Download - 2012 PowerPoint Template
Multi-Level Approaches for
Mitigating Power Quality Issues
Mark Stephens, PE, CEM, CP EnMS-Industrial
Electric Power Research Institute
SEEDZ Power Quality Workshop Part 2
Moffett Park / North Bayshore
Smart Energy Enterprise Development Zone
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Mitigation Levels
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Example PQ Solution Levels
Machine or Subsystem Level
Power Conditioning
Control Level
Power Conditioning (1/10th to 1/20th of Machine Level Power Conditioner Cost)
Control Level
Embedded DC Solution (Best done by OEM in design phase)
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New Solution for an Old Problem:
EPRI Nice Cube Block Concept & Prototype
Original “AC Ice Cube”
Drop out ~70% Vnom
Remove “AC Ice Cube” Insert
“Nice Cube” Puck Into Base
Insert “DC Ice Cube”
Drop Out ~ 25-30% Vnom
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Example Nice Cube Application
Pellet Bin ExtruderMetering
PumpRoll Stand 1
Roll Stand 2 Roll Stand 3 Roll Stand 4 Winders
Line E-Stop Relays
Legend:
Potential AC “Ice Cube” Relay Location (Depends on Line)
DC Extruder Drive
AC Drive
Rheostat Controlled AC motors (No PQ Issue)
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Example Nice Cube Installations
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PQSI “Nice Cube” Vs. Typical AC “Ice Cube”:
Plotted Against Sample PQ Data
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White Paper
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White Paper (continued)
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Uninterruptible Power Supply (UPS)
Battery Based
UPS
Are Often
“Overkill”
For Control Loads
Small 500Va to
3kVA
UPS Systems are
sometimes Used
“Abandoned in Place” UPS Systems:
A Common Problem
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DC UPS for DC Power Supplies
Battery
DC UPS
DC Power
Supply Load
• If minutes of ride through is needed a DC UPS will be necessary.
• The difference between a buffer and a UPS is the UPS provides battery management circuitry for high capacity battery banks.
• These systems typically provide the same feedback features as the buffer module discussed in the previous slide.
Ref: Mean Well DR-UPS40 data sheet
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Example PQ Mitigation Devices
1 f f - f 3 f
3f ProDySC 0% / 2 sec. 30% / 2 sec. 50% / 2 sec. at full load
45% / 30 sec. 45% / 30 sec. 50% / 30 sec.
25% / 30 sec. 25% / 30 sec. 50% / 30 sec.
1f Contrl Ckt PowerRide RTD 0% / 2+ sec.0% A-B, B-C; 70-
80% C-A / 2+ sec.70-80% / 2+ sec. 3-phase Input, 1-phase Output
1f Contrl Ckt MiniDySC0% / 0.05 sec.
50% / 2 sec.n/a n/a
1f Contrl Ckt CVT 40-50% / 2+ sec. n/a n/a
1f Contrl Ckt VDC (6T Model) 37% / 2+ sec. n/a n/a
1f Contrl CktCoil Hold-in (CoilLock
and KnowTrip)25% / 2+ sec. n/a n/a for relays, contactors, motor starters
3fAVC (two rated
models)at full load
Comparison of Power Conditioning Devices
Coverage (Vnom) / DurationApplication Device Notes
3f
3f
1f
1f
1f
1f
1f
1 f f - f 3 f
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Generalized Example:
Control Level to Equipment Level
Cost vs. Coverage
+
+
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Example Control Level Solution
Application
• The CVT is protecting only the
AC control components means
that the selected power
conditioner will be more
affordable than one that could
protect the entire machine.
• The ride-though of the AC
drives in this example can be
enhanced by modifying their
programming, thus eliminating
the need for a large power
conditioner.
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Solution Application Points
• Voltage Sags may be mitigated at a variety of locations
• Service Entrance, Panel Feeder, Panel, Machine, and Control Levels.
