Investigating the Converter-Driven Stability of an Offshore HVDC System

摘要: Offshore wind farms are increasingly built in the North Sea and number of HVDC systems transmitting power to shore increases as well. To connect offshore adjacent AC transmission systems, onshore modular multilevel converters transform transmitted from DC vice versa. Additionally, modern mainly use turbines connected point common coupling via voltage source converters. However, their control can cause unwanted interactions, referred converter-driven stability problems. The resulting instabilities be predicted by applying an impedance-based analysis frequency domain. Considering that converter models system data often confidential cannot exchanged real this paper proposes enhanced impedance measurement method suitable for black-box applications investigate interactions. A response identifies currents depending on system. subsequently added achieve higher accuracy. proposed is applied assess system’s stability, using measurements laboratory a turbine controller replica. results show interacts with grids moderate short-circuit ratios. no interactions identified between farm.