Power
line communications (PLC) or Broadband over Power Lines (BPL) allows transmission
of data over power lines.Power line communications uses the RF signal sent over
medium and low voltage AC power lines to allow end users to connect to the Internet.
The RF signal is modulated with digital information that is converted by an interface
in the home or small business into Ethernet compatible data.To gain a good understanding
of how PLC Works an excellent understanding of the Power Grid is required. Unlike
telephony and it's associated technologies there is no set standard for providing
power. An example of such a difference in standards can be seen in the difference
in voltage provided in the U.S. and the EU. Ireland uses a 220v AC power source
whereas in the US a 110v power source is used. These differences lead to differences
in basic equipment such as plugs e.g. The 3 pin plug used in Ireland compared
to the 2 pin plug used in the US made possible due to the lower voltage used in
the U.S. Despite these differences in basic equipment the basic network is similar
in nearly all countries.
Power is generated at Power stations and distributed around
a medium to large geographical area via HV lines or High Voltage lines. In areas
where power needs to be distributed to consumers transformers will be used to
convert this high voltage into a lower voltage for transport over MV or Medium
Voltage lines. These transformers are generally located at electrical substations
operated by the utility or power supplier. Such medium voltage lines will be used
to transport electricity around smaller geographical areas such as towns and small
counties etc.At the customer's house or premises a transformer is used to drop
the voltage down to safer more manageable voltages for use in the home or business.
This power is usually transported over LV or Low Voltage lines. These Low Voltage
Lines include the lines that traverse a customer's home or business.
