When a Pokémon with this Ability is hit by a move that makes contact, there is a 30% chance that the attacking Pokémon will become paralyzed. This can affect Ground-type Pokémon.
No. Static and and attacks that have a chance to cause paralysis do not stack. Also, I'd like to point out that your Raichu will only have a 30% chance to paralyze the target when it is attacked with a move that makes contact. Static has no effect on your Raichu's attacks.