Grid Integration Impacts of Hydrostatic Transmission-Based Wind Turbines

Power systems have traditionally relied on synchronous generators to maintain system strength and physical inertia, with various “synchronous” attributes being seen as increasingly important as converter-based renewable energy sources (RES) displace conventional generation. As a result, synchronous wind turbines, known as Type V, with the capability to provide similar characteristics to conventional synchronous machines may become more attractive for future high-RES power systems. Among various Type V concepts, hydrostatic transmission-based wind turbines (HSWTs) present an interesting alternative, whereby hydrostatic transmission is employed to transmit power from the turbine rotor to a directly grid-connected synchronous generator. Since many grid codes for wind turbines follow similar requirements to those for conventional machines under steady-state and dynamic conditions, this paper focuses on exploring the grid integration impacts of HSWTs in terms of grid code compliance and system service provision, to provide insights into their achievable capabilities when interacting with the grid.