Transcript Power Factor Correction and Harmonics

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What is
Power
Factor?
Power Factor is the percentage of
current delivered from the utility that
is needed to perform the actual work.
For example: A PF=0.50 means that
only 50% of the delivered current is
needed to perform the actual work.
The Math Behind PFC
Active Power (kW):
real power, working power
Reactive Power (kVAr):
inductive power,
magnetizing power
Total Power (kVA):
apparent power
kW
= cos Φ*
Power Factor =
kVA
*Phase angle difference between voltage and current
From MZI’s
Application Guide for Power Factor Correction
Motors need kVAr (reactive power, magnetizing energy) to turn,
but it does no useful work. Utility companies do not want to
provide kVAr to their customers and may charge a penalty.
Utility companies are increasingly keeping track of kW and kVAr
values. Most charge penalties if a facility’s power factor does not
meet a set threshold (typically between 85% and 95%).
Likewise, high power factor may result in a credit or rebate.
PFCCs may
lower your
utility bills.
If you have a penalty.
Penalty structure depends
on your Utility Provider
Consumers Energy
PF Adjustment
Detroit Edison
PF Penalty
Con-Ed New York
Excess kVAr Charge
PF
Penalty
PF
Penalty
PF
Penalty
> .90
- 2%
< .85
1%
< .95
(kVAr)*
.80 to .90
0
< .80
2%
< .80
(PF)*
< .75
3%
< .70
25%
*PF penalty = increase
capacity charge by a ratio of
threshold PF/ actual PF
*PF penalty = actual
kVAr – allowable kVAr
times $/kVAr
We need to take a look at your utility bill to determine if your utility company
has levied a penalty (12 months preferable).
Power Factor, You,
and Your Utility
DEMAND METER
TOTAL ENERGY
POWER FACTOR
your utility
Active Power (Current)
Reactive Power (Current)
WATT-HR METER
REAL ENERGY
you
Power Factor, You,
and Your Utility
DEMAND METER
TOTAL ENERGY
POWER FACTOR
WATT-HR METER
REAL ENERGY
PFCC
your utility
Active Power (Current)
Reactive Power (Current)
you
In some cases,
PFCCs can also
increase available
distribution capacity
reduce line losses and
associated costs
Increased distribution capacity can allow a facility to add more
equipment without adding more expensive infrastructure.
For example, a Pennsylvania ski resort applied PFCCs to its
snow-making equipment. Otherwise, it would have needed a
new power distribution system or larger transformers (a more
expensive option).
Other Considerations
Facility Details - MZI Facility Questionnaire
♦ Utility Bills
♦ Loads
♦ Non-Linear Loads
- May introduce damaging harmonics
- Examples: VFDs, AC to DC converters, UPS
systems
Who Needs PFC?
Wastewater Treatment
Lumber Mills
The Automotive Industry
Food Processing Plants
HVAC Systems
Plastic Injection Molding
If you have motors, you might need PFC.
If you have non-linear loads like Variable Frequency
Drives, you might have power quality problems and
require harmonic filters.
Myron Zucker, Inc.
offers fixed, automatic,
and custom solutions
to suit a variety of
applications.
Fixed PFC
♦ Suited for applications where:
– The load does not change
– The capacitor is switched with the load
Calmount®: At the
load correction, up
to 500 HP
Capacibank®: System
installed at the distribution
center or service entrance
for facility-wide correction
MCC Traymount®: Customdesigned trays for:
- Rockwell Automation AllenBradley
- Eaton/Cutler Hammer
- Siemens
- Schneider Electric Square D
Fixed PFC Product Selection
Correction in the Presence of Harmonics
Caltrap®: At the load correction
in the presence of harmonics
Capacitrap®: Passive filter
installed at the distribution
center or service entrance for
upstream harmonic reduction
Automatic PFC
Suited for applications where the electrical load
is not constant and requires varying amounts
of reactive power.
Autocapacibank™
Automatically-switched
system installed at the
distribution center or
service entrance for
facility-wide correction
Correction in the
presence of harmonics:
Autocapacitrap™
Automatically-switched
passive filter for loads
that vary; locate at plant
distribution center or
service entrance
Custom Applications
Customization includes but is not limited to:
– Custom enclosure
– Different entry points
– Breakers
– Voltage
MZI Services
♦ Custom design and build per customer
specifications
♦ Retrofit and Rebuild
♦ Engineering consulting
♦ Utility bill analysis and plant electrical
system review
♦ Product training and commissioning