risk based maintenance scheduling of circuit breakers using condition-based data
DESCRIPTION
PS. ERC. Risk Based Maintenance Scheduling of Circuit Breakers using Condition-Based Data. Satish Natti Graduate Student, TAMU Advisor: Dr. Mladen Kezunovic. Outline. Introduction CB Monitoring Maintenance Quantification Model Risk Based Maintenance Approach Case Studies - PowerPoint PPT PresentationTRANSCRIPT
ERCPS
Risk Based Maintenance Scheduling of Circuit
Breakers using Condition-Based Data
Satish Natti
Graduate Student, TAMU
Advisor: Dr. Mladen Kezunovic
ERCPS
IAB Meeting, Dec. 4-5, 2008
ERCPS
Outline
• Introduction• CB Monitoring• Maintenance Quantification Model• Risk Based Maintenance Approach• Case Studies• Summary of Achievements
IAB Meeting, Dec. 4-5, 2008
ERCPSIntroduction:Problem Formulation
• If it is the same availability of the labor crew, and the labor hours, and the given budget is constrained, how the maintenance decisions need to be implemented (revised)?
• Develop:
- Maintenance quantification model
- component level maintenance strategy
- system level maintenance strategy
• Apply the developments to:
- individual circuit breakers
- Multiple circuit breakers in a power system simultaneouslyIAB Meeting, Dec. 4-5, 2008
ERCPSIntroduction:Comparison of Existing and Proposed
Researches
Operationdecision
Maintenance Strategies
Quantification of maintenance
Condition-based Data
RCM, AMP, Risk-based, RCAM
Failure rate, Probabilistic maintenance
Models
Risk-based decision approach
Probabilistic approach via performance indices
IAB Meeting, Dec. 4-5, 2008
ERCPSIntroduction:
Expected Contribution
8 10 12 14 16 18 20 0 0.05 0.1
0.15 0.2
0.25 0.3
0.35 Probability Between Limits is 0.94016
De
nsi
ty
Critical Value Lower Upper (msec)
ERCPSCB Monitoring
• Operating Mechanism
- Contact Travel time Measurement
- Control Circuit Monitoring- Vibration Analysis
• Contacts
- Resistance Test
- Temperature Monitoring
• Inspection of oil (oil circuit breakers)• Partial Discharge
Over view of monitoring choices:
IAB Meeting, Dec. 4-5, 2008
ERCPSCB Monitoring: Data from CBMs
ControlDC +
Control DC _
52 TC
CC
52
Close Initiate
Trip Initiate
52a
52Y/a 52a
52Y/b
52X/a
52Y/b
X
Y CBM
PortableDevices
IAB Meeting, Dec. 4-5, 2008
ERCPSCB Monitoring: Data from CBMs
EVENTEVENT EVENT DECRIPTIONEVENT DECRIPTION SIGNALSIGNAL
11 Trip or close operation is initiated (Trip or close Trip or close operation is initiated (Trip or close initiate signal changes from LOW to HIGH)initiate signal changes from LOW to HIGH)
T1T1
22 Coil current picks upCoil current picks up T2T2
33 Coil current dips after saturationCoil current dips after saturation T3T3
44 Coil current drops offCoil current drops off T4T4
55 B contact breaks or makes (a change of status B contact breaks or makes (a change of status from LOW to HIGH or vice versa)from LOW to HIGH or vice versa)
T5T5
66 A contact breaks or makesA contact breaks or makes T6T6
77 Phase currents breaks or makesPhase currents breaks or makes T7T7
88 X coil current picks upX coil current picks up T8T8
99 X coil current drops offX coil current drops off T9T9
1010 Y coil current picks upY coil current picks up T10T10
Waveform abnormalities and signal parameters
IAB Meeting, Dec. 4-5, 2008
