Comparison between utility sub-station and imitative earthing systems when subjected under lightning response

► Performance of utility sub-station and imitative (purposely-built) earthing systems are investigated. ► Different behaviours of both earthing systems at power frequency and under impulse conditions are observed. ► At power frequency, as expected utility sub-station has lower earth resistance due to its larger size. ► However under impulse conditions, the earth resistance for imitative earthing systems is lower. ► This shows that the performance under lightning is different than that at power frequency.