eei loss prevention task force : bob edel - liu, jim mintel - aegis 1 gas turbine technology update...

EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

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Gas Turbine Technology Update

Presentation to EEI Loss Prevention / Risk Mgt Committee

Gas Turbine Issues Fall 2006

EEI Task Force CommitteeBob Edel, Jim Mintel


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Outline:

Gas Turbines

* GE Frame 7F Compressors

* R-0 Blades

* P Cut Blades Summary


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INTRODUCTION

Technical issues are not uncommon in the world of Gas Turbines.

All units of all manufacturers have undergone improvements to their original design.

The push for higher efficiencies and advances in technologies and metallurgy keep this industry on the cutting edge.

Proper “Management of Change” is generally the key to successful, reliable, loss free operation.


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Goal: To raise awareness of Utility Loss Prevention professionals to Machinery Breakdown perils.


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* It should be duly noted that the insurance community recognizes OEM’s as the technical subject matter experts for their units and that they are diligent in developing any necessary improvements as units evolve.

Furthermore, the insurance community does not claim to, and is not attempting to, supersede any recommendations made by the OEM’s.


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The Purpose of this presentation is to raise the awareness of non-operating personnel involved in managing risk By working and communicating together with owners, insurance companies, and OEM’s, Utility Owners can greatly assist in obtaining the most favorable insurance programs.

Owner/Insured

Insurance CarrierOEM


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Gas Turbine Technology Update What seems to be the issue?

GEThe following concerns do not necessarily apply to all units manufactured by this OEM

SiemensThe following concerns do not necessarily apply to all units manufactured by this OEM

AlstomThe following concerns do not necessarily apply to all units manufactured by this OEM

MitsubishiThe following concerns do not necessarily apply to all units manufactured by this OEM

Compressor

R-0 Blades

Mid Compressor

CompressorSegmented Vane pack - Hook Fit

V.xx – Tiles

Compressor

B2 Compressor

IGV Control

Compressor

Power Turbine

Peened vs.

UnPeened

Power Turbine

Trans Pieces

Row 3 Turbine Blade

Power Turbine

SEV Lance

Power Turbine

1st stage turbine blade lock-up


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Gas Turbine Technology UpdateWhat type of exposure are we looking at ?

What’s it worth?

Issue Number of losses (10yrs) Actual Loss Potential LossR-0 Blades At least 10 losses 17 million 23 million

Mid compr 11 losses 10 million 21 million

Hook fit 10 + losses 6.5 million 17 million

Trans Pieces 20+ losses $7M $16M

Tiles 10+ $2M $7M

CompressorIGV Control 3 losses 3 million 25+ million


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During this meeting, we will discuss some of the carrier concerns regarding the GE (7) FA, particularly the R0 P-Cut Blade.

According to GE, there are approximately 1,000 operating units (including 6F and 9F). 416 have P-Cut blades.

Of these 416: 314 are 7F, 10 are 6F and 92 are 9F

What is an R0 blade ? Why the concern? Why now ?


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Gas Turbine Technology Update What is an R0 Blade ?

As described by GE in GER3434D


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Gas Turbine Technology Update Why the concern?

P-Cut Failure occurred in June 06

The event occurred June 6, 2006 to a 7FA+e flared compressor unit.

The unit underwent a base-load trip for high vibration and experienced significant compressor damage.

The unit’s P-Cut blades experienced 17.5 K fired hours and 45 fired starts.

This unit had one R-0 P-Cut blade liberate and an additional 7 R-0 blades were found distressed (with cracks).

The blade failure was an “original” (Mark I) design. (No enhancements such as the larger fillet radius, dovetail relief cut for fretting, etc)


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Gas Turbine Technology Update Just One ??

Only one loss occurred due to failure of this P-Cut blade. This is considered to be a major event in the insurance industry.

Working with GE, the owner and GE have concluded a Root Cause Analysis.

The analysis has revealed that the current blade is susceptible to failure due to point of contact stresses. Additional stress modeling tools, taken from the aero division, have indicated unacceptable levels of stress exist in the P-Cut design.

At this time there is no long term fix; a new design is currently in the works.

Instruction has been published by GE as to what owners need to do.

