Download Monitoring System

Power Quality Fundamentals and Monitoring
Ross M. Ignall
Systems Applications Manager,
Dranetz-BMI
[email protected]
What We Will Cover…
- Defining Power Quality and Reliability
- PQ References & Fundamentals
- Monitoring, Measuring High Reliability
Facilities
- Case Studies
WPT
Power
Monitoring
Hardware
Devices
•measure and
monitor power
Data
Acquisition
Devices
Software and
Consulting
Services
•measures
physical processes
•power quality and
distributed generation
Aggregation of
Distributed
Generation
•load curtailment
of power sales
Defining Power Quality & Reliability
What is a Power Quality Problem?
“Any occurrence manifested in voltage,
current, or frequency deviations that
results in failure or mis-operation
of end-use equipment.”
What Does That Mean?
Given the quality of supply do I have
to worry about problems with my
equipment or systems?
It’s dependant on your susceptibility.
What You Should Be Asking…
What is my susceptibility
to power problems?
What is my economic exposure
to such problems?
$$$$
Types Of Power Quality Problems
Voltage
Swells
29%
Spikes
8%
Interruptions
3%
Voltage
Sags
60%
Who’s Problem Is It?
Customer’s Perspective*
Neighbor
8% Other
3%
Customer 12%
Utility
17%
* Georgia Power Survey
Natural
60%
Who’s Problem Is It?
Utility Perspective*
Customer
25%
Utility
1%
* Georgia Power Survey
Neighbor
8%
Other
0%
Natural
66%
The Big Picture
It’s the complete
electrical environment,
not just the
quality of supply
What You Should Be Asking…
Does my power system have the
capacity for my present needs?
How about future growth?
Be Proactive!
An Analogy…
“Just because I have blank checks
doesn’t mean that I have money in
the bank to cash them”
Ron Rainville, COO, US Data Centers
Some Factoids
Power Quality Factoids
$50 billion per year in the USA is lost as a result of power
quality breakdown.
SOURCE: EPRI, 2000
Half of all computer problems and one-third of all data loss can
be traced back to the power line.
SOURCE: Contingency Planning Research, LAN Times
Sandia National Laboratories estimates power quality and
reliability problems cost US businesses approx. $150 billion
annually in lost data, materials and productivity—60% are sags
In 1999, the amount lost as a result of power quality in the US
was five times the amount spent on power quality worldwide
…The data center houses 45,000 square-feet of computer floor
space. In one database, the company has consolidated $1.6
trillion of life insurance information.
Energy Decisions, June 2001
During power supply shortages, utilities are generally permitted
to have line voltage reductions, so-called “brown outs,” to cope
with seasonal power demands…But if equipment is already
operating on the low end of nominal voltage then the brown-out
may cause excessive heat dissipation in motors and electronic
equipment.
Building Operation and Management, May 2000
Power Density Factoids
Traditional data center or large office building – 20-30 W/sq. ft.,
Internet Data Center, on-line brokers, web hosts – 100-150
W/sq. ft.
A web-enabled Palm Pilot requires as much electricity as a
refrigerator
Mark Mills
Transformation: Former 16 story Macy’s building used to
consume 10 W/sq. ft. Now a telecommunications hotel that
according to the utility could require 50 W/sq. ft.
NY Times, July 3, 2000
Costly Downtime!
Industry
Brokerage
Credit Card
Pay Per View
Home Shopping
Catalog Sales
Airline Reservations
Tele-Ticket
Package Shipping
ATM Fees
Source: 7x24 Exchange
Avg cost of downtime ($/hr)
$6,450,000
$2,600,000
$150,000
$113,000
$90,000
$90,000
$69,000
$28,000
$14,400
Introduction to Power
Quality
Power Grid Review
L
O
A
D
GENERATOR
13.8kV-24kV
TRANSMISSION
115k-765kV
DISTRIBUTION
34.5k-138kV
4k-34.5kV
12,470Y/7200V
CONSUMER
4160Y/2400
480Y/277V
208Y/120V
240/120V
Generation
50/60hz ‘Pure’ Sine Wave
 Various Voltages
 Types





