Aurora was contracted by Ferguson Johnson to asses the Earth Potential Rise (EPR) associated with a 400kV National Grid transmission line through a planned residential estate.

Aurora’s scope of work was to assess each of the tower bases, for a phase-earth fault and calculate the associated touch potential, EPR and transferred potential risk of the Hot Zone onto the adjacent LV and 11kV earthing system. Aurora developed a detailed model of the tower base in SESCAD, and then carried out a detailed analysis of the fault current distribution in the transmission line using the CDEGS TRALIN and SPLITS modules.

In addition, Aurora also carried out an assessment of touch voltage risks for incoming lightning strikes and the risk of induced voltages on nearby metallic structures using the EMTP-ATP software package.