Recognition of Overheating with Temperatures of 150-300°C by Analysis of Dissolved Gases in Oil

Abstract

The article presents the complex analysis results of gas content in oil of 84 high-voltage transformers with "overheating in the temperature range of 150-300°C" and electric discharges of different intensity. Values of gases percentage and gas ratio for each defect type are determined. Nomograms and graphical defect areas have been constructed. A comparative analysis of the diagnostic results of the analysed transformers using 9 well-known methods is made. It is established that diagnoses made with the use of different methods may differ significantly from each other as well as from real diagnoses. The given data allow to increase the recognition reliability of the defect type according to the results of the analysis of dissolved gases in oil.