Behaviour of surge protective devices under lightning ground potential rise: Findings from a desk-top study

Specific points in IEEE Standard 1692 suggested that surge protective devices may not adequately protect equipment under conditions of lightning ground potential rise (GPR). With no further information from the standard, this behavior of a particular surge protective device (SPD) was investigated by means of a desk-top study. As reference signatures, common mode and differential mode waveforms presented by the SPD, with full complement of components and when individual components were removed from the SPD, were captured under impulse conditions without emulated lightning GPR. The SPD was then applied in the test set-up with emulated lightning GPR. The study clearly showed the importance of correctly bonding components downstream of the SPD. When not correctly bonded, the SPD behaved as if the transient voltage suppressor diode of the SPD was not present that led to expected downstream equipment damage.