Embodiments herein describe operating a first wind turbine using an auxiliary control system when a high-voltage link coupling a wind park to a grid is not functioning. When using the auxiliary control system, the first wind turbine provides power to a local AC grid which can be used to power auxiliary system in a second wind turbine while the second wind turbine is shutdown. However, when the high-voltage link is functional, the first and second wind turbines provide power to the high-voltage link using a primary control system.