Research Activities of University of
South Carolina: Joint Time-Frequency
Domain Reflectometry (JTFDR)
Speaker: Dr. Yong-June Shin
GRA: Dr. Jingjiang Wang, Mr. David Coats
Department of Electrical Engineering
University of South Carolina
IAEA CRP Kickoff Meeting
Knoxville, TN
August 2, 2011
2
Outline of Presentation
• Introduction of PI and Project • Motivations of Advanced Wiring Diagnostics
1) General Motivations 2) Concepts of Reflectometry (TDR, FDR, and JTFDR Compared)
• Health Monitoring of Electric Cable 1) Acquisition of Cable Samples 2) Monitoring of Accelerated Aging 3) Comparison of Proposed Technique with Existing Methods
(Japanese Nuclear Energy Safety Organization) 4) Recommendation of Life Cycle Determination of Operating
Cables
• Conclusions 1) Acknowledgements 2) List of Publications 3) Future Work
3
Introduction of PI
Dr. Yong-June Shin
Assistant Professor (2004) Associate Professor (2011)
Power and Energy Systems Group
Department of Electrical Engineering University of South Carolina- Columbia
• Education PhD. UT Austin (2004)* M.S. Univ. of Michigan, Ann Arbor (1997) B.S. Yonsei University, Seoul, Korea (1996) * Leave of absence to fulfill military service obligation in ROK (05/2001-
01/2003)
• Honors NSF CAREER Award (2008) GE Scholarship (1995-1996) Early Completion Honor (Yonsei Univ.)
• Research Areas Power Systems Engineering Instrumentation and Measurement Applied Signal Processing
4
Research Portfolio: Power IT
• Cable Diagnostics/Prognostics • SMART Grid
TFDR (Time-Frequency Domain)
Diagnostics/ Prognostics
Sponsor: NSF CAREER,
NASA, US NRC
Collaborator:
EPRI, Prysmian Cable, NRL
ONR ESRDC (Electric Ship Research & Development Consortium)
Virtual Test Bed (VTB)
ONR (Office of Naval Research)
PI: Dr. Roger Dougal (USC)
FSU, UT Austin, MSU, Purdue, MIT
Synchrophasor (PMU) &
Power Quality in Smart Grid
Santee Cooper Electric
NSF I/UCRC (AEP, SPP, NREL)
with Univ. of Arkansas
• SMART Electric Ship
5
Research Portfolio: Interdisciplinary Research
• Aging Aircraft Condition Based Maintenance
- Funding: DoD/ US Army, SC National Guard
- Collaborator: Dr. A. Bayoumi (USC ME)
Condition Based Maintenance Research Center
• Structural Health Monitoring
Piezoelectric Wave Active Sensor
- Funding: US AFSRO, NSF, NRC
- Collaborator: Dr. Victor Giurgiutsu
(USC ME/AFSRO)
•Shin et. al, “Applications of Time-Frequency Information Measure for Condition Based
Maintenance of Helicopter Power Trains,” to appear in IEEE Transactions on
Instrumentation and Measurement, 2011.
unbalance misalignment
unbalance
misalignment I unbalance
misalignment II
•Shin et. al, “Corrosion Detection with Piezoelectric Wafer Active Sensors using
Pitch-Catch Waves and Cross Time-Frequency Analysis,” ASME International
Mechanical Engineering Congress & Exposition, November 2009.
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Introduction: Power IT LAB members
Dr. Philip Crapse (Stone) Dr. Jingjiang Wang Mr. Md Moinul Islam
PhD Candidate
Mr. David Coats
PhD Candidate
(NSF GRFP)
Mr. Patrick Mitchelle
PhD Candidate
(Outstanding Senior)
Mr. Mohammed Hassan
PhD Candidate
(Egyptian Government
Scholarship)
Mr. Ryan Lukens
MS Candidate
Mr. Hossein Mohammadpour
PhD Candidate
Incoming Students (Aug 2011): Cuong Nguyen, Qui Deng, Amin Ghaderi
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Selected Publications • J. Wang, Philip Stone, David Coats, Y.J. Shin, and Roger Dougal, “Health Monitoring of Power
Cable via Joint Time-Frequency Domain Reflectometry,” IEEE Transactions on Instrumentation and Measurement, Vol. 60, No. 3, pp. 1047-1053, Mar. 2011.
• Jingjiang Wang, Philip Crapse Stone, Yong-June Shin, and Roger Dougal, “Diagnostics and Prognostics of XLPE and EPR Cables via Joint Time-Frequency Domain Reflectometry,” IET Signal Processing, Special Issue on Time-Frequency Approach to Radar Detection, Imaging, and Classification, Vol. 4, No. 4, pp. 395-405.