ERCPSCB Monitoring: Data from CBMs
Manufacturer and Type: GE VIB-15.5-20000-2
Date T2 (sec) T3(sec) T4(sec) T5(sec) T6(sec)
2/12/2002 0.001215 0.010417 0.028993 0.056597 0.0668402/12/2002 0.000868 0.012500 0.032639 0.058160 0.0682292/13/2002 0.001042 0.014236 0.048785 0.055903 0.0664932/13/2002 0.001736 0.011979 0.043229 0.052951 0.0661462/19/2002 0.001389 0.017361 0.037500 0.059896 0.0078132/21/2002 0.003819 0.004861 0.034375 0.056424 0.067535
6/11/2002 0.001736 0.011285 0.032292 0.063542 0.0729176/11/2002 0.000868 0.014236 0.031076 0.063021 0.0725696/11/2002 0.000694 0.010243 0.032465 0.060590 0.0708336/11/2002 0.000694 0.013889 0.032639 0.061458 0.0704866/11/2002 0.001042 0.011111 0.048958 0.057118 0.068056
Summary of Test Records During Closing Operation of Circuit Breaker
ERCPSMaintenance Quantification Model
8 10 12 14 16 18 20 0 0.05 0.1
0.15 0.2
0.25 0.3
0.35 Probability Between Limits is 0.94016
De
nsi
ty
Critical Value Lower Upper (msec)
-4 -2 0 2 4 6 80
0.1
0.2
t1 (msec)
0 5 10 15 20 25 300
0.05
0.1
t2 (msec)
10 20 30 40 50 600
0.02
0.04
0.06
t3 (msec)
45 50 55 60 65 700
0.05
0.1
t4 (msec)
55 60 65 70 75 800
0.05
0.1
t5 (msec)
History of control
circuit signals
Extract signal parameters
(T1-T10) and fit distribution to each
parameter
Define performance indices using parameter
distributions
Bayesian approach to update parameter
distribution
Monitored control
circuit data
ERCPSAssessment of CB Condition
• P(ti) is defined as the probability that the parameter ti falls in the predefined interval, and is given by
• As long as the parameter ‘ti’ falls in the specified interval, it is said that there is no violation with ‘ti’.
8 10 12 14 16 18 20 0 0.05 0.1
0.15 0.2
0.25 0.3
0.35 Probability Between Limits is 0.94016
De
nsity
Critical Value Lower Upper (msec)
pi
)Pr()( iiii utltp
ERCPSPerformance Indices
)()()(1)CC( 432 tptptpp f
)()(1)( 32 tptpFTp f
)()(1)AB( 65 tptpp f
)()(1)MT( 53 tptpp f
6
2
)(1)Br(i
if tpp
ERCPS
Bayesian Updating Approach
IAB Meeting, Dec. 4-5, 2008
ERCPSSequential Bayesian Approach
y1
P(θ|Y)
π0
Data PosteriorPriorLikelihood
yn
L(Y)
P (θ| y1)π0
Data PosteriorPriorLikelihood
y1L(y1)
P (θ| yn)
y2L(y2)
ynL(yn)
P (θ| y2)
Bayesian
Sequential Bayesian
IAB Meeting, Dec. 4-5, 2008
ERCPSConcept of Risk
IAB Meeting, Dec. 4-5, 2008
ERCPS
Optimized problem formulation
Where,
iorxCxcST
xRMax
N
iii
N
iii
10:0
1
budget Total:
i''breaker maintaningby reduction Risk :
i''breaker ofcost eMaintenanc:
breakers ofnumber Total :
breakeronindex:
C
R
c
N
i
i
i
This optimization problem is a standard Knap-sack problem and can be solved using dynamic programming techniques
ERCPS
Case Studies
Category Case study # Details of the data
Maintenance Quantification Model
Case study I CB control circuit data during OPEN operation
Case study II CB control circuit data during CLOSE operation
Case study III Approximation to the Bayesian approach in case studies I & II
Risk based maintenance Optimization
Case study IV Bus 16 of IEEE Reliability Test System
List of case studies
IAB Meeting, Dec. 4-5, 2008
ERCPS
Case Study I: Open Operation
• The sequence of occurrence of timing of parameters during opening is: t2-t3-t6-t4-t5. Rename them as y1-y5 in that order
• y1, y2 and y3 can be treated as independent.