Chemical
Mechanical
Nuclear
Solar
Transmission
Those big towers
 Voltage High
 Current Small
 Efficiency of Transmission
Power Delivered to the Load
Power Supplied From Generator

Distribution
Typically 13kV
 Commercial/Industrial - Three Phase, 480/277V
 Residential - Split Phase

480V
480V
13kV
480V
Single Phase Circuit Diagram
Is
V line
Vn
L
O
A
D
Can Wiring and Grounding Affect
Power Quality?
“That’s one of the things about living in an old
house that drives me nuts. Never enough outlets!”
ACTUAL SINGLE PHASE CIRCUIT DIAGRAM
Vpcc
Is
V line
Vdp
L1 R1
l n2
L3 R3
L2 R2
I n1
Vn
L4 R4
Vg
L5 R5
I g2
L6 R6
l g1
L
O
A
D
Sources Of Power Problems
Referenced at the utility PCC (point of common
coupling)
Utility
 lightning, PF correction caps, faults,
switching, other customers
Internal to the facility
 individual load characteristics
 wiring
 changing loads
Power Quality
References & Terms
IEEE Standards Coordinating
Committee
• SCC-22
• Oversees development of all PQ standards in the
IEEE
• Meet at both Summer and Winter Power
Engineering Society meetings
• Coordinate standards activities
• Progress reports
• Avoid overlap and conflicts
• Sponsors task forces to develop standards
 1433 Task Force to pull together terms. IEEE & IEC
IEEE Standard 1159-1995
Definition of Terms
Monitoring Objectives
Instruments
Applications
Thresholds
Interpreting Results
IEEE 1159
• 1159.x Task Force




Data Acquisition & Recorder Requirements for 1159-1995
Combination of 1159.1 & 1159.2
Coordination with IEC standards (61000-4-30 and revisions)
New recommended practice to be developed by July 2001
• 1159.3 Task Force
 Power Quality Data Interchange Format (PQDIF)
 Format for the exchange of PQ and other information between
applications
 Developed by Electrotek Concepts
IEEE 519-1992
Recommended Practice For Harmonics
 Recommends Limits at the PCC




Voltage Harmonics
Current Harmonics
Ongoing work to modify IEEE 519-1992


Limits for within a facility
Frequency dependant
International Electrotechnical Commission (IEC)


International standards for all electrical, electronic and
related technologies.
IEC Study Committee 77A – Electromagnetic
Compatibility, presently 5 Working groups
 SC77A/WG 1: Harmonics and other low-frequency
disturbances
 SC77A/WG 2 : Voltage fluctuations and other lowfrequency disturbances
 SC77A/WG 6 : Low frequency immunity tests
 SC77A/WG 8: Electromagnetic interference related
to the network frequency
 SC77A/WG 9: Power Quality measurement
methods
Types Of Power Quality Disturbances
(as per IEEE 1159)
Transients
RMS Variations
Short Duration Variations
Long Duration Variations
Sustained
Waveform Distortion
DC Offset
Harmonics
Interharmonics
Notching
Voltage Fluctuations
Power Frequency Variations
Transient Characteristics
High frequency "event"
 also called Spike, Impulse
 Rise time (dv/dt)
 Ring frequency
 Point-on-wave
 Relative versus Absolute amplitude
 Multiple zero crossings
Transients
Unipolar
Positive
Bipolar
Notching
Oscillatory
200
100
0
-100
-200
Negative
Multiple Zero Crossings
Transients
Possible Causes
• PF cap energization

