PQ Forum 2011 proceedings http://www.leonardo-energy.org/power-quality-forum-2011-tue-eindhoven

1. 31/01/2011
Fluke Power Quality and
Energy Savings
Welcome
Fluke Europe BV Eric van Riet 1
Questions to ask…
• Does a better quality of the power grid or power system
automatically lead to energy saving?
• Is energy efficiency the same as energy saving (i.e. cost
saving)?
• Is investing in energy efficient motors and lighting the road
to a trouble free power grid?
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The primary playground for
PQ and energy saving:
• What consumes the energy in the Power Grid?
– Loads
– Losses in system
• What creates the current Power Quality issue’s we face?
– LOADS
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Example with electrical motor
• Current situation:
– Standard 3-f motor, 70% mechanical load, direct connection
To save energy:
• Use energy efficiënt motors.
• Use ASD’s
• Size properly!
• Reduce load
• Perform regular maintenance
• Turn it off
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Another option: ASD in combination with
motor to “tune” motor to load
Energy loss in a
pump system when
a throttling valve
controls flow
Energy loss in a pump
system when an
adjustable speed drive
controls flow
Source: US Dep of Energy
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Energy consumption using an ASD
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Effects of long cabling
• ASD Output • Motor Terminals
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Overvoltage
• Source of EMC problems
• Disastrous for isolation of
motor windings
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Flow of harmonic Currents
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Bearing Current
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Current in PE conductor
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Power Quality and cost saving
• Where are the costs in the Power Grid?
– Energy bill (amount of € per KWh…..or)
* Connection value (size of conductor)
– Estimated lifetime power system (aging due to use)
* System loading
* Connected components/loads
• Cost saving in energy most likely marginal with same
mechanical load.
• Hidden cost saving present, but…..
• Also higher chance on PQ problems leading to higher cost
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What about lighting
• Lighting is also a large consumer of energy
• Latest trend pushing strongly for energy efficient lighting
like:
– T5 and comparable fluorescent lighting
– Electronic ballasts versus conventional ballasts
–LED Lighting
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Voltage and Current
Traditional lamp 60W Ledlamp 6W
27 Arms 18 Arms
Measured current is equivalent of 100 lamps
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Real Power comparison
Normal lamp 60W Ledlamp 6W
59 Watt/lamp 6.4 Watt/lamp
Ledlamp 10 x less dissipated power(W)
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Cos phi
Normal lamp 60W Ledlamp 6W
No difference in Cos phi
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Apparent Power
Normal lamp 60W Ledlamp 6W
60 VA/lamp 41 VA/lamp
Apparent Power ledlamp 32% less
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Harmonics
Test object :Led Lamp
Mains voltage with voltage THD of 8% (limit of EN 50160)
Harmonics far above limits IEC 61000-3-2 (2005) class D
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Transformer losses
• Transformer losses are proportional to
frequency of the harmonic current
times the amplitude of that harmonic.
• When a non-linear load is supplied
from a transformer, it is sometimes
necessary to de-rate the transformer
capacity to avoid overheating
• The de-rating of a transformer is
expressed by the k-factor
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Measured k-factor
Normal lamp Led lamp
The measured K-factor of the LED lamp is more
that 400 !!!!
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Measured k-factor
Lighting is consuming 17% of the total electric energy.
If all traditional lighting is replaced by LED then :
- Total Real Power will decrease 10-15%
- Total Apparent Power will decrease with 5-7%
- The total K-factor of the grid will increase with a
factor 5-10
This means that the total installed base of
transformers needs to be extended/replaced
multiple times.
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Answers to the questions…
• Does a better quality of the power grid or power
system automatically lead to energy saving?
• Is energy efficiency the same as energy saving (i.e. cost
saving)?
• Is investing in energy efficient motors and lighting the road
to a trouble free power grid?
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Measure to see the impact
PQ issues vary by location, so also the
measurement needs vary by location
No system is alike, hence no “solution” will
have the same effect on different systems
Real impact only visible through proper
measurements!!
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Answers to the questions…
• Does a better quality of the power grid or power
system automatically lead to energy saving?
• Is energy efficiency the same as energy saving (i.e.
cost saving)?
• Is investing in energy efficient motors and lighting the road
to a trouble free power grid?
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13. 31/01/2011
Answers to the questions…
• Does a better quality of the power grid or power
system automatically lead to energy saving?
• Is energy efficiency the same as energy saving (i.e.
cost saving)?
• Is investing in energy efficient motors and lighting the
road to a trouble free power grid?
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Food for thought
• Investing and engineering in order to save energy is a
good thing.
• Blindly applying “energy saving solutions” is NOT a good
thing.
• You can only improve a system or situation if you really
know what is going on….
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So MEASURE!
Quote Lord Kelvin (1824 – 1907):
–To measure is to know
–If you cannot measure it,
you cannot improve it
Thank you
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