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Copyright 2012 Rockwell Automation, Inc. All rights reserved.
T-68 Protecting Your Equipment through Power Quality Solutions
Dr. Bill Brumsickle Vice President, Engineering Nov. 7-8, 2012
Copyright 2012 Rockwell Automation, Inc. All rights reserved. 2
Agenda
Voltage Sag Protection
Power Quality Events & Voltage Sags
Importance of Power Quality to Industrial Users
What is Power Quality?
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Power Quality vs. Power Reliability Power Reliability: Continuity of electric power delivery measured by the number and
duration of power outages (Zero voltage) Outages are tracked by Utilities Power Reliability can be as high as 99.999% availability
Power Quality: Related to fluctuations in electricity, such as momentary interruptions, voltage sags or swells, flickering lights, transients, harmonic distortion and electrical noise Fewer such incidents indicate greater power quality Events go mostly untracked by Utilities Sag & Momentary events can take out a process as many as 20-30 times per year
3
The Grid is designed for Reliability, not Quality
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Power Quality
Frequency is regional Determined by HV & EHV network generators Problems are rare
Voltage is area-wide Determined by MV distribution network Problems occur randomly, but with regularity
Current is local Determined by facility loads Problem loads can be identified and resolved Source: DTE Energy website
4
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Utility Power Properties of AC Grid
Not always ideal sinusoidal voltages!
Highly interconnected
Transformer and line impedances between generators and loads
Terminal voltage drops with load current
System faults cause significant voltage sags (dips)
Most wiring is overhead Susceptible to lightning, animals, wind-blown
tree branches, etc.
Insulation fails, equipment fails
5
Source: NPR: Power Hungry: Reinventing The U.S. Electric Grid May 1, 2009
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Power Quality Problems
All have physical causes
6
Copyright 2012 Rockwell Automation, Inc. All rights reserved. 7
Agenda
Voltage Sag Protection
Power Quality Events & Voltage Sags
Importance of Power Quality to Industrial Users
What is Power Quality?
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Electrical Equipment Designed Assuming Power Quality
Operate with input ac voltage variation of 10% Possible new requirements:
Operate through some voltage sags SEMI F47 IEC
Present a unity Power Factor: Current phase angle near zero Current harmonic distortion low
8
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Impact of Power Quality Events
Possible Agency, Utility, or Facility Requirements Power Factor correction (current phase angle) Harmonic current limits
Load equipment mis-operation Voltage sags and momentary interruptions Voltage distortion (harmonics, notching) Voltage imbalance or single-phasing High-frequency voltage transients
Load equipment damage High-voltage transients Current inrush following voltage sag
Facility infrastructure damage High-voltage transients Current inrush following voltage sag Overheating due to current harmonics
9
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Consumer is Responsible for Power Quality
Utility cannot provide perfect power quality and are not required to. (e.g., Wisconsin PSC 113.0703)
Customers having equipment or operations that are sensitive to such voltage fluctuations may find it necessary to install, at their own expense, power conditioning equipment or other modifications
Job is to Keep the lights on.
Goals Deliver maximum energy through the existing infrastructure Maintain +/-10% (on average) voltage at service entrance Minimize outages longer than 2-5 minutes 60.00 Hz, when averaged over 24 hours Keep large industrial customers satisfied Minimize large customers disrupting neighbors power quality
10
The utility is responsible for reliability, not quality of power.the customer is responsible for protecting their sensitive equipment at their own expense
Copyright 2012 Rockwell Automation, Inc. All rights reserved. 11
Agenda
Voltage Sag Protection
Power Quality Events & Voltage Sags
Importance of Power Quality to Industrial Users
What is Power Quality?
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Power Quality Issues
Voltage sag (dip) and Momentary interruption
High voltage transients (spikes)
Current distortion (harmonics)
Voltage distortion and voltage flicker caused by distorted current loads
Voltage unbalance
Voltage notching
Uncommon issues in the U.S. and high-tech. parks: brownout voltage swell frequency variation
Poor grounding 12
EPRI (Electrical Power Research Institute)
Monitored 300 sites for 2+ years.
92% of all events were voltage sags under 2 seconds
4% of event interruptions from 2 seconds to 10 minutes
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Voltage Sag (Dip) Characterization
Sag - RMS voltage reduction between 1/2 cycle - 60 sec
Magnitude and Duration
13
-1
-0.5
0
0.5
1
0 1 2 3 4 5 6 7 8
Duration: 4 Cycles
Magnitude: 60% Remaining
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
0.0
0.2
0.4
0.6
0.8
1.0
1 10 100 1000
Duration (ms)
Mag
nitu
de (p
er u
nit)
90%
Voltage Sag
14
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Why mostly brief sags and interruptions?
