Cajetan Pinto, Global R&D Manager Machines Service, March 4, 2009
Life Expectancy Analysis Program for Electrical Machine Insulation © ABB Group October 29, 2009 | Slide 1
Presentation overview
© ABB Group October 29, 2009 | Slide 2
Life Cycle Management Approach
Reliability and failure statistics
Planning your Strategy
LEAP Methodology & Use
LEAP Standard
Case Studies
Benefits
Life Cycle Concept
Optimized Maintenance Line
Value to customer through maintenance
Continuous Upgrading/ Replacement Maintenance Overhaul Aging Repair Warranty Period
Upgrade and Modernization Period Maintenance Period
Customer Project Lifecycle
© ABB Group October 29, 2009 | Slide 3
Replacement & Recycle Period
Time
Total cost of operation (TCO)* TCO includes: • Purchase price • Specifications • Transportation • Storage • Installation • QA • Reliability • Electricity • Repairs • Administration • Inventory • etc
74 %
17.4 % 1%
2.7 %
4.9 %
Installation Purchase Cost of repair Reliability Electricity
* Information provided by MachineMonitor based on survey of 6000 machines © ABB Group October 29, 2009 | Slide 4
Basis of Analysis: Stress & Strength v/s Time
Strength Stress, strength
Premature Failure
Transients
Stress Residual Life Time © ABB Group October 29, 2009 | Slide 5
Failure
Life Expectancy Analysis: Benefits Strength
Condition assessment and taking suitable actions at this point.
Adv. 1: No Premature Failure Transients
Failure Stress Residual Life
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Adv. 2: Increase in Life
Reliability & Failure Statistics
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Failure statistics: IEEE Survey 1985-1987
Bearing Winding 11% 5% 3% 6%
37%
Rotor Shaft/coupling
5%
Brushes/slipring 33%
Detection during Normal operation
© ABB Group October 29, 2009 | Slide 8
External devices Not specified
Failure statistics : IEEE Survey 1985-1987
Bearing
4%
10%
Winding
7%
Rotor Shaft/coupling
8% 2%
Brushes/slipring
8%
61%
Detection during maintenance or test
© ABB Group October 29, 2009 | Slide 9
External devices Not specified
Failure Statistics: HV Motors Petrochemical Industry 1999 Distribution of Failures for motors below 2000KW
Bearing Stator Windings
14.60%
1.20% Rotor- Bars/rings
2.80%
57.40% Shaft or coupling
5.60%
External device 18.40% Not Specified
Distribution of Failures for motors equal and above 2000KW 7.89 IEEE transactions on industry applications . vol. 35. no. 4. july/august 1999
7.89 0.00 18.42
60.53 © ABB Group October 29, 2009 | Slide 10
5.26
For Machines less than 2000 kW anti-friction bearings are commonly used which are more likely to fail
For Machines above 2000 kW sleeve bearings are often used which are less likely to fail
Factors affecting Failure rate Total Failure Rate Vs Age
%wdg Failure Rate
7 6 5 4 % 3 2 1 0
3.5 3 2.5 2 % 1.5 1 0.5 0 0-5
5.1-10
10.1-15
15.1-20
20.1-25
3000-5000
25.1-
Age (Years)
6600-10500 1100013800
Voltage(Volts)
%wdg. Failure Rate
Wdg Failure Rate
1.4 1.2 1 0.8 % 0.6 0.4 0.2 0
2.5 2
Series1
%
1.5 1
Series1
0.5 0
2
4
6 Pole Number
© ABB Group October 29, 2009 | Slide 11
6000
8
10
1 or less
More than 1
No of Starts/day
Stator winding failures
Other 14%
Persistent Overloading 7% High Ambient Temperature 8%
Normal deterioration with age 18%
Abnormal Moisture 18%
Abnormal Voltage 5% Abnormal Frequency 1%
Poor Ventilation/ Cooling 8% Aggressive Poor Lubrication chemicals 5% 7%
High Vibration 9%
FAILURE CONTRIBUTORS © ABB Group October 29, 2009 | Slide 12
Planning your maintenance STRATEGY
Protection
Condition Monitoring
• continuous, on-line, action taken in real time
• on-line, but not necessarily continuous
• to limit the damage or prevent operation under abnormal conditions
• analysis and action is subsequent to data collection • prevents failure by taking steps with short term planning for maintenance
MST, ARGUS, DLI, PD, Telemetry, etc
© ABB Group October 29, 2009 | Slide 13
Life-time Estimation
• on-line + off-line • analysis and action subsequent to data collection • detects life limiting defects at the incipient stage, useful in both long term planning and short term planning for maintenance
LEAP
LEAP …… not just a step ahead What is LEAP?
