Impact Assessment of Converter Neutral Grounding on Transient Performance in Rigid Bipole VSC-HVDC Systems

Voltage Sourced Converter (VSC) based High Voltage Direct Current (HVDC) technology has become prominent in recent years due to increasing need for flexible, efficient, and controllable power transmission over long distances. Among the different VSC-HVDC topologies, rigid bipole configuration is widely adopted due to its simplicity and cost-effectiveness. However, unlike full bipole configurations, with a dedicated metallic return, rigid bipole DC neutral buses can often lack a direct electrical reference to ground, making it particularly sensitive to unbalanced pole loading, fault conditions and switching operations.