I first met the recruiters at my university's career showcase. I was scheduled for an interview the next day, which ended up being very relaxed. It was mostly technical. I was asked questions general transmission / distribution concepts and a few about relaying and protection. Overall not too difficult if you've learned about power systems before.
I was then contacted later in the week for a follow-up at their local offices. They told me it was casual dress as most were wearing jeans and what not. It started off with getting to talk about the company, it's many different departments and culture, and then it went into a panel interview with some guys from the office. They asked more technical questions, a bit harder than the previous 1-on-1 interview and behavioural questions at the end. I was told I'd be contacted by the end of the week about their decision (I got an offer and accepted).
Overall the process was very smooth. My recruiter was a recent alumni and was very easy to talk to. They try to make you sweat a little in the group interview but that's expected. They really just want to see that you're knowledgeable in what you know and that you'd be a good fit with the company culture. They want people, especially interns, passionate about the power industry, so look elsewhere if you just want something to put on your resume.