In automation systems, such as Substation Automation systems, the mean time to repair is reduced by remote reconfiguration and start-up of a replacement or spare Intelligent Electronic Device (IED), leaving some more hours for the maintenance personnel to repair an inactive or faulty IED. The time for the actual repair is irrelevant for the system availability as long as it is short enough compared to the IED failure rate. Exemplary embodiments can provide nearly the same availability as a hot-standby configuration, but without the need for doubling all the essential IEDs. Additionally, spare IEDs are supervised to be healthy, and a fault of the spare IED being detected before it is put in use. Only one spare online IED is needed for each set of IEDs of the same type connected to the same station bus and process bus. In a retrofit or extension case with limited downtime, a number of previous IEDs can be replaced by an equivalent set of new or real IEDs of a different type, but configured to perform the same functions as the previous IEDs.