Grid Constraint Event

On 17 February 2023, NordLink caused an unexpected reversal of power flow direction between Norway and Germany, leading to a system-level disturbance of around 1.8 GW in the Nordic synchronous area and a brief frequency drop to approximately 49.45 Hz. The Nordic disturbance reserve for loss of consumption (FCR-D down regulation), then still being scaled up by Energinet, Svenska kraftnat, Fingrid and Statnett, partially absorbed the imbalance; without it the frequency excursion would have been larger. Statnett subsequently halved NordLink's available transfer capacity from 1,400 MW to 700 MW pending control-system adjustments and announced the cut on 22 February 2023, describing the underlying event as unprecedented. The incident highlighted the challenge of disturbance-reserve sizing as Nordic HVDC capacity grows and informed wider discussions about FFR (fast frequency reserve) downward provision ahead of the planned offshore energy-island links.