technology and reliability improvements in ge’s...

Technology and Reliability Improvements

in GE’s 1.5MW Wind Turbine Fleet

James R. MaughanGeneral Manager

Product Service and WarrantyGE Wind Energy

[email protected]

September 17, 2007

Wind Turbine Reliability WorkshopSandia National LabsAlbuquerque, NM

p. 2James Maughan, GE Wind Wind Turbine Reliability Workshop

GE’s Infrastructure Businesses

GE and GE Wind

Oil & GasWater Aircraft Engines

RailEnergy Financial Services

Wind

Solar

Biomass

Hydrogen

- Nuclear

- Thermal

- Renewables


• Formed May 2002…Purchased from Enron

• Foresee significant long term, global demand for Wind Turbines

• Continue growth with…

Technology - integrate with GE to improve on starting point…reliability, capacity factor, cost

Supply Chain – more turbines, with predictability

Permitting & Transmission – more turbine locations

Policy - support Long-term commitment

• Ecomagination

GE Energy’s Start in Wind Power

“Green is Green”…For Everyone


GE Wind Growth and Investment

GE Wind since 2002:

$600MM+ technology investment …

• Unit production: 400 to 2500+

• Key suppliers: up 3x

• 2007 Revenue: $4.5B+

• Fleet size: 2000 to 8000

•Continued within 2-3 years …

• Expect policy issues to stabilize

• Continue to grow supply chain

• Expand capacity

• Becoming GE’s largest Energy product business

(units/yr)

• Managing supply chain …integrated with global suppliers

• Operational differentiation …driving dependable fulfillment

• Advancing technology …efficiency, reliability, diagnostics

‘07‘02

2,500+

~400

Accelerating global deployment

It All Depends on Reliability


Why Reliable Operation is Everything

Customer View

• Price + Capacity Factor + Availability + Operating Costs = Customer Rate of Return

• Reliability issues directly cut production

• Reliability issues increase operating costs

• Reliability issues are aggravating

Reliability and Availability

• Reliability…component focused

- Failure rates, MTBF, MTBT, starting reliability, etc

• Availability…operator focused

- Fraction of time system is able to operate as intended

- Includes impact of failure on operation

- Failure rates, faults, outage length, planned repair, maintenance, etc

- Ties to lost production, lost revenue

The Fuel is Free. The Turbine Needs To Run.


1.5sle Availability Summary - Customer Fleet View

2007

2005

0%10%

20%30%

40%50%

60%70%

80%90%

100%

0 0.2 0.4 0.6 0.8 1Availability

0 0.2 0.4 0.6 0.8 1

Per

cent

of F

leet

Engineering Availability

• Includes downtime for any reason (except grid outages)• Duration from coming off-line to return to service• Faults, repairs, maintenance, upgrades, etc

• Lost production calculated from wind speeds during downtime


0

500

1000

1500

2000

0-1 h 1-4 h 4-24 h 1-4 d > 4 d

Fau

lt C

ou

nt

0

500

1000

1500

2000

2500

Fau

lt D

ow

nti

me,

hrs

# EventsDowntime

Availability Analysis By Fault Count and Duration

System Faults Component Failures

•More frequent but shorter events from system, thermal, integration, and operation issues

- impact is primarily lost production

•Less frequent but longer events from component failures

- impact is lost production andcost of component


Fleet Relative Cost of Component Failure

•Lost Production and replacement cost data

•Failure data and predictions for continuous product improvement

Failure Data - Weibull Predictions

100.00 100000.001000.00 10000.00

0.01

0.05

0.10

0.50

1.00

5.00

10.00

50.00

90.00

99.00

0.01

0.5

0.6

0.7

0.8

0.9

1.0

1.2

1.4

1.6

2.0

3.0

6.0

β

Unr

elia

bilit

y, F

(t)

