The hiring process at PPL is a lengthy one. From first contact by a staffing agency until I started was six months. I was given technical testing and interviewed by the staffing agency and then three separate interviews by PPL. The first was a one-hour phone interview, the second was a half day with HR, and the last was a technical interview by the team lead whom I ended up working with. It was also technical. Be patient and be yourself during the interview. If you are sitting there, you obviously have something that interests them. Do not be afraid to say you don't know the answer.