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Reliability of Power Oil Transformers
Ertl, Jakub ; Szabó,, Radek (referee) ; Kratochvíl, Petr (referee) ; Hammer, Miloš (advisor)
The doctoral thesis deals with design of non-invasive methods for estimated reliability analysis of power oil transformers. Such procedures also solve two-state and multistate reliability problems together with applying of gained reliability characteristics in planning further operation of these non-rotating electrical machines. Reliability module for diagnostic system, which is developed at the training workplace, is designed in conclusion of this thesis. All the above procedures were verified on data obtained from diagnostic measurements of ten power oil transformers operating in different power plants in the Czech Republic.
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Artificial Intelligence in Power Oil Transformers Diagnostics
Janda, Ondřej ; Szabó,, Radek (referee) ; Kratochvíl, Petr (referee) ; Hammer, Miloš (advisor)
This dissertation thesis deals with the application of expert systems and soft computing methods in field of power oil transformers. The main work is divided into theoretical and practical part. First, the theoretical part presents the basic elements of the transformer, and approaches to its diagnosis. The work focused mainly on the diagnostics of the insulation system, and diagnostic methods and approaches in this specific area. Next part describes the basics of expert systems and other soft computing methods such as: fuzzy logic, neural networks, genetic algorithms and their combinations and extensions. At the end of the theoretical part, the possibility of optimization approaches by means of artificial intelligence and its application in fuzzy model optimization are described. The practical part begins with description of the used data file that runs through the entire work. The work is then divided into four parts, namely in parts which deal with the expert system for transformer diagnostics, DGA module, prediction module, and optimization using artificial intelligence. The section describing the expert system gives specific information about the particular expert system. The means and techniques used for constructing given system are described, and then the complete system design and description of all subsystems and modules are presented. The next section describes the developed DGA module and all selected approaches to its implementation and expansion. At the end of the chapter, the results of comparison between all implemented methods are evaluated. The third part deals with the prediction module and describes its design and construction, including description of the main parts which are based on the selected predictive approaches. Also, the predictions of selected quantities from the data file are included. There are two predictive approaches being used: the one step prediction, and the multiple step prediction. The comparison of prediction accuracy and computational cost of given methods is presented at the end of this chapter. The last part deals with the possibilities of optimization using artificial intelligence methods, namely differential evolution, PSO, and genetic algorithms. Both the single-objective and the multi-objective optimization are considered. The methods are compared in a series of synthetic tests and then applied to optimize the fuzzy models of DGA tests from an earlier part of this work. The dissertation also includes chapters: "The Aims", "The Contribution of the Work", and a list of publications, products, and projects of the author.
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Contribution to the Evaluation of Dissolved Gas Analysis in Power Oil Transformer Diagnosis
Ministr, Martin ; Hammer, Miloš (advisor)
This dissertation thesis is focused on the evaluation of the dissolved gas analysis in the power oil transformer diagnosis. This thesis derives from known, in standards, directives and literature shows realities which are fill in new pieces of knowledge as determining of gases important for evaluation of the transformer condition, specifying of current methods accuracy and investigating of accuracy change for interpretation of dissolved gases. The part of this thesis is the application of mathematic methods for detailed description of individual transformer failures and determining of dominant gas which are generating in power oil transformer. Obtain conclusion will be contribution for transformer diagnostics and will be applicable in industrial practice.
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Contribution to the Evaluation of Dissolved Gas Analysis in Power Oil Transformer Diagnosis
Ministr, Martin ; Szabó,, Radek (referee) ; Kratochvíl, Petr (referee) ; Hammer, Miloš (advisor)
This dissertation thesis is focused on the evaluation of the dissolved gas analysis in the power oil transformer diagnosis. This thesis derives from known, in standards, directives and literature shows realities which are fill in new pieces of knowledge as determining of gases important for evaluation of the transformer condition, specifying of current methods accuracy and investigating of accuracy change for interpretation of dissolved gases. The part of this thesis is the application of mathematic methods for detailed description of individual transformer failures and determining of dominant gas which are generating in power oil transformer. Obtain conclusion will be contribution for transformer diagnostics and will be applicable in industrial practice.
