Inertia Adequacy in Transient Stability Models for Synthetic Electric Grids

TL;DR

This paper introduces a new, scalable method to analyze inertia adequacy in low-inertia power systems, emphasizing the importance of location-specific control resources and providing a synthetic benchmark for validation.

Contribution

It proposes a novel computational technique for assessing locational ROCOF in large systems and offers a synthetic case study with validation methodology for inertia adequacy analysis.

Findings

The new method efficiently screens inertia adequacy in large-scale systems.

Locational control resources significantly impact system stability.

A synthetic benchmark case supports future inertia studies.

Abstract

If a disturbance rocks a low-inertia power system, the frequency decline may be too rapid to arrest before it triggers undesirable responses from generators and loads. In the worst case, this instability could lead to blackout and major equipment damage. Electric utilities, to combat this, study inertia adequacy in systems that are particularly vulnerable. This process, involving detailed transient simulations, usually leads to a notion of a system-wide inertia floor. Ongoing questions in this analysis are in how to set the inertial floor and to what extent the location of frequency control resources matters. This paper proposes a new analysis technique that quantifies theoretical locational rate of change of frequency (ROCOF) as a computationally efficient screening algorithm scalable to large systems. An additional challenge in moving this area forward is the lack of high-quality, public benchmark dynamics cases. This paper presents a synthetic case for such purposes and a methodology for validation, to ensure that it is well suited to inertia adequacy studies to improve electric grid performance.