lecture 14 maintenance: basic concepts · basic concepts piero baraldi politecnico di milano,...
TRANSCRIPT
![Page 1: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/1.jpg)
11Piero Baraldi
LECTURE 14
MAINTENANCE: BASIC CONCEPTS
Piero BaraldiPolitecnico di Milano, Italy
![Page 2: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/2.jpg)
22Piero Baraldi
LECTURE 14
• PART 1: Introduction to maintenance• PART 2: Condition-Based and Predictive Maintenance
![Page 3: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/3.jpg)
33Piero Baraldi
PART 1: INTRODUCTION TO
MAINTENANCE
![Page 4: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/4.jpg)
44Piero Baraldi
MAINTENANCE
“Equipments, however well designed, will not remain safe or reliable if they are not maintained”
4
FAILURE
DEGRADATION
![Page 5: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/5.jpg)
55Piero Baraldi
Maintenance expenditures in some industrialized countries
Derived from M. Garetti
5
![Page 6: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/6.jpg)
66Piero Baraldi
PART 2:MAINTENANCE STRATEGIC
PLANNING
6
![Page 7: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/7.jpg)
77Piero Baraldi
Maintenance Strategic Planning
• WHEN to act- “Before or after the fact”: maintenance intervention approach;
• ON WHAT BASIS-”Reliability, Availability, Cost, Safety, Environmental-centred”: maintenance decision-making strategy
7
![Page 8: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/8.jpg)
88Piero Baraldi
MAINTENANCE INTERVENTION APPROACHES
8
![Page 9: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/9.jpg)
99Piero Baraldi
Types of maintenance approaces
Maintenance Intervention
PlannedUnplanned
![Page 10: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/10.jpg)
1010Piero Baraldi
Planned Maintenance
Maintenance Intervention
Planned
ScheduledPerform
inspections, and possibly repairs,
following a predefined schedule
Condition-based
Monitor the health of the system and
then decide on repair actions based on the
degradation level assessed
PredictivePredict the
Remaining Useful Life (RUL) of the system and then decide on repair actions based on the predicted RUL
10
Unplanned
CorrectiveReplacement or
repair of failed units
![Page 11: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/11.jpg)
1111Piero Baraldi
Corrective maintenance
• No maintenance action is carried out until the equipment or structure breaks down.
• Upon failure, the associated repair time is typically relatively large →large downtimes
• Efforts are undertaken to achieve Small Mean Times to Repair (MTTRs) → Logistics
Failure Maintenance
11
![Page 12: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/12.jpg)
1212Piero Baraldi
Corrective maintenance: when is it applied?
• Equipments:• No safety critical• No crucial for production performance• Spare parts easily available and not expansive
Failure Maintenance
12
![Page 13: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/13.jpg)
1313Piero Baraldi
Planned maintenance
Failure Maintenance
Decision
Why?
Production and safety benefits
Costs of performing Maintenance
13
![Page 14: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/14.jpg)
1414Piero Baraldi
Maintenance Philosophies (2)
N.S. Arunraj, J. Maiti / Journal of Hazardous Materials 142 (2007) 653–661
14
![Page 15: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/15.jpg)
1515Piero Baraldi
Scheduled Maintenance
• Maintenance is carried out at scheduled intervals• Intervals can be given in terms of:
• calendar time• running time• number of start and stop• their combination
• Equipments may be repaired or replaced
Planned
Scheduled Condition based Predictive
![Page 16: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/16.jpg)
1616Piero Baraldi
Scheduled Maintenance: Objectives
• To rejuvenate the equipment = to decrease its failure rate• Planned replacement (e.g. Planned replacement of the bearing in a rotating
equipment)• To slow down degradation (wear, fatigue) = to limit the increase of the
failure rate• Lubrication• Routine maintenance (tightening of connectors)
![Page 17: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/17.jpg)
1717Piero Baraldi
Scheduled Maintenance: Pros and Cons
• Pros:• Reducing number of failures• Maintenance can be planned when it has the lowest impact on
production or availability of the systems• Cons:
• A scheduled maintenance approach generates maintenance tasks after a specific time interval which can result in a too early replacement of components, which is unprofitable.