GE has indicated all current R-0 designs are acceptable for near-term operation


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Gas Turbine Technology UpdateCompressor Damage


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Gas Turbine Technology UpdateCooling Passage debris


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Gas Turbine Technology Update GE 7FA R-0 History


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Press. Ratio 13.5:1 15:1 15:1 15.5:1

Firing Temp. Class (F) 2300 2350 2400 2420

Compressor Stages 18

Turbine Stages 3

Combustion System Can-Annular

(14 chambers)

7FPG7191

7FAPG7221

7FA+PG7231

7FA+ePG7241

Gas Turbine Technology Update MS7001F Gas Turbine Evolution(up to 7FA +e)


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From GER3950C


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7FA+e R-0 evolution•7191 “7 F” Standard R-0 Blade introduced in 1988 with un-flared compressor

•7241 “7 FA+e” introduced in 1996•Standard R-0 Blade introduced into the flared or “Snowflake” Compressor introduced in 2000

•R-0 P-Cut Blade Introduced in 2003 (both flared and un-flared compressors)

•R-0 Enhanced P-Cut Blade Introduced in 2005 (both flared and un-flared compressors)


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Gas Turbine Technology Update Snowflake Compressor


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“Standard” design R-0 blades started experiencing problems which began to mount

R-0 blade liberation in several units Blade liberation to R-0 on flared compressors

only. (Failures attributed to Corrosion, Erosion & Impact Damage initiating a defect which propagates to a crack and ultimately failure due to HCF)

R-0 and R-1 rubs led to blade tip liberation


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GE Frame 7FA/9FA – Compressor problems (list not current)

Not known 9FA April 2001 Compressor failure/R0Far East 9FA June 2001 CracksUK 9FA June 2002 CracksConfidential 9FA+e Feb, 2 2005 Compressor failure/R0 – 4.261 FHConfidential 9FA+e Feb, 6 2005 R0 cracks and rubbing – 1.384 FHConfidential 9FA+e Feb, 19 2005 Compressor failure/R0 – 12.000FHUK 9FA+e Feb/March 2005 Compressor failure/R0Confidential 9FA+e March 19, 2005 Rubbing – 7.858 FHUK 9FA+e March 2005 Compressor failure/OpsConfidential 9FA+e March 2005 Compressor failure/FODIsrael 9FA+e Feb/Mar 2005 R1 rubbingSpain 9FA+e April 29, 2005 R1 Rubbing – 20% blades damaged

Japan 7FA+e 2001 Compressor failureUSA 7FA+e Aug 2002 CracksUSA 7FA+e Jan 2003 Compressor failure/R0USA 7FA+e Feb 2003 CracksUSA 7FA+e Feb 2003 CracksUSA 7FA HF Oct 2004 Compressor failure/R0 HFUSA 7FA+e Feb 1, 2005 Compressor failure/R0 FODUSA 7FA+e March 2005 R1 RubbingUSA 7FA+e March 2005 R1 RubbingMexico 7FA+e April 19, 2005 Compressor failure/R0

Site/Customer Frame Date Comments


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GE High Flow R-0 blades

GE introduced Inconnel (IN 718) R-0 blades as a High Flow R-0 model in 2004

This design was short lived and has been subsequently pulled from all machines


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Issue• Unit with Inconel High Flow R0 blades discovered with R0 liberation and collateral damage:

• Base load trip on 10/27/04• High Exhaust Temperature, High Vibration Trip• Inlet inspection shows extensive IGV/R0/S0 damage• R0 blades had approx. 3400 hours and 50 starts

• Outage initiated to begin RCA investigation & Repair Work

Status• RCA Teams on site (GE CTS, Engineering)

• 1 R0 blade discovered liberated at root

•Inlet inspection of Sister Unit shows R0 indication at root

• Engineering/MPE reviewing high flow R0 NPI

• Recommendations for units with blades installed:

•Remove R0 blades and install Undercut GTD 450 R0 blade set at BOP outage

• Remove upper half NUV S0/S1’s and install original design

• Recommend units planning High Flow R0 installation to delay outage until RCA complete or install Undercut GTD 450 R0 blade set

R0 Fracture Surface


Inconel High Flow R0 Distress RCA


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Gas Turbine Technology Update P-Cut introduced


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P-Cut R-0 Overview The P-Cut R-0 compressor blade was introduced in

2003 and was installed on 416 units worldwide. * Approx 285 units remain since inspections began in JUN06.

The P-Cut fleet leader had approximately 25,700 fired hours and 700 fired starts as of July 06

The P-Cut R-0 blade was introduced to afford an additional margin regarding erosion, corrosion and impact damage as well as removing the need for erosion inspections IAW TIL 1389.


