Australian Snowy Mountains Hydro Scheme earthing system safety assessment

The task of determining the condition of the earthing in the Upper Tumut generation system, was undertaken as part of the Snowy Mountains Hydro Electric Authority's (SMHEA) safety risk assessment and asset condition monitoring programme. The testing programme to ascertain performance under earth fault and lightning conditions had to overcome considerable physical difficulties as well as the restrictions of 'close' proximity injection loops. The application of software, test instrumentation and testing procedures developed within Australia in collaboration between Energy Australia, Newcastle University, and SMHEA, to obtain real solutions are described in this paper. Also discussed are condition assessment processes that complement the current injection testing programme. This paper also provides a summary of the minimum requirements of an earthing system injection test to satisfactorily assess the condition of complex electrical power system installations.