Thesis
Novel applications of grid-forming converters in offshore wind farms
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2025
- Thesis identifier
- T17492
- Person Identifier (Local)
- 201972363
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- The global shift from fossil fuel-based generation to renewable energy sources is transforming the operation and stability of electrical grids. Offshore wind power plants are central to this transition, but their integration through long high voltage alternating current transmission systems presents significant stability challenges. As conventional synchronous machines are phased out, new approaches are required to provide essential services such as inertia, frequency regulation, and reactive power support. This thesis develops and evaluates a control and compensation framework to address these challenges. Several transmission system topologies were studied, combining different shunt reactor placements with either grid-forming or grid-following converter control. Steady-state, small-signal, and electromagnetic transient analyses show that the best-performing configuration is the one using grid-forming control with shunt reactors placed at both ends and at a mid-point of the transmission cable. This arrangement achieves the highest stability, particularly for long cable lengths and weak grids, increases the maximum stable transmission distance, and remains robust under variations in short-circuit ratio, avoiding the instability observed with grid-following control in similar conditions. The research also examines the ability of alternating current-connected offshore wind power plants to provide power system restoration. Results show that a balanced mix of grid-forming and grid-following control can meet all technical requirements for restoration. For top-up restoration scenarios, 40% to 60% grid-forming penetration delivers the highest stability, while for anchor restoration scenarios, 20% to 40% is optimal. The addition of an external frequency supervisory controller reduces frequency dips during restoration and enables recovery without synchronous generation, allowing reliable self-start of the plant. Through comprehensive simulations and analysis, this work demonstrates that offshore wind power plants equipped with the proposed control and compensation framework can provide both enhanced steady-state stability and dependable power system restoration capability, offering a practical pathway for replacing conventional synchronous plants in future low-carbon grids.
- Advisor / supervisor
- Egea-Àlvarez, AgustÃ
- Kneuppel,Thyge
- Resource Type
- DOI
- Funder
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PDF of thesis T17492 | 2025-10-01 | Public | Download |