NewsSouth Upgrades for electricity grid backbone 26/08/2020 FacebookTwitterEmail The upgrade project involves replacing 4,900 insulator strings on 660 transmission towers between Powerlink’s Calvale (near Biloela) and Halys (near Kingaroy) substations. PICTURE: Contributed. x Work has restarted on a $15 million project to strengthen Powerlink’s inland transmission network between Southern and Central Queensland. Powerlink […] Subscribe or Login to see the rest of the content. Username Password Remember Me Forgot Password