1. Power Quality Fundamentals and Monitoring
Ross M. Ignall
Systems Applications Manager, Dranetz-BMI

2. What We Will Cover… Defining Power Quality and Reliability
PQ References & Fundamentals
Monitoring, Measuring High Reliability Facilities
Case Studies

3. WPT Power Monitoring Hardware Devices Data Acquisition Devices
measure and monitor power
Aggregation of Distributed Generation
load curtailment of power sales
Data Acquisition Devices
measures physical processes
Software and Consulting Services
power quality and distributed generation

4. Defining Power Quality & Reliability

5. 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.”

6. It’s dependant on your susceptibility.
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.

7. What is my susceptibility to power problems?
What You Should Be Asking…
What is my susceptibility to power problems?
What is my economic exposure to such problems?
$$$$

8. Types Of Power Quality Problems

9. Customer’s Perspective*
Who’s Problem Is It?
Customer’s Perspective*
* Georgia Power Survey

10. Who’s Problem Is It?
Utility Perspective*
* Georgia Power Survey

11. electrical environment,
The Big Picture
It’s the complete
electrical environment,
not just the
quality of supply

12. What You Should Be Asking…
Does my power system have the capacity for my present needs?
How about future growth?
Be Proactive!

13. 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

14. Some Factoids

15. 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

16. …The data center houses 45,000 square-feet of computer floor space
…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

17. Power Density Factoids
Traditional data center or large office building – W/sq. ft., Internet Data Center, on-line brokers, web hosts – 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

18. Costly Downtime!
Industry Avg cost of downtime ($/hr) Brokerage $6,450,000 Credit Card $2,600,000 Pay Per View $150,000 Home Shopping $113,000 Catalog Sales $90,000 Airline Reservations $90,000 Tele-Ticket $69,000 Package Shipping $28,000 ATM Fees $14, Source: 7x24 Exchange

19. Introduction to Power Quality

20. Power Grid Review GENERATOR 13.8kV-24kV L O A D DISTRIBUTION
34.5k-138kV
4k-34.5kV
12,470Y/7200V
GENERATOR
13.8kV-24kV
CONSUMER
4160Y/2400
480Y/277V
208Y/120V
240/120V
TRANSMISSION
115k-765kV

21. Generation 50/60hz ‘Pure’ Sine Wave Various Voltages Types Chemical
Mechanical
Nuclear
Solar

22. Transmission Those big towers Voltage High Current Small
Efficiency of Transmission
Power Delivered to the Load
Power Supplied From Generator

23. Distribution Typically 13kV
Commercial/Industrial - Three Phase, 480/277V
Residential - Split Phase
480V
13kV
480V
480V

24. Single Phase Circuit DiagramIs
V line L O A D Vn

25. 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!”

26. ACTUAL SINGLE PHASE CIRCUIT DIAGRAMIs
Vpcc
Vdp
V line L O A D
L1 R1
L2 R2
l n2
I n1 Vn
L3 R3
L4 R4 Vg
L5 R5
L6 R6
I g2
l g1

27. 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

28. Power Quality References & Terms

29. 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

30. IEEE Standard 1159-1995 Definition of Terms Monitoring Objectives
Instruments
Applications
Thresholds
Interpreting Results

31. IEEE 1159 1159.x Task Force 1159.3 Task Force
Data Acquisition & Recorder Requirements for
Combination of &
Coordination with IEC standards ( and revisions)
New recommended practice to be developed by July 2001
Task Force
Power Quality Data Interchange Format (PQDIF)
Format for the exchange of PQ and other information between applications
Developed by Electrotek Concepts

32. IEEE 519-1992 Recommended Practice For Harmonics
Recommends Limits at the PCC
Voltage Harmonics
Current Harmonics
Ongoing work to modify IEEE
Limits for within a facility
Frequency dependant

33. 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 low-frequency 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

34. 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

35. 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

36. Transients Unipolar Oscillatory Bipolar Notching Positive Negative
200
100
-100
-200
Negative
Multiple Zero Crossings