Possible Effects
• Data corruption
• Lightning
• Equipment damage
• Loose connection
• Data transmission errors
• Load or source switching
• Intermittent equipment operation
• RF burst
• Reduced equipment life
• Irreproducible problems
Power Factor Correction Capacitor Transient
A transient power quality event has occurred on DataNode H09_5530. The
event occurred at 10-16-2001 05:03:36 on phase A. Characteristics were
Mag = 478.V (1.22pu), Max Deviation (Peak-to-Peak) = 271.V (0.69pu),
Dur = 0.006 s (0.35 cyc.), Frequency = 1,568. Hz, Category = 3 Upstream
Capacitor Switching
RMS Voltage Variations
 Instantaneous (0.5 - 30 cycles)
 Sag (0.1 - 0.9 pu)
 Swell (1.1 - 1.8 pu)
 Momentary (30 cycles - 3 sec)
 Interruption (< 0.1 pu, 0.5 cycles - 3s)
 Sag
 Swell
 Temporary (3 sec - 1 minute)
RMS Voltage Variations
Sag
200
150
100
50
0
-50
-100
-150
-200
Swell
Interruption
SAG
SOURCE GENERATED
 DURATION
 fault clearing schemes
 may be series of sags (3-4)
 MAGNITUDE
 distance from source
 feeder topology
 cause
 LOAD CURRENT
 usually slightly higher, decrease,
 or zero
PQ Rule
For a source generated Sag, the current
usually decreases or goes to zero
PQ Rule
For a source generated Sag, the current
usually decreases or goes to zero
SAG
LOAD GENERATED
 DURATION
 type & size of load
 usually single event per device
 MAGNITUDE
 type & size of load
 wiring & source impedance
 LOAD CURRENT
 usually significantly higher
PQ Rule
For a load generated Sag, the current
usually increases significantly.
4000
3000
2000
Volts
1000
0
-1000
-2000
-3000
-4000
2000
1500
1000
Amps
500
0
-500
-1000
-1500
-2000
-2500
12:09:54.40
12:09:54.45
CH A Vo lts
CH D A m ps
CH B Vo lts
12:09:54.50
CH C Vo lts
12:09:54.55
CH D Vo lts
CH A A m ps
09/24/00 12:09:54Threshold crossed: 2280.0 V
CATEGORY: Short Duration Momentary Sag
Magnitude: 2160.0 V
Duration: 2.901 sec.
12:09:54.60
CH B A m ps
12:09:54.65
CH C A m ps
Motor Starting - Another Cause of Sags
Timeplot Chart
Volts
Amps
222.5
900
CHA Vrms
CHA Irms
800
220.0
700
217.5
600
215.0
500
400
212.5
300
210.0
200
207.5
100
205.0
09:49:00.5
09:49:01.0
09:49:01.5
09:49:02.0
CHA Vrms
09:49:02.5
CHA Irms
09/13/96 09:49:00.50 - 09/13/96 09:49:04.00
09:49:03.0
09:49:03.5
0
09:49:04.0
Min
206.11
1.40
Max Median
222.25 219.19
847.71 207.16
Motor Starting – Inrush Current with decay
Waveforms
Vo lts
Amps
400
1500
300
1000
200
500
100
0
0
-100
-500
-200
-1000
-300
-1500
-400
-500
09:49:00.8
09:49:01.0
09:49:01.2
09:49:01.4
CHA Vo lts
09:49:01.6
CHA Amps
AI RMS Norm to Hi at 09/13/96 09:49:00.967
09:49:01.8
09:49:02.0
-2000
09:49:02.2
SWELLS
Sudden change in load
 Line-to-ground fault on another phase
 Often precede a sag