• y4=β0+β1y3+ε4
• y5 = β0 + β1y3 + β2y4+ ε5
Scatter plot analysis of timing parameters
Tolerance Limits for Open Operation
Event Lower(msec)
Upper(msec)
t2 0 2
t3 13.6 18.6
t4 26.4 35.4
t5 28.7 38.7
t6 22.4 32.4
IAB Meeting, Dec. 4-5, 2008
ERCPS
Case Study I: Open Operation
Performance indices for CB opening
Summary of Analysis for Open Operation
PerformanceIndex
Observations Maintenance required?
pf(TC) Abnormal behavior of trip coil current.
Yes
pf(AB) Auxiliary contacts are operating properly
No
pf(FT) Abnormal free travel times. Improper operation of trip latch mechanism
Yes
pf(MT) Abnormal mechanism travel times. Improper operation of operating mechanism.
Yes
pf(Br) Improper operation of breaker as a whole
Yes
IAB Meeting, Dec. 4-5, 2008
ERCPS
Case Study II: Close Operation
• The sequence of occurrence of timing of parameters during opening is: t2-t3-t4-t5-t6. Rename them as y1-y5 in that order
• y1, y2, y3 and y4 can be treated as independent.
• y5=β0+β1y4+ε5.
Scatter plot analysis of timing parameters
Tolerance Limits for Close Operation
Event Lower(msec)
Upper(msec)
t2 0 5.5t3 9.8 16.4t4 26 43.4t5 49.9 67.5t6 62 75.8
IAB Meeting, Dec. 4-5, 2008
ERCPS
Case Study II: Close Operation
Summary of Analysis for Close Operation
Performance indices for CB closing
PerformanceIndex
Observations Maintenance required?
pf(CC) Abnormal behavior of close coil current.
Yes
pf(AB) Auxiliary contacts are operating properly.
No
pf(FT) Abnormal free travel times. Improper operation of close latch mechanism.
Yes
pf(MT) Abnormal mechanism travel times. Improper operation of operating mechanism.
Yes
pf(Br) Improper operation of breaker as a whole.
Yes
IAB Meeting, Dec. 4-5, 2008
ERCPSCase Study III: Comparison
CB opening
CB closing
Comparison of index pf(Br) between Bayesian and
Sequential Bayesian approaches
ERCPSCase Study IV:
Risk Based System Maintenance
• IEEE 24 bus RTS is considered
• Generator = 155MW and Load = 100MW
• 8 breakers (B1-B8)
• Which breaker needs immediate attention?
• How to spend a fixed pool of money towards the maintenance of these breakers?
Substation configuration of bus 16IAB Meeting, Dec. 4-5, 2008
ERCPSCase Study IV: List of Events
EventEvent ##
DefinitionDefinitionEventEvent
##DefinitionDefinition
EventEvent ##
DefinitionDefinition
E1 Fault on BB1 E15 Fault on L28 E29 Fault on B2, B3 fails
E2 Fault on BB1, B1 fails E16 Fault on L28, B5 fails E30 Fault on B3
E3 Fault on BB1, B4 fails E17 Fault on L28, B6 fails E31 Fault on B3, B6 fails
E4 Fault on BB1, B7 fails E18 Fault on L29 E32 Fault on B3, B8 fails
E5 Fault on BB2 E19 Fault on L29, B2 fails E33 Fault on B4
E6 Fault on BB2, B3 fails E20 Fault on L29, B3 fails E34 Fault on B4, B5 fails
E7 Fault on BB2, B6 fails E21 Fault on G E35 Fault on B4, B7 fails
E8 Fault on BB2, B8 fails E22 Fault on G, B7 fails E36 Fault on B5
E9 Fault on L23 E23 Fault on G, B8 fails E37 Fault on B5, B6 fails
E10 Fault on L23, B1 fails E24 Fault on B1 E38 Fault on B6
E11 Fault on L23, B2 fails E25 Fault on B1, B2 fails E39 Fault on B6, B8 fails
E12 Fault on L24 E26 Fault on B1, B4 fails E40 Fault on B7
E13 Fault on L24, B4 fails E27 Fault on B1, B7 fails E41 Fault on B7, B8 fails
E14 Fault on L24, B5 fails E28 Fault on B2 E42 Fault on B8
IAB Meeting, Dec. 4-5, 2008