• David Coats, Jingjiang Wang, Yong-June Shin, Thomas Koshy, “Applications of Joint Time-Frequency Domain Reflectometry for Health Assessment of Cable Insulation Integrity in Nuclear Power Plants,” Proceedings of the 7th International Topical Meeting on Nuclear Plant Instrumentation, Control and Human Machine Interface Technologies (NPIC&HMIT 2010), November, 2010.
• Jingjiang Wang, David Coats, Yong-June Shin, Thomas Koshy, “Applications of Joint Time-Frequency Domain Reflectometry for Health Assessment of Cable Insulation Integrity in Nuclear Power Plants,” International Symposium on the Ageing Management and Maintenance of Nuclear Power Plants (ISaG), Tokyo University, Tokyo, Japan, May 2010.
• “Diagnostics and Prognostics of Electric Power Cables in Aging Nuclear Power Plants,” Korea Institute of Nuclear Safety, Taejon, Korea, June 30, 2010. (Invited Presentation)
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Relevant Research Grants
• National Science Foundation, “CAREER: Diagnostics and Prognostics of Electric Cables in Aging Power Infrastructures,” PI: Dr. Yong-June Shin, $377,000, 2008-2013.
• US Nuclear Regulatory Commission (NRC), “Diagnostics and Prognostics of Aging Electric Cables in Nuclear Power Plants via Joint Time-Frequency Domain Reflectometry,” PI: Dr. Yong-June Shin, Co-PI: Dr. Roger Dougal, $170,000, 2009-2011.
• NASA EPSCoR Space Grant Research Grant Program, “Diagnostics & Treatment of Electric Wiring Systems in Aging Aircraft,” PI: Dr. Yong-June Shin, Co-PIs: Dr. Roger Dougal, $60,000, 01/2005-05/2006.
• US Nuclear Regulatory Commission (NRC), “Ultrasonic Guided Wave Sensor for Gas Accumulation Detection in Nuclear Emergency Core Cooling Systems,” PI: Dr. Yong-June Shin, Co-PI: Dr. Lingyu Yu, $300,000, 09/2010- 08/2012.
• US Nuclear Regulatory Commission (NRC), “Condition Assessment and Predictive Maintenance of Aging High Voltage Electric Power Cables in Nuclear Power Plants,” PI: Dr. Yong-June Shin, $200,000, 2011-2013. (Pending)
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Outline of Presentation
• Introduction of PI and Project • Motivations of Advanced Wiring Diagnostics
1) General Motivations 2) Concepts of Reflectometry (TDR, FDR, and JTFDR Compared)
• Health Monitoring of Electric Cable 1) Acquisition of Cable Samples 2) Monitoring of Accelerated Aging 3) Comparison of Proposed Technique with Existing Methods
(Japanese Nuclear Energy Safety Organization) 4) Recommendation of Life Cycle Determination of Operating
Cables
• Conclusions 1) Acknowledgements 2) List of Publications 3) Future Work
10
*LOCA Failure in Nuclear Reactor
• An effective, viable condition monitoring technique for installed
cable systems in nuclear reactor is needed to detect and locate
defects before they result in failures.
*LOCA : Loss of Coolant Accident
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Radiation
Thermal
Electrical
Mechanical
Moisture
Water Tree Phenomena
Typical Sources of Cable Aging
Critical Sources of Cable Aging in Nuclear Systems
12
Present State-of-the-Art Techniques
• Mechanical – Elongation-At-Break, Compressive Modulus
• Chemical – Oxidation Induction Time
• Electrical – Dielectric loss measurements
– Voltage withstand test
– Partial discharge testing
– Reflectometry (TDR, FDR,
JTFDR)
13
Technical Needs from the US NRC*
• The “BIS method was not sensitive enough to distinguish between the different severities and
size of hot-spots.” (A sensitive detection is required.)
• “Research on the detection and location of cracking damage in cables using more realistic
simulation of the cracking damage…” (An accurate location is also required.)
• “The technique should be demonstrated on additional types of cable to determine its
usefulness for other materials and cable configurations…” (A diverse feature is required.)
• “The technique should be evaluated with different types of loads attached to the cables to
determine the impact of loads encountered in a plant environment…. The technique should be
demonstrated in an actual plant environment to determine the impact of the various
environmental factors.” (A robust diagnostic algorithm is required.)
• “The technique should be demonstrated on blind test samples in which the type, severity, size,
and location of the degradation are unknown.” (Prognostics of aging cable is required.)
* D. Rogovin, R. Lofaro, "Evaluation of the Broadband Impedance Spectroscopy Prognostic/Diagnostic Technique for Electric Cables
Used in Nuclear Power Plants," U.S Nuclear Regulatory Commission, Office of Nuclear Regulatory Research, Washington, DC 2006.