Failure
![Page 18: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/18.jpg)
1818Piero Baraldi
Scheduled Maintenance: Pros and Cons
• Pros:• Reducing number of failures• Maintenance can be planned when it has the lowest impact on
production or availability of the systems• Cons:
• A scheduled maintenance approach generates maintenance tasks after a specific time interval which can result in a too early replacement of components, which is unprofitable.
Failure
Scheduled Maintenance
Scheduled Maintenance
![Page 19: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/19.jpg)
1919Piero Baraldi
Scheduled Maintenance: Pros and Cons
• Pros:• Reducing number of failures• Maintenance can be planned when it has the lowest impact on
production or availability of the systems• Cons:
• A scheduled maintenance approach generates maintenance tasks after a specific time interval which can result in a too early replacement of components, which is unprofitable.
• Maintenance induced failures
Failure
Scheduled Maintenance
Scheduled Maintenance
![Page 20: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/20.jpg)
2020Piero Baraldi
Scheduled maintenance: decision
• Optimize the Decision:• Intervals between PM maintenance actions• Action rules
• Model:• Failure/degradation process• Maintenance effects, time to repair• Costs of planned maintenance, corrective maintenance,
production unavailability
Failure/degradation•Failure times
•Degradation evolution
Maintenance•Effects on future
failure/degradation behavior•Time to Repair
Decision•Intervals between PM actions•Action Rules
![Page 21: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/21.jpg)
2121Piero Baraldi
Scheduled Maintenance: Decision
• Optimize the Decision (intervals between maintenance and action rules)
• Model:• Failure/degradation process• Maintenance effects, time to repair• Costs
interval between maintenance
Unavailability Costs
interval between maintenance
![Page 22: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/22.jpg)
2222Piero Baraldi
Condition-Based Maintenance
Planned
Scheduled Condition based Predictive
![Page 23: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/23.jpg)
2323Piero Baraldi
Maintenance Philosophies (2)
N.S. Arunraj, J. Maiti / Journal of Hazardous Materials 142 (2007) 653–661
23
![Page 24: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/24.jpg)
2424Piero Baraldi
Condition-Based Maintenance (CBM)
• Equipment degradation monitoring:• Periodic inspection by manual or automatic systems
Failure Maintenance
Decision Monitoring
dfailure
x
0Inspection time
xdfailure
ddetection
![Page 25: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/25.jpg)
2525Piero Baraldi
Condition-Based Maintenance (CBM)
• Equipment degradation monitoring:• Periodic inspection by manual or automatic systems• Continuous observations
Failure Maintenance
Decision Monitoring
Ultrasonic Monitoring (regularly used in the oil and gas industry)
![Page 26: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/26.jpg)
2626Piero Baraldi
Condition-Based Maintenance (CBM)
• Equipment degradation monitoring:• Periodic inspection by manual or automatic systems• Continuous observations
• Equipment degradation level identification by:• Direct measure (crack depth of a mechanical component)• Indirect observations (symptoms related to the degradation
process, e.g. quality of the oil in an engine, partial discharges inelectrical cables, vibrations frequencies and amplitudes in rotatingmachinery)
Failure Maintenance
Decision Monitoring
![Page 27: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/27.jpg)
2727Piero Baraldi
CBM: Conclusions
• Identification of problems in equipment or structures at the earlystage so that necessary downtime can be scheduled for the mostconvenient and inexpensive time.
Failure
Scheduled Maintenance
Scheduled Maintenance
Failure
Condition Based
Maintenance
![Page 28: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/28.jpg)
2828Piero Baraldi
CBM: Conclusions
• Identification of problems in equipment or structures at the earlystage so that necessary downtime can be scheduled for the mostconvenient and inexpensive time.
