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Primary testing of the protection relays
Macek, Vratislav ; Topolánek, David (referee) ; Toman, Petr (advisor)
The main subject of this bachelor’s thesis is the creation of laboratory task on the issue of primary injection testing of the protection relays. The thesis is made up of two parts: theoretical and practical. In theoretical part there are information concerning the issue of protecting. One of them the meaning and relay function, requirements applicable on them, failure states, which may arise on the device operation, description of instrument transformers and methods of testing relays. In practical part is created laboratory task on the issue of primary injection testing of overcurrent relay, of which will demonstrate the influence of load current transformer to its function. In task are used Overcurrent and Earth-fault protection REJ 525A and measuring instrument Omicron CPC 100.
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DC motor controler with feedback
Dundáček, Martin ; Štohl, Radek (referee) ; Bradáč, Zdeněk (advisor)
This thesis deals with DC motor control. Main goal was design and realization of DC motor controler module with feedback. The first part dwells on methods for DC motor control and HW design of control module. The second part describes development of software for the module, testing and sums up results.
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Safety of off-grid hybrid energy system operation
Orság, Štěpán ; Vrána, Michal (referee) ; Morávek, Jan (advisor)
The thesis deals with the safety of hybrid systems in island operation. The safety requirements for electrical installation with photovoltaic system and protection against electric shock are discussed. Hybrid battery systems have a lower short-circuit performance in islanded operation, compared to parallel operation with the distribution grid, so the thesis focuses on the specifics of islanded operation and the use of protections that are part of the PV inverter or electrical installation. The work includes the design of test procedures and measurements on selected inverters with subsequent evaluation and recommendation of further protection measures.
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History of protection relays
Šafl, Pavel ; Koudelka, Jan (referee) ; Bukvišová, Zuzana (advisor)
The bachelor thesis deals with mapping the origin and history of electrical pro-tections. The work outlines the circumstances and the new types of protection. It expla-ins and introduces problems encountered in the development and operation of historical protections. On the overcurrent protection AB31, AT31 and REF615, the tripping characte-ristic was measured to evaluate and compare modern digital protection and historical electromagnetic protection. Dependent protection AB31 has been tested and measured for its dependent characteristics and the AT31 protection has been checked for short-circuit current capability. Both of these protections were compared and evaluated with the REF615 digital protection. The measurement results and calculations are processed into well-arranged tables and graphs that are part of the work. The last part of this thesis is the selection of suitable protections for describing and making small exposures.
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Design of Protection Relays for MV Distribution Grid
Sochor, Tomáš ; Bukvišová, Zuzana (referee) ; Toman, Petr (advisor)
The master´s thesis deals with the design of medium voltage power line protection and the calculation of reliability indicators. First, it deals with the possibilities of power system operation. Subsequently, it divides the networks according to the grounding of the transformer node and the switching elements and devices occurring in the MV distribution network are mentioned. It presents the basic classification of power line protection and its use, especially it focuses on overhead and cable MV power lines. It also discusses the reliability of the power supply and lists the basic reliability indicators and their possible calculation. The practical part describes the changes in the considered area of the distribution network, where the reconstruction of the power line VN872 and a new way of powering the village Drnholec will take place. The impact of this change on the reliability of the supplied energy is also calculated. Furthermore, the protection of the power line is designed and the correctness of its setting is then verified on the model in the PSS Sincal software.
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Measurement of mechanical and electrical quantities of bimetals
Kocian, Štěpán ; Bušov, Bohuslav (referee) ; Valenta, Jiří (advisor)
This bachelor thesis focuses on bimetals. In the theoretical part is described the principle of operation of bimetals, then important parameters of bimetal, including mathematical equations. Furthermore, methods of heating bimetals are mentioned and mathematically described. The last part in theory concentrates on the standards related to the use of bimetals as circuit breakers and the corresponding agreed breaking currents. The practical part deals with measurements on bimetal. This is measurement of free deflection and the force generated by the bimetal depending on the temperature change. From the measured data, the characteristics and the dependences of the properties for bimetal were processed. The last chapter was devoted to the creation of laboratory work.
