White paper on Power Line Carrier Communications for Smart Metering in AMI for India

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Smart Metering |Why Power Line Communication Is
Best Suited For India.
Smart Metering for India
Smart Metering represents an enormous opportunity to transform how India uses,
consumes and thinks about energy. Smart Metering educates both the utility and the
consumer on how the energy is put to use.
India has at least 27% Transmission and Distribution losses (T&D) across various utilities
in India, which is among the highest in the world. One of the primary reasons for such
huge losses is lack of proper measurement mechanisms at various stages till the power
reaches the end point. With Smart Metering in place it is possible to indicate Losses apart
from Energy Audit, Demand Response, Peak Demand Shaving, TOD, Prepaid etc.
Communications in Smart Metering is the core of the entire Smart Metering solution
to make the above wish list a reality. A reliable communication is the need of the
hour in the Indian Smart Metering space.

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3 out 5 Smart Meters shipped globally is on PLCC

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Comparison between RF, GPRS and Power Line
Communications
Coverage
Towers
PLCC by its intrinsic nature can reach up to the last Meter which is connected to electrical
line. RF communications would also be able to reach to the last Meter without an
additional external entity. Whereas GPRS signals has dependency on the Service Provider.
Access Points
Meters get installed at different locations in Individual homes, High rise buildings, Cellars
etc. High rise buildings are made up of high amount of steel and concrete. Meters could
also be installed inside a Metal enclosure and/or in the basement of the building. RF and
GPRS will face serious challenges in such a scenario. Such a scenario has no implication
on Power Line Communications. High rise buildings could be ideal for Power Line
Communications considering the compactness of the Meter installations, better quality of
wiring. The Physical location of the Meter installations has an implication on the RF &
GPRS communications and very little or no implication on Power Line Communications.
Topography
If the region of deployment is hilly the impact could be probably more in the case of RF,
whereas PLCC performance would not get affected. GPRS could also be uncertain and
unpredictable.
Performance
Range
PLCC signals easily propagate up to a KM if the line conditions are less noisy (>-80dB).
But in a real / harsh field conditions the signals will propagate at least up to 80 meters in
very noisy conditions (-50dB).
RF signals have propagation capabilities of up to 100 meters line of sight and in all
practical cases the signals can only reach up to 30 meters. GPRS signal propagation is
entirely under the control of the Service Provider.

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Data rate / Bandwidth
Narrow band PLCC signals will generally communicate between 2Kbps to 10Kbps. RF
signals can communicate up to 100Kbps. Data rate and Bandwidth availability in GPRS is
significantly greater than both PLCC and RF reaching up to 1Mbps
Latency
In Narrow band PLCC & RF, the point to point communication latency is between 700ms
to 1500ms depending on the number of hops (repeaters) between the Meter and the
DCU. GPRS communication would also need around 1000ms for propagation since the
communication would involve the Service Providers medium.
Customer Type
PLCC or RF solutions will be appropriate in deployments catering to
In the case of LT residential consumers each transformer would be probably be catering
to25-500 households and the installation Meter with PLCC/RF communication will be
justifiable.
Any industrial (HT Consumers) electrical topology would favor using GPRS or RF based
Meters over PLCC. Considering the density (sparsely spaced) of the Meters installed RF
would be ruled out and GPRS would be an ideal media to use.
Time of the Day
Utility would generally be interested in EOD data from the Smart Meters, upon which all
the analytics would be built upon. Once in a day (24 hours) data pull/push is all that the
Data Centre would need from all the Smart Meters.
Residents tend to not to use most of the electrical equipment’s during the night (in LT
network), this makes the power line cleaner during the nights. Signal quality and
performance in PLCC network peaks during the midnight hours (12AM to 6AM) and most
of the communication can successfully take place during those hours.
GPRS signal quality also can be expected to be slightly improved during the night
compared to the day.
This kind of distinct advantage is not available for RF.

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Communications Network
Power Line is a property of the Utility, so no additional communication infrastructure is
needed until a certain point in the network (till DCU).
RF will use the wireless media to communicate but it uses a free band.
GPRS will have dependency on the cellular network and unless M2M platforms are not
utilized, the Service Provider will always try to prioritize voice calls over the GPRS
connectivity.
In the process of improving the quality of service in either of the communications, it makes
a lot of sense for the utility to choose PLCC as the communication medium, since
eventually the Utility will also improve upon the (T&D losses) quality of power distributed
along with the improvement on communication medium.
Asset Mapping, Management & Energy Audit
Real-time Asset Mapping and Management only possible using PLCC Network – How
does it work?
• Power Line signals do not cross over between Distribution Transformers, this factor
plays an important role in Real-time Asset Management.
• As a onetime activity during installation, DCUs are mapped with DTs.
• All Meters or Communications devices under the DCU are thereby mapped to the DTs
effortlessly.
• Automatic Consumer Indexing (Meters, DTs etc).
• Generates Tree Structure / Mapping dynamically as and when Meters Register with
the DCU
• Energy Audit for thousands of DTs is effortless since DCU wise Meter data is available
at central repository and DCUs are mapped DT wise. This feature is uniquely fool proof
and uncomplicated unlike in RF and GPRS.
Data networking at affordable costs
Modem Costs
RF modems are around Rs300, PLCC modems around Rs700, whereas GPRS modems are the most
expensive at around Rs1000 (for 2G modules)
Equipment Costs

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Each solution has its own uniqueness and limitations. In RF solutions, a single DCU can handle
around 40 nodes (Smart Meters). In case of PLCC solutions, a single DCU can handle minimum
100 nodes and up to 200 nodes, depending on the power line infrastructure. Since GPRS Meters
directly link with the server there is no necessity for any DCUs.
Effectively, in RF solutions, DCU quantities is 2.5 times than that of a PLCC solution.
In Smart Meter communications, a “Signal Repeater” equipment plays an important role to boost
signal quality in the network. In either, RF or PLCC solutions the Smart Meters can act as repeaters.
But specifically in RF solutions there would be a need to install devices exclusively for signal
boosting to overcome “line of sight” issues which is never an issue in PLCC.
For an every network of a DCU and 40 nodes, we can consider to have atleast 2 “Signal
Boosters/Repeaters” to overcome bends and obstructions in the installation area.
GPRS systems may need external antenna and signal boosters in places where the GPRS signal
quality is very poor. Most of the Meter installations in India can be found in the basements or
under the stairs.
RF solutions are ideal for countries such as USA, where wooden houses are common and line of
sight issues are lesser.
Installation Costs
Power line signals from the Smart Meters cannot hop over the Distribution Transformer (DT). This
makes the installation process simple since the survey and planning of each of the networks under
a DT is independent (since no signal interference between two communications networks of
different DTs) and modular. Therefore the placement of the DCU does not require expert planning
and can be taken up by unskilled staff.
This kind of luxury is not available for the RF systems since there is signal interference between
each of the networks. Survey and planning should be undertaken extensively to mitigate under
performance and signal interference issues. Placement of DCU is very critical and requires field
tools training to execute.
Though, GPRS systems does not require any kind of would not need any skilled resources for the
installations.
Operation & Maintenance
PLCC systems are self-healing and would require very less maintenance. Therefore very less
recurring expenses associated with it.
Though, RF systems are also self-healing in nature, because of the signal interference of nearby
networks is high and absence of “isolated independent” networks are absent (unlike in PLCC), it
would require regular maintenance from trained and skilled resource.
In GPRS based systems, there will be a per node monthly recurring expense towards the usage of
the telecom network.

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Summary of Comparison
Sameer Patil | Head-Smart Metering
PowerOneData, Bangalore