• Machine or structure operate as long as it is healthy: repairs orreplacements are only performed when needed as opposed toroutine disassembly and servicing.
• Availability
• Unscheduled shutdowns of production
• Reduced costs• Improved safety
![Page 29: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/29.jpg)
2929Piero Baraldi
Predictive Maintenance
Planned
Scheduled Condition based Predictive
![Page 30: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/30.jpg)
3030Piero Baraldi
Maintenance Philosophies (2)
N.S. Arunraj, J. Maiti / Journal of Hazardous Materials 142 (2007) 653–661
30
![Page 31: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/31.jpg)
3131Piero Baraldi
Predictive Maintenance
• Equipment degradation monitoring:
• Remaining Useful Life (RUL) prediction
• Maintenance Decision
Failure Maintenance
Decision MonitoringRUL PROGNOSIS
PROGNOSIS RUL
![Page 32: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/32.jpg)
3232Piero Baraldi
Predictive Maintenance: Ex. 1
• t=300: perform maintenance now or postpone it to the next planned outage at t=400?
time
Degradation level
t=300Present Time t=400
dfailure pastdegradation observations
degradation model
RUL PREDICTION
postpone maintenance to the next planned outage at t=400
![Page 33: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/33.jpg)
3333Piero Baraldi
Types of maintenance approaches
Maintenance Intervention
Planned
ScheduledReplacement or
Repair following a predefined schedule
Condition-based
Monitor the health of the system and
then decide on repair actions based on the
degradation level assessed
PredictivePredict the
Remaining Useful Life (RUL) of the system and then decide on repair actions based on the predicted RUL
33
Unplanned
CorrectiveReplacement or
repair of failed units
![Page 34: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/34.jpg)
3434Piero Baraldi
PART 2:
CONDITION-BASED AND PREDICTIVE MAINTENANCE
![Page 35: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/35.jpg)
3535Piero Baraldi
Prognostics and Health Management
Normal operation
Remaining Useful Life(RUL)
t
1x
t
2x
Detect Diagnose Predict
Equipment (System, Structure or Component)
c2c1 c3
Measuredsignals
Anomalous operation
Malfunctioning type (classes)
![Page 36: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/36.jpg)
3636Piero Baraldi
PHM & INDUSTRY 4,036
20172012 Time
Dat
a
Available data
• Digitalization2.8 Trillion GD (ZD) generated in 2016
• Analytics
AnalyticsData
PHM
![Page 37: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/37.jpg)
3737Piero Baraldi
Maintenance Intervention Approaches & PHM
Maintenance Intervention
Unplanned
Corrective
Planned
Scheduled Condition-based
Predictive
37
Detection X X
Diagnostics X X
Prognostics X
![Page 38: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/38.jpg)
Fault Detection
Piero Baraldi
38
![Page 39: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/39.jpg)
3939Piero Baraldi
39
Measured signals
Fault Detection: what is it?
