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Voltage dip caused by the sequential energization of wind turbine transformers. I. Arana, J. Holbøll, T. Sørensen, A. H. Nielsen, O. Holmstrøm, P. Sørensen. SALES AND DISTRIBUTION. PRODUCTION. OPTIMISATION. PRIVATE CLIENTS PUBLIC CLIENTS BUSINESS CLIENTS WHOLE- SALE ENERGY EXCHANGES. - PowerPoint PPT Presentation
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Voltage dip caused by the sequential energization of wind turbine transformers I. Arana, J. Holbøll, T. Sørensen, A. H. Nielsen, O. Holmstrøm, P. Sørensen
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DONG ENERGY – Business Model
PRODUCTION OPTIMISATION SALES AND DISTRIBUTION
NATURALGAS
OIL
RENEWABLE ENERGY
COAL
BIOMASS
PRIVATECLIENTS
PUBLICCLIENTS
BUSINESSCLIENTS
WHOLE-SALE
ENERGYEXCHANGES
Power
DONG ENERGY – Past and future
Exploration and production of oil and natural gas
Generation of power at conventional power plants and renewable energy plants
Sales of electricity and gas to end consumers including energy saving consultancy services
3
After the merger, DONG Energy is active in every link of the energy chain
Current Nysted (132MW) Horns Rev (64MW) Barrow (45 MW) Burbo (90 MW)
Developing Horns Rev 2 – offshore, Denmark (209 MW) Gunfleet Sands I – offshore, UK (108 MW) Gunfleet Sands II - offshore, UK (65 MW) Walney I - offshore, UK (151 MW) Storrun - onshore, Sweden (30 MW) Karnice I, onshore, Poland (30MW) London Array On- and offshore projects in Denmark, Germany, UK, Poland, France, Sweden, and Norway
Almost 80 projects on pipeline DONG Energy’s Social Responsibility Report 07
By 2020, we will triple our capacity of renewable energy to approximately 3,000 MW. 500 Wind turbines contract with Siemens Wind Power
Wind power plants
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Nysted Offshore Wind Farm (2003)
21-04-235
GPS synchronized measuring system (2007)
21-04-236
Va, Vb, VcIa, Ib, Ic
Va, Vb, VcIa, Ib, Ic
Va, Vb, VcIa, Ib, Ic
Validated transformer model from NOWF
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Transformer energization measured and simulated currents at WT A09 from 15 ms to 70 ms.
Overview of sequential energization of transformers
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9WTx0s 5WTx5s 2WTx2s 1WTx1s
A01 0,1 5,1 6,1 8,1
A02 0,1 5,1 6,1 7,1
A03 0,1 5,1 6,1 6,1
A04 0,1 5,1 4,1 5,1
A05 0,1 0,1 4,1 3,1
A06 0,1 0,1 2,1 3,1
A07 0,1 0,1 2,1 2,1
A08 0,1 0,1 0,1 1,1
A09 0,1 0,1 0,1 0,1
Voltage phase angle switching
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Voltage and current at platformVzero A01 to A09 sequence
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Real and reactive power Vzero A01 to A09 Vzero A09 to A01
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Reactive power and voltage
higher Q are the ones where the energization starts in A01
largest Vdip are the ones with peak voltage switching
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Sympathetic current/voltage dip Vzero A01 to A09 Vzero A09 to A01
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Validated model NOWF-> several radial energizations using PSCAD voltage dip
switching angle number of simultaneously energized transformers energizing sequence direction
wind turbine transformers are switched-in independently smallest voltage dips, and lowest inrush current
energizing direction, with 0° and 90° switching angle starting with A09 the transformer at the far end of the cable radial starting with A01 at the end of the cable radial closest to the wind park transformer higher Q are the ones where the energization starts in A01 largest Vdip are the ones with peak voltage switching
The reactive power from the previously energized transformers varies every time a transformer is energized; and it was found that this reaction depends on the relative location of the transformers
Standard transformer models PSCAD Assess energization voltage dips against the UK P28
Conclusions
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Sympathetic reaction from the neighboring transformer Superimposed effects Standard transformer model On-going work
No generalization Systematic study for each wind farm
Nine wind turbine transformers energized simultaneously Not even 2% voltage dip was present.
Individual transformer energization in zero voltage switching Lowest voltage dip of 0,26%
Voltage dips can be assessed by detailed simulation studies Questionable if the UK P28 for voltage dips are at all relevant for wind farms
given that wind turbine transformers are switched at worst a few times a year.
Discussion
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This work is made as part of an Industrial Ph.D. project supported by the Danish Ministry of Science, Technology and Innovation, project number 08-041566.
The switching transient measurements used in this study were obtained in the project titled “Voltage conditions and transient phenomena in medium voltage grids of modern wind farms”, contract 2005-2-6345, supported by the Danish TSO Energinet.dk.
Acknowledgment
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