Before revision: is the fundamental component of the current and is the total current —both are root mean square-values (distortion power factor can also be used to describe individual order harmonics, using the corresponding current in place of total current).
After revision: is the fundamental component of the current , is the total current , and is the current on the hth harmonic; all are root mean square values (distortion power factor can also be used to describe individual order harmonics, using the corresponding current in place of total current).