SWELLS when Load Drops Off
750
500
Volts
250
0
-250
-500
-750
3000
2000
Amps
1000
0
-1000
-2000
-3000
14:44:04.20
CH A Vo lts
CH C A m ps
14:44:04.25
14:44:04.30
CH B Vo lts
CH D A m ps
14:44:04.35
CH C Vo lts
14:44:04.40
CH D Vo lts
14:44:04.45
CH A A m ps
14:44:04.50
CH B A m ps
Voltage Variations Sags/Swells
Possible Causes
 Possible Effects
• Sudden change in load current
• Process interruption
• Fault on feeder
• Data loss
• Fault on parallel feeder
• Data transmission errors
• PLC or computer misoperation
• Damaged Product
Magnitude & Duration Visualization
• CBEMA
• ITIC
• Equipment Susceptibility
• 3-D Mag-Dur
• DISDIP
IEEE 446 - 1995 Limits
Information Technology Industry Council (ITIC) Curve
Another Use of ITIC Curve
but vendor had tighter tolerances for outputs
Another Perspective – 3D Mag-Dur Histogram
Frequency
• Usually not the utility
• Sources of frequency problems
 Co-gen
 UPS
 Engine generator systems
• Clocks run fast
11 12 1
10
2
3
9
4
8
7 6 5
Harmonics
Event waveform/detail
Event waveform/detail
Amps
4
% o f FND
250
3
200
2
1
150
0
-1
100
-2
50
-3
11:19:27.84
11:19:27.86
11:19:27.88
11:19:27.90
CHD Amps
11:19:27.92
-4
11:19:27.94
0
Thd
H02
H04
H06
H08
H10
H12
CH D Amps
Waveform event at 10/14/93 11:19:27.75
Total RMS: 1.44 Amps
DC Level : -0.04 Amps
Fundamental(H1) RMS: 0.48 Amps
Total Harmonic Distortion (H02-H50): 246.72 % of FND
Even contribution (H02-H50):
73.96 % of FND
Odd contribution (H03-H49):
235.38 % of FND
Waveform event at 10/14/93 11:19:27.75
H14
H16
What is a harmonic?
An integer multiple of the
fundamental frequency
Fundamental (1st harmonic) = 60hz
2nd = 120hz
3rd = 180hz
4th = 240hz
5th = 300hz
…
Linear Voltage / Current
No Harmonic Content
voltage
current
Non-Linear Voltage / Current
Harmonic Content
voltage
current
NEC 1996: Non - Linear Load
"A load where the waveshape of the
steady-state current does not follow the
waveshape of the applied voltage."
voltage
current
Harmonics
Steady state distortion
Periodic or continuous in nature
 IEEE-519-1992 / US harmonics
 IEC 61000-3-2&3 European harmonic limits
Transformer Magnetizing Current
1.50
1.00
0.50
Amps
0.00
-0.50
-1.00
-1.50
0.02
0.03
0.05
Time (Sec)
0.07
0.08
Harmonic Measurements
Total Harmonic Distortion (THD)
 Ratio, expressed as % of sum of all harmonics to:
 Fundamental (THD)
 Total RMS
 Load Current (I TDD only)
Individual Harmonics
 2, 3, 4, 5, 6…50+
 Fourier Transform, FFT, DFT
Interharmonics
 Content between integer harmonics
Composite Waveform
Event waveform/detail
Vo lts
50000
40000
30000
20000
10000
0
-10000
-20000
-30000
-40000
-50000
05:35:31.26
05:35:31.28
05:35:31.30
05:35:31.32
05:35:31.34
CH A Vo lts
05:35:31.36
05:35:31.38
05:35:31.40
Harmonic Spectrum
Event waveform/detail
% o f FND
12.5
10.0
7.5
5.0
2.5
0.0
Thd
H05
H10
H15
H20
CH A Vo lts
T otal RMS: 24882.56 Volts
DC Lev el : 880.46 Volts
Fundamental(H1) RMS: 24725.89 Volts
T otal Harmonic Distortion (H02-H50):
10.60 % of FND
Ev en contribution (H02-H50):
7.97 % of FND
Odd contribution (H03-H49):
6.99 % of FND
H25
H30
PQ Rule
Even harmonics usually do not appear
in a properly operating power system.
Symmetry
Positive & Negative halves the same:
Only odd harmonics.
If they are different: Even & Odd
harmonics
Harmonics (sustained)
Possible Causes
• Rectified inputs of
power supplies
• Non-symmetrical current
• Intermittent electrical noise
from loose connections

