Modular multilevel converter(MMC)start-up is a primary problem confronted by MMC-high voltage direct current(HVDC)engineering applications.Based on the modular multilevel converter HVDC,a new ordered charging method is proposed for the remote start-up of a project to decrease the DC voltage drop of the converter valve and bridge arm current impact the instant it's unlocked the traditional way.After the process of traditional uncontrolled charging,the DC voltage station is unlocked,then other converter stations are uncontrollably charged by bypassing the sub-module according to the voltage level.Finally,the stations are unlocked until the voltage of the sub-module is sufficiently high.The method has greatly reduced the DC voltage drop and bridge arm shock current for the passive converter station during start-up.Theoretical analysis has been made to obtain the largest voltage drop using this method,and simulation has been done to verify the feasibility of the method.The method can effectively reduce voltage drop,while making no particular requirements on the boot sequence and moment for unblocking.And single-arm design enables it to be reused for all arms,making it applicable to the multi-terminal flexible DC system for remote start-up and post-locking restart online because of AC faults.