IEEE Power & Energy Magazine - March/April 2016 - 108

IF YOU HAVE
A CHALLENGE -
WE HAVE A SOLUTION
For over 100 years Slacan Industries has been Canada's largest
designer and manufacturer of Transmission, Distribution, and
Communication products. We also design and manufacture
OEM products, Substations and Structural Steelwork for the
Utility Market. We distinguish ourselves by providing customer
satisfaction, innovative design and industry experience.

SLACAN
Industries Inc.

145 Roy Blvd, P.O. Box 2500
Brantford, Ontario N3T 6E3
519.758.8888

Booth 2325

slacan.com

Wind-based projects are growing in the United States as
well, and here, as in Europe, off-shore wind stations are
increasingly attractive since ocean winds are stronger
and more consistent and the adverse scenic and noise
impact is more readily acceptable.
A consortium, the Atlantic Wind Connection, proposes to develop up to 6,000 MW of offshore windbased power that may be transmitted to shore by dc,
taking advantage of lower dc cable cost as well as its
better dynamic accommodation and reactive support
for the receiving systems (see Figure 3).

DC Utilization
It won't be long before the dc fraction of household load
will match ac's share. Modern lighting converts 60 Hz to
dc. Television, computer, sound, alarm, and many control
loads require dc. Add to that the prospect of the electric
vehicle charging load, and dc takes command. Yet efficiencies within onboard household ac-to-dc conversion systems average as low as 65%. The dc output of a rooftop
solar panel, converted to ac and then back to dc to operate
a TV set, may lose half its energy in losses...thus a new
interest in the delivery of dc directly to households, initially
supplementing ac but possibly displacing it. Conventional
wisdom, circa 1950, would have cried out on the issue of
safety since dc arcs, providing no current zeros, were dangerous and hard to interrupt. Now power electronics interrupt dc faults with speeds unimaginable then and an order
of magnitude faster than conventional ac circuit breakers.
Los Alamos National Laboratory examined the merits of using dc for microgrids rather than ac. The report
concluded that dc microgrids may be cheaper, more efficient, and more flexible than an ac microgrid option,
particularly with growth in locally based renewable generation and in vehicle charging load with its attendant
energy storage system.

DC Storage
Electrical storage is central to all smart grid proposals, and
among the options, one of several battery storage technologies is likely to be the winner. Initially considered as a
point-of-load application, battery storage systems as high
as 30 MW are scheduled for installation, again posing the
challenge of transformation either to or from an ac system
or, more efficiently, a dc system or microgrid, in the latter
case calling for dc-to-dc transformation.

Enter the dc-to-dc Transformer
DC's inroads into power generation, transmission, and
consumption have been made without a dc equivalent
to the ac transformer. In some industrial applications,
conversion between dc voltages is commonplace but not
without first converting dc to ac, transforming magnetically to a new ac voltage then converting a new ac voltage
back to dc...hardly an elegant solution. U.S. patent files

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Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - March/April 2016