I'm not familiar with the automatic transmission as all my cars are manual. But if it's the type of automatic transmission that uses a transmission control module and a little electric motor to switch gears, i would probably start there.
You might have a melted relay, this would cause a short, or if the TCM uses high side circuit board drivers, these are prone to shorting as well and would be a short on a circuit board.
First i would pull the TCM and look at any related relays first. Smell each one and visually inspect to see if they work. You can also check each relay with a multimeter to see if they are shorted while NC(normally closed). Sometimes you can smell if one has burned through the plastic housing.
If your transmission is mechanically fuxored inside, the little electric motor may also be maxed out and blow the fuse. (when an electric actuator or motor is stopped or reaches end of stroke, the current will go very high and blow fuses).