| According
to a newly released study by the Electric Power
Research Institute, power outages and power quality
disturbances cost the U.S. economy more than $119
billion annually. Further, in today’s digital
economy, power reliability and quality are key
competitive factors. The Dranetz-BMI Field Handbook
for Power Quality Analysis is both a comprehensive
reference and primer on power quality, and a field
guide for performing power quality surveys. The book
has been written and updated by Dranetz-BMI,
the leading provider of power quality and energy
monitoring instrumentation.
The book is comprised
of five chapters and a glossary of terms:
1. Fundamentals of
Power Quality
2. Planning and
Performing a Power Quality Survey
3. Waveforms
4. PQ Express
5. Appendices
- Power monitor setups
- Case studies
- International
voltages
Types of Power Problems
Most users equate the
quality of power with the number of power problems
they experience. If there are no problems, power
quality is good. If there are a large number of
problems, power quality is bad. This is an appropriate
level of assessment for a power user; however, for
professionals responsible for power quality, the
definition of a power problem and power quality are
more complicated.
· A power event is a
recorded (or observed) current or voltage excursion
outside of predetermined monitoring equipment
thresholds.
· A power disturbance
is a recorded (or observed) current or voltage
excursion (event) which results in an undesirable
reaction or condition in the electrical environment or
electronic equipment or systems.
· The term power
problem refers to a set of disturbances or conditions
which produce undesirable results for equipment,
systems or a facility.
There are no hard and
fast rules to determine if a variation from the power
norm is a power event, disturbance or problem.
Identical circumstances may produce a power event for
one user and a power problem for another. Similarly,
there is no steadfast definition of good or acceptable
power quality. In reality, power quality and
definition of a power problem depend on:
· The nature and
source of the power event.
· The susceptibility
of the load to the event.
· The effect on the
end activity or process.
Power problems appear
in the system in two ways, one internal and one
external. They are produced within the electrical
system by the generation, transmission and
distribution, or use of electrical energy. If the
problem is produced externally, they enter the system
through direct injection, electromagnetic coupling or
inductive coupling.
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