7.joint time frequency domain young

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.

6

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

7

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)

8

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)

9






Cables


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

11

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.

14

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

17

Concepts of Reflectometry

Health Monitoring of Electric Cable using TDR, FDR, and JTFDR

18

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

19

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

20

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

21

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






Cables


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.

25

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



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



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






Cables


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


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


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


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

7.joint time frequency domain young

Documents

poor mechanical strength

nuclear regulatory commission

life cycle determination

nuclear power plants

electrical engineering university

certification life performance

reference signal ws

managing cable ageing