On the stabilizing contribution of different grid-forming controls to power systems

The increasing penetration of power-electronics interfaced resources brings new challenges regarding the small-signal stability of power systems. To address this issue, grid-forming (GFM) controlled converters have emerged as an alternative to their conventional grid-following counterparts. This paper investigates the mechanisms behind converters driven stability and quantifies the stabilizing effect of GFM controls. The linearized state-space model of different combinations of control strategies is analysed in a multi-infeed system considering various operating points. Through a parametric sensitivity study and an examination of the participation factors of key eigenvalues of the linearized models, it is confirmed that GFM controls contribute to system stabilization. Moreover, this paper demonstrates that this stabilizing effect varies significantly depending on the specific GFM control implemented: whether a current control loop is used or not notably impacts stability. The article studies the stabilizing impact of grid-forming (GFM) in power systems. All things being equal (inertia, damping, and tuning), the presence of a current control in the GFM scheme significantly reduces the stabilizing impact. This phenomenon is highlighted under different setups and is explained using the analysis of participation factors.