" B" " A"
THREE PHASE FAULT
1500kVA480 VOLTS
" C"
F 1
F 2
F 3
1. 0
0. 5
0. 0
TIME
0
VOLTAGE AT "C" AND ON F1 & F3 V=0.67 p.u.
V=0.40 p.u.
20 MVA
BEGINFAULT
F2OPENS
F2CLOSES
F2OPENS
FAULTCLEARS
F2CLOSES
VOLTAGE
VOLTAGE AT "B"
69 kV12 kV
Radial Distribution
Reclosing breakers
V = Vs Zline*I
Fault results in short voltage sags and interruptions for most customers, affecting up to 200 mile radius
15
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Why Sag Durations are short
Clearing Time in Cycles Type of Fault
Clearing Device Typical Minimum Typical Time Delay Number of Retries
Expulsion Fuse 0.5 0.5 to 60 None
Current Limiting Fuse 0.25 or less 0.25 to 6 None
Electronic Recloser 3 1 to 30 0 to 4
Oil Circuit Breaker 5 1 to 60 0 to 4
SF6 or Vacuum Breaker 35 1 to 60 0 to 4
Source: IEEE Std 493
16
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Sags at High-Tech Mfg. Sites
Very few outages, still many sags!
1000 sag events from 15 Semi plants
Avg. 5.4 events below CBEMA per yearwith transmission-level service!
SEMI F47
source: International SEMATECH & EPRI, 1999
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Impact of Voltage Sags
Sensitivity of various 3-ph. 4kW drives to single-phase sag (rated speed, torque) [Djokic]
18
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Impact of Voltage Sags
19
AC Relay Voltage Sag Tolerance Curves
0102030405060708090
100
0 50 100 150 200 250 300 350 400 450 500
Duration of Sag (milliseconds)
% o
f Nom
inal
Vol
tage
Upper range Average Lower Range
Source: IEEE Std 1346-1998
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Data Corruption
Source: Djokic
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
IEEE P1668 a new standard
Recommended Practice for Voltage Sag and Interruption Ride-through Testing for End-use Electrical Equipment Less than 1,000 Volts
A standard for the response of electrical equipment to voltage sags
Expected to include: Guidance for evaluation of equipment sensitivity to voltage sags and
interruptions Minimum performance criteria to specify during the purchasing process Levels of performance for acceptance of the product Voltage tolerance curves for three-phase equipment: more useful than CBEMA
or ITIC
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Most common effect is equipment drops offline PLC shutdown Open contact or relay (As little as 80% remaining voltage for 1 Cycle)
A secondary effect is that when voltage returns, high current inrush can occur because the Soft-charge circuit is bypassed
RF Amplifiers, Gradient Amplifiers, and Low Voltage Power Supplies subjected to repeated hitsFail.
Voltage SAGS can shut-down and/or damage equipment!
Typical rectifier circuit diagram:
Effect of Voltage Sags on Equipment
22
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Voltage Sags Effect Equipment
5
Example: Inrush current measured for 1kVA electronic load
Note the scale change necessary to get the sagged results on the same page!
Normal Inrush Inrush after Sag
Peak inrush 50A Soft-charge
circuit bypassed
Peak inrush 10A Soft-charge
circuit is active
Volts
Amps
10
0
20
Volts
Amps
40
0
23
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Only some machines shut down. Why?
L1
:Y Tranf.
L2 L3
Rect.
Controls Power
Machine 1 Machine 2 Machine 3 Machine 4 Machine 5 Machine 6
480-a
480-b
L1 Tranf. N Rect.
Controls Power
L2 Tranf. N Rect.
Controls Power
L3 Tranf. N Rect.
Controls Power
L1 Tranf. L2 Rect.
Controls Power
L2 Tranf. L3 Rect.
Controls Power
L3 Tranf. L1 Rect.
Controls Power
Fabrication or Assembly Line Layout:
Machine power distribution and power supplies vary:
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Detection of Power Quality Events
Monitoring is Key to Knowing the Local Power Quality
I-Sense, I-Grid Voltage Monitoring I-Sense voltage monitor device I-Grid network of monitors and database
servers information and notification service
Email & text message notification in real time Web summary, available from anywhere PDF Reports
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
I-Grid
I-Grid
Servers &
Database
Web
Internet
I-Sense monitors record & report PQ event data via the Internet
Real-time notifications Report delivery
I-Sense Owners
Facility Engineer
Utility Engineer
Other users
Use Web browser to: View event details Manage accounts and monitors Generate reports and export data
Copyright 2012 Rockwell Automation, Inc. All rights reserved. 27
Agenda
Voltage Sag Protection
Power Quality Events & Voltage Sags
Importance of Power Quality to Industrial Users
What is Power Quality?
