DC FRT Analysis and Disturbance Propagation of Grid-Forming HVDC Converters in Future MTDC Systems

The ongoing energy transition is driving a growing interest in multiterminal DC (MTDC) systems and grid-forming (GFM) control strategies. As an increasing share of renewable energy sources (RES) is connected to power systems through converter-based interfaces, conventional synchronous generators are progressively displaced, leading to reduced system inertia and weaker voltage references. In this context, MTDC systems equipped with advanced control and protection schemes are expected to play a key role in ensuring both transmission capability and system stability. This paper presents a system-level analysis of an MTDC network behaviour during DC fault ride-through (DC FRT) events under a partially selective DC protection philosophy, with a gradual introduction of GFM control for DC voltage…