Preventive dispatch method for coordinated topology optimization of transmission and distribution networks

Extreme disasters, such as typhoons, can cause serious damage to lines, which poses a significant threat to the power supply of critical loads. An effective approach to enhance supply security is the flexible adjustment of the power system topology to redirect power flows and optimize load transfer. However, many studies have addressed optimal transmission switching (OTS) and distribution network reconfiguration (DNR) in isolation, with limited research on coordinated transmission and distribution topology optimization for improving resilience. This gap may result in overly conservative preventive dispatch strategies and an underestimation of resilience. To overcome these limitations, this paper incorporates coordinated topology optimization measures, including OTS, DNR, and post‑fault line repair, into a unified preventive scheduling framework to withstand disasters. An improved alternating direction method of multipliers (ADMM) algorithm, with a penalty multiplier updating strategy based on objective function deviation, is employed to solve the proposed preventive scheduling model. Finally, the proposed method is validated by two modified test systems. In the test system consisting of one IEEE-118 and five IEEE-33 bus systems, the results indicate an 8.91% reduction in load shedding and a 2.89% decline in total cost.