Drivetrain Development and Reliability

12006 Wind Program Peer Review

Drivetrain Development and Reliability

Sandy Butterfield

5/10/2006

•Need pictures


Design Evolution (Jason)

History of designs. Why do they look like they do.

Variable speed – enabler for control of torque loads High speed brakes gone Noise (much reduced) Integration ??? Design tools much improved Margins much lower Standards (assisted development of design practice now used

for rest of the industry) Size, lubrication, condition monitoring,


Drivetrain Evolution

1980 1985 1990 1995 2000 2005 2010

Drivetrain rating increasing

Lubrication additives and filtration

High failure rates & noise

Variable speed introduced

High speed brakeseliminated

Wind turbine standards development40,000 hr. rebuilds required

Condition monitoring


State of the art in drivetrain design

Vestas, 4.5 MW

Enercon, 6 MW Multibrid, 5 MW Clipper, 2.5 MW


Design Problems Plaguing Industry Gearbox failures have plagued the wind industry since early 80s. Current life much less than 20 years, even using best practice Reliability remains an issue throughout the drivetrain

– Mainshaft and gearbox bearings—especially planetary spherical roller bearings

– Housing deflections?– Power electronics IGBT failures– Others

Planetary Bearing Inner Race and Roller Failure •A. Toms - Gastops


Sample Wind Turbine Data

Critical Mass Loss

Critical Mass Rate

Related to AFRL Prognostics


Program contributions (Walt)

Dyno history of contributions (industry partnerships)understanding field problemsqualifying production prototypesqualifying new braking controls, lubricants, gear tooth leadtesting new concepts

multi gen (clipper)NPS (DDG) (WindPact)GEC (mediuim speed gen) (WindPact)

Standards supportrole in AGMA / IEC 61400-4gearbox guideline by errichello

WindPact drive train studyPrototypes

NPS DDGGEC hybrid


What should the DOE program be doing to foster High-Reliability Systems?

High-ReliabilitySystems

Appropriate Environmental

Conditions

Accurate Loads &Design Requirements

Designed-in

Reliabilit

y

Condition M

onitorin

g

Reduced Failure Rates Improved O&M

System R

eliability A

nalysis C

apability

O&M Data Base

Designed-in

Maintainability

Full- S ca leTe st in g


Current Programs (Full Scale Dyno Tests)

NPS WindPact Direct Drive Gen prototype test

GEC WindPact medium speed drive prototype test

NPS

GEC


Current Program (Improved O&M) Drive train R&D needs workshop (NREL 4/05)

– Identified near term needs (failure data, industry collaborative root cause analysis, condition monitoring)

– Loads validation– Greater integration between loads codes and internal stress codes– DDG appear to be heavier/more costly but hold promise for greater

reliability and lower cost with R&D, especially for offshore

Predictive Maintenance Management workshop (NREL 4/20/06)– CM technology for gearing & bearings available but challenge to

apply it economically to wind.– Other areas unique to wind turbines unexploited. (blades,

automated fault diagnosis, model assisted load monitoring, poor performance diagnosis.

– Need for integrated SCADA systems, O&M management systems and automated data interpretation tools.


Opportunities: (Reducing Failure Rates)

Reliability tools Second generation WindPact drive train study under

SeaCon and prototypes. Loads Code/Gearbox internal stress code integration


Integrated Codes are Needed Component Level

– Determine design integrity of individual components based on specified loads

– Single-physics model– Not industry-specific– Commercial products available

(ANSYS, etc.)

Full System Level

– Determine loads throughout full system for component level analysis

– Multi-physics model– Wind industry-specific– Simple modeling of components

Component Level

– Single-physics model– Uncoupled loads do not capture

housing flexure– Commercial products available

(ANSYS, ADAMS, SimPack)?

•L. Mumper - SKF


Opportunities: Industry Collaboration

O&M database – Develop automated diagnostics– Identify R&D needs– Fuel reliability models

Predictive Maintenance Management (PdM)– Sandy will finish this.


Gearbox premature mortality investigation project (Walt)


Opportunities: Exploring new concepts

SEACON extension of WindPACT drivetrain study1. Survey existing concepts2. Cost estimates3. Reliability estimates4. Better understand the direct drive / geared system reliability and cost tradeoff


Future Plans (Sandy) More workshops planned

– O&M Practices (SNL Sept 06)– Predictive Maintenance Management II (NREL March 07)

SeaCon Drivetrain concept studies

Attempt to organize industry collaboratives– Gearbox failure investigation– O&M data base– Condition monitoring opportunities

Drivetrain Development and Reliability

Documents

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