The ongoing international demonstration project (ITER) will be located on a 1200 m long and 800 m wide platform belonging to an even larger site including neighboring areas to the site boundary fences. This whole complex requires a full grounding system which constitutes an electrically large grounding grid. Due to the long construction time, a particular attention is required to deal with safety problems during the different phases. Safety of persons in contact with the cranes during a fault is a major concern and must be prevented by adequate grounding mitigation measures. This paper describes a new methodology of touch voltage assessment under a crane due to the ground potential rises and the current distribution in metallic structures during a substation fault. This paper focuses on the 50 Hz analysis and related safety aspects.
