Overall, it was quite challenging.
It was a three step process.
1. Phone interview - Basics about faults and stuff, some simple maths like calculus, and some HR related questions.
2. Video Interview - Harder, with two technical people who grilled on concepts in Power Systems and stuff. They had provided an outline of topics that they will cover beforehand. They kept assisting me if I got stuck and were very nice.
3. Onsite interview - There was a presentation (2 hours) whose topic I had to decide beforehand. It was tough, very tough. There were six-ish people in the panel and they kept delving deeper into each and every topic I had on my slides. Then there was a panel interview (2 hours) in which they asked me stuff about different things in the field, and here too they went into the very basics. Whenever I got stuck, they helped out, but it was very difficult. I did not know the answers to many questions, but I tried my best. Then there are some HR meetings and some other stuff.
Mostly they are looking for your limits and how well you cope under pressure. Be honest and answer to the best of your capabilities and you will be fine. Don't try to muddle through. Tell them if you dont know. But make sure that you know your basics thoroughly.
They took a day to reply after the phone interview and set up the video a week from that. After teh video, they took a few days to respond and set up the visit, which was two weeks later. It was a full day interview process onsite. I got the offer a week after the onsite.