Availability up, user interest in the LMS100 gains momentum

The first LMS100 began commercial operation at Basin Electric Power Co-op’s Groton (SD) Generation Station 11 years ago. As of January 2017, 61 units were operating, according to Charlotte-based Strategic Power Systems Inc (SPS), which tracks powerplant equipment performance for the industry.

The OEM reported that through Dec 31, 2016, its LMS100 fleet had accumulated more than 525,000 hours of operation and more than 78,500 starts. Interestingly, the fleet leader accounted for nearly 10% of total fleet operating hours, the starts leader 8.5% (round numbers) of total fleet starts.

Fleet availability improves. SPS engineers told participants in the LMS100 breakout at the 2017 Western Turbine Conference & Exhibition in Las Vegas that fleet availability continues to improve, based on operating data gathered from 37 of the 61 units participating in the company’s Operational Reliability Analysis Program (ORAP®) program.

More specifically, the 23 ORAP participants in peaking service recorded 95.7% availability for the November 2015 – October 2016 survey period. Additional simple-cycle plant data for this group of engines:

      • Forced outage factor (percentage of time the unit is in a forced outage), 1.7%.

      • Maintenance outage factor (percentage of time the unit is in a maintenance outage), 0.3%.

      • Planned outage factor (percentage of time the unit is in a planned outage), 2.2%.

      • Service factor (percentage of time a given unit is producing power at any level), 12.3%.

      • Service hours per start, 4.5.

Jason King, O&M manager at the eight-unit Sentinel Energy Center LLC in North Palm Springs, Calif, and the LMS100 breakout chair, developed the technical program with the OEM and Western Turbine colleagues, but was unable to attend the meeting. Board Member Rick McPherson, plant manager of NRG’s five-unit Walnut Creek Energy Park in the Los Angeles Basin, and former LMS100 Breakout Chair Don Haines, managed the sessions in King’s absence.

Users representing operating assets, and owner/operators interested in the LMS100, were among the more than 50 participants in this breakout. Haines reminded those in the first group that their commitment to information-sharing was necessary to drive continuous improvement across each plant and the overall fleet.

To support this effort, the LMS100 Users have established, and strongly recommend, using the following two avenues for ongoing communication:

      • Monthly conference call (first Wednesday at 1 p.m. Pacific). Contact the chairman for details.

      • Yahoo LMS100 Users Group, facilitated by SPS, to help users stay current on technical and logistical issues impacting the fleet.

SPS analytics. Information-sharing was a theme of the SPS presentation to the group by Tom Christiansen, who also was responsible for taking the session notes posted at www.wtui.com for registered user members of the organization. He urged those not currently participating in the ORAP program to do so, a larger sample ensuring that the metrics provided users are meaningful and statistically representative of fleet performance.

SPS’s Analytics Portal™, Christiansen continued, allows ORAP users to view their plant data in an Internet-based, on-demand business intelligence interface highlighting KPIs (key performance indicators) of interest. He encouraged users not already using the portal, which is updated quarterly, to contact SPS and get signed up.

The lion’s share of Christiansen’s presentation focused on the leading causes of LMS 100 forced outages, both in numbers of occurrences and their duration in hours.

Forced-outage incidents in the November 2015 – October 2016 evaluation period were split this way: station equipment (BOP), 37%; package, 33%; supercore, 15%; LPC (a/k/a booster compressor), 10%; generator, 4%; power turbine, 1%. The hot SCR was charged with the highest number of incidents, 66—nearly three-quarters of which were at three sites unable to control emissions and engines were shut down to avoid air-permit violations. Another 13 incidents were attributed to issues with ammonia systems at five sites.

Not surprisingly, perhaps, controllers and software were cited for 45 incidents, second on the list of top contributors. Third through fifth places: the LPC (VBV issues dominated), power distribution (breaker and relay issues dominated), and emissions monitoring.

Next were 19 incidents at four sites related to NOx water injection, 17 lubrication incidents (half attributed to leaks), combustion (10 incidents at two sites related to flame-outs and failures to light), hydraulic control-oil (package), fire protection, and engine hydraulic control.

WTUI user members can access the details on the organization’s website, where the non-OEM presentations are posted along with Christiansen’s 16-page chronology of the LMS100 sessions. GE presentation materials are available on the company’s services portal.

