Varun Nagaraj, Ravi Pragasam, Echelon Corporation
Power Line Communication has evolved into a critical energy control networking technology for the smart grid and consequently for smart meters. The growth in demand for data that can be analyzed to benefit the utility and the consumer demands a technology that can offer the reliability and performance that can satisfy this demand.
Power Line Communication is a technology that has been around for some time now and has been widely accepted as a solution that can meet the requirements of what a smart meter should do. Several countries in Europe have already rolled out smart meters in their regions to deliver the functions that are required by the utility and the consumer to proactively take action towards making the grid more efficient and smart. The PLC technology enables the utility to add value to their major assets – the distribution network that is already in place and using this as a means to facilitate the communication from the meter to the utility. By re-using the electricity distribution network for communication, the utility can also re-use maintenance tools and resources and thereby avoid costs for the maintenance of a specific communication network. With any extensions to the electricity distribution network made, the communication network grows accordingly.
It is broadly believed that the growth of energy demand has outpaced the rate at which energy generation can grow by traditional means. Additionally, many governments agree that greenhouse gas emissions need to be contained to control or prevent climate change. The necessity of modernizing the electric grid infrastructure around the world is both the consequence of the limited investments made in it in the last decades, as well as of the result of new requirements that emerge in the safe integration of utility scale renewable energy sources feeding into the transmission system. The active participation of consumers via Demand Side Management (DSM) and Demand Response (DR) programs, all of which are advocated as sustainable solutions to the energy crisis.
Balancing generation and demand at a very granular scale requires the integration of additional protection and control technologies that ensure grid stability. The concept of smart grid has emerged, along with the need for meters that provides information to the utility on the energy consumption so that the utility can act according to the demands placed on it. This has led to the concept of smart meters that enable the communication between the utility and the consumer. Because communications is such a fundamental element of the smart grid, it is important and crucial that the communication methodology chosen is reliable and consistent in its performance. Due to this basic requirement for very high reliability, wired communications are considered to be better than wireless communications. And within wired communications, Power Line Communications is the dominant technology that has been delivering the performance and reliability required for this market.
What is PLC?
Power Line Communications (PLC) systems operate by impressing a modulated carrier signal on the wiring system. Different types of power line communications use different frequency bands, depending on the signal transmission characteristics of the power wiring used. Data rates and distance limits vary widely over many power line communication standards. Low-frequency (about 100–200 k Hz) carriers impressed on high-voltage transmission lines may carry one or two analog voice circuits, or telemetry and control circuits with an equivalent data rate of a few hundred bits per second; however, these circuits may be many miles long. Higher data rates generally imply shorter ranges; a local area network operating at millions of bits per second may only cover one floor of an office building, but eliminates the need for installation of dedicated network cabling.
PLC offers the simplest type of installation out of all the neighborhood area network (NAN) access technologies and does not need any extra work other than installing the meter hardware. When competing solutions based on Wireless technology such as GPRS and RF Mesh only PLC offers the following advantages:
- No installation of additional communication wiring
- Communication is seamlessly established with powering up of the device
- No communication cables or equipment can be removed or tampered with during operation
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