HVDC control strategies to improve transient stability in interconnected power systems

Abstract—This paper presents three HVDC modulation strate-gies to improve transient stability in an interconnected power sys-tem. AC variables such as rotor speeds, voltage phasors, and tie-line power flows are used as input to the controller that modifies the power flow settings through the HVDC-links. The proposed techniques are tested on the IEEE 24-Bus reliability test system and critical clearing times obtained for several contingencies are analyzed. The paper shows that HVDC modulation can lead to substantial improvement in transient stability. I