Check the temperature of the transformer: See whether the upper oil temperature of the transformer is normal or near or over the maximum allowable limit from the thermometer. When there is a significant anomaly between the temperature that glass thermometer indicates and that the pressure thermometer indicates, it is necessary to find out whether the meter is not accurate or the oil temperature is abnormal.
The check of the oil level: Check whether the temperature of transformer oil storage cabinet is normal and if there is false oil level and oil leakage phenomenon; whether oil level of high voltage bushing and the color of oil is normal and whether bushing has oil leak phenomenon.It is necessary to find out the cause when the oil level indication is not normal. And it is also necessary to pay attention to the path of the oil level indicator and we must ensure that there is no accumulation at the entrance.
Check the sound: Check whether there is abnormal comparison between the electromagnetic sound of the transformer and the previous sound. Staff are usually accustomed to the normal noise of the transformer, and if there is an abnormal sound, they will find it easily.
Check the insulation on the top cover of the transformer: See whether the supporting insulator surface of the outline casing and extraction electric conduction is clean; whether there is a rupture or electric discharge or other defects.
Check the bolt joint that leads the conductor whether has superheating phenomeno: Check the change of the visual temperature wax sheet and the discoloring paint or directly measure it by the infrared thermometer flexibly. When there is a cable terminal box, the oil leakage of the cable head should also be checked.