In a 3-phase system, when a short circuit between 2 lines or a single or 2 lines to earth occurs, 3 types of currents are immediately produced: positive, negative and 0 sequence. Using these signals, less priority consumers can be disconnected from the grid and the power of the nuclear reactor, which supplies all consumers, can be diverted to supply priority consumers, although with only a couple of cycle times due to dwindling amplitude. This is an example of an island operation with a nuclear power reactor and prioritised consumers connected via a smart grid.