Effect of ground return path on impulse characteristics of earth electrodes

This paper investigates the effect of the return current path on the impulse characteristics of practical tower footings. A new circular ring electrode system is used as a return electrode for measuring the impulse response of earth electrodes. Initial measurements and computer simulations show that this system makes the current flow radially away from the electrode and dissipates more evenly in the ground. Measurements carried out with different test configurations allow the investigation of impulse response for the same test electrode. In particular, these results are compared with those carried out using the commonly used single return electrode, which emphasised the advantages of the test technique using circular return electrode.