© ABB Group February 29, 2012 | Slide 1

Life Expectancy Analysis Programfor Electrical Machine Insulation

Cajetan Pinto, Global R&D Manager,

© ABB Group February 29, 2012 | Slide 2

Presentation overview

Life Cycle Management Approach

Reliability and failure statistics

Planning your Strategy

LEAP Methodology & Use

LEAP Standard

Case Studies

Benefits

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Continuous Upgrading/Replacement

Upgrade and Modernization Period

Warranty Period

Overhaul

Maintenance

AgingRepair

Optimized Maintenance Line

Time

Maintenance Period

Replacement & Recycle Period

Value to customerthrough maintenance

Customer Project Lifecycle

}

Life Cycle Concept

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*Information provided by MachineMonitorTM based on survey of 6000 machines

TCO includes:

•Transportation

•Purchase price• Specifications

•Storage•Installation•QA•Reliability•Electricity•Repairs•Administration•Inventory•etc

Installation

1%

Purchase

2.7%

Cost of

repair

4.9%

Reliability

17.4%

Electricity

74%

Total cost of operation (TCO)*

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Stress

Strength

FailureTransient faults

Residual Life

Premature Failure

Time

Stre

ss, s

treng

thBasis of Analysis: Stress & Strength v/s Time

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Adv. 2: Increase in Life

Stress

Strength

Failure

Transient faults

Residual Life

Adv. 1: No Premature Failure

Condition assessment and taking suitable actions at this point.

Life Expectancy Analysis: Benefits

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Reliability&Failure Statistics

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Failure statistics: IEEE Survey 1985-1987

37%

33%

5%

6%3%

5%11%

Bearing

Winding

Rotor

Shaft/coupling

Brushes/slipring

External devices

Not specifiedDetection during Normal operation

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Failure statistics : IEEE Survey 1985-1987

8%2%

8%

7%4%

10%

61%

Bearing

Winding

Rotor

Shaft/coupling

Brushes/slipring

External devices

Not specified

Detection during maintenance or test

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Out of 33 % failures occurred during normal operation,

only 8 % could be detected during maintenance/inspection.

Out of 37 % failures occurred during normal operation,

61 % could be detected during maintenance/inspection.

BEARING FAILURES STATOR INSULATION FAILURES

Failure statistics: Inference

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Failure Statistics: HT Motors Petrochemical Industry 1999

18.42

60.53

7.89 5.26 7.89 0.00IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS . VOL. 35. NO. 4. JULY/AUGUST 1999

57.40%

18.40%

5.60%

2.80%14.60%

1.20%

Bearing

Stator Windings

Rotor- Bars/rings

Shaft or coupling

External device

Not Specified

Distribution of Failures for motors below 2000KW

Distribution of Failures for motors equal and above 2000KW

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Total Failure rate Vs Age

Total Failure Rate Vs Age

01234567

0-5 5.1-10 10.1-15 15.1-20 20.1-25 25.1-

Age (Years)

%

IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS . VOL. 35. NO. 4. JULY/AUGUST 1999

00.5

11.5

22.5

33.5

%

3000-5000

6000 6600-10500

11000-13800

Voltage(Volts)

%wdg Failure Rate

Series1

00.5

11.5

22.5

%

1 or less More than 1

No of Starts/day

Wdg Failure Rate

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Stator winding failures (link with TEAM)

FAILURE CONTRIBUTORS

Normal deterioration with

age18%

Poor Ventilation/ Cooling

8%

Aggressive chemicals

7%

Poor Lubrication5%

High Vibration9%

Abnormal Frequency

1%

Abnormal Voltage5%

Abnormal Moisture18%

High Ambient Temperature

8%

Persistent Overloading

7%Other14%

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ProtectionCondition Monitoring

