Cybersecurity Vulnerabilities in Phase-Locked Loop (PLL) of DFIG-Based Wind Power Plants

The integration of wind energy, particularly Doubly-Fed Induction Generator (DFIG) turbines, into power grids has increased significantly owing to their performance and cost-efficiency. Within the DFIG-based turbines, a critical component is the Phase-Locked Loop (PLL). This study delves into the cybersecurity vulnerabilities associated with PLL systems. Initially, a dynamic model for DFIG turbines-including voltage and current control loops and the PLL-is developed. The PLL model is assumed to work based on the fundamental frequency of the positive sequence of voltage. Then, it has been shown that when a malicious signal with the natural frequency of PLL is injected into the measurements, the estimation of phase angle will start to oscillate. This instability, in turn, leads to disruptions in the stability of the active power injected into the grid which results in DFIG disconnection and highly threatens the grid stability. We further investigate the impacts of the proposed attack under varying parameter configurations, employing the EPRI benchmark within the EMTP-RV software.