Possible Effects
• Overload of neutral conductors
• Overload of power sources
• Low power factor
• Reduced ride-through
Electronic Loads Cause Excessive Neutral Currents
Electronic
Loads
Phase A (50 Amps)
Phase B (50 Amps)
Phase C (57 Amps)
Neutral (82 Amps)
Additive Triplen Harmonics
Equipment Susceptibility
 Least Susceptible
 Electrical Heating
 Oven
 Furnaces
 Most Susceptible
 Communications
 Data Processing
 Zero crossing Clock Circuits
 Transformers, Motors, other inductive loads
IEEE 519 Harmonic Limits
Limits depend on ratio of Short Circuit
Current (SCC) at PCC to average Load
Current of maximum demand over 1 year
For example,
 Isc/IL < 20, odd harm <11 = 4.0%
 Isc/IL 20<50, odd harm < 11 = 7.0%
 Isc/IL >1000, odd harm > 35 = 1.4%
IEEE 519 Harmonic Limits
 Voltage Harmonic Limits depend on Bus V
 For example,
 69Kv and below, ind. harm = 3.0%
 69Kv and below, THD= 5.0%
 161kv and above, ind.harm = 1.0%
 161kv and above, THD = 1.5%
Harmonics Demo Tool
150
100
50
0
-50
-100
-150
0
50
100
CH A
150
CH B
CH C
200
Neutral
250
Voltage Unbalance
 Several ways to calculate
 Small unbalance can cause motor
overheating (3% results in 10% derating)
 Caused by
 Unequal loading
 Unequal source impedance
 Unequal source voltage
 Unbalanced fault
Voltage Fluctuation
Voltage Fluctuation
 Amplitude variation 1-30 Hz
 Extent of light flicker depends on
 type of lights
 amplitude and frequency of variation
 person's perception
 Typical causes
 High current loads, like arc furnaces
 Windmill-generated power
Voltage Flicker
Timeplot
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
02/06/2002
02/08/2002
02/10/2002
02/12/2002
02/14/2002
02/16/2002
CHA VPst()
CHB VPst()
CHC VPst()
02/07/2002 00:05:00
02/18/2002
02/20/2002
How Many Can You Find?
Suggested References
[1] Electrical Power Systems Quality, R.C. Dugan et al, McGraw-Hill,
1996
[2] Handbook of Power Signatures, BMI, 2nd Edition, 1993
[3] IEEE Standard 1159-1995, IEEE Recommended Practice for
Monitoring Electric Power Quality
[4] IEEE Standard 519-1992, IEEE Recommended Practices and
Requirements for Harmonic Control in Electrical Power Systems
[5] IEEE Standard 1250-1995, IEEE Guide for Service to Equipment
Sensitive to Momentary Voltage Disturbances
[6] IEEE Standard 446-1995, IEEE Recommended Practice for
Emergency and Standby Power Systems for Industrial and
Commercial Applications
[7] IEEE Standard 142-1991, IEEE Recommended Practice for
Grounding of Industrial and Commercial Power Systems
[8] Federal Information Processing Standards Publication (FIPS PUB
94) Guideline on Electrical Power for ADP Installations
Case Study
Laser Printer
TIMEPLOT - LINE VOLTAGE vrs NEUTRAL-GND VOLTAGE
Vl-n= 120 --> 108
45 seconds
Vn-g = 0 --> 6V
SAG when heater turns on
V l-n
I load
V n-g
Overlay Waveforms - Heater turn on
Current Waveform - heater on
HARMONIC DISTORTION - heater on
2.3%
Harmonics V l-n
4.4%
Harmonics I load
Harmonics V n-g
Waveforms when heater turns off
V l-n
I load
V n-g
Harmonic Distortion - Idle
2.3%
Harmonics V l-n
94%
Harmonics I load
Harmonics V n-g
Current With Printer Idle
EQUIVALENT CIRCUIT
I Load
V Load
0.47 ohms
+
Source Impedance
10.4A @ 117V
0.6A @ 121V
121 Vac
Idle Load
202 ohms
+
V n-g
-
Heater Load
11.9 ohms
-
OBSERVATIONS and PARAMETERS

Nearly Sinusoidal Current
–

Low Harmonic Distortion (4%)
Voltage and Current In-phase
–
Power Factor Near One

Flat-topping of Voltage when Idle

Corresponds with Current Pulse
OBSERVATIONS and PARAMETERS
Line Voltage Negative Transient on Turn on
– Corresponds with Vn-g Positive Transient
 Nearly Constant Repetition Rate

