The invention relates to the field of cooling oil-immersed self-cooled transformer, in particular to a mobile spray cooling device convenient for storing and installing the oil-immersed self-cooled transformer. The connecting seat of the invention comprises a connecting part, two locking parts, a connecting table and a connecting head, wherein the connecting table is arranged on the upper part ofthe connecting head, mounting holes are arranged on both sides of the connecting table, and the two locking parts are respectively installed on both sides of the connecting table through locking screws; A connection portion includes a first outer protrusion, first inner protrusion, second inner protrusion, second outer protrusion, A loc part comprises a clasp re and a locking screw, wherein that clasp ring is arranged in the groove. The loc part comprises a clasp ring and a locking screw, and the clasp ring is arranged in the groove. The invention can quickly reduce the working temperature ofthe transformer, and ensures the long-term stable operation of the transformer.