For the forced oil circulation air-cooled transformer, the upper oil temperature is 75℃ with a temperature rise of 35℃. For the oil-immersed natural circulation, self-cooling, and air-cooling transformer, the upper oil temperature generally should not frequently exceed 85℃, and the maximum temperature should not exceed 95℃. The temperature rise should not exceed 55℃. If during operation it is found that one of the limits exceeds the specified value, it should be immediately reported to the dispatching center and measures to limit the load should be taken.