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Principles/Mission of Reflectometry
Fault detection, localization and impedance measurement by TDR
15 15
Problems with TDR
1. Detection
2. Localization
3. Measurement
4. DC Charging
5. Multiple Reflections
16 16
COTS products (FDR) 5. Anritsu™ Sitemaster S251C
Microwave Cable Fault
Locator FDR
•Frequency domain information is transferred via IDFT
for DTF (Distance to Fault) calculation
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Concepts of Reflectometry
Health Monitoring of Electric Cable using TDR, FDR, and JTFDR
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Experimental Equipment and Setup
Signal Generation and
Acquisition Setup Accelerated Aging Test
Heat Chamber
AWG
Oscilloscope
PC
Optimal
Reference Amplified
Signal Cable Through
Port (x2)
Heating
Controller
Local peak
at the reflection
“Hot spot”
Aging Process of XLPE Cable
Peak
at the cable end
System Function Diagram
Incipient
Defect
Amplifier
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TDR/FDR in Coaxial Control Cable
Agilnet™ 86100B Infiniium Oscilloscope
with 54754A differential TDR modules. Anritsu™ Sitemaster S251C
TDR FDR
Cable Type: RG-58
Cable Length: 15 m
Defect Location: 10 m
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JTFDR
'),'(),'(2
)( dtdttWtWEE
tC sr
rs
sr
dtdtWE ss ),(
dtdtWE rr ),(
)(2/)(2/)(4/1 002
02
0)/()(ttjttjtt
ets
Incident Signal:
detststW j
)2
1()
2
1(
2
1),( *
Wigner-Ville Time-Frequency Distribution:
Time-Frequency Cross-Correlation:
Expected Defect
Reflected signal
Parameters of reference
• f0: 450 MHz,
• B: 100 MHz,
• T : 50 ns.
Cable Type: RG-58
Cable Length: 15 m
Defect Location: 10 m
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Time- Frequency Domain Reflectometry
Time-Frequency descriptions of a reference signal Ws(t,ω), a delayed version of
the reference signal Ws(t - td,ω), and the actual propagated signal Wu(x)(t, ω)
through a lossy media to evaluate time delay via time offset and frequency offset
22
Concept of Diagnostics and Prognostics
23
Outline of Presentation
• Introduction of PI and Project • Motivations of Advanced Wiring Diagnostics
1) General Motivations 2) Concepts of Reflectometry (TDR, FDR, and JTFDR Compared)
• Health Monitoring of Electric Cable 1) Acquisition of Cable Samples 2) Monitoring of Accelerated Aging 3) Comparison of Proposed Technique with Existing Methods
(Japanese Nuclear Energy Safety Organization) 4) Recommendation of Life Cycle Determination of Operating
Cables
• Conclusions 1) Acknowledgements 2) List of Publications 3) Future Work
24
Diagnostic: Defect Detection and Location
• Cable Sample – Length: 10 meter – Type: Rockbestos Firewall III,
14 AWG, 2 conductors, 600 V, XLPE Insulated
• Defect – Size: Removal of 0.25 in. of
outer insulation around half the circumference
– Actual Location: 5.5 meters
• Results – Detected Location: 5.43 meters
Parameters of reference signal:
Center frequency - 125 MHz
Bandwidth - 50 MHz
Time duration - 50 ns.
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Acquisition and Accelerated Thermal Aging Test of Cables
)]11
([as
a
TTB
E
a
s et
t
Arrhenius
Equation
Simulated Service Temperature
Simulated Service Life
Accelerated Aging Temperature
Accelerated Aging Duration
Insulation Type Manufacturer, Type,
and Level Activation
Energy (eV) Temperature
(˚C) Experimental Duration (Hr)
Cross-linked polyethylene (XLPE)
Rockbestos, Firewall III XHHW , 600V
1.33 140 24
Ethylene Propylene Rubber (EPR)
Nexans, MIL-DTL-24640 TXW-4, 600V
1.1 160 48
Silicon Rubber (SIR)
Nexans, LSTSGU-9: M24643/16-03UN, 600V
2.1 120 12
Summary of Cable Information and Experimental Duration
1. “Time to breakdown” Useful for predicting the
cable life expectancy
2. “Preset time” Useful for comparative
performance of different types of material
26
Aging Process of XLPE Insulated Cable
Simulated Service: Temperature: 50 °C Life: 120 years
Accelerated Aging : Temperature: 140 °C Time: 32 hours
10 20 30 40 50 60 70 80 90 100 110 120
30
40
50
60
70
80
90
100
Years
Lif
e F
racti
on
(%
)
27
Aging Process of EPR Insulated Cable
Simulated Service: Temperature: 50 °C Life: 120 years
Accelerated Aging : Temperature: 160 °C Time: 48 hours
10 20 30 40 50 60 70 80 90 100 110 120
40
50
60
70
80
90
100
Years
Lif
e F
racti
on
(%
)
28
Aging Process of SIR Insulated Cable
Simulated Service: Temperature: 50 °C Life: 120 years
Accelerated Aging : Temperature: 120 °C Time: 12 hours
10 20 30 40 50 60 70 80 90 100 110 12075
80
85
90
95
100
Years
Lif
e F
racti
on
(%
)
29
Comparable Methods: EAB (Elongation-at-Break)
• EAB (Elongation-at-Break) – is a measure of a material's resistance to fracture
under an applied tensile stress (ductility)
– is defined as the percent increase in elongation at the time of fracture
– cable insulation losses ductility as they age
– classical technique and widely accepted as a reference in evaluating other techniques
– destructive and large amounts of cable sample
30
Comparison of JTFDR and EAB
Adopted from, Japan Nuclear
Energy Safety Organization Safety
Standard Division, \The Interim
Report of The project of
Assessment of Cable Aging for
Nuclear Power Plants," JNES-SS-
0619, Dec. 2006.
