All the relays of the PROTECTA and SMARTLINE lines share the same design principle: they are made up of Software Function Blocks (SFB). These blocks allow a simple and fast assembly in production to obtain the required functionality of the protection relay. The corresponding electronic boards are combined and assembled according to the blocks needed for the protection. This particular way of assembling the software function blocks and the electronic boards that make up the relay hardware ensures a high reliability of the firmware embedded in the protections and of the electronics, since they are common to all devices and therefore deployed on a large scale.