TECHNOLOGY / Powerline Communication

Powerline communication: An overview

Sharing information between different devices is becoming a requirement in a world where communication is more and more available. While there are many means of transferring information, cost and reliability are always to be considered. Electrical power systems constitute a universal wiring network that ultimately link together electrical devices. This is why powerline communication (PLC) is clearly becoming an excellent choice to create that inter-devices link. Using existing electrical lines as a communication medium, PLC offers a low-cost and reliable networking solution without requiring the installation of additional wiring.

Powerline communications are not new; they are being used since the early 1900’s. But due to technology evolution and new emerging markets, PLC is today a viable technology for both low speed and high speed networking. While the Broadband over Power Line (BPL) represents a potential interesting alternative to cable and DSL, the rising energy requirements has refocused attention on a potentially vast market for narrowband PLC-based command and control applications. The electric, gas and water utilities are adopting PLC as a means to communicate with meters, allowing them to send and receive information on current consumption, on diagnostics and remote control for load managements. Building owners and managers are using powerline communication to monitor, diagnose and control loads such as lighting and HVAC systems. Municipalities are also more and more concerned to manage their infrastructures and are looking for PLC solutions to save energy and reduce maintenance costs.

PLC systems operate by superposing a high-frequency modulated carrier signal on the DC or low-frequency AC power line. The carrier signal is then de-coupled and demodulated at the receiving end to recover the information. Different types of PLC systems use different frequency bands. Low-speed command and control applications typically use the frequency range between 9 kHz and 500 kHz. However, the power lines were not initially designed for data transmission and they constitute a very harsh environment for communication. Varying impedance, considerable noise and high signal attenuation are the main factors that affect the communication performance. PLC technologies must cope with all these issues and provide reliable data transfer.

A wider overview of the potential and recent activities on PLC is given in the Powerline Potential white paper.