37.  Transients Possible Effects Possible Causes • Data corruption
• Equipment damage
• Data transmission errors
• Intermittent equipment operation
• Reduced equipment life
• Irreproducible problems
Possible Causes
• PF cap energization
• Lightning
• Loose connection
• Load or source switching
• RF burst 

38. Power Factor Correction Capacitor Transient
A transient power quality event has occurred on DataNode H09_ The event occurred at :03:36 on phase A. Characteristics were Mag = 478.V (1.22pu), Max Deviation (Peak-to-Peak) = 271.V (0.69pu), Dur = s (0.35 cyc.), Frequency = 1,568. Hz, Category = 3 Upstream Capacitor Switching

39. RMS Voltage Variations
Instantaneous ( cycles)
Sag ( pu)
Swell ( pu)
Momentary (30 cycles - 3 sec)
Interruption (< 0.1 pu, 0.5 cycles - 3s)
Sag
Swell
Temporary (3 sec - 1 minute)

40. RMS Voltage Variations
-200
-150
-100
-50 50
100
150
200
Sag
Swell
Interruption

41. 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

42. PQ Rule
For a source generated Sag, the current usually decreases or goes to zero

43. PQ Rule
For a source generated Sag, the current usually decreases or goes to zero

44. SAG LOAD GENERATED DURATION type & size of load MAGNITUDE LOAD CURRENT
usually single event per device
MAGNITUDE
wiring & source impedance
LOAD CURRENT
usually significantly higher

45. For a load generated Sag, the current usually increases significantly.
PQ Rule
For a load generated Sag, the current usually increases significantly.

46. Motor Starting - Another Cause of Sags

47. Motor Starting – Inrush Current with decay

48. SWELLS Sudden change in load Line-to-ground fault on another phase
Often precede a sag

49. SWELLS when Load Drops Off

50. Voltage Variations Sags/Swells
Possible Causes
• Sudden change in load current
• Fault on feeder
• Fault on parallel feeder
Possible Effects
• Process interruption
• Data loss
• Data transmission errors
• PLC or computer misoperation
• Damaged Product

51. Magnitude & Duration Visualization
CBEMA
ITIC
Equipment Susceptibility
3-D Mag-Dur
DISDIP

52. IEEE Limits

53. Information Technology Industry Council (ITIC) Curve

54. Another Use of ITIC Curve
but vendor had tighter tolerances for outputs

55. Another Perspective – 3D Mag-Dur Histogram

56. Frequency Usually not the utility Sources of frequency problems
Co-gen
UPS
Engine generator systems
Clocks run fast 1 12 2 3 4 5 6 7 8 9 10 11

57. Harmonics

58. What is a harmonic? An integer multiple of the fundamental frequency
Fundamental (1st harmonic) = 60hz
2nd = 120hz
3rd = 180hz
4th = 240hz
5th = 300hz …

59. Linear Voltage / Current No Harmonic Content

60. Non-Linear Voltage / Current Harmonic Content

61. 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

62. Harmonics Steady state distortion Periodic or continuous in nature
IEEE / US harmonics
IEC &3 European harmonic limits

63. 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

64. Composite Waveform

65. Harmonic Spectrum

66. PQ Rule Symmetry Positive & Negative halves the same:
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

67. 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 

68. Electronic Loads Cause Excessive Neutral Currents
Phase A (50 Amps)
Phase B (50 Amps)
Phase C (57 Amps)
Neutral (82 Amps)

69. Additive Triplen Harmonics

70. Equipment Susceptibility
Least Susceptible
Electrical Heating
Oven
Furnaces
Most Susceptible
Communications
Data Processing
Zero crossing Clock Circuits
Transformers, Motors, other inductive loads