SIMILAR SITUATIONS
• Coffee Pot
• Coke Machine
• Heat Pump
Monitoring, Measuring & Managing
High Reliability Facilities
Why Monitor Your Electrical Supply?
Paradigm Shift?
You may no longer be able to rely
on the utility to be your primary
source of power!
Be Prepared
Why Monitor Your Electrical Supply?
• Quality of supply is of paramount importance
• Huge investment in protection & mitigation is
not a guarantee!
• You have a high economic exposure
• Your facility is core to your business or maybe
is your business
• You already monitor other critical items
• Your electrical environment is just as important
• You need to balance your needs with available
supply
• Loading, cost allocation, etc
You May Already Monitor Your Facility
• Traditional Data Center
• Building Management Systems (BMS), Human
Machine Interface Software (HMI)
• Wonderware, Sitescan, ALC, Datatrax, etc
• Via Bacnet, Lonworks, Incomm, modbus, etc
• Internet Data Center
• Network Operations Center (NOC)
• HP Open View, etc
• Via SNMP
What You May Already Monitor
• Traditional Data Center
• UPS - On Bypass, other alarms
• Traditionally do not measure quality
• Sub Metering
• HVAC, Fire, Security
• Internet Data Center
• Network/System Health
• HVAC, Fire, Security
• Electrical Supply is often overlooked
• Quality of supply, Energy/cost allocation
• Power monitoring can interface with existing
systems for single point alarming, logging, etc…
Approaches to Power Monitoring
Reactive — Forensic, after the fact.
Proactive — Anticipate system dynamics
Be Proactive!
Reactive Approach
•
Problem Solving, hopefully you’ll find it!
•
Portable instrumentation typically used
Proactive Approach
•
Permanently installed monitoring systems
•
Anticipate the future – on-line when
trouble occurs
•
Monitor system dynamics
•
Preventive Maintenance, Trending, identify
equipment deterioration
Be Proactive!
Power Quality vs. Power Flow
• Power Quality Monitoring - Quality of Supply
• Monitor for harmful disturbances, harmonics, etc
Microsecond, Sub-Cycle Measurements
• In close accordance with IEEE 1159 & IEC
•
• Power Flow Monitoring - How much, cost, when & where?
• Energy & Demand, Measured over seconds
•
Be Careful! False sense of security
• Blind to common PQ problems
Use a PQ instrument for PQ monitoring!
Comprehensive Power Monitoring
• Combined Power Quality and Flow
•
Monitor PQ at critical locations
• Utility service, UPS, PDU’s, loads
• Energy provided along with PQ
•
Monitor Energy at less critical locations
& individual loads
• Loading
• Sub Metering
• Cost Allocation, etc…
Emerging Technologies
• Reduced Cost
• Web monitoring
• Networked systems
• Native web access
• Maximize Assets
• Sharing of information among systems
and groups within the organization
• Expert Systems
• Enterprise Systems
• Pull together various separate systems
Enterprise Systems
• Traditional Facilities
• Power monitoring system interfacing with
building management, HMI or other systems
• Notification, metering, trending
• OPC. Modbus, e-mail
• Internet Data Center
• Interface with Network Operations Center (NOC)
• Notification, metering, trending
• Simple Network Management Protocol (SNMP)
Expert Systems
• Reduced budgets means less people!
• Less expertise
• Analysis of Data in order to Identify Problems
• Automatic, no user intervention, results
embedded in data
• Identify certain disturbances and directivity.
• Upstream or downstream
• Answers Questions Such As…
• Was that Sag from the utility or within my facility?
Expert Systems
• UPS Performance Verification
• Correlation of Input vs. Output
• Verify continued performance over time
• Proactively identify downstream problems
• Monitor UPS status via analog/contact inputs
• Remotely access UPS status signals
• Compare recorded data to UPS status
Expert Systems
Expert Systems
Automatically Identifies the Transient as a Capacitor Switching
Operation
Where To Monitor?
• Utility Service Entrance
• Evaluate your energy provider
• Monitor redundant feeds
• UPS Output
• Is your UPS working as designed?
• Evaluates critical bus as problems could be
downstream
• PDU/Distribution
• Provides the ability to identify the source of a
problem. Why did that breaker trip?
• Loading/Cost allocation
• Actual loads
Case Study
DHL Airways Call Center
• Tempe AZ
• Services DHL customers nationwide
• Newly Constructed, went online in June 2000