XLPE EPR
SIR
Adopted from, Japan Nuclear Energy Safety Organization Safety Standard Division, “The Interim Report of The project of
“Assessment of Cable Aging for Nuclear Power Plants”,” JNES-SS-0619, Dec. 2006.
31
Proposed Concept
“Assessing and Managing Cable Ageing in Nuclear Power Plants,”
IAEA Nuclear Energy Series Report, January 2011.
32
Comparison of XLPE, EPR and SIR by Estimated Life Fraction/Peaks
Multi-stage deterioration,
poor mechanical strength
Better certification
life performance
Better extended
life performance
33
Outline of Presentation
• Introduction of PI and Project • Motivations of Advanced Wiring Diagnostics
1) General Motivations 2) Concepts of Reflectometry (TDR, FDR, and JTFDR Compared)
• Health Monitoring of Electric Cable 1) Acquisition of Cable Samples 2) Monitoring of Accelerated Aging 3) Comparison of Proposed Technique with Existing Methods
(Japanese Nuclear Energy Safety Organization) 4) Recommendation of Life Cycle Determination of Operating
Cables
• Conclusions 1) Acknowledgements 2) List of Publications 3) Future Work
34
Conclusions
• JTFDR is a hybrid-type reflectometry which provides many of the benefits of TDR while also offering benefits of FDR.
• The cross-correlation peaks of JTFDR could be implemented in prognostic curves while distance-fault can be estimated from peak locations.
• Efficacy of JTFDR for prognostics in XLPE, EPR, and SIR insulation
35
Proposed Tasks for IAEA CRP
Task 1: Acquisition of Cable Sample
Task 2: Monitoring of the Accelerated Aging Test
Task 3: Comparison of Proposed Technique With Other Techniques
Task 4: Recommendation of Life Cycle Determination of Operating Cables
Task 5: Implementation of CBM Sensors
Task 6. Documentation and Publication
36
Future Work – Three Paths
1) Analysis of LOCA on Cable
– Perform more in-depth aging procedures (longer preset time, time to break-down, environmental and LOCA tests).
– Extend the JTFDR metric to additional cable types (both control/instrumentation level and transmission level).
37
Future Work – Three Paths
1) Experiments for LOCA
– Example steam exposure test facility courtesy of JNES for tests similar to IEEE 323 and 383
Adopted from, Japan Nuclear Energy Safety Organization Safety Standard Division, “Advanced Environmental
Qualification Test and Condition-based Environmental Qualification for Cables”,” JNES-SS-0619, Nov. 2010.
38
Future Work – Three Paths
2) High Voltage Tests and Partial Discharge
a. Acquisition of high voltage very low
frequency VLF hipots test equipment and
measurement system.
b. Acquisition of high voltage (HV) cable
samples.
c. Design of optimal parameters of the
reference signal in JTFDR for HV cable.
d. Expanded capability in water-related aging
emulation
e. Further validation of JTFDR via
comparison with other techniques such
as partial discharge
39
Future Work – Three Paths
3) Implementing JTFDR Method
– Obtain and compare lifetime aged cables to accelerated aging samples to develop health prognostic curves.
– Develop a prototype sensor for online monitoring with goals of:
• Periodic in-situ monitoring
• Wireless transmission of health data to processing unit
40
Proposed Concept
“Assessing and Managing Cable Ageing in Nuclear Power Plants,”
IAEA Nuclear Energy Series Report, January 2011.
41
Comparison of XLPE, EPR and SIR by Estimated Life Fraction/Peaks
Multi-stage deterioration,
poor mechanical strength
Better certification
life performance
Better extended
life performance
42
Thank you for your attention!
Questions?
46
Motivations for Advanced Wiring Diagnostics
Nuclear energy forms greater than 14.7% of world generation* and 19.6% of US generation
*US Energy Information Administration statistics updated Jan. 2010