In this paper

the operation status of AC and DC filter capacitor in domestic DC converter station is introduced

and through comprehensive analysis and comparison of internal structure of AC and DC filter capacitor as well as fault in recent years

the three reasons leading to high fault rate of capacitor is summarized: Internal insulation aging

unstable performance of internal fuse and unreasonable design of connector.Four optimization suggestions are proposed

which provide a definite reference value in optimizing design of capacitor and improving operation reliability of AC and DC filter capacitor of DC converter station.