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Sag Correction Solutions
CVT Protection
On-Line UPS Protection
Stand-by UPS Protection DySC Protection
28 28
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
DySC and UPS Correction Capability
29
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
UPS Product Offering
30
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
DySC (Dynamic Sag Corrector)
DySC (pronounced Disk) is an adaptive power supply that optimizes the remaining power during a sag by using patented inverter technology to compensate for the sag thereby maintaining an uninterrupted flow of optimal power to the load thus maximizing uptime, minimizing inventory loss and reducing maintenance costs
MiniDySC (single-phase; 0.25-12 kVA) ProDySC (3-phase; 9-167 kVA) MegaDySC (3-phase; 263-2000 kVA)
Up to 5 seconds of ride through
U.S. and International voltages available
Scalable solution
31
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Cross- Coupling
Transformer
Power Conversion
Core
Static Switch
Auto By-Pass
Utility Load
DySC DSP Controller
Rectifier Inverter
DySC - Normal Operation
Normal Operation - The DySC monitors power quality continuously, while the power electronics are in standby 99.99% of the time
Component Activity DSP Controller Constantly monitors incoming power, system integrity and load Static Switch (99% efficient) Closed. Sends power directly to the load Cross-Coupling Transformer Idle Power Conversion Core Idle Automatic By-Pass Idle
32
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
Power Conversion
Core
Static Switch
Auto By-Pass
Utility Load
DySC DSP Controller
Inverter Cross-
Coupling Transformer
Rectifier
DySC - Voltage Event
Component Activity
DSP Controller Detects the leading edge of a voltage sag, immediately routing power thru the C-C Transformer and Power Conversion Core Static Switch (99% efficient) Open Cross-Coupling Transformer Pulls additional power from the grid Power Conversion Core Rectifies and inverts to recreate a true sinusoidal Output Automatic By-Pass Idle
DySC is On in under 2 milliseconds and recreates a true sinusoidal output 33
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
DySC Operation
Example: voltage sag to 60%, full load We keep load voltage at 100%,
so load power remains 100% Input Current rises briefly
to (100% / 60%) = 167% Load energy comes from ac input,
not from capacitors!
100%
67%
167%
167%
100%
100%
V = 100% V = 60%
(V = 40%)
LOAD
Normal Operation (Monitoring) Static Switch ON, Highly efficient Power electronics OFF Capacitors charged & ready No thermal cycling, long life Low maintenance Voltage Sag Correction 1-2 millisec. detection Static switch OFF Power Electronics ON, to produce
corrected sinusoidal load voltage Energy from capacitors needed only
for sags below 50%
V = 100%
Static bypass 99.99% of the time
Corrects voltage by maintaining power flow (P = V x I)
Most of the time the DySC is in a monitoring mode
34
patented
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
DySC Sag Correction
input waveforms
output waveforms
330 kVA MegaDySC responding to 3-phase 50% voltage sag, duration 4.5 seconds
35
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
DySC Interruption Correction
input rms voltage
output rms voltage
90%
330 kVA MegaDySC-ER
3-phase interruption
for 250 ms (15 cycles)
36
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
For More Information or Questions
Power Quality at Automation Fair 2012 Essential Components (Booth 127): Protection Solutions
Energy Management (Booth 541): Power Quality Monitoring
Backroom Session: Hands-on DySC and I-Sense / I-Grid More information available at Booths
Copyright 2012 Rockwell Automation, Inc. All rights reserved.
www.rockwellautomation.com
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Thank you for your attention. Questions?
T-68 Protecting Your Equipment through Power Quality SolutionsAgendaPower Quality vs. Power ReliabilityPower QualityUtility Power Properties of AC GridPower Quality ProblemsAgendaElectrical Equipment Designed Assuming Power QualityImpact of Power Quality EventsConsumer is Responsible for Power QualityAgendaPower Quality IssuesVoltage Sag (Dip) CharacterizationVoltage SagWhy mostly brief sags and interruptions?Why Sag Durations are shortSags at High-Tech Mfg. SitesImpact of Voltage SagsImpact of Voltage SagsData CorruptionIEEE P1668 a new standardEffect of Voltage Sags on EquipmentVoltage Sags Effect EquipmentOnly some machines shut down. Why?Detection of Power Quality EventsI-GridAgendaSag Correction SolutionsDySC and UPS Correction CapabilityUPS Product OfferingDySC (Dynamic Sag Corrector)Slide Number 32Slide Number 33DySC OperationDySC Sag CorrectionDySC Interruption CorrectionFor More Information or QuestionsThank you for your attention. Questions?