Power line communication is one of the most today used technologies, for both automatic meter reading and many other smart grid applications. In this framework, a characterization of electrical network in PLC frequency range is needed in terms of impedance measurement and received signal level. This can allow choosing the most suitable and less noisy frequency ranges for PLC transmission. Usually, these characterization measurements are performed with dedicated instrumentation and in the absence of mains voltage. This paper wants to propose an alternative solution, which allows these kinds of measurement to be performed using electronic boards currently used as on-field applications such as smart meters. To this aim, an innovative measurement tool is proposed, which does not need a specific characterization signal to be injected, because it uses the preamble of a generic PLC transmission. Moreover, the impedance calculation is performed using a FFT analysis, which does not require high computational capabilities. These features allowed the proposed tool to be implemented using a G3-PLC transceiver, embedded in many commercial smart meters, and low-cost additional hardware. The paper shows how the proposed system correctly measures the PLC impedance on CENELEC A, B and FCC frequency ranges.

This paper proposes a new coupling solution for transmitting narrowband multicarrier power line communication (PLC) signals over medium voltage (MV) power lines. The proposed system is based on an innovative PLC coupling principle, patented by the authors, which exploits the capacitive divider embedded in voltage detecting systems (VDS) already installed inside the MV switchboard. Thus, no dedicated couplers have to be installed and no switchboard modifications or energy interruptions are needed. This allows a significant cost reduction of MV PLC implementation. A first prototype of the proposed coupling system was presented in previous papers: it had a 15 kHz bandwidth useful to couple single carrier PSK modulated PLC signals with a center frequency from 50–200 kHz. In this paper, a new prototype is developed with a larger bandwidth, up to 164 kHz, thus allowing to couple multicarrier G3-PLC signals using orthogonal frequency division multiplexing (OFDM) digital modulation. This modulation ensures a more robust communication even in harsh power line channels. In the paper, the new coupling system design is described in detail. A new procedure is presented for tuning the coupling system parameters at first installation in a generic MV switchboard. Finally, laboratory and in-field experimental test results are reported and discussed. The coupling performances are evaluated measuring the throughput and success rate in the case of both 18 and 36 subcarriers, in one of the different tone masks standardized for the FCC-above CENELEC band (that is, from 154.6875–487.5 kHz). The experimental results show an efficient behavior of the proposed coupler allowing a two-way communication of G3-PLC OFDM signals on MV networks.

The paper proposes a monitoring and control architecture for distributed measurements based on a hybrid Power Line Communication (PLC) / Radio Frequency (RF) redundant communication solution for medium (MV) and low voltage (LV) distribution networks. The proposed architecture aims at introducing a redundant communication system to reliably transfer measurement data and commands for the management of the electrical network, including the remote control of DG and ESS. Two devices have been developed and related firmware has been implemented to measure performance parameters both in terms of communication link quality and latency. Laboratory tests have been carried out to compare the measured parameters with those obtained by reference instruments. Experimental measurement tests are performed on field in three different configurations: between two MV substations using PLC over MV; between a MV/LV secondary substation and a point on an LV line using PLC over LV communication; and between a MV substation and a point on an LV line connected to a second MV substation. In all these configurations, both PLC and RF solutions are tested. Moreover, a hybrid PLC/RF redundancy test was also implemented to verify the possibility of exploiting the hybrid communication as a redundant system for the transfer of sensitive information from the DSO to remote terminal units, such as distributed generators and storage systems, with the purpose of preventing their uncontrolled operation in critical conditions.