We worked closely with Jacobs Engineering to provide specialist earthing system consultancy for the Shell Corrib Gas Terminal, Co. Mayo. The Terminal is an on-shore gas processing facility that will provide up to 60% of Ireland’s gas at peak supply. Premium Power conducted an engineering study to determine if earthing grids installed at the facility were compliant with IEEE80.
The Terminal was constructed on an excavated bog. The majority of the terminal site was constructed on bed rock which is not conducive to a suitable earthing system. Earth grids were therefore installed in bog soils adjacent to the terminal site but at a distance away from switchrooms. Premium Power were engaged to determine if the earth grids would create dangerous touch and step voltages during electrical faults.
Premium Power conducted a detailed analysis of the earthing grids at the terminal site. A software simulation was developed that reflected the characteristics of the soil and the copper conductors placed in the ground at the terminal site. The software model was utilised to analyse the touch and step voltages that would be observed during faults.
“We modelled the earth grids and were able to identify that the earth grids designed were within the limits imposed by IEEE80. These studies are of critical importance in the design of substations and ensure the safety of workers both within and outside of the substation fence boundary."
Premium Power determined that the earth grids were sufficient to ensure that touch and step voltages were within limits guided by IEEE80. As a result, the Client did not have to make alterations to existing installations and the proposed fencing off of the ground above the earth grids or the placement of rock or crushed stone was not required.