LINE IMPEDANCE MEASUREMENT FOR PLC CHANNEL CHARACTERIZATION WITH COMMERCIAL SMART METERING PLATFORMS

Power line communication (PLC) is widely used in power systems, for automatic meter reading andits use has been also investigate for other smart grid applications, such a secondary substationautomation, remote control of distributed generator, and so on. To fully exploit the technology andface the problems related to disturbances and signal attenuations, it is important to characterize thecommunication channel, in the used PLC range, in terms of frequency response and line impedance,in the PLC frequency range of interest. This can allow individuating the best frequency bands forsignal transmission, avoiding using those with higher levels of attenuation and/or noise. PLC lineimpedance depends on network topology, cables and loads and it can be time-varying; moreover, itsmeasurement can be strongly affected by noise. Furthermore, the measurements are carried out in theabsence of mains voltage, and they entail the use of and high-cost instrumentation (network analyzersor dedicated measurement systems based on data recording and processing software) and the gridtopology knowledge.This paper investigates the feasibility of an alternative approach, which allows to measure the lieimpedance by means of the typical electronic boards, equipped with a PLC modem, which arecurrently used for smart metering purposes; the proposed solution exploits the PLC signal itself as testsignal for the impedance measurement. In this way, no dedicated measurement equipment is neededand the impedance measurement can be theoretically obtained for each signal transmission.