The degradation of insulation oil in power transformers by the evolution of gases, Tan $\delta$, moisture and total acid number

가스량, Tan $\delta$, 수분량, 전산가에 의한 유침 전력 변압기의 열화현상에 관한 연구

The various degradation phenomena, such as the evolution of gases, tan $\delta$, moisture content and total acid number in power transformer insulation oil, have been measured and analyzed. Mineral oil has been degraded at laboratory by the forced thermal stress of $60^{\circ}C$ and $90^{\circ}C$ respectively. Thermal aging oil has been degraded about 17, 34, 72 days. Also, we extracted insulation oil from working transformers. We measured gases dissolved in samples, tan $\delta$, moisture content, total acid number. Activation energy and resistivity is calculated from them. It is found that gases and tan $\delta$ increases as partial discharge and total acid number increases and that conductivity of the sample increases as activation energy increases.