In a new type of power system, submodules play a key role as the basic unit in the power system that constitutes a complex power electronic device, especially in the modular multilevel converter. The modular multilevel converter is usually composed of a large number of submodules in series, and at the same time, a multi-submodule structure is proposed for different application scenarios and optimization objectives, with several fixed voltage outputs for each submodule, and each submodule usually contains a half-bridge circuit or a full-bridge circuit, which achieves precise voltage control through PWM modulation. At this stage, most of the data transmission between the submodules and the valve control system in the power system adopts the point-to-point transmission mode, and each submodule is configured with a pair of transceiver optical fibers, thus requiring a large number of optical fibers to be laid between the valve control equipment and the valve tower, which is difficult to construct, costly, and inconvenient to maintain, etc. This paper proposes a networked communication scheme between the submodules in response to this problem, which greatly reduces the communication optical fibers between the valve control and the submodules without reducing the original communication fiber between the valve control and submodule, while not reducing the original control accuracy, for the design of subsequent projects with reference to reference significance.