POWERQUALITY BY RICHARD P. BINGHAM
Flash forward to PQ interest group
meetings at the IEEE Power & Energy
Society summer meeting. Every year,
attendees relate stories that demonstrate
how wrong those executives were. Typical PQ problems persist. Data centers
still shut down; remember the Delta Airlines computer center outage in August?
There are countless vegetation- and
animal-contact-initiated events (from
squirrels, monkeys, snakes and even
humans), and harmonics continue to
increase with failures of capacitor banks,
transformers and electric motors.
At the PQ interest meetings, case
studies of unique and intriguing PQ-related problems are brought up to tap
the group’s collective knowledge and see
if anyone can figure out the cause.
The group has seen everything.
The interconnection of a large solar
farm on one feeder results in misoperation
of protective circuits on a different circuit.
Hundreds of light-emitting diode (LED)
lamps on a dimmer circuit in a chicken
farm building cause an exterior spotlight
on a separate circuit to “go all disco,” flashing like a strobe light whenever the interior
lights are dimmed. Harmonics above the
highest limited frequencies (typically
3-kilohertz reference point of the 50th
harmonic) are rising with the increase in
inverters used in energy-saving devices
(such as compact fluorescent and LED
lamps) and renewable-energy sources
(such as photovoltaic panels). This is causing misoperation of power-line-carrier
communication and system-protective
devices miles away.
Promises of smart-grid initiatives to minimize or eliminate PQ problems haven’t
really fared better than those executives’
comments 25 years ago. The proliferation of smart meters is perhaps the most
visible result from the 2007 Energy
Independence and Securities Act and
the American Recovery and Reinvestment Act of 2009 (only 1 percent of the
$787 billion spent went toward energy-reliability projects).
As studies from the Electric Power
Research Institute and others have
shown, many of these meters don’t do
much for PQ reporting besides outage
reports; although, they have little energy
storage to keep them operating during
an interruption so they could produce a
report. The PQ functionality also is often
minimal or turned off because utility
communication systems cannot deal with
the massive increase in data as compared
to hourly revenue data.
PQ monitoring and troubleshooting remains a viable revenue source for
electrical contractors and is anticipated
to be like the quest for the perfect wave
in that old surfing movie; an endless
pursuit that will continue well into the
foreseeable future. The basic problems
and solutions will still exist in addition
to a new set of complications resulting
from changes in electricity production
and consumption that will need fixing if the beer is to stay cold and the
An Endless Summer
Problems in PQ persist despite past predictions
WHILE RENOVATING A BASEMENT, I came across a poster for “The Endless Summer,” a film released 50 years ago in which two surfers travel the world’s oceans,
chasing warm weather and surfing adventures. It reminded me of a meeting with
a group of executives in a multibillion-dollar company 25 years ago. They were
all convinced there would be no need for power quality (PQ) monitors in 10 years
because manufacturers would make equipment immune to PQ-related problems.
BINGHAM, a contributing editor for power quality, can be reached at 732.248.4393. IST