The applications, selection principles, technical requirements, and test requirements for dry type and liquid-immersed neutral-grounding devices used with high-voltage direct current (HVDC) converter transformers are discussed. HVDC converter transformers with a star-connected winding on the grid side and a delta-connected winding on the valve side are applicable to this guide.

This guide recommends the application conditions, selection principles, technical requirements, and test items for neutral-grounding devices (reactors) of converter transformers in high-voltage direct current (HVDC) transmission systems. This guide applies to converter transformers with a star-connected winding on the grid side and a delta-connected winding on the valve side.

The purpose of this guide is to summarize the principles of selecting neutral-grounding devices for HVDC converter transformers to help address the problem of single-phase short-circuit currents in HVDC substations with directly grounded converter transformers.