Usually, the thermometer installed on the transformer is used for temperatura measurement and control of collecting temperature signals. There are two types of local measurement and remote measurement for measurement; for control, there are start-stop and temperature alarms for controlling cooling equipment. A few transformers are also equipped with an analog winding thermometer, which indirectly reflects the average temperature or hot spot temperature of the winding according to the load current of the transformer (measured by the bushing current transformer) and the pre-adjusted ratio. If the winding hot spot temperature is measured, the difference between the hot spot temperature rise and the average temperature rise at this time is usually the design calculation value.