100.00 100000.001000.00 10000.00

0.01

0.05

0.10

0.50

1.00

5.00

10.00

50.00

90.00

99.00

0.01

0.5

0.6

0.7

0.8

0.9

1.0

1.2

1.4

1.6

2.0

3.0

6.0

β

Cycles100.00 100000.001000.00 10000.00

0.01

0.05

0.10

0.50

1.00

5.00

10.00

50.00

90.00

99.00

0.01

0.5

0.6

0.7

0.8

0.9

1.0

1.2

1.4

1.6

2.0

3.0

6.0

β

Unr

elia

bilit

y, F

(t)

100.00 100000.001000.00 10000.00

0.01

0.05

0.10

0.50

1.00

5.00

10.00

50.00

90.00

99.00

0.01

0.5

0.6

0.7

0.8

0.9

1.0

1.2

1.4

1.6

2.0

3.0

6.0

β

Cycles


Typical Failure Root Cause Analysis Process

Slip Ring

Above rated pitch motor currents- (Temperature/Wear)

Protection devices CB for slip ring 400 V, 50 A

WTG SystemDesign

Maintenance Other

Humidity

Temperature.

Assembly error Slip Ring Assembly

Lightning Strikes

BAA Faults

Old Style to new style transition in design

Mechanical Wear of Brushes

Inadequate Brush Replacement

Slip ring cleaning procedures.

Slip Ring Lubrication procedures

EliminatedRoot Cause Contributor

Bearing Friction

Mechanical Wear of gold coating on slip ring.

Slip Ring

Above rated pitch motor currents- (Temperature/Wear)

Protection devices CB for slip ring 400 V, 50 A

WTG SystemDesign

Maintenance Other

Humidity

Temperature.

Assembly error Slip Ring Assembly

Lightning Strikes

BAA Faults

Old Style to new style transition in design

Mechanical Wear of Brushes

Inadequate Brush Replacement

Slip ring cleaning procedures.

Slip Ring Lubrication procedures

EliminatedRoot Cause Contributor

Bearing Friction

Mechanical Wear of gold coating on slip ring.

RCA Fishbone, Identification, Validation

Annual energy

production per w ind bin (kWh)

Annual number of

revolutions

Probability per w ind

bin

Annual energy


Annual num ber of

revolutions


bin

Annual energy


Annual num ber of revolutions


bin

Avg w indspeed (m /s) >>>

7.5 7.5 7.5 8.5 8.5 8.5 10 10 10

8.463 8.463 8.463 9.591 9.591 9.59 11.284 11.284 11.2841 0 0 0.03 0 0 0.02 0 0 0.0162 0 0 0.05 0 0 0.04 0 0 0.0303 0 437,410 0.07 0 350,384 0.06 0 260,294 0.0444 33,552 529,028 0.09 27,462 433,008 0.07 20,835 328,517 0.0555 112,715 604,015 0.10 94,850 508,278 0.08 73,935 396,202 0.0646 221,454 712,198 0.10 192,774 619,961 0.09 155,321 499,511 0.0717 358,705 807,086 0.10 325,002 731,254 0.09 272,299 612,672 0.0758 511,763 839,611 0.09 485,599 796,685 0.09 425,625 698,290 0.0769 655,944 775,207 0.08 655,858 775,105 0.08 605,008 715,009 0.075

10 714,918 668,306 0.07 757,894 708,480 0.07 740,242 691,979 0.07211 675,418 548,684 0.06 763,851 620,523 0.06 794,694 645,579 0.06712 565,133 434,475 0.04 686,033 527,424 0.05 764,846 588,016 0.06113 445,726 332,263 0.03 584,380 435,622 0.05 702,385 523,587 0.05414 332,432 245,653 0.03 473,629 349,991 0.04 617,419 456,246 0.04715 238,760 175,728 0.02 371,946 273,753 0.03 529,049 389,380 0.04016 165,366 121,709 0.01 283,414 208,593 0.02 442,511 325,688 0.03417 110,951 81,660 0.01 210,494 154,923 0.02 362,944 267,126 0.02818 72,146 53,099 0.01 152,449 112,203 0.01 292,036 214,938 0.022

