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Sensors for electromagnetic detection of partial discharges
Pločeková, Natália ; Čáp, Martin (referee) ; Drexler, Petr (advisor)
Tato bakalářská práce se zabývá návrhem externího typu UHF sensoru, který bude umístněný na štěrbině transformátorové nádoby. V prvním kroku byl vlnovod-koax adaptér simulován v programu Ansys HFSS. Na základě poznatků byl zkonstruován sensor. Sensor využívá pro měření dva typy buzení vlnovodu, buzení proudovou sondou a buzení magnetickou smyčkou. Simulovaný a vyrobený sensor je porovnán z hlediska funčnosti a citlivosti.
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MV Cables Failures and Malfunctions
Holuša, Martin ; Pelikán, Luděk (referee) ; Krbal, Michal (advisor)
The aim of this diploma thesis is to define cable and his accessories and describe defects and fault which can appear on the cable and his accessories. The thesis also divides the cable and his accessories into individual parts, which are describe in more detail. Diagnostic methods that can be used to detect individual faults and monitor their status on individual parts of the cable and cable accessories are also listed. The thesis's practical part focuses on the test of one component of the cable assembly using PD measurement and monitoring its surface temperature.
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Simulator of partial discharge signal in the UHF band
Škoda, Martin ; Kasárník,, Milan (referee) ; Drexler, Petr (advisor)
This master thesis deals with the problem of the origin and expression of partial discharges in dielectric materials. In the thesis the theoretical foundations, types and parameters of partial discharges are described. In particular, it deals with UHF (ultra high freqeuncy) electromagnetic radiation using UHF method of partial discharge detection. It also deals with the partial discharge UHF signal simulation. The development of UHF sensor systems for partial discharges requires a dive that can simulate them as accurately as possible. Furthermore, a workplace was designed for simulation and detection of partial discharges and processing of their time and frequency characteristics.
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Diagnosis of high voltage capacitors for cascade voltage multiplier
Baev, Dmitriy ; Zatloukal, Miroslav (referee) ; Krbal, Michal (advisor)
The main subject of the final thesis is to find a suitable method for measuring the partial discharge (PD) in the dielectric of high-voltage capacitor. In the theoretical part of thesis contains from the mechanisms of origin and the harmful effects of partial discharge at high voltage insulation of capacitor. It describes the global galvanic method of partial discharge measurement, the principle of cascade voltage multiplier, its main components (high-voltage capacitor and diode). Nowadays are presented the possibilities of measuring the quality of capacitors for voltage multipliers. In the experimental part of the diploma thesis is familiar with the diagnostics of high – voltage capacitors by means of laboratory measurements on the electronic bridge and with the help of partial discharge measurement system. It describes the design of a suitable electrode arrangement that eliminates the influence of the corona, which makes it impossible to measure partial discharges and the dissipation factor tg . The thesis analyzes the obtained data from measurements and determines the quality level or the degradation of the measured capacitors. The result of the project should be designed the methodology for finding poor quality capacitors in order to increase the reliability of the voltage multiplier.
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Diagnosis of high voltage capacitors for cascade voltage multiplier
Baev, Dmitriy ; Špinka, Jiří (referee) ; Krbal, Michal (advisor)
The main subject of the final thesis is to find a suitable method for measuring the partial discharge (PD) in the dielectric of high-voltage capacitor. In the theoretical part of my thesis contains from the mechanisms of origin and the harmful effects of partial discharge at high voltage insulation of capacitor. It describes the global galvanic method of partial discharge measurement, the principle of cascade voltage multiplier, its main components are high-voltage capacitor and diode, facilities quality measurement of capacitors for voltage multipliers, advantages and disadvantages and principles of HIPOTRONICS DDX-8003 with the pulse discrimination system. In the experimental part of the diploma thesis is familiar with the diagnostics of high – voltage capacitors by means of laboratory measurements on the electronic bridge and with the help of partial discharge measurement system. Design of suitable electrode arrangement is described which eliminates the influence of corona which makes it impossible to measure partial discharges and the dissipation factor (tg ). Analysis data from measurement and determination of quality level, eventual degradation of measured capacitors. The result of this project should be designed the methodology for finding of poor – quality capacitors in order to increase the reliability of the voltage multiplier.
