Test methodology for impedance characterization of a low voltage power line channel for broadband communication applications

Impedance characterization is one of the most important measurements required for the correct design, construction and performance of couplers, modems and many others common devices in the communications area. It is also important for the correct estimation and calculation of the incidence of certain factors in the development of research about power lines. Previous research about power line communications (PLC) have shown that the line behavior changes according to the frequency, wiring practice, topology and loads plugged in, among other factors. The variable behavior of the low voltage power line makes it a harsh environment when it is used as a channel for communication applications. Characterization is an important issue because the knowledge of the conditions that regulate the performance of the line is a useful tool to provide solutions and get significant improvements. This paper presents a general test methodology suitable to measure the line impedance for a wide frequency spectrum. The proposed method can be applied to different deployed power networks. The results obtained for a specific line are shown as an example of its application in a real-life environment.