Diode rectifiers (DRs) have elicited increasing interest from both industry and academiaas a feasible alternative for connecting offshore wind farms (OWFs) to HVDC networks. However,before such technology is deployed, more studies are needed to assess the actual capabilities ofDR-connected OWFs to contribute to the secure operation of the networks linked to them. This studyassessed the capability of such an OWF to provide support to an onshore AC network by means of(active) power oscillation damping (POD). A semi-aggregated OWF representation was considered inorder to examine the dynamics of each grid-forming wind turbine (WT) within a string whenproviding POD, while achieving reasonable simulation times. Simulation results corroboratethat such an OWF can provide POD by means of OWF active power controls similar to thosedeveloped for OWFs connected to HVDC via voltage source converters, while its grid-forming WTsshare the reactive power consumption/production and keep the offshore voltage frequency andmagnitude within their normal operating ranges. Open-loop test results show that such capabilitycan, however, be restricted at operating points corresponding to the lowest and highest values ofactive power output.
Coordinated Control of Offshore Wind Farm and Onshore HVDC Converter for Effective Power Oscillation Damping
