Polling Power: User feedback from the 7F 2020 Digital Conference

A valuable feature of Power Users conferences is audience polling, which was pioneered by the 7F Users Group a few years ago. The steering committee and presenters use polling to ask owner/operators for their opinions on industry trends, the information needs of attendees, etc. Because the feedback is virtually instantaneous, it can identify where clarification or more detail is required on a particular subject during the presentation of interest.

Below are some of the polling questions asked during the 7F 2020 Digital Conference. The responses both characterize the audience and provide a snapshot of what your industry colleagues are thinking on topics of importance to owner/operators. Users can access presentations from the conference, a plethora of recorded technical presentations, and ask questions on the forum at the Power Users website.


How many times have you attended a 7F Users Group conference (including this year)?

  My first meeting, 46%

  Two years, 20%

  Three to five years, 21%

  Six or more years, 13%

How would you rate your level of 7F knowledge?

  Newbie, 14%

  Rookie, 10%

  Intermediate, 37%

  Seasoned, 25%

  Expert, 4%

What is your primary role?

  Maintenance manager, 12%

  Plant manager, 10%

  Maintenance engineer, 16%

  Turbine engineer, 28%

  Asset manager, 11%

  Other, 22%

How often do you interact with power traders or dispatchers?

  Multiple times a day, 7%

  Daily, 22%

  Weekly, 12%

  Rarely, 29%

  Never, 29%


What is the average age of your 7F and steam-turbine units based on COD?

  Less than 10 years, 15%

  10-15 years, 24%

  16-20 years, 48%

  More than 20 years, 13%


What system/component gives you the biggest headache, or impacts reliability the most, on your unit(s)? Check all that apply.

  Valves (for example, gas, compressor bleed valves, etc), 45%

  Instrumentation (for example, transmitters, T/Cs, etc), 38%

  Protection systems (for example, haz-gas detection, etc), 14%

  Inlet filtration system, 4%

  Covid-19, 12%

  Starting system (for example, static starter, etc), 7%

Three years into the future, how do you see your CCGT operating profile changing?

  More starts, fewer hours, 50%

  More starts, more hours, 13%

  Fewer starts, fewer hours, 5%

  Fewer starts, more hours, 16%

  No change, 15%

Three years into the future, how do you see your CCGT operating and ramp profiles changing?

  More part-load operation, more ramping, 65%

  More full-load operation, less ramping, 6%

  More full-load operation, more ramping, 9%

  More part-load operation, less ramping, 3%

  No change, 16%

Which type of flexibility would you choose if you could upgrade your plant today?

  Higher maximum output, 17%

  Lower minimum output, 31%

  Faster ramping, 5%

  Faster startup, 12%

  All of the above, 35%

Plant managers, maintenance managers/engineers, turbine engineers: If you had the ability to cost-effectively cycle overnight versus turndown, would you want to cycle?

  Yes, 29%

  Absolutely not, 49%

  Maybe, 22%

Traders, asset managers: If you had the ability to cost-effectively cycle overnight versus turndown, would you want to cycle?

  Yes, 41%

  Absolutely not, 37%

  Maybe, 22%

Which type of generating unit do you think the more flexible CCGT displaced to produce additional megawatt-hours?

  Less-flexible CCGTs, 21%

  Simple-cycle GTs, 36%

  Steam turbines, 17%

  All of the above, 26% 

How would you react if your trader/dispatcher asked you to cycle between 2 and 4 a.m.?

  No way, 26%

  Are you crazy? 21%

  OK, as long as power payments make up for the increased maintenance cost, 54%

What was the cause of your last failed start (pick one only)?

  Valves, 23%

  Static frequency converter, 3%

  Burners and nozzles, 7%

  Controls, 22%

  Instrumentation, 20%

  Hardware, 8%

  Excitation and generator, 14%

  Other, 4%

What concerns you the most at your site for forced-outage days (pick one only)?

  Transformer, 19%

  Instrumentation, 29%

  Rotor, 15%

  Bearings, 7%

  Steam-turbine unavailable, 19%

  Other, 11%

What is your most recent annual unit/block start/stop count on average?

  Fewer than 100 start/stops per year, 67%

  100-200 start/stops per year, 33%

  More than 200 start/stops per year, 0%

In the last 10 years, what start/stop count trend are you experiencing?

  Minimal or no change, 56%

  Up to 50% increase, 29%

  Roughly doubled, 11%

  More than doubled, 3%

Which 7F HGP TIL most keeps you up at night?

  2045, 7F AGP Stage 3 bucket tip shroud creep, 40%

  2181, Stage 1 nozzle creep degradation model, 23%

  2006, 7F and 9F Stage 3 bucket airfoil distress, 17%

  Other/none, 20%


What rodent issue have you seen the most?

