Video: Distribution networks: what six technical webinars teach

Video transcript

Six technical webinars on distribution networks, summarised. What solar, batteries and electric cars have done to a network that was designed to flow one way, and what can actually be measured down there. The starting point of every one of these sessions is the same, and it is uncomfortable. Most distribution networks are close to blind. There are almost no sensors out there. Onto that blind network arrived distributed generation.

Solar on the roofs, batteries behind the meter, and cars that each draw about what a whole house used to. And behind it sits a physical problem the sessions explain well. The grid is a constant balance between demand and generation, and renewable output is set by the weather rather than by a control room. So what can be measured at the bottom of the network? A low voltage monitor at the distribution transformer turns out to answer 4 different questions at once, which is what makes it affordable.

The sessions include what actual utilities asked for, and the list is more practical than any specification. Which raises the obvious question: if distribution transformers fail in the same ways as big ones, why is almost none of this monitored? The answer in these sessions is not the one you expect. So the sessions set out what is realistic by size of unit, and it is a genuinely useful table.

One of those rows deserves expanding, because it is about fire. Pressure inside the tank is the earliest indicator of an internal arc, and the energy of that arc is simply voltage times current times time. And power quality, which has stopped being a specialist subject and become part of ordinary asset management. The last session in the set asks whether any of this is worth it, and answers honestly: it depends where you are. The economics are not universal.

Five things the 6 sessions agree on. Distribution network monitoring, from Amperis.