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POWER QUALITY IMPROVEMENT IN A HARMONIC
ENVIRONMENT
G. N. C. Ferguson, B.Tech., MI & SS, LM.IEEE
Abstract - The effect of
single-phase, non- linear loads, as sources of positive-,
negative- and third-order, zero-sequence harmonic
currents in low voltage electrical distribution systems, is
discussed. Various traditional methods for dealing with these
harmonic currents are outlined and their shortcomings identified.
Alternative methods, which provide harmonic current reduction,
and power quality improvement, are presented. Results of the
application of alternative devices in typical environments are
given.
A paper reprint from the
InterNational Electrical Testing Association (NETA) Annual
Technical Conference, March 19, 1997, St. Louis, MO
Full copy.
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COSTS AND BENEFITS OF HARMONIC CURRENT
REDUCTION
FOR SWITCH-MODE POWER SUPPLIES
IN A COMMERCIAL OFFICE BUILDING
Thomas Key and Jih-Sheng Lai
Abstract – Harmonic currents
generated by modern office equipment cause power system heating and
add to user power bills. By looking at the power-related losses, in
a specific electrical system – representing a commercial building –
energy costs are quantified. The analysis shows that building wiring
losses related to powering nonlinear electronic load equipment may
be more than double the losses for linear load equipment.
Current-related power losses such as I2R,
proximity of conductors, and transformer winding eddy currents (I2h2)
are considered. The cost of these losses is compared to the cost of
reducing harmonics in the equipment design. Results show that an
active-type harmonic-elimination circuit, built into the common
electronic equipment switch-mode-power supply, is cost-effective
based on energy loss considerations alone.
A paper reprint from IEEE IAS
Annual Meeting, October 1995, Orlando, Florida
Full copy.
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COSTS AND BENEFITS OF HARMONIC CURRENT
REDUCTION FOR SWITCH-MODE POWER SUPPLIES IN A COMMERCIAL OFFICE
BUILDING
Thomas Key and Jih-Sheng Lai
GRAPHIC SUMMARY
by
Power Quality International, Inc.
Introduction - This summary
graphically displays selected information contained in the attached
IEEE paper entitled: ‘Cost and Benefits of Harmonic Current
Reduction for Switch-Mode Power Supplies in a Commercial Office
Building’, authored by Thomas Key and Jih-Sheng Lai.
The paper’s Case Study is based on typical 60kW commercial office
building loads, supplied by a conventional ‘unmitigated’ electrical
distribution system, for 12 hours per day, 365 days per year, at a
power cost of $0.10 per kWh.
The graphs, included in this summary, extrapolate the selected
information in order to demonstrate the cost and benefits for
electrical distribution systems with higher ratings and heavier
loads.
In producing these graphs, it is understood that each electrical
distribution system is unique and the results will vary. However,
the graphs can be adjusted for variations in the electrical
distribution system’s configuration, its components, loads and the
cost-of-power.
Neither the paper nor this summary discusses the cost benefits
associated with power quality improvement, increased productivity or
the potential for capital cost reduction for a new distribution
system, any one of which may be greater than the costs and benefits
discussed here.
All contents Copyright © 1999,
Power Quality International, Inc., All Rights Reserved
Full copy.
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THE BENEFITS OF HARMONIC CURRENT REDUCTION
IN A LOW VOLTAGE DISTRIBUTION SYSTEM
Gregory N.C. Ferguson, B.Tech., MI & SS, LM.IEEE
Abstract - Harmonic currents,
generated by single- and three-phase non-linear electronic loads,
cause ‘penalty losses’ throughout the electrical distribution
system. These losses result in apparatus overheating, higher air
conditioning costs and higher power costs. Harmonic currents
effectively de-rate every element of an existing distribution system
and, if accommodated by over-sizing and K-Rating, add substantially
to the capital cost of a new or upgraded system. The magnitude of
the various costs will be examined and alternative harmonic
mitigating system designs will be presented.
A paper reprint from World
Energy Engineering Congress, October 2001, Atlanta, Georgia
Full copy.
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CUTTING ENERGY COSTS THROUGH IMPROVED SYSTEM
EFFICIENCY
Gregory N.C. Ferguson, President, Power Quality
International, Inc.
Abstract - The electrical
distribution systems, which support hospitals’ administrative
offices, now supply primarily non-linear electronic loads. These
loads typically include fluorescent lighting, security systems,
facility monitoring systems, servers, computers, printers,
telephones, facsimile machines and virtually all office peripherals.
