Hi,
I've been reading through posts regarding transmission lines and the pros & cons of using AC or DC but one thing I haven't found much of is a discussion on is the efficiency of converting DC voltages (stepping up or down). I realize using high voltage decreases power loss and that's why we started using transformers & AC back in 1895 at Niagara Power but I've also read a lot about DC transmission lines that are in use today, notably the Pacific lines.
How does the efficiency of the DC to DC converters used by the power companies compare with transformers that would be handling simiilar amounts of power?
I've read that interconnection and switching are other issues with DC transmission, could someone explain these, why DC has issues, why AC doesn't, and what might be done to make DC work? Also, are there any other serious disadvantages to using DC for transmission now days, aside from infrastructure changes?