A prediction technique of power transformer condition assessment via DGA parameters

This dissolved gas analysis is the most important tool for determining the condition of power transformer. It is the first indicator of a problem and can identify deterioration of the insulating such as overheating, hot spot, partial discharge and arcing. Therefore, this paper presents a prediction technique of power transformer condition assessment, by using DGA parameters in the analysis. The key gas parameters include hydrogen (H2), methane (CH4), acetylene (C2H2), ethane (C2H6), carbon monoxide (CO) and carbon dioxide (CO2). The historical test results of the dissolved gas analysis of power transformers rated 115/22 kV 50 MVA analyzed as an example. There are two procedures used in the condition assessment; one is total dissolved combustible gas while the other is key gas. Firstly, the total dissolved combustible gas is considered. Next, the key gas is utilized for specify the incipient faults. Finally, the known condition can be used to plan appropriate maintenance effectively in the utility. This results in higher system reliability and longer useful lifetime of the power transformer.