LEAP is not just a package of inspections; it is a systematic approach to managing Machine Maintenance © ABB Group October 29, 2009 | Slide 14
Lifetime Expectancy Analysis Program or LEAP is a unique Maintenance Tool for the Stator Winding Insulation of Electric Machines.
LEAP provides information on Machine winding and expected life, and will optimize the Machine Maintenance Plans
LEAP developed by ABB Machines Service, India, is in use for over 12 years, with a database of measurements and analysis in excess of 4000 machines worldwide
Measurements are performed by Local or Global ABB Service centers and data analyzed at the LEAP Center of Excellence
Level Based Inspections Opportunities for Inspections
Inspection Schedule
Basic
When the machine is operating
Every 5% of the estimated lifetime
Standard
When the machine is stopped but assembled
Every 10% of the estimated lifetime
Advanced
When the machine is stopped and partially dismantled
Every 25% of the estimated lifetime
Premium
When the machine is stopped and rotor removed
Every 50% of the estimated lifetime
90
Confidence Level
75 60 45 30 15 0
© ABB Group October 29, 2009 | Slide 15
Basic
Standard
Advanced
Premium
Level Based Inspections Solution Levels
Basic
Data collection (on site or remote): Operational hours, voltage, current, power, slip,
Starts/Stops, Temperature (Winding, Coolant and Ambient), Duty cycle & loading pattern, Failure and Maintenance history, Information on power supply, breaker-cable configuration, etc
Standard
Advanced
Level
Condition Based Inspection and Maintenance Plan
Condition Assessment of Stator Windings for
Standard Data Collection Visual Inspection on end windings Partial Discharge Probe measurements & Dynamic
Condition Assessment of Stator Windings with Standard
Stress analysis of End-windings
© ABB Group October 29, 2009 | Slide 16
Life Expectancy Analysis 65% Confidence
Basic Data Collection Polarization Depolarization Current Analysis PDCA Tan Delta & capacitance Analysis Non-Linear Insulation Behaviour Analysis Partial Discharge Analysis
Mechanical Response of Windings
Premium
Deliverables
Packages
Advanced Data Collection Wedge Tightness Map & Coupling resistance measurements Visual inspection, including slot areas Stress analysis of Windings
Contamination, ageing, looseness, delamination, stress grading system Life Expectancy Analysis 80% Confidence Level Condition Based Inspection and Maintenance Plan
Package + End-winding assessment Life Expectancy Analysis 85% Confidence Level Condition Based Inspection and Maintenance Plan
Condition Assessment of Stator Windings with Advanced Package + slot region assessment Life Expectancy Analysis 90% Confidence Level Condition Based Inspection and Maintenance Plan
LEAP Methodology & Use of LEAP
© ABB Group October 29, 2009 | Slide 17
LEAP methodology
Collection of Data Operating data, test measurements and machine information
Analysis of Data ABB has developed UNIQUE analytical tools aimed at life assessment
Calculation of Stresses Life Expectancy Analysis is performed and factors and conditions that affect lifetime are identified
Estimating Life & Condition Based Maintenance Lifetime is estimated with different Confidence levels depending on the LEAP package Possible further inspections, maintenance, replacements or even upgrades are drawn up
© ABB Group October 29, 2009 | Slide 18
LEAP Standard
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LEAP Standard package P o la r iz a tio n -D e p o la r iz a tio n C u r r e n ts U PHASE
Pol-Depol Currents (microAmp)
100
DC Measurements
10
1
Polarization De-Polarization Current Analysis
0 .1 1
10
100
1000
T im e (s e c )
C h a r g in g
D is c h a r g in g
TAN DELTA MEASUREMENTS
AC Measurements
4.00
3.50
Non Linear Behavior Analysis
Tan δ and Capacitance Analysis
Partial Discharge Analysis
Tan Delta (%)
3.00
2.50
2.00
1.50
1.00
0.50 1
2
3
4
5
6
7
8
Voltage (kV)
U Phase
V Phase
W Phase
UVW Phase
Remark: DC tests are sensitive to the surface condition, and AC tests give more information on the insulation volume
© ABB Group October 29, 2009 | Slide 20
DC measurements Polarization-Depolarization Currents UVW PHASE
Q1, Q2 Q3
Pol-D epol C urrents (m icroA m p)
100
10
1
0.1
0.01 1
10
100
Time (sec)
Charging
Remark: Conventional IR & PI Measurements may have satisfactory values even with highly contaminated windings
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Discharging
1000
Parameters Derived Time constants T1, T2, T3 Charge storage : Q1, Q2, Q3 Ageing Factor Dispersion Ratio (1+Q1+Q2+Q3) Volume Resistivity
Polarization - De-polarization Current Analysis Besides
leakage and absorption current, PDCA test gives an idea of quantity and location of charge storage within the machine
Identifies
contamination even when IR, PI values are “acceptable”.
