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and various wireless technologies
including ZigBee, 6LoWPAN, and sub-
1GHz connectivity.
Consumers tend to associate smart
grids with smart meters-home-
monitoring devices that can provide
the consumer with fine-grained data
about usage trends-allowing them to
modify consumption to, for example,
take advantage of cheaper tariffs
and allow utilities to smooth demand
peaks. However, smart-grid metering
comprises much more than the
individual devices outside of homes,
factories, and offices. Advanced-
metering
infrastructure
(AMI)
provides the two-way communications
necessary for utilities to automate
billing, remotely connect/disconnect
individual meters, and implement
demand-response programs. AMI
networks also provide the ability for
real-time monitoring of grid operations
and immediate notification of outages
to accelerate utilities’ response.
What is more, renewable energy is a
major challenge as generation extends
beyond hydroelectricity and wind farms
to “microgrids” comprising groups
of households feeding power back
into the network from solar panels.
The inverter is a critical component
responsible for the control of electricity
flow between the PV cells making up
the panel and the power grid. The
challenge for engineers is how to do
this in an efficient, reliable, and cost-
effective manner[2].
In the U.S., ten states-including
California, Florida, New York,
Pennsylvania, and Texas-are leading
the national effort to deploy the
country’s smart grid. Together, these
states have already been the recipients
of $1.9 billion of the $4.5 billion
earmarked in the American Recovery
and Reinvestment Act for investment
in the smart grid.
This momentum is set to increase and
is fueling demand for the electronics
that are the foundation of many
smart-grid systems. Silicon vendors
have reacted by developing a range
of components that enable electronic
engineers to design products that
underpin smart-grid applications; and
each of these products demands a
power supply uniquely matched to
the exacting demands of intelligent
electricity distribution.
Reacting to outages
Apart from efficiency improvements,
the key advantage of a smart grid is
its ability to recover from faults caused
by factors such as lightning, high
winds, or falling tree branches. Utilities
are understandably keen to prevent
catastrophic failures such as the
Northeast blackout of 2003. This was a
widespread power outage that affected
an estimated 10 million people in
Ontario, Canada and 45 million people
in eight U.S. states. Some people were
without power for two days.
Smart grids incorporate protection
devices such as circuit breakers,
which cut the supply when they detect
anomalous events such as excess
current or voltage. By establishing
the location of the fault and taking
advantage of the bi-directional energy
flows enabled by a smart grid, utilities
can isolate the small section of
distribution line where the fault has
occurred while using alternative lines
to quickly restore power to the rest of
the grid.
Many of these protection devices
depend on power supplies from
major semiconductor companies.
Texas Instruments (TI), for example,
offers a small form-factor, 12W power
supply reference design to power the
protection relays used in smart-grid
circuit breakers (Figure 2).
The design is notable because it is
able to handle a wide range of both
Figure 1: Smart grids will feature conventional and diversified electricity
generation. (Courtesy of Infineon)
Figure 2: Wide-input-range
power supply reference design
for protection relays from Texas
Instruments.
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