If you own and/or operate a GE MS7001A, B, C, E, or EA gas turbine, the technical meeting offering the most “bang for the buck” is the 2019 conference and exhibition conducted by the 7EA Users Group, November 3 – 7, at the Galt House Hotel in Louisville, Ky. If you haven’t already signed up, you missed out on the $50 registration fee but can still reserve a seat for $150 (until September 11)—still the best deal in town.

If you haven’t attended a 7EA Users Group meeting previously, you can expect to be among about 100 owner/operators willing to share their experiences—both successes and failures—with colleagues. Presentations and discussion sessions will provide ideas and experience on strategies to accommodate must-take renewables, what upgrades others have found worthwhile for maximizing availability and starting reliability, when you should replace—not repair—parts, etc.

If you’re new to 7EAs, you won’t feel out of place at this meeting. Roughly one-third of the attendees in any given year are first-timers. The reason, of course, is that user-group meetings are invaluable training forums.

And your involvement with the people you’ll meet in Louisville, and others in the greater community of 7EA users, doesn’t end with the last session. The organization’s online forum, which is accessed via the website, helps users stay in touch and get answers to their questions between meetings.

This service, provided by Gregory Carvalho, Simplified Technology Co, and the steering committee (see box), was implemented in summer 2003. Over the years there have been, in round numbers, 20,000 postings. Registered 7EA users have access to this unique information resource through the website link above. You’ll find presentations from the last decade there as well.

The 2019 conference agenda, posted on the user group’s website, can help you organize your thoughts/questions ahead of the meeting. The program kicks off Monday morning (November 4) with Advanced Turbine Support’s annual assessment of fleet findings by the company’s inspection team. This is of particular value to first-timers requiring an engine orientation lesson (the photos are invaluable) as well as a primer on what to look for and where during inspections to assure reliable service from generating assets.

The remainder of the first day is dedicated to presentations by the OEM’s engineers. By the end of the Monday program, the novice will be able to participate in discussions about the 7EA with confidence. More than a dozen technical presentations by industry experts, and discussion sessions, fill the final two days of the meeting.

HIGHLIGHT: Engine inspection from the borescope experts

A review of Advanced Turbine Support’s presentation last year is a good primer/refresher for every attendee. Several of President Rod Shidler’s discussion points will be reiterated in Louisville given the size and average age of engines in the 7B-EA fleet. Better preparation will help you extract maximum value from the meeting.

The goal of every engine inspection, Shidler began, is not to miss something that could contribute to a forced outage. Success requires qualified technicians equipped with the most sophisticated tools available and well connected to company experts with deep and applicable experience ready to help diagnose findings that may be unfamiliar to those at the plant site.

What follows are the highlights of Shidler’s presentation:

• • TIL 1884, “7EA R1/S1 Inspection Recommendations,” which addresses the need to inspect R1 and S1 airfoils for possible damage caused by clashing—the unwanted contact between the leading edges of S1 stator-vane tips and the trailing edges of rotor blades in the platform area.

  • TIL 1980, “7EA S1 Suction Side Inspection Recommendations,” which advises users to inspect for crack indications on S1 vanes made of Type-403 stainless-steel, regardless of whether clashing damage is in evidence on S1 and R1 airfoils.

While the TIL recommends visible or fluorescent dye, Advanced Turbine Support favors eddy current for these inspections using previous discoveries to support its opinion. Shidler said that if the stator vanes are coated, visible or fluorescent dye penetrant inspections may not be dependable, nor will they have an acceptable probability of detection. UT results also could be compromised if coating degradation, such as disbonding, occurs.

Shidler explained that if the stator vanes are coated, the company’s eddy-current technique—featuring ultra-high sensitivity and very high resolution—has the ability to maintain sizing capabilities through coatings of up to 0.125 in. thick. He added that eddy current also is preferred when looking for crack initiation because it can detect problems sooner than ultrasonics.

• • TIL 1854, “Compressor Rotor Stages 2 and 3 Tip Loss,” which suggests blending and tipping to mitigate the impact on availability and reliability of R2 and/or R3 tip loss. This TIL supplements information provided by the OEM in the O&M manual provided with the engine.

Shidler cautioned that 1854 does not address first-stage rotor blade tips, does not recommend in-situ inspections, and suggests tip losses are considered low risk. He questioned the OEM’s beliefs noting that Advanced Turbine Support has performed more than 1000 in-situ visible dye penetrant inspections, identifying over 64 cracked rotor blades and more than 40 tip liberations in the course of this work.

In this portion of the presentation, the inspection expert took time to “brag” a bit about his company’s in-situ blending capabilities for both rotor blades and stator vanes and its ability to reach deep into the compressor to perform this work. Photos illustrated repairs to 11^th-stage vanes and 12^th-stage rotor blades.

• • TIL 1562-R1, “Heavy-Duty Gas Turbine Shim Migration and Loss,” which informs users on the need to monitor the condition of compressor shims and corrective actions available to mitigate the risks of migrating shims.

  • Distress in the 11^th stage air-extraction section, including casing cracking and material liberation.

  • TIL 1090-2R1 on compressor R17 platform and spacer movement was something else users should be mindful of.

  • TIL 1744, “S17, EGV1, and EGV2 Stator-Ring Rail and CDC Hook Fit Wear Inspection,” provides guidance on the repair of dovetail wear and suggests hardware and software enhancements available to mitigate the potential risk caused by operating conditions that promote such wear.

Steering committee

Syed Mehdi Ali, GM operations, K-Electric Ltd (Pakistan)
Dale Anderson, GT technician/foreman, East Kentucky Power Co-op Inc
Tracy Dreymala, facility manager, San Jacinto Peakers, EthosEnergy Group
Ronald Eldred, plant manager, Rosemary Power Station, Dominion Energy
Guy LeBlanc, supervisor, Consolidated GT Plants, First Energy Corp
Tony Ostlund, combustion turbine technician, Puget Sound Energy
Doug Reves, outage coordinator, Arkansas Electric Co-op Corp
Randall Rieder, mechanical engineer, ATCO Power (Canada)
Mike Vonallmen, maintenance supervisor, Clarksdale Public Utilities
Lane Watson, account engineer, FM Global

Stay connected with colleagues year-round via the user forum.