Electrical Industry Canada Power Quality Issue - 19

Why is poor power quality causing so many
problems for today's buildings? Part of the
answer lies in the age and complexity of the
electrical grid. For years, as long as the power
was on - and within a defined basic range of
quality - that was acceptable. ANSI and CSA
voltage limits for the service entrance of a
facility are wide and not optimal for many
types of modern end-use equipment. The
result is a growing gap between the
decreased power quality generated by a
volatile grid and the increased sensitivity of the
buildings they feed. These days, with
buildings full of sensitive electronics, systems,
VFDs and computers, old standards that are
quite broad and tend to see the challenges of
a modern grid in discrete levels aren't
sufficient.
Conditions and demand in buildings change
constantly throughout a 24-hour cycle,
weekday vs. weekend, and seasonally; yet
they have a voltage supply that varies by a
minimum of two to three percent over a
24-hour cycle. Legend Power® Systems has
seen client buildings that can experience a 10
percent change in voltage levels over the
same time period.
The utility companies have been aware of
these issues for some time. In an effort to
scope them, the Electric Power Research
Institute (EPRI) has run and updated the
Assessment of Distribution System Power

Quality (commonly referred to as the " DPQ
Project " ) focusing on grid-delivered power
quality data at a national level:

" One of the most important utility needs is
an understanding of the actual power quality
being provided to their customers. Often this
information is not available because
conventional monitoring systems and analysis
techniques have focused on reliability and
steady-state voltages and currents instead of
the full spectrum of power quality variations
that impact customer equipment. " [1]
Part of the purpose of the study was also to
understand how the utilities might be able to
meet the emerging need for a " premium
power " product:
" In addition, 'premium power' options
cannot be offered to customers without first
understanding this critical information. " [1]

Knowing that equipment has become more
sensitive and that it is interconnected in
increasingly complex systems, premium
power is essentially what building owners and
maintainers are after today.
Expensive, large-scale power quality
management options have been available to
the industrial sector for some time due to the
very high and measurable cost of downtime.
There is an energy efficiency price to be paid
though, in that these systems use as much as
five percent more power while assessing the
power quality. Industrial systems are simply
too large and too expensive to be viable for
commercial buildings.
While perfect power may not be out there,
there are technologies available that can
deliver a premium power level to
light-industrial and commercial buildings.
Energy efficiency platforms can analyze and
assess incoming power, and then literally
reshape the electricity to optimal levels for a
specific building. This mitigates - or fixes - key
power quality issues, delivers three to six
percent (or more) electrical cost savings, offers
related drops in GHG emissions, and provides
ongoing reductions in machinery and systems
wear and tear - and does so with 99.5 percent
efficiency.
From an operational point of view, there are
significant follow-on benefits from the precise
voltage control of an entire facility, including

[1] The EPRI Research Project, An Assessment of Distribution System Power Quality (RP3098-01 and RP3797-03 - The DPQ Project)

ELECTRICAL INDUSTRY CANADA

VOLUME 1, ISSUE 2

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Electrical Industry Canada Power Quality Issue

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