Like other modern facilities, hospitals’ heating, ventilation and
air-conditioning systems and elevators also utilize electronic motor
drives. However, in addition to these typical facility loads,
hospitals’ electrical distribution systems must also supply critical
electronic medical equipment.
All non-linear electronic loads generate
positive- and negative-sequence harmonic currents. Single-phase
non-linear electronic loads, which are connected phase–neutral in a
three-phase, four-wire distribution system, also generate
zero-sequence harmonic currents. These load-generated harmonic
currents are injected into the hospitals’ electrical distribution
systems.
Business Briefing: Hospital
Engineering & Facilities Management 2003
Full copy.
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THE COSTS AND BENEFITS OF HARMONIC CURRENT
REDUCTION
IN LOW VOLTAGE DISTRIBUTION SYSTEMS
Gregory N.C. Ferguson, B.Tech., MI & SS, LM.IEEE
Abstract – Harmonic currents,
generated by non-linear electronic loads, produce ‘penalty losses’
in every element of an electrical distribution system. These
harmonic-related losses reduce system efficiency, cause apparatus
overheating, and increase power and air conditioning costs.[1]
Harmonic currents effectively de-rate existing
systems and, when accommodated, add substantially to the capital
cost of new systems which must be de-rated or K-Rated.
The magnitude of typical ‘penalty losses’ and
increased operating costs will be evaluated. The capital cost of
conventional and harmonic mitigating system designs will be
discussed, and the financial benefits will be calculated.
Reprint from the International
Power Quality Conference, October 2002, Singapore
Full copy.
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THE MEASUREMENT AND EVALUATION OF
DISTRIBUTION TRANSFORMER LOSSES UNDER NONLINEAR LOADING
Aleksandar Damnjanovic, Ph.D., Member IEEE and
Gregory Ferguson, BSc., Life Member IEEE
Abstract – Harmonic currents,
generated by non-linear electronic loads, produce ‘penalty losses’
in every element of an electrical distribution system.[1]
These harmonic-related losses reduce system efficiency, cause
apparatus overheating, and increase power and air conditioning
costs.[2] Harmonic currents effectively de-rate existing
systems and, when accommodated, add substantially to the capital
cost of new distribution systems. The measurement and evaluation of
transformer losses under linear and non-linear load conditions will
be discussed. In addition, typical financial benefits that result
from the application of high efficiency harmonic mitigating
distribution transformers, under non-linear loading, will be
calculated.
IEEE Power
Engineering Society General Meeting, Denver, CO, June 9, 2004 /
PESGM 2004-000721
Full
copy.
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MISSION-CRITICAL SYSTEM & LOAD EFFICIENCY
Gregory N.C. Ferguson, BSc., Life Member IEEE and
Aleksandar Damnjanovic, PhD., Member IEEE
Abstract – It is understood that
data centers’ mission-critical loads require absolute continuity of
electrical supply and a high degree of electrical distribution
system-load compatibility. However, based on a review of typical
system configurations and their component and load technologies, it
becomes clear that there is an opportunity for significant energy
efficiency improvement.
With an ever-increasing demand for electrical
energy and the prospect of ever-increasing power costs, facility
stakeholders, and government regulators, are now focusing on energy
efficiency improvement. The application of ultra-efficient
transformers, which improve system-load compatibility, can
significantly reduce the ‘penalty losses’ associated with
conventional system designs.
In addition, the selection of power factor
corrected switch-mode power supplies, which do not depend on the
application of input capacitors to reduce harmonic current injection
into the distribution system, would reduce their internal ‘penalty
losses’, increase their efficiency and eliminate the leading power
factor problems associated with their application.
This paper will discuss the high costs associated
with conventional non-mitigating designs,[1] alternate
mitigating designs, [2] the measurement of system losses
and efficiencies under normal operating conditions,[3]
and the financial benefits resulting from harmonic current reduction
and/or voltage optimization.
Full copy.
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MEASUREMENT OF THREE-PHASE TRANSFORMER DERATING
AND REACTIVE POWER DEMAND UNDER NONLINEAR LOADING CONDITIONS
E, F. Fucks, Fellow, IEEE, D. Lin and J.
Martynaitis
Abstract – The measurement of real
and apparent power de-rating of three-phase transformers is
important for transformers feeding nonlinear loads. This paper
presents a new digital data-acquisition method for measuring
de-rating and reactive power demand of three-phase transformers
under full or partial load conditions. The accuracy requirements of
the instruments employed (potential, current transformers, shunts,
voltage dividers, optocouplers volt- and current meters) are
addressed. Application examples demonstrate the usefulness of this
new digital data-acquisition method.
Full copy. |
