When transmission lines operate with series capacitors and shunt reactors， under certain circumstances， the series capacitor of fault phase can discharge through the shunt reactors and the secondary arc after the fault phase is shut off. It is a low frequency component against the single pole reclosure. With the EMTDC simulation and Laplace transformation analysis， this paper analyzes the feature of this low frequency component in a long-distance series compensated transmission line with and without switching station. With the increase of transmission distance， the decay factor and oscillation frequency increases at the same time， and the stored charge will be discharged faster. When the transmission line is with switching station， although the series capacitor of fault phase in fault line section is bypassed， the series capacitor of fault phase in healthy line section still discharges through the secondary arc under certain conditions. This low frequency component sometimes is serious and harmful to single pole reclosure. Based on these results， adoption of limiting the low frequency component and optimizing the scheme of series and shunt compensations are discussed.