Protection Strategies for the Connection of Diode Rectifier-Based Wind Power Plants to HVdc Interconnectors

The connection of diode rectifier (DR)-based wind power plants (WPPs) to existing or planned high-voltage dc (HVdc) interconnectors can lead important savings on cost and system robustness. Since the DR station usually operates in a bipolar configuration, its symmetric monopoles is particularly challenging. However, there are no published detailed studies protection WPPs monopole even interconnectors. This article includes comparative study five different strategies for such systems, including both solid resistive grounding with without use dc-circuit breakers (dcCBs). An analytical allows calculation fault current during onset half-bridge hybrid modular multilevel converter (MMC) stations. Using electromagnetic transient (EMT) simulation studies, evaluated terms current, voltage, isolation requirements each element, as well need dcCBs, fast communication, larger surge arresters. Moreover, distance detection algorithm included turbine converters distinguish between local ac-grid dc-cable faults. From results, it possible conclude that high-impedance grounding, together protection, be used DR-based offshore connected requiring dcCBs.