Inspec keywords: HVDC power transmission; relay protection; HVDC power convertors; power transformer protection; power transmission protection

Other keywords: DC under-voltage protection relay; DC harmonic current-restraining element; current-restrained DC under-voltage protection method; inrush phenomenon; bipolar HVDC system

Subjects: Transformers and reactors; Power system protection; d.c. transmission; Power convertors and power supplies to apparatus