Transcript Document

Risk Based Maintenance
Scheduling of Circuit
Breakers using
Condition-Based Data
Satish Natti
Graduate Student, TAMU
Advisor: Dr. Mladen Kezunovic
IAB Meeting, Dec. 4-5, 2008
PSERC
Outline
•
•
•
•
•
•
Introduction
CB Monitoring
Maintenance Quantification Model
Risk Based Maintenance Approach
Case Studies
Summary of Achievements
IAB Meeting, Dec. 4-5, 2008
PSERC
Introduction:
Problem Formulation
PSERC
• 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 simultaneously
IAB Meeting, Dec. 4-5, 2008
Introduction:
Comparison of Existing and Proposed
Researches
Operation
decision
RCM, AMP, Riskbased, RCAM
Failure rate,
Probabilistic
maintenance
Models
Maintenance
Strategies
Quantification of
maintenance
Condition-based
Data
IAB Meeting, Dec. 4-5, 2008
Risk-based
decision approach
Probabilistic
approach via
performance
indices
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Introduction:
Expected Contribution
Bus
15
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L24
BB1
G
B1
B4
B2
B5
B3
B6
B7
Bus 14
L23
Probability Between Limits is 0.94016
L29
0.35
0.3
Bus
19
Density
0.25
B8
0.2
0.15
BB2
L28
0.1
0.05
0
8
10
Lower
12
14
Critical Value
16
Upper
Condition
Based Data
Performance
Indices
• CB Control Circuit
• Signal Processing
• CB Failure
• Bayesian
Approach
18
(msec)
Load
20
Risk Analysis
• Probability
• Consequence
• Risk
Bus 17
System
Maintenance
• Risk Reduction
• Optimization
CB Monitoring
Over view of monitoring choices:
• Operating Mechanism
- Contact Travel time Measurement
- Control Circuit Monitoring
- Vibration Analysis
• Contacts
- Resistance Test
- Temperature Monitoring
• Inspection of oil (oil circuit breakers)
• Partial Discharge
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CB Monitoring: Data from CBMs
Close
Initiate
Trip
Initiate
Control
DC +
52a
52X/a
52Y/b 52Y
52Y/b
CC
52X 52a
TC
52Y/a
Control
DC _
CBM
Portable
Devices
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PSERC
CB Monitoring: Data from CBMs
Waveform abnormalities and signal parameters
EVENT
EVENT DECRIPTION
SIGNAL
1
Trip or close operation is initiated (Trip or close
initiate signal changes from LOW to HIGH)
T1
2
Coil current picks up
T2
3
Coil current dips after saturation
T3
4
Coil current drops off
T4
5
B contact breaks or makes (a change of status
from LOW to HIGH or vice versa)
T5
6
A contact breaks or makes
T6
7
Phase currents breaks or makes
T7
8
X coil current picks up
T8
9
X coil current drops off
T9
10
Y coil current picks up
T10
IAB Meeting, Dec. 4-5, 2008
CB Monitoring: Data from CBMs
Summary of Test Records During Closing Operation
of Circuit Breaker
Manufacturer and Type: GE VIB-15.5-20000-2
Date
T2 (sec)
T3(sec)
T4(sec)
T5(sec)
T6(sec)
2/12/2002
2/12/2002
2/13/2002
2/13/2002
2/19/2002
2/21/2002
0.001215
0.000868
0.001042
0.001736
0.001389
0.003819
0.010417
0.012500
0.014236
0.011979
0.017361
0.004861
0.028993
0.032639
0.048785
0.043229
0.037500
0.034375
0.056597
0.058160
0.055903
0.052951
0.059896
0.056424
0.066840
0.068229
0.066493
0.066146
0.007813
0.067535
6/11/2002
6/11/2002
6/11/2002
6/11/2002
6/11/2002
0.001736
0.000868
0.000694
0.000694
0.001042
0.011285
0.014236
0.010243
0.013889
0.011111
0.032292
0.031076
0.032465
0.032639
0.048958
0.063542
0.063021
0.060590
0.061458
0.057118
0.072917
0.072569
0.070833
0.070486
0.068056
PSERC
Maintenance Quantification Model
Probability Between Limits is 0.94016
0.35
0.3
Density
0.25
0.2
0.15
0.1
0.05
0
History of
control
circuit
signals
8
10
Lower
12
14
Critical Value
16
Upper
18
(msec)
20
Extract signal
parameters
(T1-T10) and fit
distribution to each
parameter
Define
performance
indices using
parameter
distributions
0.1
0.2
Monitored
control
circuit data
0.05
0.1
Bayesian approach to
update parameter
distribution
0
-4
-2
0
2
t1 (msec)
4
6
0
8
0
5
10
15
20
t2 (msec)
25
30
0.06
0.04
0.1
0.02
0.05
0
10
20
30
40
t (msec)
50
0
45
60
50
55
60
t (msec)
3
4
0.1
0.05
0
55
60
65
70
t (msec)
5
75
80
65
70
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Assessment of CB Condition
PSERC
• P(ti) is defined as the probability that the parameter ti falls in
the predefined interval, and is given by
p(ti )  P r(li  ti  ui )
• As long as the parameter ‘ti’ falls in the specified interval, it
is said that there is no violation with ‘ti’.
