<p>This thesis is an evaluation of a new design concept for statorfeets in Gallejaur hydro power plant. Founder of the work is Vattenfall AB Vattenkraft. During the 70- and 80´s nuclear power began to be phased in to the Swedish grid, which meant that hydropower became an important source of rules. The generators began running in so called intermittent operations instead of basic operations, which meant 300-600 start/stop per year instead of one-ten numbers start/stop per year. In order to deal with the thermal forces that arise at every start and stop suppliers began to mount so called sliding joints, which is to take advantage of these forces and maintain the stator shape. This, however, led to unforeseen consequences.</p><p>The evaluation is a part of a major project, witch started in 2005 with regards to bring down the shutdown time on generators because of the sliding joints, witch are mounted on many older machines today. The sliding joints have tended to stick during operation resulting in serious consequences. Consequences such as cracks in the concrete foundations and stator core buckling causing long shutdown and providing a high level of production lost.</p><p>VG Power who delivered the concept has developed a foot, which ensures that the stator retains its shape when it expands due to the thermal forces arising from the boot and stop of the generator. Analysis and validation of design and calculations made at VG Power shows that the concept is very well dimensioned and can handle the demands that Vattenfall has in the specification. Analysis and validation of operational data from five operational cases also shows that the concept works very well. The concept shows among other things that:</p><ul><li>Movement of the new feet’s follows a clear pattern of movement when starting and stopping the unit.</li><li>The concept is well dimensioned, good margins for safety and stability are provided.</li><li>The concept is suited well for older units.</li><li>The design allows for a safer operation because of reduced maintenance that the concept requires.</li><li>High availability</li></ul><p>Further studies concerning the test of the concept strength is to start a fatigue rig to test whether the concept can handle the intense stress of the micro – movement that occurs during operation. It is important that Vattenfall is examining and doing an analysis on the micro – movement that occurs in the blocks where Vattenfall surveillance system Conwide not allow sufficiently high sampling rate. During a visit to Vattenfall Research And Development in Älvkarleby rust was discovered on the attachment, which requires further consideration of VG Power. It is and important parameter relevant to maintenance and durability.</p>
| Identifer | oai:union.ndltd.org:UPSALLA/oai:DiVA.org:uu-120078 |
| Date | January 2010 |
| Creators | Karlsson, Daniel |
| Publisher | Uppsala University, Industrial Technology |
| Source Sets | DiVA Archive at Upsalla University |
| Language | Swedish |
| Detected Language | English |
| Type | Student thesis, text |
| Relation | TVE ; 10 002 |
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