This month, the feature column discusses the DC grid, and the History column looks at the hybrid DC breaker. So, it may be a good time to look at a little theory about that. When I took the European HVDC tour discussed in the History column, I spent a day with Claes Rytoff visiting ABB’s facilities in Switzerland and discussing HVDC theory. It was a very enjoyable day and recently, I found a video interview with Claes discussing the DC breaker. The video is below – enjoy.