Substation assembly type small prefabricated foundation suitable for rotary drilling mechanical operation

The utility model relates to the technical field of electric power engineering infrastructure, in particular to a transformer substation assembly type small prefabricated foundation suitable for rotary drilling mechanical operation, which comprises a prefabricated base used for being buried in the ground and an external prefabricated foundation used for being installed on the prefabricated base. The shape and the size of the lower end of the external prefabricated foundation are matched with the shape and the size of the inserting groove of the prefabricated base so that the lower end of the external prefabricated foundation can be inserted into the inserting groove of the prefabricated base, the prefabricated base and the external prefabricated foundation can be prevented from rotating relatively, and an installation bolt is arranged on the top face of the external body. When small transformer substation outdoor equipment is installed, installation can be completed only by installing the equipment on the ins