(2) Check the casing for flashover and discharge during heavy fog days.
(3) Snowy days check whether there is snow cover or ice hanging between the top cover of the transformer and the connection between the casings, whether the oil level gauge, thermometer, and gas relay have snow cover;
(4) Check transformer sides after thunderstorm; Arrester register operation conditions, check the casing for damage, cracks and discharge traces.
(5) When the temperature suddenly changes, check the changes in the oil level and the changes in the oil temperature.
