Current limiting control method with adaptive virtual impedance for grid-forming STATCOM

摘要

Current limiting is an important issue in the static synchronous compensator (STATCOM) with grid-forming (GFM) control. However, the conventional methods are difficult to deal with the application scenarios of different grid faults. In this paper, an improved current limiting method with the adaptive virtual impedance is proposed for the GFM STATCOM. The specific implementation strategy of the GFM control is introduced firstly. The generation method of the adaptive virtual impedance and the realization of current limiting strategy are also presented in detail. The proposed adaptive virtual impedance can be adjusted automatically by following voltage sag, which realizes the adaption of different grid faults situations. The proposed method is realized by the GFM STATCOM simulation platform with PSCAD/EMTDC, it is confirmed that the proposed method has a faster current limiting response speed when the voltage sag is larger, which can improve the supporting effect of GFM STATCOM for the grid voltage drop.