The existing 3x Sag Mill Cycloconverter transformer utilises a loop in loop out cable supply arrangement (instead of dedicated supply to each transformer). This has cramped the 33kV termination box, particularly as the existing cables utilised are 300mm2 Cu 19/33kV three core ind.screened PVC/SWA/PVC Sheathed. This resulted in high levels of Partial Discharge between the various cores as they were not meeting the 33kV minimum clearance requirements at the various points of the termination/cable core tails.
ERM was engaged to redesign the cable entries and the termination box/busbar arrangement in order to maximise clearances (compliant to Australian Standards – AS2067) and re-terminate all cables. ERM produced a detailed Scope of Work document as well as design drawings and executed the works on site with highly skilled and specialised resources