Sustained Overvoltages in Offshore Wind Farm Array Cables under Islanding Conditions

Offshore wind plays a pivotal role in the UK’s net-zero transition and the decarbonisation of power systems. The increasing deployment of high-capacity wind turbine generators (WTGs) and the expansion of larger, higher-voltage (66 kV) offshore array networks introduce new challenges for transient analysis and stability. This paper presents electromagnetic transient simulation results investigating sustained overvoltages in offshore wind farm inter-array cable systems. An asymmetrical fault followed by islanding was studied, revealing significant phaseto-earth overvoltages on healthy phases, reaching up to 3.5 pu and persisting for several cycles.