Update on Dissolved Gases Analysis for condition monitoring of Generator Step Up Transformers

Dissolved gas analysis is power tools used for monitoring incipient faults in oil filed high voltage electrical equipment, in particular transformers. Application of this technique will help to monitor condition of transformers in-service. The methodology for analysis of dissolved gases was developed over 40 years and until today, is the most widely and accepted method of diagnostic used by power utilities and transformer manufacturer for the identification of incipient faults. Since its creation and dissemination in the Electrical Sector, there were improvements in the analytical instruments, extraction techniques, interpretation of results and even in the aterials used for construction of the equipment. The authors conducted a survey of the state of the art of the method, evaluate the influence of these changes and examine other aspects of the diagnostic such as the formation of gas due to partial discharges, insulating paper, stray gassing or unexpected interactions among raw materials.

Keywords:

power systems , transformers , mineral insulating oil , dissolved gas analysis , DGA , chromatography