Impedance Source Inverter Wind Turbine and DC Collection System: Fault Ride-Through Analysis

This paper investigates into Fault Ride-Through (FRT) competency during momentary fault interruption of 40 parallel-connected offshore Wind Turbine (WT) unit, in Medium Voltage Direct Current (MVDC) configured transmission system. It proposes to model both aggregative MVDC collection and wind energy conversion systems using Impedance Source Converter (ZSC) in solid-state transformer design and define their corresponding control system architecture. To verify, analytical studies on FRT capabilities against voltage violation events and high inrush current during WTs' start-up were compared with IEEE1547-2018 requirements based on grid-following operation. Simulation studies were conducted in PSCAD environment and have shown positive FRT performances when injected with 100ms fault signals at WT's low-voltage AC line. It proved to efficiently regained stability in a reduced timespan due to aggressive droop control feature rendered by ZSC and endorses positive power quality regulatory despite direct coupling to a weak distribution network: closer to demand loads.