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Differential Protection for Power Transformer
Bukvišová, Zuzana ; Wasserbauer, Vojtěch (referee) ; Orságová, Jaroslava (advisor)
This thesis explores power transformer protection and focuses on differential protection. It attempts to explain its principles and operating characteristic settings. The measurement was executed on devices SPAD 346 C and REF542plus, which can be used for differential protection. At the end, there is a comparison of results of operating characteristic measurement on both devices. Their function was tested at different cases, specifically when the differential current occurs in all phases or just one. The thesis includes a comparison of reaction times under fast increase of current. OMICRON CMC 256 plus was used as the test device. The data obtained by the measurement are processed in tables and charts.
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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 three-wire transformer parameters
Kováč, Frederik ; Bukvišová, Zuzana (referee) ; Wasserbauer, Vojtěch (advisor)
Thebachelor’sthesisdealswithmeasuringsymmetriccomponentalimpedanciesofthree winding transformer. Thesis is divided into a theoretical and practical part. In theoretical part is described principle of transformer operation, its parameters, open-circuited and short-circuited measuring, measuring of zero-sequence impedance and connection schemes. Practical part deals with design of workplace in laboratory, description of used instruments and practical measurements with real connection schemes. For measuring parameters of three winding transformer is created a laboratory instruction manual.
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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.
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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.
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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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Protection functions of the REX 640 terminal in case of earth faults
Siegel, Josef ; Bukvišová, Zuzana (referee) ; Wasserbauer, Vojtěch (advisor)
This bachelor thesis deals with the protection, implementation and evaluation of test for fault condition indicators. Thesis focus on earth fault indicators. These protections must be able to evaluate earth faults in compensated, compensated with auxiliary resistor, unearthed and high-resistance earthed networks. Furthermore, part of the thesis is research of methods of earth fault detection, including their principles and function description.
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Finding The Fault Inception Time Using Wavelet Transform
Bukvisova, Zuzana
This paper deals with the transient detection method utilizing the wavelet transform, which proved to be more suitable for this purpose than the Fourier transform. The aim of this work is to analyze data, obtained from the power network model created in PSCAD software, and to determine the time of the fault inception. This calculated time is then compared with the actual fault inception time set in the model. The results show that the wavelet analysis can successfully detect all tested faults.
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Protection functions of the REX 640 terminal in case of earth faults
Siegel, Josef ; Bukvišová, Zuzana (referee) ; Wasserbauer, Vojtěch (advisor)
This bachelor thesis deals with the protection, implementation and evaluation of test for fault condition indicators. Thesis focus on earth fault indicators. These protections must be able to evaluate earth faults in compensated, compensated with auxiliary resistor, unearthed and high-resistance earthed networks. Furthermore, part of the thesis is research of methods of earth fault detection, including their principles and function description.
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