Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Analys av tryckmätningar i Kaplanturbiner
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
2019 (Swedish)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesisAlternative title
Analysis of pressure measurements in Kaplan turbines (English)
Abstract [en]

In a risk situation the flow through a hydropower turbine must be reduced under a short amount of time. The reduction in flow causes low pressures in the region called draft tube under the runner in the turbine. If the pressure drops below vapor pressure the water in the turbine may evaporate and form large cavities. The phenomenon called water column separation describes the situation when these cavities of vapor forms and eventually collapses which may damage the unit and canbe a danger to personnel at site.

Different types of flow reducing maneuvers are tested before commissioning turbines in order to detect dangerously low pressures but these measurements can be difficult to interpret. The measured draft tube pressure can be filtered numerous ways and in addition other measured or calculated parameters must be studied to fully understand the consequence of a measured emergency stop.

In this paper the different ways of filtering and interpreting the measurements from stops in Kaplan turbines were analyzed. The results show that the choice of filtering method can significantly impact the interpretation of a stop and that the filter parameters often used do not result in equivalent results. The standard way to filter draft tube pressure with moving average filters is shown to result in much higher draft tube pressures than low-pass filters and the filter parameter used needs to be further investigated to correctly isolate pressures caused by water column separation. The main difference between different companies when it comes to these measurements are the used cutoff frequency when using low-pass filters and the sampling frequency of measurements.

Place, publisher, year, edition, pages
2019. , p. 54
Series
UPTEC ES, ISSN 1650-8300 ; 19016
Keywords [en]
Hydropower, pressure transients
Keywords [sv]
Vattenkraft, trycktransienter
National Category
Energy Systems
Identifiers
URN: urn:nbn:se:uu:diva-387852OAI: oai:DiVA.org:uu-387852DiVA, id: diva2:1330818
External cooperation
Vattenfall AB
Educational program
Master Programme in Energy Systems Engineering
Supervisors
Examiners
Available from: 2019-06-26 Created: 2019-06-26 Last updated: 2019-06-26Bibliographically approved

Open Access in DiVA

Analys av tryckmätningar i Kaplanturbiner(2223 kB)25 downloads
File information
File name FULLTEXT01.pdfFile size 2223 kBChecksum SHA-512
236628c33a474529ed6c5e4e8b586fb533540f442f7b99ffd5dfb8c4abff9f31a5e76d49864efeb2dec6514351219f6b3c96face4be13af7a4267f50f9417ea8
Type fulltextMimetype application/pdf

By organisation
Department of Physics and Astronomy
Energy Systems

Search outside of DiVA

GoogleGoogle Scholar
Total: 25 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 116 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf