A Strategy for Enhanced Resilience of the NEOM Grid U-shape HVDC

U-shaped multiterminal HVDC (MT-HVDC) modules, deliberately designed to facilitate largescale integration of renewable generation. Each U-shaped module resembles a four-terminal bipolar system with a dedicated metallic return (DMR). One of the U-shaped terminals feeds a 2 GW isolated load island (Giga-Grid); therefore, incorporating an energy storage system (ESS) or generation into the Giga-Grid can improve transient stability and short-term security of supply when one or both poles of the demand-side converters fail. To provide a sustainable solution for Giga-Grid security of supply, this paper presents various strategies to address the vulnerabilities of the U-shape or Giga-Grid to critical contingencies such as DC faults or incidents that incapacitate one or both poles of the demand-side converters. The effectiveness of the presented strategies is substantiated by extensive electromagnetic transient (EMT) simulations. Results of carefully selected simulation cases are presented, discussed, and contextualized, and the major findings of the study are highlighted.