Dynamic Equivalence Algorithm for AC-DC Hybrid System

With the large-scale integration of new energy and the sustained growth of the number of high-voltage DC lines, the operational characteristics of power grid in China have undergone profound changes, and the security and stability of the power grid is facing enormous challenges. Studying the stability of large-scale AC-DC hybrid power grid is of great significance for the development of power grid in China. However, the large-scale AC-DC hybrid power grid has many dynamic components and complex topology structure, which is limited by hardware resources and difficult to accurately model each component. Therefore, it is necessary to combine dynamic equivalence algorithm to reduce the system scale while ensuring simulation accuracy. A dynamic equivalence algorithm for AC-DC hybrid power grid is proposed in this paper, which preserves the main network and simplifies the low-voltage power supply areas. The algorithm can ensure that the bus voltage, power flow distribution, short-circuit current, etc. of the main network are basically consistent before and after equivalence, with low computational complexity and fast calculation speed. The effectiveness of the algorithm is verified through simulation verification and comparative analysis of the power grid of a certain city in China before and after equivalence.