Seminar Report On
Digital Power Line Carrier
Communication
www.fakengineer.com
Need of PLCC
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To cope up with ever
increasing size of power
grid
Need for economic and
reliable means of
intercommunication
between various
generating station,
substation and control
room
Avoid dependence of
busy telephone lines
Power Line Carrier
Communication
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Voice signal modulated on carrier frequency and
transmitted on power line
No need for lying separate cable for transmission
Integrates transmission of voice and data through
same line
Allows flow of information through same cording
which supplies electrical power
Digital PLCC-The Challenges
ahead
Two biggest problems1)Excessive Noise
Level
2) Cable Attenuation
Excessive Noise Level
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Noise and disturbance includes-over voltages, under
voltages, frequency variation and so on.
Most harmful noise for PLCC is that superimposed
on power lines
Switching device such as light dimmers, induction
motors and television cause such superimposed
noise.
Avoid noise superimposition
“Frequency Hoping”
For PLCC to operate reliably it must be able to
avoid, or cope up with different type of noise
encountered which exist at different frequencies
at unpredictable times
FREQUENCY HOPINGIt is a spread spectrum communication
technique meaning that the total available
spectrum is split up into smaller sections so as to
be better utilized.
Signal Attenuation
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Signal attenuation in power line is often great and
unpredictable measured up to 100db /km.
As devices connected and disconnected from
power network characteristics changes drastically
This makes coupling a signal to power network
difficult.
PLC Regulations
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Private-user communications must occur in the
bandwidth 95-150kHz.
Within this bandwidth, the section from 125140kHz is reserved for devices that use unique
addressing schemes. Such schemes avoid
possible interference from neighboring PLCC
devices.
PLCC devices should operate at a maximum
transmitted power of 500mW. This limitation is
for many reasons, some chiefly being so as to
avoid possible radio-frequency interference
problems, and neighboring device interference
Applications
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Internet access
Telephony
AMR( automated meter readings)
Home automation
Home security
Video conferencing
Advantages
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The electric grids are modern, well maintained, and far superior to any
of the wired communications networks.
There are more electrical customers than telephone, cable, and other
wired communications customers together.
The backbone of the Internet as well as the long distance telephone lines
are all fiber optic cables which can carry a signal for only 20 miles,
without regeneration, coaxial cable 15 miles and copper telephone wire
miles. Signals over the power grid can travel more than 2000 miles
without regeneration.
The analog spread spectrum waves have much greater bandwidths or
carrying capacity than the digital switched systems.
Another inherent advantage to the Digital Power line model is the fact
that it works well over the existing electric power infrastructure. Only
the substation server equipment and customer conditioning/service units
need to be installed in order to establish a Digital Power line network.
New technology in PLC
PLC has a number of new applications as –
 Broadband PLC
 Microwave Technology
 Frequency conditioned power networking
Broadband PLC
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Developed a low cost reliable means of
transmitting data, voice and video at high
speeds using the infrastructure of electrical
power grids and existing utility providers
Electrical power grid is most widespread,
maintained worldwide network which provide
economical broadband and LAN to every
customer that has an electrical outlet
Microwave Technology
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Used to pull data through magnetic field created by
AC flowing through electrical power
Modulating signals onto magnetic field allow to
transmit signal through transformer over high
voltage electrical transmission and distribution lines
at speed up to 2.5 GB per second
Microwave signals propagated onto mag.flux field
can travel up to 2000 miles without regeneration.
This allows the electrical grid to carry these
communication services at near light speed
Frequency Conditioned Power
Networking
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Send over a billion bit of data per second
over electrical power lines
It breaks the signals into multiple streams,
each of which is pulled across the magnetic
field in power grid.
Special receivers combine mini streams of
data back into original data configuration.
Why Power Lines For
Internet??
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Offers right balance of cost, convenience and
speed
It gives high speed internet access through
electrical networks
Lower costs are achieved because the service is
implemented on standard electrical lines and is
already connected to almost all residence and
business through electrical lines
It speed would be 1Mbps, 20 times faster then a
standard modem connection
No need for bulky apparatus associated with
wireless access.
Will Electrical line replace
phone lines?
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New power line technology would provide data at
almost 10 times the speed of fastest connections
currently available to home users
The new rate would be 1 Mbps
The flat rate price of most customer is 20 to 30
pound a month but the tap card cost nearly 150 to
200 pound per month.
Conclusion
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Tests in PLC have been carried out in 20 countries in
around 1500 residences. The mapping of results has
been extremely positive and forecasts a great
demand for the system
Digital power technology is definitely an exciting
alternative to connect internet via phone and modem.
Though this technology is not commercially available
yet, it should be available over other broadband
technologies due to relatively low cost of its local
loop. Moreover, its high speed will provide internet
access, local phone, and long distance service to
customers