The arc furnace electric system will make appearance of more harmonic current at the series resonant point and the parallel resonant and influence of series resonant is larger for the system.

Although this may be sad from a physical point of view, all nonphysical forces shall retract and carry on, returning to those creations that they are resonant with for their own return cycle ahead.

The difference between a hard switching and quasi resonant flyback converter is the turn on time point of the primary switch.