Control Strategy for Smooth Transition of DC Distribution Network Operation Mode

With the development of society, traditional AC distribution networks are increasingly difficult to meet the higher requirements brought about by economic and social development. Compared with the traditional AC distribution network, the DC distribution network has obvious advantages. Due to the large scale of the traditional power grid, it is cost-effective to transform the existing distribution network into an AC/DC hybrid distribution network. In order to make the DC distribution network achieve voltage stability under different working conditions, this paper introduces an improved voltage deviation control strategy to optimize the traditional voltage deviation control strategy and droop control strategy. This paper verifies that the improved voltage deviation control strategy can balance the load when the main converter station is out of operation. In addition, the operating modes of each power electronic device are analyzed, and the voltage smoothing control strategy that can maintain the AC network voltage and load demand that loses power is introduced. Simulations show that these two control strategies can work effectively when the system changes in operating mode.