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Annual Report 2015
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NOWITECH
Norwegian Research Centre for Offshore Wind Technology
WPC
GRID AND WINDFARMS
Summary of results 2015
WPC has good cooperation between industry and
research partners. The annual work programme
is determined through a match between industry
needs for research and innovation and the
scientific expertise amongst research partners. In
2015 two new activities were the result of high
industry prioritisation by wind farm developers:
The investigation into long distance HVAC cable
transmission, and wideband modelling of a 66
kV wind farm for investigation of harmonics and
resonance phenomena.
Three PhD students associated with WPC
successfully defended their theses, Dr RA Barrera
Cardenas, Dr. Z Zhang, and Dr M Valavi. All three
have wind energy related employment. The three
remaining Nowitech funded PhD candidates (M
Pedersen, PC See, A Soloot) are expected to defend
their theses in 2016. Two associated candidates
(VC Tai and PK Olsen) are also expected to finish
in 2016, while one (AG Endegnanew) will continue
into 2017.
WPC has produced seven peer-reviewed scientific
articles in 2015, five reports, and ten conference
presentations and posters. Two key publications are
• M Valavi, A Nysveen, R Nilssen,
Effects of
Loading on Radial Magnetic Forces and
Vibration in Low-Speed Permanent Magnet
Machine with Concentrated Windings,
IEEE
Transactions on Magnetics
51
(2015), doi:1109/
TMAG.2014.2377014. This study investigates
vibrations in wind turbine direct-drive
generators, and shows that the spatial harmonic
responsible for some of the vibration is affected
by d-axis currents. The result is important
because it gives an improved knowledge basis
for designing better wind turbine generators
with lower
vibrations.
• A Soloot, HK
Høidalen, B
Gustavsen,
Influence of the
winding design
of wind turbine transformers for resonant
overvoltage vulnerability,
IEEE Transactions on
Dielectrics and Electrical Insulation
22
(2015),
doi:10.1109/TDEI.2015.7076828. This study
investigates potential resontant overvoltages
in wind turbine transformers due to switching
transients, and their dependence on winding
Methods to supply wind energy
to offshore oil and gas platforms
has been a big activity in
NOWITECH.
PhD candidate
Current employer
Thesis title
Cárdenas, René
Alexander Barrera
JSPS fellowship
Univ Tsukuba
Meta-parametrised meta-modelling approach for
optimal design of power electronics conversion
systems: Application to offshore wind energy
Valavi, Mostafa
PostDoc
NTNU
Magnetic Forces and Vibration in Wind Power
Generators: Analysis of Fractional-Slot Low-Speed PM
Machines with ConcentratedWindings
Zhang, Zhaoqiang
Greenway Energy AS
Ironless Permanent Magnet Generators for
Direct-Driven Offshore Wind Turbines
Table 5: WPC PhD candidates successfully finishing in 2015.