Material Analysis

AnalyticsFailure Analysis


0

500

1000

1500

2000

0-1 h 1-4 h 4-24 h 1-4 d > 4 d

Fau

lt C

ou

nt

0

500

1000

1500

2000

2500

Fau

lt D

ow

nti

me,

hrs

# EventsDowntime

Availability Analysis By Fault Count and Duration

System Faults Component Failures

•More frequent but shorter events from system, thermal, integration, and operation issues

- impact is primarily lost production

•Less frequent but longer events from component failures

- impact is lost production andcost of component


Availability Analysis by Return to Service Process Step

Return to Service Process Steps

1. Identification, remote diagnostics, waiting period (if required)

2. Assemble needed teams, tools, and parts

3. Repair time

0

50

1000

1500

2000

2500

3000

Fau

lt H

andl

ing

/ M

anda

tory

Wai

t

Pen

ding

Rep

air

In R

epai

r

Pla

nned

M

aint

enan

ce

Un

avai

lab

ility

(h

ou

rs)

Pla

nned

Rep

air0

Un

avai

lab

ility

(h

ou

rs)

p. 12

James M

aughan, G

E W

ind

Wind Turbine Relia

bility W

orksh

op

Typ

ical Fault A

nd Ava

ilability D

ata

0 50

100

150

200

250

300

Blade angle asymmetry

Battery charging voltage

Planned repair

Rotor CCU fault voltage

Program start PLC

Rotor CCU collective faults

Pitch thyristor 1 fault

Cabinet Over temperature

Motor protection

Main switch released

Rotor CCU fault current

Planned Maintenance

Gearbox oil pressure

Weather downtime

Yaw runaway

Unavailability (hrs)


0 30 60 90

120

150

180

Lost Production, MWhr



Planned repair


Program start PLC



Motor protection



Planned Maintenance


Weather downtime

Yaw runaway

•Lo

st productio

n guides te

chnica

l effo

rt, field

solutio

ns, co

mponent re

desig

n, sy

stem im

provement

Unavaila

bility

Lost P

roductio

n


Wind Turbine Blade Angle Asymmetry

Background

• Electronic pitch control system sets blade angle during high load wind control

• Under some conditions on some units, one blade lags behind, unit shuts down

Motor

Gear box

Drive gear

Bearing

Electronic Control

Motor

Gear box

Drive gear

Bearing

Electronic Control


Anatomy of a Blade Angle Asymmetry Fault

0

2

4

6

8

10

12

14

16

18

20

200 250 300 350 400 450 500

Time [sec]

Bla

de

An

gle

, deg

Blade Angle 1 - Actual



Blade Angle Setpoint

2. Blade 3 begins to lag behind

3. Unit shuts down due to potential asymmetric loads

4. Blades return to feathered position on grid or battery power. Unit restarts.

1. Blades all following setpoint


BAA - Root Cause Analysis

0

10

20

RMS Torque, Nm

Fre

quen

cy

Torque Capability

Bearing Torque Characteristics

Bearing Torque Data Summary

Revised Torque Capability

Root Cause Analysis• Variability in torque requirements

not seen in prototype data• ~4% of bearings outliers• Cause of variation not definitively

identified

System Solution• Torque applied to bearing

increased with use of higher ratio gearbox

• Loads, lifing, response time all validated

Possible Corrective Action• Uprate pitch gearbox • Avg 87% reduction in impact

validated

Pitch System Gearbox

Outliers


Cabinet Over Temperature Faults

Background

• Energy dissipated in pitch motors and hub increases cabinet temperatures

• Temperature protection shuts down unit if necessary…

• … in some cases below spec of 40C outside ambient

Impact

0

5

10

15

20

25

30

FW01 FW10 FW19 FW28 FW37 FW46

Lo

st P

rod

uct

ion

, MW

hrs

Hub Axis Cabinet (3)

