What spell does Hermione use to free the dragon?
the Revulsion JinxThe spell used may have been a non-verbal form of the Revulsion Jinx. In the film version Harry Potter and the Deathly Hallows: Part 2, it was Hermione Granger who used this jinx to free the dragon guarding the high-security vaults in Gringotts Banks during the 1998 Break-in of Gringotts Wizarding Bank.
What does protego Totalum do?
Protego totalum was the incantation of a protective enchantment used to shield a certain area or dwelling for an extended period of time.