Under Frequency Load Shedding based on PMU Estimates of Frequency and ROCOF

TL;DR

This paper proposes a distributed under-frequency load shedding scheme utilizing PMU-based frequency and ROCOF measurements to improve response during large contingencies, validated through real-time simulation.

Contribution

It introduces a novel load shedding and restoration method that leverages PMU-derived ROCOF estimates during fast transients, enhancing traditional frequency-only strategies.

Findings

ROCOF-based scheme improves detection speed during large contingencies

Performance validated with IEEE 39 bus system simulation

ROCOF estimates are effective during fast transients

Abstract

The paper describes a distributed under-frequency load shedding and load restoration scheme, that exploits frequency and Rate-of-Change-of-Frequency (ROCOF) measurements produced by Phasor Measurement Units (PMUs) as detectors of a large contingency. The paper further discusses the appropriateness of using the synchrophasor model for estimating ROCOF during fast transients following a severe generation-load imbalance. The performance of the proposed relaying scheme is compared with a frequency-only based strategy, by means of a real-time digital simulator implementing the time-domain full-replica model of the IEEE 39 bus system.