Life-time Estimation

• continuous, on-line, action taken in real time

• to limit the damage or prevent operation under abnormal conditions

• on-line, but not necessarily continuous

• 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

LEAP

• 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

Planning your maintenance STRATEGY

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LEAP is not just a package of inspections; it is a systematic approach to managing Machine Maintenance

LEAP …… not just a step ahead

What is LEAP?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

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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

45

60

75

90

Con

fiden

ce L

evel

Basic Standard Advanced Premium

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Level Based Inspections

Solution Levels

Packages Deliverables

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

Life Expectancy Analysis 65% Confidence LevelCondition Based Inspection and Maintenance Plan

Standard Basic Data Collection Polarization Depolarization Current Analysis PDCA Tan Delta & capacitance Analysis Non-Linear Insulation Behaviour Analysis Partial Discharge Analysis

Condition Assessment of Stator Windings for Contamination, ageing, looseness,delamination, stress grading system Life Expectancy Analysis 80% Confidence LevelCondition Based Inspection and Maintenance Plan

Advanced Standard Data Collection Visual Inspection on end windings Partial Discharge Probe measurements & Dynamic Mechanical Response of Windings Stress analysis of End-windings

Condition Assessment of Stator Windings with Standard Package + End-winding assessmentLife Expectancy Analysis 85% Confidence LevelCondition Based Inspection and Maintenance Plan

Premium Advanced Data Collection Wedge Tightness Map & Coupling resistance measurements Visual inspection, including slot areas Stress analysis of Windings

Condition Assessment of Stator Windings withAdvanced Package + slot region assessmentLife Expectancy Analysis 90% Confidence LevelCondition Based Inspection and Maintenance Plan

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LEAP Methodology&Use of LEAP

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Collection of DataOperating data, test measurements andmachine information

Analysis of DataABB 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 MaintenanceLifetime is estimated with different Confidence levels depending on the LEAP package

Possible further inspections, maintenance, replacements or even upgrades are drawn up

LEAP methodology

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LEAP Standard

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DC Measurements

Polarization De-Polarization Current Analysis

AC Measurements

Non Linear Behavior Analysis

Tan and Capacitance Analysis

Partial Discharge Analysis

P o la riz at io n -D e p o lar iza t io n C u rre n tsU P H A S E

0 .1

1

1 0

10 0

1 1 0 10 0 1 0 0 0T im e (s e c)

Pol-D

epol

Cur

rent

s (m

icro

Am

p)

C h arg ing D isch arg in g

TAN DELTA MEASUREMENTS

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

1 2 3 4 5 6 7 8

Voltage (kV)

Tan

Del

ta (%

)

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

LEAP Standard package

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DC measurements

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.

Polarization-Depolarization CurrentsUVW PHASE

0.01

0.1

1

10

100

1 10 100 1000Time (sec)

Pol-D

epol

Cur

rent

s (m

icro

Am

p)

Charging Discharging

Parameters DerivedTime constants T1, T2, T3Charge storage : Q1, Q2, Q3Ageing FactorDispersion Ratio (1+Q1+Q2+Q3) < 1.25Volume Resistivity

Q3

Q1, Q2

Remark:Conventional IR & PI Measurements may have satisfactory values even with highly contaminated windings

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AC measurements

Non Linear Behavior Analysis, Tan and Capacitance Analysis, Partial Discharge Analysis

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

INSTANTANEOUS CAPACITANCE VARIATIONS@ 5.8 kV

-70

-25

20

65

110

40 42 44 46 48 50 52 54 56 58 60

TIME (msecs)

CAP

AC

ITA

NC

E (A

rbitr

ary

Uni

ts)

U - PHASE V - PHASE W - PHASE UVW - PHASE

Remarks:Conventional measurement interpretation is generally based on trends

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LEAP – How is it different?

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 in Level III and IV inspections.

Can be related to time and integrated into a Maintenance Plan

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Towards a New Dimension

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 othercomputerized systems and related to scheduling actions

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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

LEAP - Value for the Customer

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