
Palko, Richard ; Bodor, Alfred (referee) ; Topolánek, David (advisor)
This bachelor thesis describes the procedure of setting the numerical model and calculating the distribution system in the newly developed three-phase numerical model. After performing measurements on physical models, the obtained data are compared and evaluated. To comparasion the accuracy of the calculation, the operational status of the network will be simulated, the calculation of the symmetrical and unsymmetrical short-circuits and earth connections.
Testing of the admitance principle of the fault indicator
Musil, Milan ; Vyčítal, Václav (referee) ; Topolánek, David (advisor)
The thesis deals with the proposal, implementation and evaluation of test for fault condition indicators. Thesis focusing on earth fault indicators based on admittance principles. These indicators must be able to evaluate earth faults in compensated, compensated with auxiliary resistor, unearthed and high-resistance earthed networks. The proposed tests verify the current and voltage measurement errors in inputs including monitored characteristic variables such as conductance and susceptance. The proposed test are applied to a selected ample of the fault indicator. As part of the tests, the indicator is subjected to secondary test using the Omicron CMC256plus tester as well as test on fault records that have been converted to COMTRADE for this purpose. The last series of tests carried out uses the physical model of the medium voltage system, where the tested equipment is subjected to fault states in the compensated whit auxiliary resistor system and isolated system. Furthermore, part of the thesis is research of new methods of earth fault detection, including their principles and function description. Also included in the thesis is an overview of manufacturers of indicators, or protection, who are involved in the production of earth fault protection.
Evaluation of MV/LV network earthing systems
Sítař, Martin ; Topolánek, David (referee) ; Kopička, Marek (advisor)
This master's thesis deals with the measurement of grounding systems in HV/LV distribution networks, which includes grounding system of distribution substation and transmission lines. Explores the issue and principles for the measurement of parameters, which are important for the protection of persons and animals in order not to touch exposed conductive part accidentally, protection of electrical machines and equipment against high fault current and dangerous surges while the correct function of the connected electrical equipment is maintained. These parameters include earth potential rise, ground resistance, soil resistivity, touch voltage, step voltage and transferred potential to the LV network. The aim of this work is the preparation, analysis and subsequent evaluation for the real measurement in practice. These earthing-system measurements were carried out at the distribution station and the concrete pole with a section disconnector. Then a numerical model of the grounding system of concrete pole was created in ANSYS. Subsequent evaluation of the results as numerical terms (comparison measurements and simulated results) and evaluation in terms of analytical (measurement results compliance with the standard) including the numerical model of the earthing system is solved in the practical part of the master's thesis.
Analyses of the breaker/limiter functions for low voltage supply points
Procházková, Denisa ; Toman, Petr (referee) ; Topolánek, David (advisor)
The diploma thesis provides an insight into the remote control and disconnection of DSO supply points phenomenon. The remote or local disconnection/connection of supply point is allowed by the breaker function. The automatic disconnection of supply point is enabled by the limiter function. Due to the anticipated implementation of smart meters in the Czech Republic in the future, this work contains the comprehensive description of breaker/limiter function with proposed possibilities of use in the Czech Republic. The thesis deals with the current breaker/limiter function use in the Czech Republic and in other countries. It introduces the smart meter installation in pilot projects to analyze the breaker/limiter function use in other countries. The thesis is focused on the technical solution of breaker/limiter. Moreover, it describes the ways of connecting the breaker, settting the limiter, connecting/disconnecting a supply point and breaker operation. Further, the thesis introduces the ways of activating the breaker by a customer and defines in which cases it is possible to limit and interrupt the electricity supply in the Czech Republic currently. The main aim of thesis is to describe the specific possibilities of breaker/limiter function use in the Czech Republic. With regard to the function use in other countries and the limiting or interrupting the electricity supply by DSO according to energy law, the possibilities of use are proposed. Each possibility of use is analyzed when implementing the breaker function or the breaker/limiter function. The benefits are defined for a DSO and for a customer. The proposed uses are evaluated in terms of applicability and valid legislation in the Czech Republic. The result of this work is the summary of information about breaker/limiter function which is one of the new features in the implementation of smart metering. The function installation and the implementation of possibilities described in the thesis depends on the DSO decision.
Protection setting concept for given MV substation
Váhala, Václav ; Holub, Jiří (referee) ; Topolánek, David (advisor)
The thesis is focused on the protection concept for medium voltage substation. The first theoretical part of thesis describes given medium voltage substation. Substation consists of two incoming feeders and six outgoing feeders. Due to the size of the substation was selected one outgoing feeder which is the subject of description and protection concept. Next part of the thesis is a description of the protective functions used to protect the elements in the selected feeder. This part contains a detailed description of the function and setting options for protection. The main part of the thesis describes calculation of specific protection functions and consequently with secondary testing of protective functions. Tests were performed on protective functions in the digital protections REF615 and REM620. The final part of the thesis deals with the evaluation of the secondary test results and verification saturation of the specified current transformers.
High Speed Transients Modelling
Bukvišová, Zuzana ; Topolánek, David (referee) ; Orságová, Jaroslava (advisor)
This thesis deals with the high speed transient modelling in the electrical networks. The introduction of this work discusses mathematical models of the individual devices used in the system and focuses on the line representation. It also contains a more detailed description of Bergeron and frequency dependent line model. The objective of this thesis is to design a network model using ATP-EMTP simulation program. In this model, the switching overvoltage caused by shunt reactor switching and lightning overvoltage are simulated. The thesis thoroughly describes the settings of the components used in the model of analysed network and in conclusion evaluates obtained simulation results in a relation to the insulation coordination.
The Indication of Earth Faults in Overhead Lines
Pospíšil, Zdeněk ; Topolánek, David (referee) ; Toman, Petr (advisor)
This master´s thesis deals with the indication and localization of earth faults in overhead lines. Earth fault is the most frequently occurring type of fault in medium voltage overhead lines – it covers approx. 95% of all faults and is very difficult to indicate and localize them correctly and in time with currently available methods on the market. Therefore is very important to study earth fault and its indication, localization. The thesis consists of a theoretical and a practical part. The theoretical part deals with faults in overhead networks with different type of neutral grounding, mainly with one phase to the ground fault in the compensated, ungrounded, solidly grounded and via resistance grounded networks. Most of the theoretical part is dedicated to one phase to the ground fault in the compensated and ungrounded networks, where this type fault is called the earth fault. In the compensated and ungrounded networks is described in details behavior – voltage and current relations during both steady state and transient state earth fault. The theoretical part is further dedicated to detection methods of earth faults and their preconditions for use. There is described also in details the complete procedure of earth fault detection, which includes indication, unhealthy feeder determination and exact position or line section localization. End of the theoretical part is then focused on determination of accuracy requirements for measurement of basic quantities and computation of other parameters. The practical part deals with a work at medium distribution network model, which includes familiarization with the model, detailed verification of its functionality and behavior during the earth fault, obtaining faults records and algorithmization of methods: method of qu – diagram and method of first half - period, which are able to detect unhealthy feeder. This part of the thesis was put together based on a demand of company Mega, corp., which wanted to verify function of both above mentioned and by them not yet tested methods.

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