ERCPS
Case Study IV: Event Risk
Risk curvesRisk associated with each
event and breaker
IAB Meeting, Dec. 4-5, 2008
ERCPSCase Study IV: Risk Reduction
Interesting to note that, the amount of risk reduced by maintaining B6 is less compared to B3 and B8
B3 and B8 should be given priority based on the risk reduction levels 0
2000
4000
6000
8000
10000
12000
14000
16000
18000
Ris
k R
edu
ctio
n
1 4 7 10 13 16 19 22 25 28 31 34 37 40
Event
For the test system under consideration, it can be concluded For the test system under consideration, it can be concluded that, breakers B3 and B8 are more important followed by B6 that, breakers B3 and B8 are more important followed by B6 and should be given priority in budget allocationand should be given priority in budget allocation
)()()( EConEpERisk
ERCPS
Summary of Achievements
• A probabilistic methodology, ‘Maintenance Quantification Model’ is proposed and implemented
• An approximation to the Bayesian approach, called Sequential Bayesian approach is implemented
• Risk based system level maintenance strategy is proposed and implemented
IAB Meeting, Dec. 4-5, 2008
ERCPS
Financial Support
Power Systems Engineering Research Center (Pserc), Project:
“Automated Integration of Condition Monitoring with an Optimized Maintenance Scheduler for Circuit Breakers and Power Transformers”.
Iowa State University: James D. McCalley
Vasant Honavar
Texas A&M University: Mladen Kezunovic
Chanan Singh
IAB Meeting, Dec. 4-5, 2008
ERCPS
Publications
• S. Natti and M. Kezunovic, “Assessing Circuit Breaker Performance Using Condition-Based Data and Bayesian Approach”, IEEE Trans. On Power Systems. (In Review).
• S. Natti and M. Kezunovic, “Risk-Based Decision Approach for Maintenance Scheduling Strategies for Transmission System Equipment Maintenance”, 10th Int. Conference on Probabilistic Methods Applied to Power Systems, Rincon, Puerto Rico, May 2008.
• M. Kezunovic, E. Akleman, M. Knezev, O. Gonan and S. Natti, “Optimized Fault Location”, IREP Symposium 2007, Charleston, South Carolina, August 2007.
• S. Natti and M. Kezunovic, “Model for Quantifying the Effect of Circuit Breaker Maintenance Using Condition-Based Data”, Power Tech 2007, Lausanne, Switzerland, July 2007.
ERCPS• S. Natti and M. Kezunovic, “Transmission System Equipment Maintenance: On-line
Use of Circuit Breaker Condition Data”, IEEE PES General Meeting, Tampa, Florida, June 2007.
• M. Kezunovic and S. Natti, “Risk-Based Maintenance Approach: A Case of Circuit Breaker Condition Based Monitoring”, 3rd International CIGRE Workshop on Liberalization and Modernization of Power Systems, Irkutsk, Russia, August 2006.
• M. Kezunovic and S. Natti, “Condition Monitoring and Diagnostics Using Operational and Non-operational Data”, CMD 2006, Pusan, Korea, March 2006.
• S. Natti, M. Kezunovic and C. Singh, “Sensitivity Analysis on Probabilistic Maintenance Model of Circuit Breaker”, 9th Int. Conference on Probabilistic Methods Applied to Power Systems, Stockholm, Sweden, June 11-15, 2006.
• S. Natti, P. Jirutitijaroen, M. Kezunovic and C. Singh, “Circuit Breaker and Transformer Inspection and Maintenance: Probabilistic Models”, 8th Int. Conference on Probabilistic Methods Applied to Power Systems, Ames, Iowa, September 2004.