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DC/AC one-phase inverter 230 V / 50 Hz / 60 VA for a back-up supply source with a galvanic separation
Šoupal, Ondřej ; Procházka, Petr (referee) ; Vorel, Pavel (advisor)
The aim of this thesis is to design power circuits and control circuits of single phase DC/AC inverter and its practical realization. This work describes basic principle of single phase inverter. Next step is a solution of output LC filter, input capacitor and semiconductor devices. It contains block diagram of control circuits and it focuses on design of oscillator for pulse width modulation and current limiting. The thesis gives details about practical realisation and testing measurements. Technical documentation was prepared for this inverter.
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Distance Protection Design Using Digital Input Data
Wannous, Kinan Hasan Wafaa ; Müller,, Zdeněk (referee) ; Braciník, Peter (referee) ; Toman, Petr (advisor)
Standard IEC 61850-9-2 definuje přenos vzorkovaných měřených hodnot (sampled measured values, SMV) prostřednictvím sítě Ethernet a využití SMV získaných ze slučovacích jednotek nebo přístrojových transformátorů. Implementace IEC 61850-9-2 závisí na vlastnostech datového souboru, jakými jsou časová synchronizace, počet vzorků a časový interval. Dizertační práce je zaměřena na algoritmy chránění a analýzu vlivu standardu IEC61850-9-2LE na fyzická zařízení ochran s analogově/digitálními vstupními daty o proudu a napětí. S ohledem na narůstající míru interakce mezi fyzickými zařízeními a komunikačními prvky byl navržen test pro analýzu komunikace pro rozvodnu využívající konvenční metody (analogové vstupy) a metody digitální založené na standardu IEC 61850-9-2. Práce dále popisuje funkci slučovací jednotky využívající standard IEC61850-9-2LE. Navržená metoda definuje zdroj SMV a analyzuje přenos dat. V rámci práce byl za využití softwaru Matlab naprogramován algoritmus ochrany. Vytvořený model je schopen vyhodnotit vliv harmonického zkreslení na funkci digitálních ochran a vliv přesycení proudového transformátoru na distanční ochranu. V práci jsou zhodnoceny i možnosti zrychlení testování systémů chránění s využitím neuronové sítě. Závěrečná kapitola se zabývá aplikacemi v reálném čase, využívajícími data z rozvodny v blízkosti Vysokého učení technického v Brně. K přenosu dat z rozvodny do univerzitní laboratoře je zde využíváno SMV přenášených optickým kabelem o délce 16 km. Aplikace je vytvořena v programu Matlab a je schopna číst data z ethernetového portu, dekódovat je, převést z formátu ASCII do desítkové soustavy a poté vykreslit průběhy proudu a napětí. Mezi vlastnosti aplikace se řadí jednoduchost použití, schopnost implementace funkcí distanční ochrany, výpočet RMS hodnot proudu a napětí a harmonického zkreslení, harmonická analýza prostřednictvím rychlé Fourierovy transformace a výpočet impedance poruchové smyčky. Všechny výpočty běží v reálném čase a provedena je i citlivostní analýza modelu.
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History of protection relays
Šafl, Pavel ; Koudelka, Jan (referee) ; Bukvišová, Zuzana (advisor)
The bachelor thesis deals with mapping the origin and history of electrical protections. The work outlines the circumstances and the new types of protection. It expla-ins and introduces problems encountered in the development and operation of historical protections. On the overcurrent protection AB31, AT31 and REF615, the tripping characte-ristic was measured to evaluate and compare modern digital protection and historical electromagnetic protection. Dependent protection AB31 has been tested and measured for its dependent characteristics and the AT31 protection has been checked for short-circuit current capability. Both of these protections were compared and evaluated with the REF615 digital protection. The measurement results and calculations are processed into well-arranged tables and graphs that are part of the work. The last part of this thesis is the selection of suitable protections for describing and making small exposures.
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