Propagation of UWB Transients in Low-Voltage Power Installation Networks

In this paper, the propagation of ultra-wideband (UWB) transients through different types of junctions of low-voltage power cables and one real power network of a building were investigated. For the laboratory test, it was seen that the main mode of propagation in the cables and through the junctions tested is transverse electromagnetic (TEM). The received voltage could thus be, within a small error, estimated from transmission-line theory. The main cause for decreased voltage received at the loads of the branches of the junctions is reflections due to impedance mismatch of the junctions. Large voltages can be delivered to many unprotected loads connected to the junctions. UWB transients were also injected into a residential house using a power outlet available on the outside wall of the house. It was seen that the complexity of this network creates deviation from the TEM mode. However, relatively large voltages were still received at the various outlets inside the house. It is recommended that power outlets or lamp sockets outside buildings are controlled from inside using two-pole switches that reduce the received voltage to reduce the risk of conducted intentional electromagnetic interference.