Noise Detection on The Low Voltage Network PLC Channel for Direct and Indirect Connections A. Emleh, A.S. de Beer, H.C. Ferreira Department of Electrical and Electronic Engineering Science University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa {aemleh, asdebeer, hcferreira}@uj.ac.za A.J. Han Vinck Institute for Experimental Mathematics Duisburg-Essen University Ellernstr. 29, D-45326, Essen, Germany {vinck}@iem.uni-due.de Abstract - The power-line communications channel (PLC) is one of the harsh and challenging channels due to heavy load and noise impairments. Sending and/or receiving of data bits over the PLC channel can be easily affected; therefore, several investigations have been conducted to illustrate interference effects over PLC where intermittent noise plays a major role in this type of communications channel. The in-building network is a non-stable system due to the heavy traffic in the wiring system; therefore the power-line communication system gets affected by the internal and external communications factors. In this paper we apply direct connections to the PLC networks in a “unique” method when the 220V mains are on and when off. Indirect connections are also conducted using different types of equipment and connections and results are presented. Index Terms – Power-line Communications, Direct and Indirect Connections, House Wiring, Interference, Probes and Couplers. I. INTRODUCTION The power-line networks are available in a very large number of buildings and households worldwide and they can be used for communication purposes. One of the factors that severely affect the communications over the power-line channel is the interference and noise impairments which can have a detrimental effect on the PLC channel [1]. Therefore, this paper investigates the noise effects on the PLC channel where a special measurement set-up was organized at the power source as a direct connection. The direct experiments were conducted when the mains of 220V power was on and powering appliances. A direct link between the power-line and the receiving device was created in a new method of connection which highlights the importance of conducting this study since the power-line channel has been considered as a medium for low-rate, control communications and high-speed data communications [2]. A detailed explanation regarding this method is given in section III. The same experiment was also repeated when the mains network is off. The procedure of the measurements was made to comply with CENELEC narrowband rules in one case, and to serve the broadband signals in the other case [1]. For both, direct and indirect measurements, a set of couplers and probes [3], [4], [5], [6], [7], as well as an oscilloscope, spectrum analyzer, and an uninterrupted power supply (UPS) are used [8]. II. MEASUREMENT SET-UP The ALP1042C and Tektronix digital storage oscilloscopes, as well as a loop antenna and TOP101 UPS power supply unit were used during the experiments that took place inside a residential house and an experimental university lab. Fig. 1 shows the design of a coupling circuit that was used to detect the signal on the PLC channel where the TX is the transmitter and the RX is the receiver. A differential probe and X100 times probe were also used during the experiments and measurements [9]. In this case, the UPS AC output power supply is used to ensure the isolation of the measurement equipment from the PLC channel by the instrument’s power supply. This is a 3000VAC unit that gives an output of 220V at 50Hz frequency and it was tested on different electric devices to prove the output of the clean sine-wave status. Fig.1. Simple coupling design. TX: Transmitter, RX: Receiver. 17th IEEE Mediterranean Electrotechnical Conference, Beirut, Lebanon, 13-16 April 2014. 978-1-4799-2337-3/14/$31.00 ©2014 IEEE 203