A power supply arrangement adapted to provide auxiliary power to a wind farm that feeds into a HVDC transmission link is provided. The power supply arrangement has an auxiliary power supply to deliver auxiliary power (Paux) to the wind farm; a backfeed control for initiating provision of a backfeed voltage on the HVDC link during a wind farm downtime; a backfeed switch to close a DC current path between the HVDC link and the auxiliary power supply; and a power converter for converting the backfeed voltage into auxiliary power (Paux). A wind farm arranged to feed into a HVDC transmission link is also provided, having such a power supply arrangement for providing auxiliary power (Paux) to the wind farm during a wind farm downtime. A method of providing auxiliary power (Pbackfeed) to a wind farm during a wind farm downtime is also provided.