Follow Current (i-follow)    IEC

The current immediately following an impulse through an EGLA with the power frequency voltage as the source; the external series gap shall be able to interrupt follow current due to external leakage current on a polluted arrester body (SVU) as well as due to internal resistive current through the non-linear metal oxide resistor blocks; that is, the performance of the EGLA under polluted conditions is introduced by the gap resealing performance under wet and polluted condition, and it is verified by the follow current interruption test.