• norsk
    • English
  • English 
    • norsk
    • English
  • Login
View Item 
  •   Home
  • Fakultet for informasjonsteknologi og elektroteknikk (IE)
  • Institutt for elkraftteknikk
  • View Item
  •   Home
  • Fakultet for informasjonsteknologi og elektroteknikk (IE)
  • Institutt for elkraftteknikk
  • View Item
JavaScript is disabled for your browser. Some features of this site may not work without it.

Harmonic filter design for large offshore wind power plants

Rasmussen, Stian
Master thesis
Thumbnail
URI
https://hdl.handle.net/11250/2787225
Date
2021
Metadata
Show full item record
Collections
  • Institutt for elkraftteknikk [2339]
Description
Full text not available
Abstract
 
 
This thesis was written in collaboration with Vattenfall, with the objective of simulating, analysing, and

identifying the main factors influencing the harmonic distortions in HVAC connected offshore wind power

plants and, with this information, discuss methods for harmonic filter design and its location.

The sensitivity analysis contained many cases and DIgSILENT PowerFactory was used to simulate them.

The cases covered changes in external grid modeling, changes in various components impedance, varying

cable lengths, landfall cable voltage level, as well as TSO filter type, size, location, and component tolerances.

The results were sorted into three broadly defined impact categories: Low, medium, and high impact,

based on the harmonic distortions at the four PoC buses. Very few of the cases significantly influenced the

voltage profile at the PCC. It was also found that the external grid harmonic emissions were the cause of

the largest harmonic distortions in the system, and not the wind turbines. Some of these findings are most likely model specific, and more rigorous testing might be needed to generalize the findings. However, some key takeaways from this thesis is that the level of detailed knowledge about the external grid harmonic emissions and impedance profile has a large influence on the resulting harmonic voltage profile in the system. This is likely true independent of the model. Another large influence on the harmonic distortion is the landfall cable lengths, voltage level, and cable types.

Three filter groups were designed for various buses in the system. Two of them had adequate performance,

and only one was used for further testing. Two of the cases from the sensitivity analysis were simulated with

the filter installed, which found that the filters were unable to properly attenuate the distortion at the PCC in

one of the cases. An analytical model was then created for the two buses around the landfall transformer,

where two Th´evenin equivalents were used: One for the external grid, and one for the landfall cable and

wind turbines. This was done in trying to evaluate the influence of the landfall transformer. A sensitivity

analysis was conducted based on the impedance in this circuit. It was hypothesized that the combination of

the landfall transformer and external grid impedance was the cause, although more detailed testing and analysis

would be needed to make firm conclusion based on this. Thus, the results indicate that close proximity

to the most severe source of harmonic injections might not be an adequate location of the filter. The findings

from this assessment are thought to be case (or model) specific, and it is uncertain whether they apply to

other systems as well.
 
Publisher
NTNU

Contact Us | Send Feedback

Privacy policy
DSpace software copyright © 2002-2019  DuraSpace

Service from  Unit
 

 

Browse

ArchiveCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsDocument TypesJournalsThis CollectionBy Issue DateAuthorsTitlesSubjectsDocument TypesJournals

My Account

Login

Statistics

View Usage Statistics

Contact Us | Send Feedback

Privacy policy
DSpace software copyright © 2002-2019  DuraSpace

Service from  Unit