A paradigm shift from Grid Following (GFL) to Grid Forming (GFM) converter control has been proposed by some transmission system operators to address challenges around severe contingencies, and other stability problems that are observed in power systems with few remaining synchronous generators and large long-distance power flows. In Europe, requirements for GFM converter controls for Power Plant Modules (PPMs) have been included as additional requirements in the German grid code for HVDC-connected PPMs, and as an non-compulsory service in the GB grid code. Compared to GFL controls, GFM-controlled converters’ power setpoint tracking exhibit larger dynamic excursions during network disturbances. In wind turbine generators (WTG), GFM reverts to stronger coupling between network dynamics and turbine mechanical loads than hitherto largely decoupled with GFL in full-converter turbines. Implementation of GFM on WTGs therefore faces several obstacles that make the application challenging. A concept study is presented in this paper showing how GFM controls may be implemented on a WTG while respecting design limitations and providing key GFM control functions, including inertia power provision and fast reactive power response to voltage amplitude changes. Electro-magnetic transient simulation results and full-scale converter test rig results are provided.
Engelken et al. (Sun,) studied this question.