The constant power control of new energy and load side converters in short-term voltage oscillations will show negative impedance characteristics

weaken the damping of DC power grid

and easily induce continuous DC voltage oscillations. We firstly establish a transient stability model of DC distribution network under droop control

expound the definition of DC voltage inertia and damping

and analyze the key factors influencing the transient characteristics of the system. Secondly

we propose a control strategy that the DC bus voltage variation is introduced to dynamically adjust the droop coefficient and enhance DC voltage damping. In view of the increase of DC voltage drop caused by the damping control strategy

a transient voltage stability control strategy is proposed by improving the DC bus voltage outer loop control and combining it with the voltage damping control strategy

which can not only improve the system damping

but also reduce the voltage deviation caused by the damping control after the voltage oscillation is suppressed. Finally

a six-terminal DC simulation system is built to verify that the proposed control strategy can effectively suppress the system oscillation

reduce the voltage deviation after oscillation

and significantly improve the transient stability of the system.