Impedance measurement in operating conditions for PLC applications

The influence of the electromagnetic environment of the indoor power line grid (Houses' Power Grid) is increasingly important on the Power Line Communication transmission. The household equipment operating changes considerably the network impedance. Several procedures exist to evaluate the network impedance. Two impedance measurement techniques seem to be the most adequate and allow to characterize loads under their operating conditions. The first one uses current injection and reception probes and the second one uses capacitive coupling. With a proper pre-measurement calibration process, the proposed methods allow to measure the evolution of the impedance versus frequency of the active loads (TV screen, Fluorescent lamp…). This study deals with the analyses of these two methods in order to evaluate their advantages and disadvantages. The measurements are carried in narrowband and broadband in the frequency range of 10 kHz to 100 MHz.