  Cable damage in cable tray, 27%

  Wire damage in electrical cabinets, 38%

  Insulation damage on piping, 15%

  Other, 20%

Do you currently use adjustable rigging in your lift planning for turbine rotor or case removal?

  Yes, 66%

  No, 34%


How familiar are you with gas-turbine combustion?

  I’m a flame-stability expert, 5%

  I’m pretty good with what runs in my units, 42%

  I know the difference between a DLN 2.6+ and DLN 2.6, 27%

  Harry Potter’s wand must be involved, 20%

  Gas turbines have combustors? 7%

What is your biggest concern when it comes to combustion operability?

  Tuning, 24%

  Hardware, 22%

  CDM and T/C health, 17%

  AutoTune, 15%

  Cold weather, 17%

  Nothing, my unit runs well, 6%

Have you experienced fuel-nozzle damage?

  Yes, 56%

  No, 44%

What was the cause of the fuel-nozzle damage?

  Quat operation, 8%

  Fuel contamination, 28%

  Other, 45%

  Unknown, 19%

If it was quat operation or unknown, are you changing your quat limits seasonally?

  Yes, 13%

  No, 86%

Do you have issues during cold weather with high-dynamics alarms that require operator response?

  No, 45%

  Rarely, 41%

  Frequently, 14%


What is your most common unplanned stator repair/upgrade finding during an outage?

  Endwinding dusting/greasing or resonance repair, 69%

  Belly-band tightening (or new belly-band install), 8%

  Stator rewedge, either full or partial, 23%

  Stator core looseness, 0%

What is your most common unplanned field /rotor repair/upgrade finding during an outage?

  Slot content (amortisseur spring) migration, 35%

  Main lead cracking or separation, 8%

  Field turn shorts, 49%

  Field ground, 8%

Does your site or HQ/fleet have a spare/exchange 7FH2 field?

  Yes, 21%

  No, 79%

How much time is on the outage schedule for generator rotor removal and replacement—including setup and tear down?

  Less than one day, 7%

  Two days, 28%

  Almost one week, 48%

  Too long, 17%


Have you converted to electric actuators on your gas control valves?

  Yes, 13%

  No, 87%

Are you planning to convert the hydraulic actuators on your gas control valves to electric?

  Yes, 11%

  No, 57%

  Don’t know, 32%


How well do you know RLE (rotor lifetime extension)?

  Extremely well. We currently are in discussions and formulating a plan, 35%

  Have discussed it with our engine representative, 24%

  Know what the acronym stands for, 35%

  Don’t know about RLE, 7%

What’s your rotor maintenance plan?

  Exchange rotor, 29%

  Lifetime extension, 32%

  New rotor, 12%

  Not decided/do not know, 27%

Is your rotor affected by TILs 1971 and/or 1972?

  Yes, 46%

  No, 20%

  Not sure, 31%

  It was, 3%

Is your turbine rotor maintenance hours- or starts-based?

  Hours, 52%

  Starts, 16%

  Multiple units, some with both 27%

  Was hours, now starts, 4%

  Was starts, now hours, 1%

Do you have maintenance factoring calculated in your DCS logic?

  Yes, 14%

  No, 37%

  Not sure, 16%

  Tracking outside the DCS, 33%

Are you planning on conducting 7F rotor maintenance in the next five years?

  Yes, based on GER-3620 guidance, 57%

  No, 29%

  Learning more before deciding, 14%

Exhaust system

How often do you inspect your exhaust-frame flex seals?

  HGP interval only, 47%

  Annually, 50%

  More frequently than annually, 3%


How long does your oil last?

  Five years or less, 10%

  Six to nine years, 31%

  More than nine years, 60%

How many hours do you lose annually because of an oil-related failure?

  Less than 12, 81%

  12 to 24, 5%

  24 to 48, 9%

  More than 48, 5%

What are your MPC values?

  Less than 15, 77%

  15 to 35, 20%

  More than 35, 3%

Does your lab report the MPC hold time as required?

  Yes, 13%

  No, 28%

  Not sure, 59%

What type of lube oil do you use?

  Mineral groups 1 and/or 2, 58%

  Synthetic hydrocarbon groups 3 and/or 4, 26%

  PAG, 16%

Have you used an aftermarket turbine-oil additive?

  Yes, 31%

  No, 69%

Do you use a varnish-removal system?

  No, 30%

  Yes, rotating on several units, 33%

  Yes, full time, 37%

When did you install your varnish-removal system?

  Following a failed lab result, 60%

  Following an onsite failure, 28%

  With a new charge of oil, 12%

Have you changed the type of lube oil in your gas turbine?

  Yes, 29%

  Considering it, 20%

  No, 51%

What type of evaluation was done prior to changing the type of oil?

  Full technical evaluation, 60%

  Lube-oil supplier performed the evaluation, 18%

  Relied on the experience of others, 22%

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