Equipment
![Page 40: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/40.jpg)
4040Piero Baraldi
40
Measured signals
f1
f2
Forcing functions
f1
f2
Normal condition
Fault Detection: objective40
Equipment
Automatic algorithm
![Page 41: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/41.jpg)
4141Piero Baraldi
41
• Methods for Fault Detection:• Limit-based• Model-based• Data-driven
![Page 42: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/42.jpg)
4242Piero Baraldi
Data & Information for fault detection (I)
• Normal operation ranges of key signals
Normal operation
range
Abnormal condition
Abnormal condition
Pressurizer of a PWR nuclear reactor
10.2 m
3.8 m
Water level
Example:
time
42
![Page 43: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/43.jpg)
4343Piero Baraldi
• Normal operation ranges of key signals
• Limit Value-Based Fault Detection
Normal operation
range
Abnormal condition
Abnormal condition
Pressurizer of a PWR nuclear reactor
10.2 m
3.8 m
Example:
time
Methods for fault detection (I) 43
Water level
![Page 44: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/44.jpg)
4444Piero Baraldi
• Normal operation ranges of key signals
• Limit Value-Based Fault Detection
Normal operation
range
Abnormal condition
Abnormal condition
Pressurizer of a PWR nuclear reactor
10.2 m
3.8 m
Example:
time
Methods for fault detection (I)
Drawbacks:• No early detection•Not applicable to fault detection during operational transients•Control systems operations may hide small anomalies (the signal remains in the normal range although there is a process anomaly)
44
Water level
![Page 45: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/45.jpg)
4545Piero Baraldi
Methods for fault detection (II)
• Normal operation ranges of key signals• Physics-based model of the process (used to reproduce the expected behavior of
the signals in normal condition)
Pressurizer model
Signalreconstructions
Example:
45
![Page 46: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/46.jpg)
4646Piero Baraldi
Methods for fault detection (II)
• Normal operation ranges of key signals• Physics-based model of the process (used to reproduce the expected behavior of
the signals in normal condition)
Pressurizer model
≠Abnormal Condition
Signalreconstructions
Realmeasurements
Example:
46
![Page 47: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/47.jpg)
4747Piero Baraldi
Methods for fault detection (II)
Abnormal Condition Typically not availablefor complex systemsLong computational time
47
Pressurizer model
≠Signal
reconstructionsReal
measurements
Example:
• Normal operation ranges of key signals• Physics-based model of the process (used to reproduce the expected behavior of
the signals in normal condition)
![Page 48: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/48.jpg)
4848Piero Baraldi
Data & Information for fault detection (III)
• Normal operation ranges of key signals• Physics-based model of the process in normal operation• Historical signal measurements in normal operation
Water level
PressurePressureLiquid
temperature
Steam temperat
ure
Spray flow
Surge line flow
Heaters power Level
150.2 321 362 539 244 0 7.2
150.4 322 363 681 304 0 7.5
150.3 323 364 690 335 1244 7.7
… … … … … … …
Example:
48
![Page 49: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/49.jpg)
4949Piero Baraldi
Methods for fault detection (III)
• Normal operation ranges of key signals• Physics-based model of the process in normal operation• Historical signal measurements in normal plant operation
Empirical model of the process:• Auto Associative Kernel Regression• Principal Component Analysis• Artificial Neural Networks• …Water level
Pressure
49
![Page 50: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/50.jpg)
5050Piero Baraldi
50
Abnormal Condition
• Normal operation ranges of key signals• Physics-based model of the process in normal operation• Historical signal measurements in normal plant operation
EMPIRICAL MODEL OF PLANT BEHAVIOR
IN NORMAL OPERATION
Methods for fault detection (III)
≠Signal
reconstructionsReal
measurements
Example:
![Page 51: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/51.jpg)
5151Piero Baraldi
51
COMPARISON
MODEL OF COMPONENT BEHAVIOR IN NORMAL
CONDITIONS
ŝ1
t
t
ŝ2s1
t
t
s1 – ŝ1 s2 – ŝ2
s2
t
…
DECISION
t
NORMALCONDITION:
No maintenance
ABNORMALCONDITION:maintenance
required
The fault detection approach
Pb. 1
Pb. 2
SignalreconstructionsReal
measurements
Residuals
![Page 52: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/52.jpg)
5252Piero Baraldi
52
• Modeling the component behavior in normal conditions• The Auto Associative Kernel Regression (AAKR) method
![Page 53: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/53.jpg)
Auto Associative KernelRegression (AAKR)
![Page 54: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/54.jpg)
5454Piero Baraldi
What is AAKR?
• Auto-associative model
• Empirical model built using training patterns = historical signal measurements in normal plant condition
x1
x2
Auto-Associative
Model
1x
2x
nx
1x̂
2x̂
nx̂
( )ni
xxxfx ni
,...,1,...,,ˆ 21
=∀=
=
−−
−−
−
ncobsNnNj
ncobsN
knkjk
ncobsnj
ncobs
ncobs
xxx
xxx
xxx
X
.........