Top contributors to forced-outage hours during the evaluation period were divided this way: GE-supplied package, 41%; station equipment, 31%; LPC, 17%; supercore, 10%; generator, 1%. The LPC was charged with the highest number of forced-outage hours. About half of the 917-hr total was assessed against VBV trips caused by solenoid trips, broken gearwheel, servo malfunction, etc.

Package lubrication issues were second in FO hours, three-quarters of those caused by oil leaks and another 10%-plus by chip detector problems. Controllers and software, power distribution, and emissions monitoring were the No. 3, 4, and 5 top contributors in terms of hours.

Outage experiences and lessons learned surfaced several times during the two-plus days of breakout sessions. Interestingly, much of the information shared also is applicable to other aero models as well as frames. The takeaways are summarized below.

The performance of field-service organizations is a frequent topic of discussion at user-group meetings. The editors have observed over the years that it is not unusual for plant managers to review the lineup of service personnel scheduled for a given outage and possibly postpone work until people with a good track record at their facility are available.  

If you’re successful in this regard, consider taking the extra step during negotiations to lock in key personnel for the duration of the outage—in writing. One user at the meeting experienced a so-called “hand-off.” Despite an agreement in principle, the service provider pulled the plant’s primary contact within two days of the outage. In this case, the user’s perseverance paid off and the promised staffing was reinstated.  

An example was shared during one of the LMS100 breakout sessions by a user who had two very different experiences with one service organization during consecutive annual outages. In the first outage, all the variable-geometry hardware was pulled and on install a blade was inadvertently turned 180 deg. It came lose in operation and trashed the engine. A different team performed well during the next outage and the site will request that group for future work.  

Another attendee suggested adhering to the cardinal rule of always checking the work done by any supplier because when they leave the site it’s still your engine and you have the responsibility for its performance. This, of course, means that your “checker” must have the knowledge and experience to know when something might be wrong with the work done.    

Yet another participant said he always assigns a person to work directly with field-service personnel to oversee what they are doing. Hold points may be of value, too. Work can proceed to a specified point and then must stop until what has been done is inspected and signed off by the plant. Once again, it is incumbent on you to provide a capable person for that assignment—in-house or from outside your organization.

Specific to the LMS100, a site reported having to replace two low-pressure compressors within a period of only a few months. The service provider, which was affiliated with the OEM, was said to have been good with the supercore, but not as experienced with the LPC side, which was derived from the MS6001FA frame. In prior outages, the attendee continued, tooling also was lacking for the LPC. Apparently, better communication between the OEM’s aero and frame engineers would have benefitted this owner.

Two points of view during open discussion about the value of CSAs, contractual services agreements:

      • Case 1. CSA signed by previous management. Although the fee was thought reasonable, expectations were very high and not always met.

      • Case 2. Site ran without a CSA for several years and it was difficult. Once a CSA was in place, the user felt GE had “skin in the game” and things got better at the site.

FOD prevention and awareness. Foreign object damage is not unique to any engine model. The OEM reported that there were five FOD events in the LMS100 fleet in the last year, usually discovered during a periodic borescope inspection. Findings were throughout the engine: booster compressor (LPC), HPCR, IPTR (second-stage blade), and power turbine. A GE engineer offered insights on how to mitigate FOD risk. One: Vigilance by site personnel is critical to preventing FOD events. Maintaining combustion-air flow path cleanliness is especially important.

Lube-oil best practices received some discussion. Points made included these:

      • Sample lube oil quarterly, maintaining a level of consistency on how the fluid is sampled and tested. Be aware, the group was told, that inconsistent sampling and test procedures can skew results.

      • Two reports of significant oil losses, one plant lost 350 gal and the other about 1200, both attributed to loose connections. The OEM recommended periodic inspections of oil connections.

Fire protection. Keep a spare set of CO2 bottles on hand to speed recovery in case of an accidental dump. A heads-up from a user who told the group his plant’s insurance company requires a fan pressure check every time the package roof is pulled to ensure that CO2 will not leak out. The site had to purchase testing equipment for this purpose. No one else in the room reported being saddled with the same requirement—yet. 

Plant and instrument air. A site reported using a jockey compressor to manage air requirements when the unit is not operating. ROI was two years—lower electrical costs, less wear and tear on the large air compressor. Jockey sizing can be tricky, so plant personnel rented until they found the correct size and then made the purchase.

Turning-gear failures were reported by several sites because of water in the oil. One plant’s solution: Install a desiccant breather on each machine. Another’s: Change oil semi-annually.

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