Introduction

The growth of energy demand has outpaced the rate at which generation capacity can grow by traditional means. The International Energy Outlook 2013 projects that world energy consumption will grow by 56% from 2010 to 2040. The rise in energy consumption is not only due to population growth, but also the proliferation of consumer electronics and other plug-in devices such as electric vehicles. Traditional ways to meet increasing demand include constructing large-scale power plants and laying new transmission lines, which are expensive and time-consuming. For example, a 1000 MW nuclear plant costs up to $2B and takes over 15 years to build; and laying transmission lines costs $0.6M per kilometer and typically takes 5-10 years.

To solve the energy crisis in a more sustainable way, distributed energy resources (DER) are used to provide an alternative to, or an enhancement of, traditional centralized power plants. DERs are small-scale power generation sources (typically in the range of 1 kW to 104 kW), including renewable energy resources (e.g. wind turbines and solar panels) and decentralized energy storage (e.g. the battery of electric vehicles and photovoltaic batteries). These resources may deliver low-cost power to the grids during peak hours, or provide standby energy for emergency uses. In addition, they also have a lower impact to the environment compared to traditional power plants.

The integration of DERs have transformed the power grids into much more dynamic and complex systems than they used to be. To manage such systems, a large amount of information needs to be measured, communicated and analyzed in real time. On the utility's side, transducers such as the Phasor Measurement Units are deployed over the grids to precisely measure AC voltages and currents at high speeds (typically 30 observations per second), with time resolutions better than 1 us. These measurements provide grid operators with a picture of real-time grid conditions, and are helpful to speed up their response in the case of unexpected demand disturbance and power outage. On the customer's side, advanced metering infrastructure (AMI) is deployed to implement time-dependent and load-dependent electricity rates, and to make energy usage profiles available to the customer. Such information gives them more incentives to better manage their energy consumption. During peak hours, AMI also enables customers to offer power-to-grid from their personal owned DERs at the market price.

The desire to use two-way flow of information to create an intelligent energy delivery network has inspired the concept of the "smart grid". A smart grid couples a traditional power grid with a communication network. Within a smart grid, communication technologies for smart metering applications have recently obtained great interest. Such communication network typically consists of three primary components.

  1. Home area networks that connect smart appliances and sensors on indoor power lines to smart meters;
  2. Neighborhood area networks that connect smart meters and data concentrators that are deployed by local utilities on medium-voltage (MV) lines (in the US) or low-voltage (LV) lines (in Europe); and
  3. Communication backhaul to carry traffic between data concentrators and local utilities.
Smart grid communications will likely be supported by a heterogeneous set of network technologies, ranging from wireless to powerline, since no single solution fits all scenarios.

Within a smart grid, we seek to enable higher data rate monitoring and control applications for making homes and small businesses more efficient in their use of energy. We focus on power delivery at the neighborhood level, and the accompanying communication network is from a neighborhood concentrator to the local area subscribers along low-voltage lines (e.g. 220V/380V single/three phase in France). In this case, the local area power network is a shared medium that has anywhere from several subscribers (as in the US) to hundreds of subscribers (as in France, Spain and other parts of Europe). The concentrator is analogous to a basestation in cellular systems or an access point in wireless local area networks.

Among communication standards for low-voltage power networks, G3 and PRIME transmit data using multiple carrier frequencies, a.k.a. orthogonal frequency division multiplexing (OFDM). PRIME uses a transmission band of 40-90 kHz and delivers up to 100 kbps from subscriber to concentrator on a single phase. In the case of PRIME, the concentrator would be located on either the low-voltage side or medium-voltage side of the neighborhood transformer.

The last two paragraphs are by Prof. Brian L. Evans. The other paragraphs are taken from the spring 20014 PhD dissertation by Dr. Jing Lin at The University of Texas at Austin entitled Robust Transceivers to Combat Impulsive Noise in Powerline Communications.

Mail comments about this page to bevans@ece.utexas.edu.