...
.........
......
.........
...
.........
1
1
1111
Signal
Observation
![Page 55: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/55.jpg)
5555Piero Baraldi
How does AAKR work?
55
Training pattern = historical signal measurements in normal plant condition
Test pattern: input = measured signals at current time
Output = signal reconstructions (expected values of the signals in normal condition)
),...,( 1obsn
obsobs xxx =
=
−−
−−
−
ncobsNnNj
ncobsN
knkjk
ncobsnj
ncobs
ncobs
xxx
xxx
xxx
X
.........
...
.........
......
.........
...
.........
1
1
1111
AAKR
obsx1
obsx2
obsnx
ncx1ˆncx2ˆ
ncnx̂
ncobsX −
)ˆ,...,ˆ(ˆ 1ncn
ncnc xxx =
![Page 56: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/56.jpg)
5656Piero Baraldi
How does AAKR work?
56
Training pattern = historical signal measurements in normal plant condition
Test pattern: input = measured signals at current time
Output = weighted sum of the training patterns:
),...,( 1obsn
obsobs xxx =
x1
x2
=
−−
−−
−
ncobsNnNj
ncobsN
knkjk
ncobsnj
ncobs
ncobs
xxx
xxx
xxx
X
.........
...
.........
......
.........
...
.........
1
1
1111
)ˆ,...,ˆ(ˆ 1ncn
ncnc xxx =
![Page 57: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/57.jpg)
5757Piero Baraldi
How does AAKR work?
57
Training pattern = historical signal measurements in normal plant condition
Test pattern: input = measured signals at current time
Test pattern: output = weighted sum of the training patterns:
),...,( 1obsn
obsobs xxx =
x1
x2
=
−−
−−
−
ncobsNnNj
ncobsN
knkjk
ncobsnj
ncobs
ncobs
xxx
xxx
xxx
X
.........
...
.........
......
.........
...
.........
1
1
1111
)ˆ,...,ˆ(ˆ 1ncn
ncnc xxx =
On all the training pattern
∑
∑
=
=
−⋅= N
k
N
k
ncobskj
ncj
kw
xkwx
1
1
)(
)(ˆ
![Page 58: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/58.jpg)
5858Piero Baraldi
How does AAKR work?
58
• Output = weighted sum of the training patterns:
• weights w(k) = similarity measures between and (the test and the k-th training pattern):
• with Euclidean distance between and
• h = bandwidth parameter
On all the training pattern
∑
∑
=
=
−⋅= N
k
N
k
ncobskj
ncj
kw
xkwx
1
1
)(
)(ˆ
)ˆ,...,ˆ(ˆ 1ncn
ncnc xxx =
obsx ncobskx −
2
2
2)(
21)( h
kd
eh
kw−
=π
∑=
−−=n
j
ncobskj
obsj xxkd
1
22 )()( obsx ncobskx −
x2
x1
high weight
low weight
![Page 59: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/59.jpg)
5959Piero Baraldi
Bandwidth parameter
-6 -4 -2 0 2 4 60
2
4
6
8
10
12
14
h=0.2h=2
d=0 w=0.40/h d=h w=0.24/h
d=2h w=0.05/hd=3h w=0.004/h
( ) 60004.024.0
)3(==
==
hdwhdw
d
w w
![Page 60: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/60.jpg)
6060Piero Baraldi
Example 1
),...,( 1obsn
obsobs xxx =
•Signal values at current time: •Signal reconstructions?•Normal or abnormal condition?
x1
x2
•available historical signal measurements in normal plant condition
![Page 61: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/61.jpg)
6161Piero Baraldi
Example 1: Solution
),...,( 1obsn
obsobs xxx =
•Signal values at current time: •Signal reconstructions: based on the available historical signal measurements in normal plant condition
)ˆ,...,ˆ(ˆ 1ncn
ncnc xxx =
ncobs xx
ˆ≅
x1
x2
normal condition
![Page 62: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/62.jpg)
6262Piero Baraldi
Example 2
),...,( 1obsn
obsobs xxx =
•Signal values at current time: •Signal reconstructions?•Normal or abnormal condition?