• Toshiba 7000 Series UPS
• Three 300KVA parallel redundant units
• Facility manager has nationwide responsibilities
• Current Expansion Plans
DHL Objectives
• Benchmark performance
• Ensure future reliability
• Easily troubleshoot any problems that may occur
• Automatic notification
• Remotely monitor over DHL network
• Since the facility is new and due to its critical
nature, monitoring approach was very proactive
DHL Monitoring System
• Monitoring Points
• UPS Input (Utility Supply)
• UPS Output (Critical bus)
• Connected to DHL Intranet
• Dial-up modem connection
• Web browser access from anywhere within DHL
• Automatic E-mail notification
• Web browser access from anywhere with a dial-up
connection
Known Problems?
• None!
• Facility operating as planned
• No Outages or other major
problems identified
• No UPS Alarms
Utility Supply
50+ Disturbances in the first few months
UPS Output
No disturbances
Utility Monitoring Summary
• Uncovered problems with the utility supply
• 50+ disturbances recorded over a 2 month period.
• Sags, transients, waveshape distortion
• Results reported to the utility, they did not know
• Utility investigation
• Faulty relay caused the majority of the
disturbances. Corrected
UPS Output Monitoring Summary
• No disturbances on the conditioned UPS output
• Output regulated to within manufacturers
specifications
• UPS mitigated many disturbances on the utility feed
• Did what they paid for
• Justified the investment
Conclusion
• Being proactive uncovered problems with the utility
supply that required correction
• Continuous monitoring proved power conditioning
equipment worked as design and to manufacturer’s
specifications. Protected loads were unaffected
• Provided justification to management for power
monitoring systems at other key facilities
• Load profiling helping to determine power requirements
of a planned expansion
Case Study
Major Financial Institution
• New York City
• Worldwide company with several facilities in NY
& NJ
• 3 UPS Modules
•2 static, 1 rotary
Problem
• Utility Sag
• Damaged elevator controls
• No UPS alarms
• No reported problems with critical systems
02/19/2002
00:29:29.26
PMODULE
INPUT
Temporary
Sag
Rms Voltage
AB
Mag = 366.V (0.76pu), Dur = 3.300 s, Category = 2,
Upstream Sag
02/19/2002
00:29:29.26
SYSA Input
Temporary
Sag
Rms Voltage
AB
Mag = 353.V (0.73pu), Dur = 3.300 s, Category = 2,
Upstream Sag
02/19/2002
00:29:29.26
SYSB Input
Temporary
Sag
Rms Voltage
AB
Mag = 372.V (0.78pu), Dur = 3.300 s, Category = 2,
Upstream Sag
Utility Sag
Utility Supply RMS Trend
Utility Supply Waveforms
Corresponding UPS Swell
Utility Supply
UPS Swell
UPS Output
Conclusion
• Utility sags damaged elevator controls.
• Corresponding UPS Swell coincident with Utility return
to normal.
• Cause of Swell being investigated…
• Possible effects of Swells:
• Damaged power supplies and other devices.
• Without monitoring would have never seen this. The
next time it could be worse.
Case Study
Federal Aviation Administration
Air Route Traffic Control Center
(ARTCC)
Monitoring System
Simplified Air Traffic Flow
ARTCC
ARTCC
TRACON
ARTCC
TRACON
Tower
Tower
Your Flight
FAA’s Objectives
• Monitor critical points throughout each ARTCC
• Determine present status of each ARTCC Facility
• Is the electrical supply operating within design
parameters?
• Catch problems before they occur
• Change approach from Reactive to Proactive
• Correlate power quality to status indicators, panel
meters, transfer switch positions, etc
FAA’s Objectives
• Benchmark long term performance in order to
improve reliability
• Compare measured parameters to simulations
• Have web browser access from anywhere within the
FAA system
• Local ARTCC personnel
• OKC Airway Operational Support (AOS) personnel
Monitoring System
• Monitor 15 points for quality of supply & energy
• Utility Service
• Generators
• UPS’s
• Key distribution points
• Critical Power Centers
• In parallel monitor other data such as
• Transfer switch & breaker positions
• Panel meters
• Misc indicators
• Web based access to each site via intranet
Initial Results
• Key points operating out of design specs
• Ex: Adjust transformer taps
• Routine maintenance not always performed
as per procedures
• Wiring inconsistent with drawings
Power Quality Fundamentals and Monitoring
Thank You!
Questions?
Ross M. Ignall
Systems Applications Manager,
Dranetz-BMI
[email protected]