Improved overhead line conductors using aluminium alloy 1120

Power conductors utilising the new high conductivity medium strength aluminium alloy type 1120 have been used for transmission and distribution lines in Australia since 1984. Unlike traditional aluminium alloys such as 6201 and 5005 the 50% increase in strength of alloy 1120 over standard EC grade aluminium is accompanied by only a slight reduction in conductivity. Overhead line conductors using this alloy provide lower I²R losses without appreciable capital cost penalty. Introduction of these new alloy conductors provides a significant development in transmission line technology. This paper traces the introduction of this alloy in Australia, the development and testing of such conductors, together with details of its application by one major utility