Active Power Adaptive Improvement Strategy and Transient Stability Analysis Based on Virtual Synchronous Generator System

Virtual synchronous generator (VSG) have the support capability of synchronous generators, which can effectively improve the stability of dual high power systems. However, in practical applications, they still face large and small disturbance stability issues. Among them, the stability of large disturbances is a very challenging issue, such as short circuits or line trips. At this point, the traditional small signal stability analysis theory is no longer applicable. This article proposes a current limiting strategy under large disturbances. Firstly, the equivalent circuit diagram before and after current limiting and the state equation of the rotor motion equation are established. Qualitatively and quantitatively, the impact of active power command value and grid drop voltage on system transient stability is analyzed. Then, the transient instability mechanism of VSG after current limiting is analyzed by combining the phase diagram curve. Finally, an adaptive control strategy for active power command value is proposed, The accuracy of theoretical analysis and the effectiveness of the proposed strategy were verified through experiments.