A Comparative Study on the Non-Destructive Diagnostic Methods of the insulation Oils in Power Transformer

전력용 변압기 절연유희 비파괴 진단 시험법 비교연구

The various degradation phenomena, such as the evolution of gases, tan e, moisture content and total acid number in insulation oils of power transformer have been measured and analyzed as a function of aging temperatures and periods. The insulation oils have been degraded at laboratory in the period of 17, 34, and 72 days. We have also extracted the insulation oils from the working power transformers. The dissolved gases (such as CO, CO2, H2, CH4 C2H2---), tane, moisture content and total acid number in laboratory samples and field samples have been measured and characterized. It has been found that gases increase with degradation temperature and tane increases with total acid number while the moisture content does not increase with tane.