With the development of DC transmission technology

the operation reliability and economicefficiency of DC filter HV capacitor has become a research focus.In this paper

the aspects of grading between capacitor unit

internal fault protection of the capacitor and economic issue are analyzed in accordance with the condition of HV capacitor of DC filter of certain UHVDC transmission project and for the 3 types of H wiring unbalance protection scheme of HV capacitor of DC filter

thinking that under the premise of allowable design and manufacturing level

the HV capacitor of UHVDC filter adopts proposal 1 and/（with internal fuse capacitor） type H wiring internal fault unbalance protection mode.In case of big harmonic current

the internal fault unbalance protection of HV capacitor of UHV DC filter can still adopts original principle which is set as per the breakdown short serial number of the element

but the fuse feature and corresponding of the internal fuse need to be calibrated.