A Novel Adaptive Inertia Strategy in Large-Scale Electric Power Grids

The increasing penetration of new renewable sources of energy in today's power grids is accompanied by a decrease in available electromechanical inertia. This leads to a reduced dynamical stability. To counterbalance this effect, virtual synchronous generators have been proposed to emulate conventional generators and provide inertia to power systems. The high flexibility of these devices makes it possible to control the synthetic inertia they provide and to have them operate even more efficiently than the electromechanical inertia they replace. Here, we propose a novel control scheme for virtual synchronous generators, where the amount of inertia provided is large at short times - thereby absorbing local faults and disturbances as efficiently as conventional generators - but decreases over a tunable time interval to prevent long-time coherent oscillations from setting in. This new model is used to investigate the effect of adaptive inertia on large-scale power grids. Our model outperforms conventional constant inertia in all scenarios and for all performance measures considered. We show how an optimized geographical distribution of adaptive inertia devices not only effectively absorbs local faults, but also significantly improves the damping of inter-area oscillations.