A duct for electrical cables comprises a plurality of filiform elements arranged substantially parallel to one another according to the longitudinal development of the duct. Threats are assessed by utilizing internal information assurance mechanisms of the device to detect such cyber-attacks without requiring external modification of the software andor hardware of the computers or nodes of the network to be protected. The inductance of the inductor can be set and can be interconnected with a stepped capacitor bank in such a way that the generator can be operated on virtually exclusive active power. The first SVD address is associated with the SVD key in a first SVD associated with a first task. The maximum span between the inner edges of the converging lower ends of the arms is smaller than or equal to the half of the inner diameter at a distance from the appendix that is substantially equal to the inner diameter. The system then stores the data representing the visibility of open sky.