Determination of a frequency-dependent transformer model through grid impedance measurements
Publication date
2020-12-01
Document type
Konferenzbeitrag
Organisational unit
Project
Publisher
VDE Verlag
Book title
NEIS 2020 : Conference on Sustainable Energy Supply and Energy Storage Systems, Hamburg, 14 – 15 September 2020
First page
121
Last page
127
Peer-reviewed
✅
Part of the university bibliography
✅
Language
English
DDC Class
620 Ingenieurwissenschaften
Keyword
Grid impedance
Transformer model
Frequency-dependent parameters
Abstract
In this work, a frequency-dependent transformer model is derived with the help of a measurement device that determines the frequency response of the grid impedance at an arbitrary point of connection to the power grid. In this case, the measurement device was connected to a 20 kV medium voltage grid of a wind farm. The disconnection and reconnection of the wind turbine’s transformers revealed the impact the open circuit input impedance of the transformers has on the positive sequence component of the grid impedance. First deriving a positive sequence grid model from the measurement without the transformers, later analyzing the impact the transformers have on the grid impedance, allowed the calculation of the positive sequence component of a frequency-dependent open circuit transformer model, which results in the same impact on the overall grid impedance as observed in the measurements.
Version
Published version
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Metadata only access