Probability Between Limits is 0.94016
0.35
0.3
Density
0.25
0.2
0.15
pi
0.1
0.05
0
8
10
Lower
12
14
Critical Value
16
Upper
18
(msec)
20
Performance Indices
Performance
of close/trip
coil
Performance
of Auxiliary
contacts
• Coil
• Free Travel
Time
• Contacts
• Mechanism
Travel Time
p f (CC)  1  p(t 2 ) p(t3 ) p(t 4 )
p f ( FT )  1  p(t 2 ) p(t3 )
p f ( AB)  1  p(t5 ) p(t 6 )
p f ( MT)  1  p(t3 ) p(t5 )
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Performance
of breaker
• Failure
Probability
Index
6
p f ( Br )  1 
 p(t )
i
i 2
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Bayesian Updating Approach
Initial Data
Formulation
• Scatter plot
analysis
• Interdependency
among parameters
• Normal
distribution
• Prior
• Likelihood
• Posterior
Analysis
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Implementation
• MCMC
• Updated distributions
Sequential Bayesian Approach
Data
Likelihood
y1
Prior
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Posterior
π0
P(θ|Y)
L(Y)
yn
Bayesian
Data
Sequential Bayesian
Likelihood
Prior
π0
Posterior
y1
L(y1)
y2
L(y2)
P (θ| y2)
yn
L(yn)
P (θ| yn)
IAB Meeting, Dec. 4-5, 2008
P (θ| y1)
Concept of Risk
Event, E
• Failure of a component
or group of components
• Line, Bus bar, Breaker
Event Probability,
p(E)
• Control circuit data
• Failure probability
index
Event
Consequence,
con(E)
• Loss of Load (CCDF)
• Loss of Line (OPF)
• Loss of Generator
(OPF)
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Risk(E)
• p(E)*con(E)
• Risk associated with
each event
• Risk reduction
• Maintenance decisions
Optimized problem formulation
PSERC
N
Max
 R x
i 1
i i
N
ST :
c x
i 0
i i
C
x  0 or 1 i
Where,
i
: index on breaker
N : T ot alnumber of breakers
ci : Maint enance cost of breaker' i'
Ri : Risk reduct ionby maint aningbreaker' i'
C : T ot albudget
This optimization problem is a standard Knap-sack problem
and can be solved using dynamic programming techniques
Case Studies
PSERC
List of 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 Case study IV
Optimization
Bus 16 of IEEE Reliability Test
System
IAB Meeting, Dec. 4-5, 2008
PSERC
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
Tolerance Limits for Open Operation
Scatter plot analysis of timing parameters
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
PSERC
Case Study I: Open Operation
Summary of Analysis for Open Operation
Performance
Index
Observations
Maintenance
required?
pf(TC)
Abnormal behavior of
trip coil current.
Auxiliary contacts are
operating properly
Abnormal free travel
times.
Improper
operation of trip latch
mechanism
Abnormal
mechanism
travel times. Improper
operation of operating
mechanism.
Improper operation of
breaker as a whole
Yes
pf(AB)
pf(FT)
pf(MT)
pf(Br)
Performance indices for CB opening
IAB Meeting, Dec. 4-5, 2008
No
Yes
Yes
Yes
PSERC
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.
Tolerance Limits for Close Operation
Scatter plot analysis of timing parameters
Event
Lower
(msec)
Upper
(msec)
t2
0
5.5
t3
9.8
16.4
t4
26
43.4
t5
49.9
62
67.5
75.8
t6
IAB Meeting, Dec. 4-5, 2008
PSERC
Case Study II: Close Operation
Summary of Analysis for Close Operation
Performance
Index
Observations
Maintenance
required?
pf(CC)
Abnormal behavior of
close coil current.
Auxiliary contacts are
operating properly.
Abnormal free travel
times.
Improper
operation of close latch
mechanism.
Abnormal
mechanism
travel times. Improper
operation of operating
mechanism.
Improper operation of
breaker as a whole.
Yes
pf(AB)
pf(FT)
pf(MT)
pf(Br)
Performance indices for CB closing
IAB Meeting, Dec. 4-5, 2008
No
Yes
Yes
Yes
Case Study III: Comparison
PSERC
CB opening
Comparison of index pf(Br) between Bayesian and
Sequential Bayesian approaches
CB closing
Case Study IV:
Risk Based System Maintenance
Bus 15
L24
BB1
G
B1
B4
B2
B5
B3
B6
B7
Bus 14
L23
L29
Bus 19
B8
BB2
L28
Load
Bus 17
PSERC
• 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 16
IAB Meeting, Dec. 4-5, 2008
Case Study IV: List of Events
Event
#
E1
Definition
Fault on BB1
Event
Definition
#
E15 Fault on L28
Event
Definition
#
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
PSERC
Case Study IV: Event Risk
Risk associated with each
event and breaker
Risk curves
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PSERC
Case Study IV: Risk Reduction
PSERC
Risk( E )  p( E )  Con( E )
18000
16000
14000
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
12000
10000
8000
6000
4000
2000
0
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
that, breakers B3 and B8 are more important followed by B6
and should be given priority in budget allocation
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
PSERC
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
PSERC
Publications
PSERC
•
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.
•
S. Natti and M. Kezunovic, “Transmission System Equipment Maintenance: On-line
Use of Circuit Breaker Condition Data”, IEEE PES General Meeting, Tampa, PSERC
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.