Overload Control of the Embedded HVDC for Hybrid AC/DC Power System Security Enhancement

This brief presents an overload control scheme for hybrid AC/DC power system security enhancement by utilizing the flexible controllability of the embedded HVDC. Sensitivities of AC line power with respect to the embedded HVDC are deduced based on the structural characteristics of the grid, predetermining transmission lines that can be effectively adjusted by the embedded HVDC. The overload control of the embedded HVDC system is then proposed based on flexible DC power adjustment and AC/DC interaction. Overloads can be quickly relieved through real-time emergency power support, avoiding further risks that may threaten system security and reliability. Simulations under the IEEE 39-bus system with the embedded HVDC prove the effectiveness of the proposed control, realizing the rapid elimination of potential overloads and higher regulation capabilities of the hybrid AC/DC power system.