National Repository of Grey Literature 92 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
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.
Surge arresters, their construction and use in power system
Novický, Marek ; Pelikán, Luděk (referee) ; Orságová, Jaroslava (advisor)
The bachelor thesis deals with the means used to protect the equipment from the effects of overvoltage. The first of the thesis outlines basic information regarding the used overvoltage protections in the distribution system. The thesis also features the practical part outlining measurements carried out on the surge arrester. The last chapter deals with the dimensioning of the surge arrester in the high voltage distribution system.
Dynamic loading of overhead lines
Šimák, Josef ; Jurák, Viktor (referee) ; Orságová, Jaroslava (advisor)
The bachelor's thesis is focused on the introduction of equipment and principles in dynamic current loading of lines. The individual methods are introduced and described with a focus on online monitoring systems. Furthermore, the calculation of the dependence of the parameters of AlFe conductors on the temperature change is performed.
The algorithm of protection function for the unsymetries location
Kopáček, Petr ; Jurák, Viktor (referee) ; Orságová, Jaroslava (advisor)
The Master Thesis deals with a proposal of algorithm of a protective function for assymetric faults location in resistance-grounded medium voltage networks with decentralized measurement of instantaneous voltage and current values. The theoretical part describes a single pole fault in the resistance-grounded network including the network analysis using the symmetric component method. Furtherly follows brief reserse of nowadays considered possibilities of faults location in the medium voltage networks. The proposed algorithm which works on the principle of negative sequence changes and change differencies of voltage and current is described by mathematical operations and flowchart, and it is furtherly tested in the PSCAD simulator on the proposed network model. Also the algorithm is tested in the Matlab program using the real data from the local distribution network Pod Palackeho vrchem where the initial pilot implementation is assumed. The last part of the thesis includes also the algorithm sensitivity analysis.
Direct load angle measurement on the laboratory generator unit
Dvořáček, Jiří ; Bukvišová, Zuzana (referee) ; Orságová, Jaroslava (advisor)
Synchronous generators are the most used machines for production of electricity. Therefore it is critical to use various methods for checking operating parameters. One of the worst faults is falling out of synchronism which can even lead to machine damage. Main objective of bachelor thesis is to design a method for load angle measurement using available laboratory equipment and to calculate saturated synchronous reactances using load angle. Load angle is measured using incremental sensor and output voltage waveform.
Theory and practice of fault location on MV cable lines in E.ON distribution networks
Macků, Dominika ; Holub, Martin (referee) ; Orságová, Jaroslava (advisor)
This thesis gives an overview on the fault of high-voltage cable transmission lines in the distribution system of the E.ON company. The first part of this thesis introduces reader to the topic of cable transmission lines, types of commonly used cables and the most commonly occurring faults. In the second part of this thesis, the methods of locating faults in cable transmission lines by professional personnel are explained. The third part deals with the analysis of a group of chosen occurred faults. The final part focuses on the statistics of fault occurrence on South Moravian region from 1.1.2017 until 1.1.2019.
Assessment of connectivity of the new source to the 110 kV network
Kopečný, David ; Fojtík, Martin (referee) ; Orságová, Jaroslava (advisor)
This thesis focuses on the connectivity problems of the new sources to the electrical network. The first part of the thesis deals with the description of the new source and the method of its connection to the electrical network. Furthermore, in work, there are elaborated the blocking conditions for substation TR Neratovice expanded distribution point. A distribution network operator must receive an attachment application for connecting before the actual connection. The attachments consist of study cases of conjunction that values the inverse influence on the distributional network and informs the operator about the required measures for the reliable service with the new source. PSS Sincal computer software was used to survey the inverse influences on the distributional network. Based on processed data, the evaluation of conjunction of the synchronous generator to the grid at TR Neratovice substation was reconsidered.
Compensation of reactive power to avoid its overflow into the MV system
Jurák, Viktor ; Ptáček, Michal (referee) ; Orságová, Jaroslava (advisor)
This master thesis is focused on analysis of reactive power flow in LV and MV networks. In the first part there is a definition of reactive power and description of individual parts of electrical networks that contribute with their reactive power to distribution network. The second part is dedicated to calculation of power flow in simulation software PSS® Sincal where on numerical models of network different types of network configuration are tested and consequently its influence on reactive power flow is evaluated. A more detailed analysis is dedicated to reactive power compensation in networks with distributed generation equipped with Volt-Var regulation and its possible negative mutual influence. This thesis also includes general recommendation on the basis of network simulation analysis concerning installation of compensating systems in distribution transformer station.
Comparison of conventional CT and VT with current and voltage sensors
Dvořák, Petr ; Drápela, Jiří (referee) ; Orságová, Jaroslava (advisor)
The diploma thesis deals with conventional transformers and current and voltage sensors. The first half of thesis describes mainly the basic concepts and accuracy classes of these converters used in electrical substations. The emphasis is given primarily on the differences. In the second half of thesis is presented an exact type of converters, which are installed in the substation Medlánky. There is an analysis of measured data from long – term monitoring from this substation and comparing the results from conventional transformers compared to the results from more modern sensors.
The issue of evaluating of interlocking in substations using GOOSE messages
Ditrych, Marek ; Fíla, Vlastimil (referee) ; Orságová, Jaroslava (advisor)
This master thesis focuses on problematics of GOOSE messages used for evaluation of blocking conditions of substations in the electrical power plant in Opatovice (EOP). Firstly, the thesis describes the multifunctional electrical protection relay 7SJ64 as well as GOOSE messages, that are run by protocol IEC 61850. Next, it contains a brief description of the energy consumption of EOP itself, since the project was written for its protection relays. In the practical part of the thesis, an experimental network consisting of two distinct substations with three 7SJ64 multifunctional protection relays was designed together with simple blocking conditions. These require information about the state of circuit breakers. The whole communication is carried by GOOSE messages. Moreover, to inform about the loss of GOOSE messages, the logical function SI_GET_S (decoder) was used inside the coding interface of DIGSI programme called CFC. This function was then tested in the experimental network using each different condition, that experienced interruptions of communication caused either by simulated defect of optical cabels, or by „user‘s mistakes“ in the settings of communication parameters in DIGSI. Finally, the system protecting from the loss of GOOSE messages was incorporated into the existing project evaluating blocking conditions in the block substation of EOP.

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