Transient power stabiliser for a virtual synchronous machine control in doubly-fed induction generators

The increasing penetration of converter-interfaced generation technologies in power systems entails new stability issues. Power oscillations, particularly in weak power systems, are of significant concern among these. Besides, grid-forming strategies often adversely affect the damping of power oscillations due to the synchronous generator dynamics they emulate. In this research paper, a novel PSS (Power System Stabiliser)-like strategy is proposed to address this issue for Virtual Synchronous Machine (VSM) grid-forming (GFM) controls in type 3 wind turbines. This control aims to replicate the inertial response of a synchronous generator, which introduces a second-order dynamic to the synchronisation loop and produces an oscillatory mode if the damping constant is insufficient. However, the proposed strategy transiently increases this damping constant while remaining passive during steady-state operation, thereby not affecting the frequency response of the generator. This paper analyses this proposal through small-signal stability analysis and real-time simulation using control hardware-in-the-loop testing. The stability analysis aids the tuning of the PSS function parameters and demonstrates its impact on the frequency domain by enhancing the damping of local oscillation modes. Simulation results validate this strategy by testing it using comprehensive power system models under various scenarios.

Transient power stabiliser for a virtual synchronous machine control in doubly-fed induction generators Articles