A direct current to alternating current inverter sub-system is for a HVDC distribution system. The DC to AC inverter sub-system includes an enclosure and a DC to DC galvanically isolated buck converter having a DC input electrically connectable to a HVDC cable and a DC output. A DC to AC inverter includes a DC input electrically connected to the DC output of the DC to DC galvanically isolated buck converter and an AC output electrically connectable to an AC transmission line. The DC to AC inverter is mounted in an enclosure with the DC to DC galvanically isolated buck converter, in order that the DC output of the DC to DC galvanically isolated buck converter is directly electrically connected within the enclosure to the DC input of the DC to AC inverter.