Determines
state of the winding insulation, ageing, looseness, etc.
AC measurements CAPACITANCE (Arbitrary Units)
INSTANTANEOUS CAPACITANCE VARIATIONS @ 5.8 kV
110
65
20
-25
-70 40
42
44
46
48
50
52
54
56
58
TIME (msecs) U - PHASE
V - PHASE
W - PHASE
UVW - PHASE
Non Linear Behavior Analysis, Tan δ and Capacitance Analysis, Partial Discharge Analysis
Remarks: Conventional measurement interpretation is generally based on trends
© ABB Group October 29, 2009 | Slide 22
Confirm the results from DC Measurements
Assess the condition of Corona protection shield
Determine the extent of de-lamination or void content in terms of a percentage of discharging Air Volume to Insulation Volume
Assess condition of the Stress Grading system at slot ends
Trend Ageing effects
60
LEAP from the Case Book
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Contamination indicated by LEAP
IR >>1000 MΩ PI >> 2
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Contamination indicated by LEAP
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Slot discharge / wear detected by LEAP
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Surface discharge detected by LEAP
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Case study 1: LEAP – Maintenance Planning 11MW 11kV 1500 RPM, Synchronous Motor (Air Separation problem) Purpose of Testing: The motor was in operation for 69,000 hours with no outage. LEAP Standard carried out to determine the need for L3 or L4 Maintenance. On-line pd alarm had appeared.
Results - PDCA Test IR- 2310 Meg ohm PI- 2.02 Q1(%) – 9.63 Q2 (%) – 11.30
Key Findings: LEAP Standard indicated presence of oil/carbonized contaminants predominantly on the overhangs
Q3 (%) – 44.54 DR – 1.65
AgF – 60.12
Vol Res – 1013.78 Ohm-m
Recommendation:
Open the end covers and clean end windings (L3). No immediate need of overhaul with rotor removal (L4)
Benefits: Optimized Maintenance Planning © ABB Group October 29, 2009 | Slide 28
Case Study 3: LEAP Maintenance Verification 6034 HP, 6 kV, 502A, 1481rpm
RESULTS - PDCA TEST Before Overhauling IR - 2205 Mohm PI - 4.79 Q1 – 78.68 %
Q1, Q2
Q2 – 65.49 % Q3 – 128.56 % Q3
DR – 3.73
After Overhauling IR - 32464 Mohm PI – 5.63 Q1 – 7.84 % Q2 – 8.84 % Q3 – 8.86 % DR – 1.25
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LEAP – Usage
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LEAP for Maintenance Planning
LEAP for L1, L2, L3, L4 inspection
LEAP for Run/Replace/Retrofit Decisions
Measurements and Analysis are to be done at a single occasion (L4) with additional assessment of other components besides the stator windings
LEAP for Life Extension/ Upgrade Decisions
Stress/Strength
Life Improvement
Strength
Developed Stress
Years Improvement in life by restoring strength droop Improvement in life by upgrading machine © ABB Group October 29, 2009 | Slide 34
Stress/Strength
Life Improvement
Strength
Developed Stress
Improvement in life by restoring original stress developed
LEAP for ‘Life Extension’
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Years Improvement in life by reducing stress through redesign
LEAP – How is it different?
© ABB Group October 29, 2009 | Slide 36
Methodology is not dependent on old records of measurements performed. Single occasion of measurements will suffice for making decisions. Parameters are derived from measurements to quantify problems such as contamination, ageing and looseness.
65-72% of failures are related to Thermal and Ambient reasons which may not be detected by measurements that rely only on partial discharges. ABB’s measurements and analysis focuses also on detection non-partial discharge related problems.
Analysis software is UNIQUE and parameters derived from analysis can be utilized in Life Expectancy Calculations
Sophisticated FEM analysis can be deployed during L3 and L4 maintenance.
Can be related to time and integrated into a Maintenance Plan
Towards a New Dimension
© ABB Group October 29, 2009 | Slide 37
We change the units !
Machinery status is typically expressed in vague units (green, yellow, red)
We change that into a measurable dimension: time that can be easily interpreted by other computerized systems and related to scheduling actions
LEAP - Value for the Customer
© ABB Group October 29, 2009 | Slide 38
Optimizes Maintenance Planning of Electrical Machines by moving from Scheduled Maintenance to Condition Based Maintenance
Life Extension of machines would lead to increased earnings capability and thereby greater return on investment.
Facilitate decision making (short and long term maintenance planning)
Focus mainly on essential maintenance, and machines that are vulnerable, thereby reducing downtime at lower risk levels
Provides important “lifetime ” inputs for more realistic estimates of Life Cycle Costing
© ABB Group October 29, 2009 | Slide 39
