The overhead line of HVDC power transmission system needs positive and negative leads only, allowing for high power, low loss and long distance power transmission;
Shackle insulators for high voltage overhead lines
Insulators and fittings for overhead lines. Metal fittings. Twining and bracing rods (TG).
Insulators and fittings for overhead lines. Metal fittings. Galvanized square tubes (TG).
Insulators and fittings for overhead lines. Metal fittings. Sealing arm (BS).
Pin insulators of ceramic material for high voltage overhead lines--Dimensions and characteristics
The paper describes the basic switching impulse test results of phase-to-phase insulation in EHV substations and overhead lines.
That makes installing subsurface cables 12 to 17 times as pricey as overhead lines, according to National Grid (they also need replacing sooner).
