Supervisor:
Professor Frede Blaabjerg

Co-Supervisor:
Professor Claus Leth Bak

Assessment Committee:
Associate Professor Sanjay K. Chaudhary, AAU Energy (Chair)
Professor Soledad Bernal-Perez, Universitat Politècnica de València
Christian Frank Flytkjær, Energinet

Moderator:
Associate Professor Filipe Miguel Faria da Silva

Abstract:

The share of offshore wind power in power generation is growing faster than ever to meet the ambitious net-zero targets and boost sustainability. Thus, offshore wind farms (OWFs) may need to provide advanced grid services such as black start, previously provided by conventional power plants. To become new black-start sources, OWFs may use a self-start unit, in the form of a grid-forming converter and additional energy storage to enhance availability despite adverse wind conditions. Based on this, the focus of this Ph.D. project is to investigate the integration of grid-forming converters and storage systems into OWFs to provide black-start capabilities. To do this, black-start requirements for non-conventional power plants and the analysis of the challenges that these new requirements pose to current OWF design have been presented. Furthermore, the analysis of grid-forming control, as opposed to grid-following, and the different control topologies available in the state-of-the-art literature has been carried out. Finally, the black-start control and operational philosophy for the OWF have been outlined. Hence, this Thesis presents the implementation of two different configurations which could carry out a black start by an OWF with an integrated battery energy storage system (BESS) and grid-forming control. Electromagnetic transient (EMT) simulation results are performed and compared with additional sensitivity analysis to show the resilience of the proposed operation. Overall, the black-start capability of an OWF with the proposed configurations is validated.