Powerline earthing design in compliance with the latest Australian Standard on Overhead Lines, AS/NZS 7000:2010

This paper presents a powerline earthing assessment carried out based upon the latest Australian Standard on Overhead Lines, AS/NZS 7000:2010. The 33kV powerline under study supplies a mining process plant spread over a relatively large geographical area. A number of on-site soil resistivity tests have been undertaken to identify the electrical characteristics of the local soil, followed by network analysis in DIgSILENT PowerFactory to obtain the most onerous earth fault parameters. Safety step and touch voltage limits are obtained in accordance to AS/NZS 7000. Finally detailed modelling analysis in CDEGS software package investigates the most economically efficient earthing design that complies with the safety voltage criteria obtained from AS/NZS 7000.