Abstract:This paper analyzes the flexible interconnected distribution network, and analyzes the principle of MMC converter and its control strategy. On the basis of hybrid MMC topology, the protection system of MMC converter is studied, and then the control and protection device is arranged, and the basic functions of the test device are analyzed and verified. Then the distribution center is divided into three sections, including DC distribution center, AC micro grid and DC micro grid, which is studied in different operating modes. Under the multi-controller''s multiple control strategies, the fault recovery and undisturbed switching and other related capabilities are studied under different operating modes. It also interacts with the vertical information between the system layer and the system layer, then use RTLAB to build a flexible interconnected power distribution network control test model, and verify the development whether the control and protection system meets the requirements of the project. Finally, the simulation results of the established model show that the device has high reliability and accuracy, meets the actual engineering requirements, and has great research value.