Modeling offshore wind farm disturbances and maintenance service responses within the scope of resilience

Offshore wind farms are becoming ever more important means of energy production. Accordingly, they are started to be considered critical infrastructures with heightened attention on their protection and resilience. This paper studies how the maintenance service can sustain or recover offshore wind farm operations under different stressors. We conduct this study by modeling the failures in an offshore wind farm and how maintenance service is able to correct them. Our model enhances the traditional cause-consequence trees by including dynamical aspects, and the modeling of the maintenance process. Special attention in the maintenance model is given to limited personnel and material resources, as well as limited access to wind turbines. This limit is a result of occasional harsh weather conditions that make conducting repairs unsafe. The model is applied for two representative disturbance scenarios: a cyber-attack leading to high failure rates and a high-impact incident causing numerous simultaneous failures. The second scenario integrates results from a physical power system simulation that are used for depicting the incident. The results show that our model can present scenarios where different stressors challenge the operations. These can be used for testing and defining requirements for future countermeasures to improve the resilience.