•available historical signal measurements in normal plant condition
x1
x2
![Page 63: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/63.jpg)
6363Piero Baraldi
Example 2: Solution
63
x1
x2
•available historical signal measurements in normal plant condition
ncobs xx
ˆ≠
abnormal condition
),...,( 1obsn
obsobs xxx =
•Signal values at current time: •Signal reconstructions: based on the available historical signal measurements in normal plant condition
)ˆ,...,ˆ(ˆ 1ncn
ncnc xxx =
![Page 64: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/64.jpg)
6464Piero Baraldi
AAKR: Computational Time
• Computational time:• No training of the model• Test: computational time depends on the number of training
patterns (N) and on the number of signals (n)
64
∑=
−−=n
j
ncobskj
obsj xxkd
1
22 )()(
![Page 65: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/65.jpg)
6565Piero Baraldi
AAKR Performance: Accuracy
• Accuracy:• depends on the training set:
• ↑N ↑ Accuracy
65
x1
x2
![Page 66: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/66.jpg)
6666Piero Baraldi
AAKR Performance: Accuracy (2)
• Accuracy:• depends on the training set:
• ↑N ↑ Accuracy
66
x1
Few patterns and not welldistributed in the training space
Inaccurate reconstruction
x2
![Page 67: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/67.jpg)
6767Piero Baraldi
FAULT DETECTION IN NPPAPPLICATION
Reactor coolant pumps
![Page 68: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/68.jpg)
6868Piero Baraldi
Fault Detection: Application*68
COMPONENT TO Reactor Coolant Pumps of a PWRBE MONITORED Nuclear Power Plant
x4
__________________________________________________
MEASURED 48 signals
Training patterns = historical signal measurements in normal plant condition measured for 1 year, every 30 seconds
* Work developed with EDF-R&D
![Page 69: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/69.jpg)
6969Piero Baraldi
Results: reconstruction of three different sensor failures
0 10 20 30 40 50 60 70 80 90 100Ti
xtest nc (4a)xtest ac (4a)
0 10 20 30 40 50 60 70 80 90 100-1
-0.5
0
0.5
1
Time
resi
dual
s
SENSOR: Temperature of the water flowing to the first seal of the pump in line 1:
Failure 2 = sensor offset
Failure 3 =sensor stuck
Time
0 10 20 30 40 50 60 70 80 90 100Time
e
0 10 20 30 40 50 60 70 80 90 100-1
-0.5
0
0.5
1
Ti
resi
dual
s
Time
0 10 20 30 40 50 60 70 80 90 100Time
Time
0 10 20 30 40 50 60 70 80 90 100-1
-0.5
0
0.5
1
Time
resi
dual
s
Failure 1 = measurement noise increase
resi
dual
resi
dual
resi
dual
Fault injection
![Page 70: LECTURE 14 MAINTENANCE: BASIC CONCEPTS · BASIC CONCEPTS Piero Baraldi Politecnico di Milano, Italy. piero.baraldi@polimi.it. Piero Baraldi 2 LECTURE 14 ... Piero Baraldi 11 Corrective](https://reader036.vdocuments.mx/reader036/viewer/2022071210/6021f922d270cf6480338207/html5/thumbnails/70.jpg)
7070Piero Baraldi
Results: seal deterioration detection70
COMPARISON
DECISION
ŝ1
t
t
s1 – ŝ1
t
s1
ABNORMAL CONDITION: seal deterioration
(SEALOUTCOMING
FLOW)
MEASURED SIGNALS
NORMALCONDITION
ABNORMALCONDITION
AUTO-ASSOCIATIVE MODEL OF PLANT
BEHAVIOR IN NORMAL CONDITIONS