71. 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%

72. 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%

73. Harmonics Demo Tool

74. 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

75. Voltage Fluctuation

76. 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

77. Voltage Flicker

78. How Many Can You Find?

80. Case Study
Laser Printer

81. TIMEPLOT - LINE VOLTAGE vrs NEUTRAL-GND VOLTAGE
Vl-n= > 108
45 seconds
Vn-g = 0 --> 6V

82. SAG when heater turns on
V l-n
I load
V n-g

83. Overlay Waveforms - Heater turn on

84. Current Waveform - heater on

85. HARMONIC DISTORTION - heater on
2.3%
Harmonics V l-n
4.4%
Harmonics I load
Harmonics V n-g

86. Waveforms when heater turns off
V l-n
I load
V n-g

87. Harmonic Distortion - Idle
2.3%
Harmonics V l-n
94%
Harmonics I load
Harmonics V n-g

88. Current With Printer Idle

89. EQUIVALENT CIRCUIT I Load V Load + - + - 0.6A @ 121V 10.4A @ 117V
0.47 ohms +
Source Impedance
121V
117V
121 Vac
Idle Load
202 ohms
Heater Load
11.9 ohms - +
V n-g -

90. 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

91. OBSERVATIONS and PARAMETERS
Line Voltage Negative Transient on Turn on
Corresponds with Vn-g Positive Transient
Nearly Constant Repetition Rate

92. SIMILAR SITUATIONS
Coffee Pot
Coke Machine
Heat Pump

93. Monitoring, Measuring & Managing High Reliability Facilities

94. Why Monitor Your Electrical Supply?

96. Paradigm Shift?
You may no longer be able to rely on the utility to be your primary source of power!
Be Prepared

97. 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

98. 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

99. 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
Electrical Supply is often overlooked
Quality of supply, Energy/cost allocation
Power monitoring can interface with existing systems for single point alarming, logging, etc…

100. Reactive — Forensic, after the fact.
Approaches to Power Monitoring
Reactive — Forensic, after the fact.
Proactive — Anticipate system dynamics
Be Proactive!

101. Reactive Approach
Problem Solving, hopefully you’ll find it!
Portable instrumentation typically used

102. Permanently installed monitoring systems
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!

103. Use a PQ instrument for PQ monitoring!
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!

104. 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…

105. 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

106. Enterprise Systems
Traditional Facilities
Power monitoring system interfacing with building management, HMI or other systems
Notification, metering, trending
OPC. Modbus,
Internet Data Center
Interface with Network Operations Center (NOC)
Simple Network Management Protocol (SNMP)

107. 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?

108. 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

109. Expert Systems

110. Expert Systems
Automatically Identifies the Transient as a Capacitor Switching Operation

111. Where To Monitor? UPS Output Is your UPS working as designed?
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

113. Case Study

114. 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

115. 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

116. 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 notification
Web browser access from anywhere with a dial-up connection

118. Known Problems? None! Facility operating as planned
No Outages or other major problems identified
No UPS Alarms

119. 50+ Disturbances in the first few months
Utility Supply
50+ Disturbances in the first few months

120. UPS Output
No disturbances

121. 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

122. 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

123. 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

124. Case Study

125. Major Financial Institution
New York City
Worldwide company with several facilities in NY & NJ
3 UPS Modules
2 static, 1 rotary

126. Problem Utility Sag Damaged elevator controls No UPS alarms
No reported problems with critical systems
02/19/ :29:29.26
PMODULE
INPUT
Temporary Sag
Rms Voltage AB
Mag = 366.V (0.76pu), Dur = s, Category = 2, Upstream Sag
SYSA Input
Mag = 353.V (0.73pu), Dur = s, Category = 2, Upstream Sag
SYSB Input
Mag = 372.V (0.78pu), Dur = s, Category = 2, Upstream Sag

127. Utility Sag
Utility Supply RMS Trend
Utility Supply Waveforms

128. Corresponding UPS Swell
Utility Supply
UPS Swell
UPS Output

129. 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.

130. Case Study

131. Air Route Traffic Control Center (ARTCC) Monitoring System
Federal Aviation Administration
Air Route Traffic Control Center (ARTCC) Monitoring System

132. Simplified Air Traffic Flow
ARTCC
ARTCC
ARTCC
TRACON
TRACON
Tower
Tower
Your Flight

133. 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

134. 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

135. 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

136. 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

137. Thank You! Questions? Power Quality Fundamentals and Monitoring
Ross M. Ignall
Systems Applications Manager, Dranetz-BMI