Placement and Implementation of Grid-Forming and Grid-Following Virtual Inertia and Fast Frequency Response

TL;DR

This paper develops explicit models for grid-forming and grid-following virtual inertia devices, optimizing their placement to enhance stability in low-inertia power systems with renewable generation.

Contribution

It introduces detailed models for virtual inertia devices and formulates an optimization framework for their optimal placement and parameters.

Findings

Optimized placement of virtual inertia devices improves system resilience.

Explicit models effectively emulate inertia in low-inertia systems.

Case study demonstrates increased stability in the Australian system model.

Abstract

The electric power system is witnessing a shift in the technology of generation. Conventional thermal generation based on synchronous machines is gradually being replaced by power electronics interfaced renewable generation. This new mode of generation, however, lacks the natural inertia and governor damping which are quintessential features of synchronous machines. The loss of these features results in increasing frequency excursions and, ultimately, system instability. Among the numerous studies on mitigating these undesirable effects, the main approach involves virtual inertia emulation to mimic the behavior of synchronous machines. In this work, explicit models of grid-following and grid-forming virtual inertia (VI) devices are developed for inertia emulation in low-inertia systems. An optimization problem is formulated to optimize the parameters and location of these devices in a power system to increase its resilience. Finally, a case study based on a high-fidelity model of the South-East Australian system is used to illustrate the effectiveness of such devices.