Study on the time and duration of restart on the AC/DC interconnected system based on dynamic energy

Abstract

Concerning the difficulty in determining the restart strategy for AC/DC interconnected systems, this paper proposes a method of calculating the optimal restart strategy for AC/DC interconnected systems based on dynamic energy. First, a dynamic energy function that characterises the stability of system is constructed. Then, the analytical expressions of the dynamic energy function are calculated separately for the deionisation stage, the restart stage, and the alpha retard stage of the entire restart process. On this basis, the variation rate of the system dynamic energy is defined as the energy accumulation rate, which quantifies the accumulation or consumption of dynamic energy during the restart process, and facilitates detailed analysis of the effects of the restart time and restart duration on the stability of system. Then, a method to calculate the optimal restart time is proposed with the goal of minimising the dynamic energy accumulated in the system. Finally, hardware-in-the-loop tests are carried out on the RT-LAB platform for simulation verification. The experimental results show that the dynamic energy function constructed in this paper can reflect the stability of system. Using the proposed optimal restart strategy can reduce the accumulation of dynamic energy and improve the stability of system.