1949-3053 (c) 2016 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/TSG.2016.2630804, IEEE Transactions on Smart Grid > REPLACE THIS LINE WITH YOUR PAPER IDENTIFICATION NUMBER (DOUBLE-CLICK HERE TO EDIT) < 1 Abstract —The paper proposes and verifies the performance of an innovative and low cost coupling system for power line communication (PLC) on medium voltage (MV) smart grids. The coupling system makes use of the capacitive divider of the voltage detecting systems (VDS) to inject and receive the PLC signal. VDS are usually already installed in the MV switchboards of the major electrical manufacturer all over the world according to IEC 61243-5. VDS are used to detect the presence of the mains voltage to guarantee personnel safety. An interface circuit has been developed to be connected between the PLC transceiver and the VDS socket. In this way, the PLC signal can be coupled to the MV network without installing a dedicated MV coupler, thus avoiding the related costs of the coupler, the installation, and the temporary service interruption. The innovative device is able to couple digitally modulated narrowband PLC signals with modulation rate up to 19.2 kbit/s. In the paper, firstly a description of the proposed solution is reported. Secondly, its communication performance has been tested in laboratory. Finally, different tests have been carried out in two MV smart grid real installations under normal operation, i.e in the presence of the mains voltage. Index Terms—Power system communication, communication systems, couplers, narrow band power line communication, communication signal couplers, power system communication, power system measurements, smart grids. I. I NTRODUCTION HE transmission of communication signals through the medium voltage lines (MV) is gaining an increasing interest in recent years. The development of the distribution networks into smart grids requires a continuous exchange of data between the distribution system operator (DSO) and the energy users and prosumers related to different This research was supported by StMicroelectronics. The authors wish to thank Eng. Salvatore Russotto (Impresa Elettrica D’Anna e Bonaccorsi s.n.c.) and Eng. Marco La Russa (SEA Spa) for their support during the Ustica and Favignana field tests respectively. Giovanni Artale, Antonio Cataliotti, Valentina Cosentino, and Salvatore Guaiana, are with the Department of Energy, Information engineering and Mathematic Models (DEIM), Università degli Studi di Palermo, Italy (email: giovanni.artale@unipa.it, acataliotti@ieee.org, cosentino@dieet.unipa.it, salvatore.guaiana@unipa.it) Dario Di Cara, and Giovanni Tinè are with the Institute of Intelligent System for Automation (ISSIA), National Research Council (CNR), Palermo, Italy, (e-mail: dicara@pa.issia.cnr.it, tine@pa.issia.cnr.it). R. Fiorelli is with the ST Microelectronics S.r.l., Agrate 20864, Italy (e- mail: riccardo.fiorelli@st.com). smart applications, such as the remote control of secondary substation equipment, the automatic meter reading (AMR), the monitoring of distribution network power flows, and so on [1]-[7]. For these purposes, wireless or GSM systems are usually suggested, even if they have weak reliability (particularly in bad weather conditions) and a high intrinsic cost of the communication provider. Besides these communication systems, narrowband PLC has been chosen and already widely implemented to support different smart applications, such as automatic meter reading and demand side management applications in low voltage (LV) networks [8]. The use of PLC is also suggested by recent standards on the connection of distributed generation and its remote control. Despite a slower transmission data rate, narrowband PLC has the great advantage of a lower installation cost, because the power lines are already present, and they have no service cost for the communication provider, because the DSO is usually owner of the power lines. Moreover, PLC is also more secure from cyber-attacks because the communication system is not easily accessible from an intruder. Other advantages of PLC, when it is employed for utility applications, are summarized below [9]: redundancy in protection and control is an utility typical requirements and it can be obtained only with a redundant communication system, which can be easily and economically supported by PLC based on an existing wired infrastructure; PLC uses the most direct route between controllers and distributed IEDs, thus can allows to obtain lower latencies when compared to packet switched public networks; the PLC channel, i.e. the power line, is under the direct and complete control of the utility which is a fundamental benefit in those countries where the communication market is deregulated. For these reasons, the PLC solution can be used as redundant communication system in parallel to a faster communication system or it can be used for those applications which have lower transmission data rate requirements, when important messages has to be delivered such as commands or signals on the status of the network, or when data has to be collected off-line, such as in meter reading systems. On the other hand, few commercial solutions are available for power line communication (PLC) on MV networks. Some new studies have been developed in recent years to understand the behavior both of the line and of the power transformer in the PLC frequency range [10]-[11]. The authors have also deeply investigated this topic [12]-[14], developing a model of the different components of the A New Low Cost Coupling System for Power Line Communication on Medium Voltage Smart grids Giovanni Artale, Student Member IEEE, Antonio Cataliotti, Member IEEE, Valentina Cosentino, Dario Di Cara, Member IEEE, Riccardo Fiorelli, Salvatore Guaiana, Giovanni Tinè, Member IEEE T