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Analysis of hydraulic pressure transients in the waterways of hydropower stations
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
2011 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Hydropower plants have the ability to go from a full load to no load in just a few

seconds. In order to go from full load to no load in a few seconds the flow is

controlled by movement of guide vanes. At fault detection the guide vanes closes

quickly for safety reasons. This causes hydraulic transients in the waterways, which

leads to a pressure rise in the spiral case and a pressure drop in the draft tube.


There have been a few accidents related to these quick closures of the guide vanes

where the runner blades break and entire power stations are damaged. These

incidents are caused by a full column separation in the draft tube. An early sign of a

full column separation is large cavities. The main objective of this degree project is to

analyse the effects of a quick closure of the guide vanes and to make a guide book of

how to find indications of large cavities when performing closure tests. Data taken

from commissioning and status tests for several turbines were analysed.


In conclusion, the guide book of how to find indications of large cavities will help

analyse the results of a quick closure of the guide vanes. Due to the unique

appearance of pressure transients for each power station this guide book will not be

enough for a complete analyse of a closing test. Although, it will help to notify when

there is a need for further analyses by expert personnel.

Place, publisher, year, edition, pages
2011. , 73 p.
UPTEC ES, ISSN 1650-8300 ; 11007
Keyword [en]
Hydropower, pressure transients, full column separation, large cavities, reverse waterhammer
Keyword [sv]
Vattenkraft, trycktransienter, separation av vattenpelare, vattenslag, större kaviteter
URN: urn:nbn:se:uu:diva-152187OAI: diva2:412851
Available from: 2011-05-02 Created: 2011-04-26 Last updated: 2011-05-02Bibliographically approved

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