Example Network:
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• AB PLC 5
– 78% Vnom
– Remote rack – 72% Vnom
• Idec RY4S – ac “Ice Cube” relays
– ~70% Vnom RR3B
AB
Example Problem – Multiple Cabinets Fed from Centralized Control Power Panels
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Example Solution: Distribution Panel Level Mitigation
• Remove abandoned UPS and use UPS bypass switch already in place
• Four distribution panels in room for Extruder lines plus one additional for other related control loads (5 total)
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Another Distribution Panel Example
• Sometimes the most effective
solution is to provide
conditioned power for the entire
IPP Panel. Advantages of this
approach include:
– Simplified Cut Over/Fewer
Touch Points
– Single Power Conditioner for
many loads
– When sized to support kVA
of transformer, this approach
will support future expansion
in panels
3-Phase
480Vac
Power
Conditioner
Xformer
480/208
3-Phase
30kVA
IPP-PC
480Vac
3-Phase
MCC Bus
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Example Measured Loading of IPP Panel
• Panel Lightly Loaded
– Several Spare CB in Panel
– 480Vac CB Rating is 50A
– 480Vac Phase Currents
• Phase A – 4.89A
• Phase B – 4.11A
• Phase C – 1.67A
• Measurements were taken when
line was running.
• It is possible that some loads
could be cycled off.
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Example Series Boost Mitigation
Input Voltage
Missing Volts
DySC Output Voltage
DySC
AVC
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Example Three Phase Solution – ProDySC
• The Dynamic Sag Corrector
from Softswitching Technologies
• Deep Sag Coverage especially
when lightly Loaded
• Has Capacitors that allow for
some ride-through for
interruptions
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Example Three Phase Solution – AVC
• Three-Phase Correction to
50%
• Single-Phase Correction to
25%
• No capacitors, therefore no
deep sag or interruption ride-
through
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Example Control Level Option
(Area Wide Power Distribution for CPT Primaries)
• Fewer, larger sag mitigation devices
– Fewer touch points but more expensive mitigation devices
– New 480Vac Panel, new conduit and wiring to machine controls
– Labor costs
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Feeder Level Mitigation Scenarios
• Multiple very large sag
mitigation devices
– Fewer installation points, less
wiring, conduit, & labor
– Higher Equipment Costs
– More Comprehensive
Coverage
– Some Typical Voltage Sag
Solutions
• Omniverter AVC
• Softswitching DySC
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CAT UPS – Machine or Feeder Level
• Flywheel speed 8000 RPM. In recent years there has been a number of installations in US for bridge power application; provides 15 second protection under rated load condition.
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CAT UPS Performance from Test in EPRI Lab
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Static Transfer Switch
• Solid State thyristor or GTO switches
transfer between independent
distribution sources for interruptions
and sags
• 1/4 to 1/2 cycle response
• medium voltage, 600 A
• no energy storage
• electronics require cooling
• ~ $350k to $700k each
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Series Voltage Boost Devices
• Synthesizes missing part of waveform
• Medium voltage applications, up to 40 MVA
• May contain energy storage, usually DC capacitors
• Ride-thru for 0.2
to 1.0 sec
• 1/4 cycle response
• Up to 60% boost
• ~$600K per boost
MVA
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Conclusions
• It’s a team effort to solve these problems, the utility, industrial, and sometimes consultants need to come together.
•Understanding why your equipment is vulnerable is paramount. You can’t fix a problem without understanding the true cause.
•Moving forward (sometimes with some simple modifications) you can make industrial systems more robust. Don’t forget including PQ standards in your purchase specs.
• Don’t assume battery based systems are required. Smaller solutions may be more cost effective.
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For More Information Contact:
Mark Stephens, PE, CEM, CP EnMS - Industrial
EPRI | Senior Project Manager
Industrial PQ & Energy Efficiency
942 Corridor Park Blvd, Knoxville, TN 37932
Desk: 865-218-8022
Mobile: 865-773-3631
www.epri.com
http://f47testing.epri.com
http://mypq.epri.com