1. Gas Turbine Technology Update
Presentation to EEI Loss Prevention / Risk Mgt Committee Gas Turbine Issues Fall 2006
EEI Task Force Committee Bob Edel, Jim Mintel
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

2. Gas Turbine Technology Update Outline:
Gas Turbines * GE Frame 7F Compressors * R-0 Blades * P Cut Blades
Summary
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

3. Gas Turbine Technology Update
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.
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

4. Gas Turbine Technology Update
Goal: To raise awareness of Utility Loss Prevention professionals to Machinery Breakdown perils.
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

5. Gas Turbine Technology Update
* 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.
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

6. Gas Turbine Technology Update
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.
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

7. Gas Turbine Technology Update What seems to be the issue?GE
The following concerns do not necessarily apply to all units manufactured by this OEM
Siemens
Alstom
Mitsubishi
Compressor
R-0 Blades
Mid Compressor
Segmented Vane pack - Hook Fit
V.xx – Tiles
B2 Compressor
IGV Control
Power Turbine
Peened vs.
UnPeened
Trans Pieces
Row 3 Turbine Blade
SEV Lance
1st stage turbine blade lock-up
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

8. Gas Turbine Technology Update
What type of exposure are we looking at ?
What’s it worth?
Issue Number of losses (10yrs) Actual Loss Potential Loss
R-0 Blades At least 10 losses 17 million 23 million
Mid compr losses 10 million 21 million
Hook fit losses 6.5 million 17 million
Trans Pieces 20+ losses $7M $16M
Tiles $2M $7M
Compressor
IGV Control 3 losses 3 million 25+ million
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

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

10. Gas Turbine Technology Update
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 ?
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

11. Gas Turbine Technology Update What is an R0 Blade ?
As described by GE in GER3434D
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

12. 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)
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

13. 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
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

14. Gas Turbine Technology Update Compressor Damage
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

15. Gas Turbine Technology Update Cooling Passage debris
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

16. Gas Turbine Technology Update GE 7FA R-0 History
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

17. EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis
Gas Turbine Technology Update MS7001F Gas Turbine Evolution (up to 7FA +e) 7F
PG7191
7FA
PG7221
7FA+
PG7231
7FA+e
PG7241
As I had previously indicated, We Currently have 4 7F Gas turbine designs starting with the PG7191 thru the current production 7241FA, and we will now the 7251FB.
Each model is in incremental improvement in performance from the last via, not just increased firing temperature, but increased PR, which I will discuss more in a moment, as well as improvements in materials and cooling and sealing technologies.
Furthermore, each model is based on the the same or a variant of the same 18 stage F compressor, 3 stage turbine, and 14 chamber can annular combustion system.
And so, for the 7F series Gas Turbine, we have achieved growth thru fine tuning of proven tech.
Press. Ratio 13.5: :1 15:1 15.5:1
Firing Temp. Class (F)
Compressor Stages 18
Turbine Stages 3
Combustion System Can-Annular
(14 chambers)
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

18. Gas Turbine Technology Update From GER3950C
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

19. Gas Turbine Technology Update 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)
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

20. Gas Turbine Technology Update Snowflake Compressor
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

21. EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis
Gas Turbine Technology Update “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
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

22. EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis
Gas Turbine Technology Update GE Frame 7FA/9FA – Compressor problems (list not current)
Site/Customer
Frame
Date
Comments
Not known 9FA April Compressor failure/R0
Far East 9FA June Cracks
UK 9FA June Cracks
Confidential 9FA+e Feb, Compressor failure/R0 – FH
Confidential 9FA+e Feb, R0 cracks and rubbing – FH
Confidential 9FA+e Feb, Compressor failure/R0 – FH
UK 9FA+e Feb/March 2005 Compressor failure/R0
Confidential 9FA+e March 19, 2005 Rubbing – FH
UK 9FA+e March Compressor failure/Ops
Confidential 9FA+e March Compressor failure/FOD
Israel 9FA+e Feb/Mar 2005 R1 rubbing
Spain 9FA+e April 29, 2005 R1 Rubbing – 20% blades damaged
Japan 7FA+e Compressor failure
USA 7FA+e Aug Cracks
USA 7FA+e Jan Compressor failure/R0
USA 7FA+e Feb Cracks
USA 7FA HF Oct Compressor failure/R0 HF
USA 7FA+e Feb 1, Compressor failure/R0 FOD
USA 7FA+e March R1 Rubbing
Mexico 7FA+e April 19, 2005 Compressor failure/R0
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

23. Gas Turbine Technology Update 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
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

24. EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis
Gas Turbine Technology Update
Inconel High Flow R0 Distress RCA
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 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
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

25. Gas Turbine Technology Update P-Cut introduced
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

26. Gas Turbine Technology Update 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.
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

27. EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis
Gas Turbine Technology Update R0 Blade Erosion Upgrade Options
Hardware Description
P-cut Blade
Inlet case removal for R0 blade change out
Erosion tolerant
P-Cut Blade Root
Baseline
P-cut
P-cut was touted as a blade that reduces root stress from the LE enabling the blade to tolerate erosion
Root Stress Profiles
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

28. Gas Turbine Technology Update Enhanced R-0 Blade design
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

29. EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis
Gas Turbine Technology Update Enhanced R-0 Blade design
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

30. 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)
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

31. 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.
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

32. Gas Turbine Technology Update 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
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

33. Gas Turbine Technology Update What is the status of the 7F fleet?
The following is a summary of information provided by GE:
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

34. Gas Turbine Technology Update P-Cut R0 Inspection Findings
Frame Size 6FA 7FA 9FA
P-Cut fleet
# Inspected
Cracked
0% 40% 0%
Compressor Configuration
Unflared Flared Flared
Comp-IGV Config Cambered Cambered Uncambered
7FA P-Cut Fleet
# Inspected
Cracked
21% 33% 50%
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

35. Gas Turbine Technology Update 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%)
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

36. Gas Turbine Technology Update What is GE recommending ?
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

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

38. 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
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

39. 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.
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

40. 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
EEI Loss Prevention Task Force : Bob Edel - LIU, Jim Mintel - Aegis

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

42. 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