|
|
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.
|
|
|
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.
|
|
|
Firmware for partial discharge calibrator
Turinský, Matěj ; Baštán, Ondřej (referee) ; Fiedler, Petr (advisor)
The goal of this thesis is to create a firmware which realizes processor control for a given hardware (calibrator of partial discharge meters). Thesis describes what options are availible in the field of processor control of devices, their advantages, disadvantages and possible applications in real life. Concrete realization then provides a closer look on firmware creation in C programming language for STM32 processors using the standard CMSIS interface.
|
|
|
Design Of The Pulse Generator For Testing And Validating Partial Discharge Measuring Systems
Hejtmánek, Tomáš
This article deals with the design and implementation of a pulse generator serving as acalibration generator for setting up measuring systems for monitoring the activity of partial discharges(PD) in the high-voltage power transformers or gas insulated switchgears (GIS). After installingthe measuring device, it is advisable to test the entire measuring chain and, if necessary, setparameters that would affect the correct detection of PD signals. Calibration pulse generators areused for setting and validating measuring chain. These are usually used in systems that sense theelectromagnetic activity of PD. Correct and timely detection of PD can avert a transformer accidentand thus contribute to higher safety in power plants. The proposed generator should serve as theoutput part of a programmable generator, which did not reach sufficient parameters of output pulses.The goal was to achieve a rising time around 100 ps and an amplitude of more than 6 V usingmodern and very fast operational amplifiers and step recovery diodes as a sharpener of the inputpulse. The measurements show waveform of the output voltage pulse.
|
|
|
Switchable Filter For UHF Band
Sedlák, Milan
The contribution deals with the design of a multi-channel switchable filter for ultra high frequency band. The device is primarily designed for the system of sensors which are used for detection of the electromagnetic pulses. They are emitted by the partial discharges in power transformers as a consequence of aging of the dielectric. The main task of the multi-channel switchable filter is to ensure better reliability of the entire system by filtering of undesirable signals with lower frequencies content which are usually products of the external and internal disturbance.
|
|
|
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.
|
|
|
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.
|
|
|
The Partial Discharges Diagnostic in Gas-Insulated Switchgears
Ficek, Jan ; Hrnčíř, Bohumil (referee) ; Orságová, Jaroslava (advisor)
This work is focused on the measurement of partial discharges in gas insulated conductors manufactured by ABB. The theoretical part contains the definition of partial discharges, their analysis and detection methods. It also deals with the general description of gas-insulated substations and then with the concrete components manufactured at ABB in the Brno-Slatina production plant. The practical part describes the course of measurement, definition of the main problems and their explanation. The output from the practical part is a measurement library with given characteristics, which show the location and character of the problem in detecting partial discharge in a given encapsulated assembly.
|
|
|
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.
|
|
|
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.
|
guest ::