Hub Battery Cabinets (3)

Hub Center Cabinet Top Box

Hub Axis Cabinet (3)

Hub Battery Cabinets (3)


Hub Ventilation Schematic

Ambient Air

Screen and deflector

Center

Cabinet

Flexible hose

exhaust

Root Cause Analysis

• Vendor cabinets tightly sealed

• Hub is stagnant and unventilated

• Internal hub temperature can peak higher than ambient

Possible Corrective Action

• Create consistent air flow through hub with vent

• Screen and deflectors to limit water, snow, debris, etc


Typical Hub Temperature Data With Ventilation

0

5

10

15

20

25

30

35

40

45

50

4-Mar-07 5-Mar-07 6-Mar-07 7-Mar-07 8-Mar-07 9-Mar-07 10-Mar-07 11-Mar-07 12-Mar-07

Tem

p, C

, or

Spe

ed, m

/s

Tamb

Thub

Wind

Tcenter Center Cabinet

Hub

Ambient

Wind Speed

- Hub temperature within a few degrees of outside ambient temperature

p. 19

James M

aughan, G

E W

ind

Wind Turbine Relia

bility W

orksh

op

0 30 60 90

120

150

180

Lost Production, MWhr



Planned repair


Program start PLC



Motor protection



Planned Maintenance


Weather downtime

Yaw runaway

Typ

ical Fault A

nd Ava

ilability D

ata

Unavaila

bility

Lost P

roductio

n

Field Solutio

ns D

eveloped

��

��

��

New

Syste

m D

esig

ns

��

0 50

100

150

200

250

300



Planned repair


Program start PLC




Motor protection



Planned Maintenance


Weather downtime

Yaw runaway

Unavailability (hrs)



GE Pitch Control System

00 12000024000 48000 72000 96000

Time, hrs

Cum

ulat

ive

Num

ber

of T

rips

120000

System Redesign

• Higher torque and temperature capability

• Improved batteries and chargers

• PWM conversion, reduced slip ring current

• Digital control, fewer components

• Ethernet-based diagnostics

Validation

• Fault counts at validation site

• Half old system, half new

GE Redesign

Legacy System


1.5 MW DFIG IGBT-based Power Converter

60 Hz to Grid

AC from Generator

DC to 60 Hz AC

AC to DC

Power Conditioning

Liquid Cooling

DC linkControlCards

60 Hz to Grid

AC from Generator

DC to 60 Hz AC

AC to DC

Power Conditioning

Liquid Cooling

DC linkControlCards

Grid Voltageat Converter

Reactive Current

Power

0.200 sec

Continued operationGrid Disturbance

Power Converter• Replaces multiple vendors• Based on GE’s motor drive

and generator exciter technology

• Enhanced diagnostics, capability, reliability

• Operates under authority of legacy main control

Low Voltage Ride Through

• Digital monitoring and control technology

• Remains connected during grid disturbance

• Uses reactive power flow to ride through disturbance


Electrical System Simplification and Integration

System Redesign

• Integrates converter, main controller, and power distribution into a single cabinet

• Ethernet diagnostics and control across converter, pitch, control, generator, all electrical

• Modernized software, blockware, and toolkit, - identical to Mark VIe control in gas turbines

• Discrete components in top box replaced with circuit boards

• Prototypes in installation now


Summary - Improving GE’s Fleet Reliability

0%

10%

20%30%

40%50%

60%70%

80%

90%

100%

0 0.2 0.4 0.6 0.8 1Availability

0%

10%

20%30%

40%50%

60%70%

80%

90%

100%

0 0.2 0.4 0.6 0.8 1

Per

cent

of F

leet

Summary

• Focus on total reliability- component failure rates andsystem faults

• Increase production and revenue

• Reduce operating costs

• Grow the industry It All Depends on Reliability

technology and reliability improvements in ge’s...

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