In my area, "buckets" of average load are prepared ahead of time in coordination between the transporter (who gives the order to shed), the distributer (who imp

In my area, "buckets" of average load are prepared ahead of time in coordination between the transporter (who gives the order to shed), the distributer (who implements the shedding operation as close to consumers as possible), and representatives of the state (who define priority areas that can't be load-shed, or that should be load-shed last). When yhe time comes, you just shed enough "buckets" to stabilize. Load shedding is not a precise task, when you're at that point, you'd rather load a few more megawatt and be safe, than play with the limits and be sorry. > So how do grid operators know what amount of load will be cut if they disconnect point A123 Opening a line within the grid isn't used to shed load, as the grid is mainly redundant. It's used 1) to protect the line itself (either by letting it trip, or by opening it preventively), or 2) to force power to flow differently through the network, by modifying its impedance. Opening a line from the transport network is not a way to load shed. In this totally random example [1], opening the line A-B increases impedance in the right part of the network, forcing power to re-route through the left part, and reduces the load on another line in the right path that was overloaded. [1]: https://excalidraw.com/#json=5l8OS96Wdke6l9YEClQt8,NJ-r2PtiEMVqaKqviq7yuA https://excalidraw.com/#json=5l8OS96Wdke6l9YEClQt8,NJ-r2PtiE... > Or is there continual measurement? (e.g. there's XYZ MW of load behind A123 as of 2:36pm) The network is, indeed, monitored continually, and we do have potential network equipments failure simulations every few minutes, with contingency plans also simulated to make sure that they work in that particular case. This way, when shit hits the fan, we at least have a recently tested plan to start from.