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Gas Turbine Technology Update R0 Blade Erosion Upgrade Options

P-Cut Blade Root

Hardware Description1. P-cut Blade

• Inlet case removal for R0 blade change out

• Erosion tolerant

Root Stress Profiles

Baseline P-cut

P-cut was touted as a blade that reduces root

stress from the LE enabling the blade to

tolerate erosion


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Gas Turbine Technology Update Enhanced R-0 Blade design


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Gas Turbine Technology Update Enhanced R-0 Blade design


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Gas Turbine Technology Update P-Cut Failure occurred in June 06

The event occurred June 6, 2006 to a 7FA+e flared compressor unit.

The unit underwent a base-load trip for high vibration and experienced significant compressor damage.

The unit’s P-Cut blades experienced 17.5 K fired hours and 45 fired starts.

This unit had one R-0 P-Cut blade liberate and an additional 7 R-0 blades were found distressed (with cracks).

The blade failure was an “original” (Mark I) design. (No enhancements such as the larger fillet radius, dovetail relief cut for fretting, etc)


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Gas Turbine Technology Update R-0 Design History Summary

The R(0) Compressor Row continues to pose reliability problems for 7FA/9FA operators. TIL 1303R1 in 2001 regarding

impact of erosion on leading edge first alerted industry.

Change in materials from Custom 450 to IN 718 did not work.

Addition of P-Cut to blade root to relieve stress in airfoil lead edge did not work.


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What has been done ?

GE has been very proactive in their communication to owners and carriers.

• RCA, evolution of findings• WebEx’s with clients and carriers• Carrier Meetings• Unit inspections, etc


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What is the status of the 7F fleet?

The following is a summary of information provided by GE:


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Gas Turbine Technology Update P-Cut R0 Inspection Findings

Frame Size 6FA 7FA 9FAP-Cut fleet 10 314 92# Inspected 2 185 15Cracked 0 74 0

0% 40% 0%

Compressor Configuration

Unflared Flared FlaredComp-IGV Config Cambered Cambered Uncambered7FA P-Cut Fleet 67 17 230# Inspected 56 12 117Cracked 12 4 58

21% 33% 50%


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P-Cut R0 UT Re-Inspections

128 units passed the initial P-Cut R0 UT Inspection 35 of these units have been re-inspected in

accordance with GE reinspection intervals Of these 35 units, 9 units were found with

crack indications (27%)


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What is GE recommending ?


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Gas Turbine Technology Update P-Cut R-0 blade Care(Original & Enhanced Designs) Require Ongoing UT inspections

Continue p-cut inspections and re-inspections… TIL forthcoming Fleet inspection experience and RCA supports distinguishing inspection

intervals between flared and unflared configurations for initial inspection Until further notice, 9FA p-cuts should follow inspection intervals previously

communicated


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Gas Turbine Technology Update Standard R-0 blade Care(Non-P-Cut)

Require existing inspections and care for root leading edge damage

TIL 1509 F-Class Front End Compressor Inspections

TIL 1389 F Class Erosion Inspections (non-p-cut units)

TIL 1518 Maintenance & Inspection Requirements for GT Air Inlet Systems

TIL 1509 Inspection


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Gas Turbine Technology Update What are the implications ? Operations Testing Maintenance Inspection Procedures Training

This is what Insurance companies will want to verify to maintain their comfort level.


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Gas Turbine Technology Update P-Cut R0 Summary Continued inspections of P-Cuts at initial inspection

intervals for new or un-inspected blades, and re-inspection intervals for previously cleared blades

GE R0 production returned to original, standard non-P-Cut. Plans include eliminating the P-Cut R0 from the 7FA fleet

On-going testing to characterize vibratory stress level drivers to develop options for increasing R0 robustness

Accompanying testing, GE is evaluating options to enhance the non-p-cut design. Once developed and validated, GE will provide further information


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Gas Turbine Technology Update Summary OEM Guidelines should be followed

GE is making the recommendations, it’s their technology. Insurance companies are attempting to understand the relative risk and how well the process is being implemented/managed.

The more insurance companies understand about what you are doing, the more comfortable we are in assuming risk


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Gas Turbine Technology Update Summary

Avoiding loss is all of our common goals. Recognizing the risk and mitigating the contributing

factors should minimize the probability of failure. GE has provided interim recommendations to avoid

reoccurrence. GE is now recommending their standard R-0 blade be

installed for the short term if R-0s require replacement. Awareness and compliance will minimize the

probability of similar failure Ultimately, GE will provide a long term solution.

eei loss prevention task force : bob edel - liu, jim mintel - aegis 1 gas turbine technology update...

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