Before the operation of the Kuanbang project

the Gaoling back-to-back DC（here in after referred to as the Gaoling DC） transmitting system has such problem as insufficient voltage support capability and DC blocking after the fault of AC line.After operation of Kuangang project

a channel to the truck of northeast grid is added from Gaoling DC.Power flow analysis

short-circuit ratio analysis

transient stability analysis

etc.are commonly used in the stability analysis of DC and its supporting projects.In this paper

static voltage stability analysis based on the forward analysis is added.Finally

the control strategies of pre-control DC power and returning DC power by the stability control device are proposed for the voltage stability problem after the fault of the near-area AC system in the Gaoling DC transmission terminal.This strategy can improve the stability of Gaoling DC and has been applied for actual operation.The analysis method and control strategy used in this paper have a definite applicability in the stability analysis of DC system and its accessory project.