Research Group Description

To reduce electrical losses and investment cost of HVDC-connected offshore wind power plants, it is proposed to let the wind farm’s internal power collection network become medium-voltage DC rather than medium-voltage AC. Such a paradigm shift entails new solutions in the entire chain from wind turbine to HVDC export cable:

• Wind turbine DC converters (~10MW, ±50kV)
• MVDC cables
• MV/HV DC/DC converters (~hundreds of MW, ±50kV/±320kV)
• MVDC distribution substation and network control & protection.

This not only requires development of new essential components that work together in a new system configuration. Therefore, we:

• Investigate different DC network topologies for power flow control, security of supply, while establishing a foundation for equipment rating (cables, converter stations
• Explore and demonstrate 50kV converter design using relevant power semiconductors
• Explore and demonstrate high‐frequency converter transformer designs with low‐loss steels, suitable winding arrangement and insulation systems, leading to the construction of a prototype
• Study methods to secure DC network stability and power quality
  Develop insulation co‐ordination for DC networks and assure fault clearance capability
• Promote early standardisation of the ensemble of components in DC networks and equipment functionalities based on findings
• Develop MVDC system simulation models and simulation environment.

With the above, we aim to identify the optimal - and feasible - DC collection solution(s) in terms of configuration, equipment ratings, operational characteristics.

MVAC based offshore wind farm: One or more wind plants with substation, connected to a single HVDC offshore converter.

MVDC based offshore wind farm: plant power collection at medium-voltage DC & offshore step-up HVDC converter.