Measured and calculated GIC at the TRP1 transformer in Vandellòs. They correspond to the event on 24 to 25 October 2011. The measured GIC is in red. The results are from analyses that used either a uniform ground conductivity set to 0.001 S/m (blue), a layered conductivity structure according to Pous et al. (1995) (green), a layered conductivity structure according to Viljanen et al. (2012) (black), or a uniform ground conductivity under the condition where the Vandellòs-Pierola transmission line was switched off (pink).