Impact Mechanism of DC Power Recovery Speed on Transient Stability After Sending-End AC Fault

The sending-end power systems with high proportion of new energy have insufficient support capacity and poor ability to withstand fault shock. It is urgent to improve the transient stability of sending-end power systems (TSSPS). This paper theoretically analyzes the mechanism of the effect of DC power recovery speed on TSSPS after AC faults at the transmitter side. Firstly, the sending end power system and the DC power recovery process were modelled. Secondly, the direction of oscillation of the relative rotor angle is discussed, which is caused by the AC faults at the transmitter side. Then, the DC power flow model is established, and the analytical expression of the relative power angle with respect to the DC power is derived theoretically, thus the impact mechanism of the power recovery speed on the TSSPS is revealed. Finally, the correctness of the presented impact mechanism is validated using the AC/DC asynchronous interconnection test power system.