Transformer with protection device

The utility model discloses a transformer with a protection device, which comprises a transformer oil tank, a tank cover is arranged at the upper end of the transformer oil tank, a connecting column is arranged in a cavity of the transformer oil tank, an explosion-proof device is arranged on the connecting column and is connected to a plate wall of the tank cover, and the explosion-proof device is arranged on the connecting column. An oil expander is arranged in a cavity of the transformer oil tank, an oil purifier is arranged on the oil expander, a humidity sensor is arranged to detect the humidity in the transformer oil tank, and an exhaust fan and a heating pipe are arranged, so that transformer oil is prevented from being oxidized and affected with damp, the aging speed of the oil is slowed down, and it is ensured that the transformer oil does not deteriorate; by means of the explosion-proof device, when faults occur in the transformer, such as short circuit, insulating oil burns and is sharply decomposed