It depends, when talking about interconnecting cables between countries, yes the majority are DC, both to minimise transmission losses and also to tie together

It depends, when talking about interconnecting cables between countries, yes the majority are DC, both to minimise transmission losses and also to tie together grids working at different frequencies.... In terms of km installed I think it will be HVAC just from the sheer number of offshore windfarms built over the last 10yrs in Europe. These things can be huge - 60km in length, 220kV ~1500A....