The 18-year-old, who sits 10th in the Championship table, will race at Oulton, Cheshire on 4-5 June.
"I feel pretty confident, I had really good pace there in pre-season so hopefully I'll go out there and get a podium finish," Powell told BBC Oxford.
"I don't feel apprehensive. I enjoy racing there, it's a great circuit."
The Oxford-based driver added: "If you're on for a good result and you don't get it then you're disappointed like I was last time, so I've got to try really hard again to get a good result.
"But I'm working really closely with the team, just getting my head down and working on a few things to make sure I have the right information about the track so I can just get in there and go."