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Partial Discharges Detection and Spatial Localization in High Power Transformers Using UHF Method
Čáp, Martin ; Král, Bohumil (referee) ; Zemánek,, Ivan (referee) ; Drexler, Petr (advisor)
The thesis discusses the design and experimental verification of a new method for detecting partial discharges in oil-cooled high-power transformers, emphasizing the origin of the measured signal from the outer and inner regions of the transformer tank. The detection and spatial localization of partial discharges utilizes UHF (Ultra High Frequency) electromagnetic signal measurement. The UHF partial discharge detection method, also referred as UHF PD, is one of the most advanced techniques for the accurate spatial localization of the signal source position. The focus of the thesis lies in the development of technical and software solutions for the separation of partial discharge signals originating from the internal space of the transformer and the spurious signals from the connection lines. The proposed technical and program solutions constitute a signal discriminatory method. The precise and repeatable diagnostics of the transformer state are guaranteed by observing the measurement methodology and special setting of the diagnostic system. The functionality of the signal discriminatory method was verified during real measurement of the oil-cooled power transformers at the Dukovany nuclear power plant in operation. The output of the designed methodology is to set up a calibration procedure and follow-up steps to ensure objective, repeatable, and comparable measurements for the purposes of regular predictive maintenance in transformers.
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Insulation system of synchronous and induction motors for 18kV
Šporcr, Viktor ; Vetiška, Vojtěch (referee) ; Ondrůšek, Čestmír (advisor)
Bachelor’s thesis is divided into two separate sections. First part is concentrated on insulation system of high voltage machines impregnated by vacuum pressure impregnation. This part of semester thesis concisely describes the composition of individual components used for construction insulation systems of air and water cooled rotation machines. Second practical part contains evaluation of dielectric resistance of coil set with insulation system designed for voltage level 18 kV. This part contains a short description of used insulations. Further includes a report of dielectric tests of used coil set. This set of coils was tested on following tests. Heating measurement semi conductive tape with infrared camera at impulse voltage. The coils was exposed to impulse voltage for one 100 hours and sinus voltage for one 1000 hours. Before and between, aging was measured value of charge partial discharges and dissipation factor.
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Faults identification of AC windings in production process
Samek, Josef ; Kurfűrst, Jiří (referee) ; Ondrůšek, Čestmír (advisor)
In this paper stator manufacturing process of stator is described. Mainly description is aimed on winding, insulation and copper wire. Discussion about origin of insulation damage possibilities during manufacturing is included. Statistics survey about failure causes of stator revealed during manufacturing process and warranty claims is presented. One test method from list of market available winding tests is chosen - partial discharge; described in detail and applied on the correct stator and the damaged stator. Results are interpreted.
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Partial Discharge in Electronic Equipments
Mammadov, Anar ; Maschke, Jan (referee) ; Dřímal,, Jiří (referee) ; Boušek, Jaroslav (advisor)
Tato disertační práce se věnuje studiu částečných výbojů (PD) způsobených poklesem spolehlivosti a životnosti elektronických zařízení a systémů. Diagnostika PD je dnes známá metoda pro vysoké napětí u vysoko-výkonných zařízení. V případě elektronických zařízení PD testování není ale běžně používáná metoda, přestože je zde také potenciál pro vysoké elektrické zatížení vzhledem k velmi krátké vzdálenosti. Tato práce je zaměřena na vyšetřování PD činnosti u elektronických zařízení. Bylo navrženo a provedeno pracoviště pro diagnostiku PD v elektronických zařízeních. Pracovní frekvence se pohybuje od několika stovek Hz až 100 kHz. Maximální amplituda PD testovaného napětí je vyšší než 10 kV. Navzdory jednoduché konstrukci toto zařízení přináší vysokou spolehlivost měření. Více než 300 PD testů bylo provedeno na různých elektronických zařízeních a elektronických součástí,např. na planárních transformátorech a elektronických komponentách používaných při vysoko-napěťových měničích
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