OIL & GAS INDUSTRY FOCUS REDUCING DOWN-TIME
When regular maintenance checks on a high voltage 60MW generator at a large oil refinery signalled a potential earth fault in the rotor, engineers were keen to have a repair completed as soon as possible. The engineering manager contacted Sulzer to carry out the repair and subsequent testing
S
ulzer specialises in delivering rapid repairs to high voltage equipment and was able to offer
an efficient, bespoke service to repair the rotor at the refinery in just eight weeks. Sulzer operates manufacturing and testing facilities located throughout the world, so is able to provide a global turnkey service to keep power plant generation capacity in operation. In the power generation business, speed is of the essence, especially for maintenance work that can result in generating capacity down- time. When it is the generator’s rotor itself that needs repairing, the timing of the steps toward resuming normal output is crucial. Sulzer worked in partnership with the client to
quickly identify a solution and formulate a plan of action for the repair of the rotor. Sulzer provided an inspection report and quote to overhaul the rotor within the constricted deadline.
A PLAN COMES TOGETHER With lost production costs looming, the plan was put into action. The rotor was shipped from Italy to the Birmingham Service Centre site, where work began on the initial strip down. In a project such as this it is frequently possible to reuse the rotor’s retaining rings, provided they are in satisfactory condition. However, detailed inspection following the strip down revealed that in this case they would have to be replaced. To provide a fast track solution
for the client and minimising site down-time costs, Sulzer was able to produce a set of replacements for the vented 800mm diameter stainless steel rings utilising its established materials supply network and in-house large precision machining facility. In many cases rotor windings can also be reused,
having first cleaned them and reapplied the insulation. However, in this instance, reuse was not possible and so new windings had to be manufactured and tested before the rebuild. Upon further inspection by the Sulzer team, it
was found that the rotor body wedges would also have to be replaced - a further task for the designers and the machine shop. With all of the new components remanufactured and tested, the team could begin to rebuild the rotor. Sulzer’s Keith Barbier commented, “Having
worked in this industry for over 30 years I have seen many rotors being repaired, and it is rare for
Sulzer
www.sulzer.com T: 0121 766 6161 /AUTOMATION
all three components to be in need of replacement at one time. Our repair team at Birmingham Service Centre was able to remain flexible and we were able to deal with every aspect of the rotor repair, managing the project from concept to completion on behalf of the client.” Having completed the rebuild and the
electrical, static and mechanical tests, the rotor was then checked for rotational balance, using the company’s own purpose built large capacity overspeed balancing pit. During the process the rotor is first accelerated to its normal operating speed of 3,000rpm, any balance corrections are made, then the rotor is subsequently tested in an overspeed condition, in this case specified by the client at 3,600rpm. Barbier added, “The balancing facility in
Birmingham can accommodate rotors up to 12 metres in length and weighing up to 40 tonnes, with the ability to test at speeds up to 5,200rpm. High speed balance relieves residual stresses introduced during the repair process and allows the rotor components to settle into place. Following a high speed balance
at the Birmingham Service Centre, engineers review the results to ensure that any imbalances have been corrected and will not affect the future performance of the rotor. This forms the final step in a truly unique in-house, turnkey offering for the power generation industry. “Fortunately the client employed excellent proactive maintenance procedures which were able to highlight a potential issue before it developed into a fault. Fortunately we were able to manage the project in-house. This meant we could control costs and meet very short deadlines - even as the task escalated in complexity and resource requirements, while keeping the client informed throughout the repair process.”
Enter 206
Enter 11
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56