2013 Siemens 501F and 501G Users Group: Issue 2

ALERT: Steam can flow backwards and erode trailing edges of last-stage turbine blades

Steam turbines (ST) often exhibit leading-edge erosion on the last-stage blades (LSB) of the low-pressure (LP) section. Combined-cycle steam turbines often operate at part load, introducing a new problem to the LSB row: Erosion of the trailing edge (TE). Brent Gregory and Ryan Yamane of Creative Power Solutions, Fountain Hills, Ariz, told the editors they are seeing cases where a flow condition, developed in the ST itself, has caused TE erosion of LSBs. While last-stage steam-flow behavior at partial load may be well understood by turbine OEMs, that may not be the case for condenser manufacturers, which play significant roles in determining ST discharge conditions. more

HRSG, valve issues addressed during major overhaul; M&D added to GTs, transformers

NV Energy had the luxury of time for the first gas-turbine major inspection at its Walter M Higgins Generating Station, located in Primm, Nev, near the California border about 40 miles southwest of Las Vegas. Higgins is a 2 x 1 combined cycle powered by 501FD2 gas turbines from Siemens Energy Inc. With demand still down from pre-recession levels, the company conducted the outage when temperatures were moderate, from February to May, thereby avoiding the overtime and premium services normally associated with a major. This was the only GT major conducted by the utility in 2013. more

Ultrasonic flowmeter differentiates between water and steam in HRSG drain lines

You may recall the old one-liner, "Everyone complains about the weather, but no one does anything about it." The same could be said about superheater and reheater drain systems for heat-recovery steam generators (HRSGs). Improperly specified, designed, and/or installed drains continue to support welders and aftermarket suppliers of SH and RH harps, headers, and tubes despite years of discussion at user-group meeting regarding the origin of the problem and appropriate corrective action. However, ongoing work sponsored by EPRI is expected to finally help owner/operators protect their HRSGs by providing positive indication of condensate-free heat-transfer panels and drain systems prior to plant startup. more

Fleet-wide transformer monitoring program reduces losses

In 2011, a large generating company experienced unplanned outages at two of its powerplants when a generator step-up unit (GSU) failed unexpectedly because of bushing problems. The loss of generating capacity, the cost of replacement, and the fear that other units might be at risk made it clear to the company that it needed to get a better handle on its transformers and their health. In response, the power producer created an enterprise-level Transformer Program. In operation for little more than a year, the program has already identified eight critical problems and estimates are that it has avoided more than $6 million in replacement/outage costs. more

Aftermarket competition among OEMs, third parties benefits 501F owner/operators

The annual meetings of the 501F and 501G Users Groups are among the best industry events for conducting due diligence on engine parts, services, and upgrades, and for purchasing decision-making. The reason is simple: Two major OEMs, Siemens Energy Inc and Mitsubishi Power Systems Americas Inc (MPSA), participate and compete head-to-head to serve a global fleet of about 450 F-class engines. Both manufacturers get significant podium time at the conference and by listening carefully to each you can decide on questions to ask the other. No machine is perfect and competitors generally are willing to share what they believe is wrong with the other guy's equipment. more 

You can never be too safe

The 501G Users Group, chaired by Plant Manager Steve Bates, GDF Suez-Wise County Power Co LLC, is a close-knit organization. Unlike most other user groups, it has a low percentage of first-timers. Almost everyone in the meeting room either knows most everyone else present or knows someone from his or her plant. Another factoid that sets the 501G users apart from the pack. Each plant in the fleet sends an average of two or three employees to the meeting. Most other groups average about one or less. At the last meeting, the safety discussion, led by Bates, was robust and beneficial to virtually all plants powered by gas turbines. more 


2014 Annual Conference
Feb 16-20 @ Rancho Mirage, CA


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