Advanced Signal Processing Schemes for Power Line Communication

I. INTRODUCTION

Power Line Communication (PLC) refers to provisioning of communication services over the electricity power grid. The main characteristics of PLC involves sending high frequencies using a PLC Carrier unit over power lines and injecting the frequencies (or picking them up) via a coupler linked directly to the power grid. It is general to categorize the PLC systems as Broadband PLC and Narrowband PLC. Broad band PLC systems cater to the need of high data rate applications such as providing internet access over the wall socket and home entertainment. Narrowband PLC systems are meant to provide low data rate applications such as power system communication in a substation environment, building/home automation, automatic meter reading, real time pricing and energy management. It is surprising to note that in the last 7 years, India could provide broadband connectivity to less than 2.5 million subscribers as against its target of 20 million in 2010.The broadband subscriber market is expected to increase to 30 million by 2013.Broadband services are the current requirement of rural development. Where broadband access has lagged notably in rural areas, PLC opens up a new communication infrastructure. Nearly 70% of the population lives in rural areas in India, where the issues of information, education and communication become paramount for development of the same. At this juncture it is relevant to mention that gap between target and achievement to accomplish broadband penetration in India will go over 30 million by 2013. Adequate infrastructure for Internet information services in the rural areas need to be made available to rural folk to connect them with urban and semi urban population as knowledge and education help develop stronger economies and more social equalities. SCADA (also called tele control) in substations has one or more computers with appropriate application software (Master Stations) connected by a communication system (wire, radio, power line carrier or fibre optics), to a number of remote terminal units (RTUs) which are referred to as intelligent electronic devices (IEDs), placed at various locations to collect data and to perform intelligent autonomous (local) control of electrical systems and report results back to the remote master(s). Use of an appropriate data highway which loops through the substation is thus necessary. The design of PLC modem (modulator demodulator) to facilitate the power line as a medium of communication is a challenging task. Power lines constitute a rather hostile medium for data transmission. Varying impedance, considerable noise and high attenuation are the source of degradation of the signals on power line. Moreover, typical power lines are unshielded, high frequency current flowing in power lines turns power lines into antennas and electromagnetic radiation will propagate out of the wires.

Advanced Signal Processing Schemes for Power Line Communication