Considering the importance of the status of secondary arc to the single-phase auto-reclosure of extra high voltage transmission line
a novel approach based on the harmonic of faulted phase is proposed to determine the arc status
where the characteristics of the prime and secondary arcs and the oscillation of the faulted phase with different compensation levels are analyzed
then the total harmonic distortion(THD)is introduced to reflect the harmonic content of the faulted phase. The EMTP simulations at different compensation levels indicate that after the arc extinction
the THD of the faulted phase gets distinctly low to judge arc status.