Contribution to the Diagnosis of Power Oil Transformers

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