A Voltage Integrated Strategy in DC Distribution Network Based on Droop Control

DC power distribution technology has become the focus of attention because of its small line loss, high power supply capacity, saving a large number of DC/AC commutation links and controllable components. In this paper, the multi-terminal DC distribution network containing distributed generations is taken as the research object. Firstly, the voltage droop control method of DC distribution network is discussed. The purpose of optimizing voltage is achieved by voltage deviation compensation, and then controller structure at converter station is designed. Secondly, the voltage integrated control strategy is proposed. The voltage adjustment mode is divided into normal voltage regulation, accident voltage regulation and emergency voltage regulation according to the magnitude of DC voltage deviation. The main converter station acts as a balance node during the normal voltage regulation. During the accident voltage regulation, the battery is switched from the standby state to the voltage droop control to maintain the DC voltage. In the emergency voltage regulation, measures such as reducing power of the wind turbine and photovoltaic unit or cutting off some loads are adopted. Finally, simulation model of the six-terminal low-voltage distribution network is established on Matlab/Simulink, and the effectiveness and real-time performance of the voltage integrated control strategy are verified.