is the fairy tail OVA 1-5 in the same story lina as one another and what is fairytail x rave?

Ovas are not like a serie itself they are related with the anime i mean ova 5 is before episode 175 and ova 6 is after it...they are like extra episodes and ova 6(rave master)is a combination with the rave master characters and fairy tail characters if you dont know rave master is the previous manga serie of fairy tails author hiro mashima...