Fastening structure for transformer box lid

The invention relates to a fastening structure for a transformer box lid. The invention comprises a tank which is covered by a tank cap and is provided with a connecting ear. The connecting ear is provided with a pressing block for the connecting ear. One end of the pressing block for the connecting ear presses on the tank cap. A screwed hole where a bolt is arranged is arranged in the connecting ear and the pressing block for the connecting ear. The screwed hole is an unthreaded hole. A hole where a connecting ear shaft is inserted is arranged horizontally in the connecting ear. Another bolt is arranged inside another screwed hole arranged in the middle of the connecting ear shaft. At least 3 connecting ears and pressing blocks for the connecting ear are uniformly distributed. The number of the connecting ears and pressing blocks for the connecting ear is 6. The tank cap is under even stress at many places. Furthermore, as no aperture is opened in the center of the tank cap, the sealing property between the