Dissipativity Conditions for Maximum Dynamic Loadability

TL;DR

This paper establishes dissipativity conditions to enhance the maximum dynamic loadability of power grids with inverter-based resources, using modeling, aggregate variables, and high-frequency reactive power sources, supported by simulations.

Contribution

It introduces physically intuitive dissipativity conditions for stabilizing fast electromagnetic interactions and increasing grid loadability through reactive power support.

Findings

Dissipativity conditions support maximum loadability.

High switching frequency reactive power sources improve stability.

Simulations confirm theoretical predictions.

Abstract

In this paper we consider a possibility of stabilizing very fast electromagnetic interactions between Inverter Based Resources (IBRs), known as the Control Induced System Stability problems. We propose that when these oscillatory interactions are controlled the ability of the grid to deliver power to loads at high rates will be greatly increased. We refer to this grid property as the dynamic grid loadability. The approach is to start by modeling the dynamical behavior of all components. Next, to avoid excessive complexity, interactions between components are captured in terms of unified technology-agnostic aggregate variables, instantaneous power and rate of change of instantaneous reactive power. Sufficient dissipativity conditions in terms of rate of change of energy conversion in components themselves and bounds on their rate of change of interactions are derived in support of achieving the maximum system loadability. These physically intuitive conditions are then used to derive methods to increase loadability using high switching frequency reactive power sources. Numerical simulations confirm the theoretical calculations, and shows dynamic load-side reactive power support increases stable dynamic loadability regions.