Improved observability in the power system: Rotor angle measurements and support from faster voltage control swegrids-logo

SweGRIDS research area Flexible Power Systems
SweGRIDS project code FPS20
Project type PhD
Status running
Researcher Vinicius Albuquerque   (webpage)
University UU
Project period 2020-05 to 2023   
Project supervisor Urban Lundin   (webpage)
Industrial sponsors Svenska kraftnät, Vattenfall


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Project abstract

This project is linked with FPS19, having the same reference group and shared supervision.

The new kinds of energy producers connected to the grid add challenges to the power stability by not contributing to inertia, voltage control, or damping.

Power system stability relies that larger synchronous machines stay synchronized. During contingencies, and even normal operation, the rotor angle swings. If the swings are too large the electrical machine falls out of phase with the grid and is disconnected. The stability is governed the equal area criteria, but also depends on the amount of damping from voltage regulators and damper circuits. The rotor angle can be estimated from knowledge of stator voltages and currents, field current and machine constants including saturation.

The project aims at investigating rotor oscillations in hydropower stations during faults, in expectation on finding ways to damp oscillations that may cause de-synchronization.


Summary of work

Real data from the Älvkarleby Hydroelectric station has been processed through a frequency-estimation algorithm on SIMULINK. This data has allowed the estimation of both electrical and rotor angles, making it possible to identify small-signals oscillations on the rotor angle. The same oscillations were also identified on the instantaneous power, in both active and reactive, delivered by the machine. In the near future, we expect to use the same code to analyze more prominent grid faults, and its effects on the physical quantities of the generator.

Additionally, we have been working on a parallel project that aims at further controlability of the exciter circuit of a generator by placing a rotating power electronics box at the rotor of the machine. We hope to investigate how fast-switching at the exciter field can help with oscillations damping through experimental work.


Event log

2020-11-12. Project Pitch Presentation at SweGRIDS 2020 Conference (digital).


Project reference-group

Project-specific reference group
Robert Eriksson,  SvK
Jonas Persson,  Vattenfall
Mehrdad Ghandhari,  KTH
Urban Lundin,  UU

Broader reference group connecting to other generator-related work at UU
Jouni Ahtiainen,  Fortum Hydro AB
Peter Altzar,  Fortum Hydro AB
Per-Olof Andersson,  Vattenfall Hydro AB
Rolf Gustavsson,  Vattenfall R&D
Mats Wahlén,  Svea Power AB
Mattias Nässelqvist,  Vattenfall Hydro AB
Per Norrlund,  UU/Vattenfall R&D
Bo Hernnäs,  VOITH Hydro
Jesper Nyberg,  Svenska kraftnät
Mikael Sendelius,  SWECO
Håkan Hermansson,  Vattenfall V-kraft emeritus
Joakim Näsström,  Vattenfall R&D
Christer Lundblad,  Skellefte kraft AB


Publications by this researcher

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Publication list last updated from DiVA on 2021-09-18 22:00.


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Page started: 2020-05
Last generated: 2021-09-18