How to Tailor Power-Electronic Inertia to the Constraints of Its Resource

In recent years, research on power-electronic contributions of inherent inertia via grid-forming (GFM) control schemes has made significant progress. But several technical hurdles still stand against major progress towards an optimized use of resources and minimized cost on the way of providing enough power-electronic inertia for the next decade. Oriented at basic properties of virtual synchronous machines (VSMs), this article indicates generic technical solutions for respecting active-power (P) constraints of devices, tapping all working-point-dependent potentials of P variation for inertia, implementing RoCoF dead bands, circumventing the inherent slowness of a VSM to follow setpoint changes while retaining the GFM characteristic, and maximizing the combined P variation ranges of inertia and P(f) control. The overall objective is to tap the full P-variation potential of resources at/behind the DC link, even and particularly of the fluctuating ones. The proposed approach of realizing ‘tailored inertia’ is kept as generic as possible to allow for cherry-picking or combination with alternative approaches. After explanation of the technical concepts in sufficient detail, simulations demonstrate the feasibility of tailored inertia and adequate behaviour in challenging circumstances. This technical article is accompanied by the background article [1] in the same issue of this journal.