Power line communication system transmits digital data on high voltage transmission lines, which are also used for electric power transmission. Power line communication is also known as Power Line Carrier (PLC), Power line Digital Subscriber Line (PDSL), mains communication, power line telecom (PLT), power line networking (PLN), or Broadband over Power Lines (BPL). Powerline Communications offers high speed broadband internet through the existing electrical wiring in your home.

Electrical power is transmitted over high voltage transmission lines, distributed over medium voltage, and used inside buildings at lower voltages. Powerline communications can be applied at each stage. Most PLC technologies limit themselves to one set of wires (for example, premises wiring), but some can cross between two levels (for example, both the distribution network and premises wiring). Typically the transformer prevents propagating the signal, which requires multiple PLC technologies to be used to form very large networks.

Operating Principle of Powerline Communication (PLC)

All power line communications systems operate by impressing a modulated carrier signal on the electrical wiring system. Different types of powerline communications use different frequency bands, depending on the signal transmission characteristics of the power wiring used. Since the power wiring system was originally intended for transmission of AC power, in conventional use, the power wire circuits have only a limited ability to carry higher frequencies.

Powerline Communication (PLC) Applications

  • Home Networking or Local Area Network (LAN)
  • High-Speed Powerline Internet Access (Broadband over Powerlines)
  • Home Appliance Control Communication Network for control and telemetry of electrical equipment such as meters, switches, heaters and domestic appliances
  • Automotive In-Vehicle Network Communication – Power-line technology enables in-vehicle network communication of data, voice, music and video signals by digital means over direct current (DC) battery power-line.
  • Home/Building Utility Metering for automatic meter reading and transmission.
  • Radio Coomunication over Powerline
  • Powerline Telephone Communication
  • Powerline HD Video/Audio Sharing Network, as modern powerline communication network adapters offer upto 200Mbps speed which is enough for a live video streaming.

Failure Mechanisms of Powerline Communication (PLC)

There are many ways in which the communication signal may have error introduced into it. Interference, cross chatter, some active devices, and some passive devices all introduce noise or attenuation into the signal.

  • Interference: Interference from nearby systems can cause signal degradation as the modem may not be able to determine a specific frequency among many signals in the same bandwidth.
  • Signal Attenuation by Active Devices: Devices such as relays, transistors, and rectifiers create noise in their respective systems, increasing the likelihood of signal degradation.
  • Signal Attenuation by Passive Devices: Transformers and DC-DC converters attenuate the input frequency signal almost completely. “Bypass” devices become necessary for the signal to be passed on to the receiving node. A bypass device may consist of three stages, a filter in series with a protection stage and coupler, placed in parallel with the passive device.