High voltage earthing system testing - an investigation into the effects of test lead coupling on test results

Abstract

High voltage earthing system testing is the focus of this research project, in particular the effects of test lead coupling when conducting soil resistivity tests. Many of the tests conducted to verify the correct and efficient design of an earthing system, are carried out using and AC signal of specified frequency, with very low level readings of voltage and current recorded by a test set or technician. With measured signals being very low amplitude (often in the milli-volt and milli-ampere range, for example) the effects of test lead coupling, can reasonably be expected to have a significant effect on the results obtained. The intent of this research project is to attempt to quantify such effects and to deduce a mathematical relationship to predict or quantify coupling effects. The aim is to allow for improved test accuracy and hence improve the quality of the results, of such testing