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Selected Problems of Diagnosis of Insulation Systems for Rotating Electrical Machines
Pavlík, Josef ; Radek,, Szabó (referee) ; Singule, Vladislav (referee) ; Hammer, Miloš (advisor)
This dissertation thesis deals with the measurement of insulation resistance for rotating electrical machines and polarization indices calculated from them. The first part contains a short theoretical introduction, methods of measurement and basic formulas for calculations. The second part discusses the results obtained in laboratory measurements in both the model and the real coil of high voltage machine. There are also elucidated some of the principles and causes of some phenomena with which the measurement of insulation resistance is encountered. The third part deals with the results of measurements on real machines. There are mainly discussed the dependences of insulation resistance and polarization index on the influences that occur in measurements such as temperature measured insulation, moisture in the insulation, but also the influence of measuring instruments on the measured values. It is also expressed how much these factors affect the measurement results. In addition, this part deals with some other influences that have a negative affect on the measurement of insulation resistance. There is processed a new methodology for measuring insulation resistence in the fourth part of this thesis. The need to develop a metodology of measuring is based on the needs of engineering practice, where is considerable inconsistency of measurement in the present time. Measurement, and often performed on the same machine, are not nowadays often comparable, because measurements are not met even the basic rules resulting from the findings of research and development, which were discovered in the last few decades. Measurement of insulation resistance in our nowdays methodology stagnated on the level of the seventies of 20th century. For this reason, we have developed a new methodology of measurement that takes into account all significant influences affecting the measurement. The purpose of the methodology is to ensure full repeatability and comparability of measurements not only on the same machine but on machines of the same type, in optimal cases, the machines of different types. There are the chapters "The objectives of the work" and "Conclusion" the part of the work. A very important chapter is "The contribution of thesis", which summarizes the original results of this work and results, the use of which is expected in engineering practice.
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Contribution to the Diagnosis of Power Oil Transformers
Šimková, Martina ; Poliak,, Ján (referee) ; Szabó, Radek (referee) ; Hammer, Miloš (advisor)
This dissertation thesis deals with the diagnotics of power oil transformer. It consists of the theoretical and practical part At its beginning, the theoretical part deals with an general description of the transformer and its connection. Focus is given to aspects of the life of the transformer insulation system (oilpaper). Further, the technical diagnostics is analyzed, with description of quantities of gasliquid chromatography, the oil condition and condition of conductor insulation. Another important part of the thesis consists of an expert system, which is described generally from the past to the present. Characteristics, types and structure of expert systems are mentioned here, with its advantages and disadvantages. The practical part starts with a description of the data file, which is further used in the thesis. Main practical part is divided into three parts - the results of gas-liguid chromatography, selected results and expert systems. In the section entitled "Results of gasliquid chromatography", there is an analysis of selected properties of time series and temperature dependency of gases. Moreover, the methods of the ratios of gases such as Duval Triangle method are described. The second part entitled "Selected other results" shows the time dependency of variables and the neutralization number, along with the breakdown voltage dependency, and time of dependency, gas and moisture content in insulating oils. There is also a temperature dependency of moisture content dissolved in insulating oil discussed, as well as results of selected correlations, such as the correlation values of gas chromatography with state variables insulation of wires. The last part, "Expert systems", provides specific information about developed expert system. It describes the environment chosen for its development, followed by a description, features and verification of the expert system. Examples of the consultation results are included. All achievements of the individual parts are always summarized at the end of each section. The thesis contains chapters "Objectives of the work" and "Conclusion". The most important chapter is "The contribution of the work." It contains original work results and the results applicable in industry.
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Calibration of roughness standards
Šrůt, Petr ; Hammer, Miloš (referee) ; Jankových, Róbert (advisor)
This master´s thesis deals with the measurement of surface roughness on a roundness instrument Talyrond TR595S. The aim was to expand possibilities of measuring on this roundness instrument. The main benefit of this thesis is creation of the proposal for the roughness measurement components in a horizontal and vertical plane. Thesis also includes the procedure for measuring of the roughness of the circular components including calculation of measurement uncertainty.
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Quality assessment of shotgun barrel bore
Vespalec, Vítězslav ; Hammer, Miloš (referee) ; Jankových, Róbert (advisor)
The diploma thesis deals with the issue of a quality assessment of a bore of shotgun barrels. There are mentioned both definitions of a quality shotgun barrel and also a quality of shotgun barrel bore. In conclusion, there are presented particular proposals for evaluation of parameters of surface texture of forged shotgun barrel blanks.
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Thermodiagnostics – contact and contact-free temperature measurements
Mikula, Martin ; Jankových, Róbert (referee) ; Hammer, Miloš (advisor)
This thesis is concerned with thermodiagnostics in industrial practise, which is very important for the assessment of technical condition of object on the basis of temperature, in today's time. It includes summary of contact and contact-free methods and their principle, advantages and disadvantages for aplication in industrial practise. Because of thesis it was carried out measurement in company Daikin Device Czech republic with the use of contact thermometer and two available thermocameras for solving of topical tasks relating to production.
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