Frequency Response Assessment of U.S. Power Grids in High PV Penetration

TL;DR

This study assesses how high levels of photovoltaic penetration affect the frequency response of U.S. power grids, using validated models and real measurements to inform policy and operational strategies.

Contribution

It develops validated dynamic models for U.S. power interconnections under high PV scenarios and analyzes frequency response trends and mitigation solutions.

Findings

Frequency response declines with increased PV penetration.

Up to 65% PV and 15% wind penetration simulated.

Practical solutions to improve frequency response discussed.

Abstract

Nonsynchronous generations such as photovoltaics (PVs) are expected to undermine bulk power systems (BPSs) frequency response at high penetration levels. Though the underlying mechanism has been relatively well understood, the accurate assessment and effective enhancement of the U.S. interconnections frequency response under extra-high PV penetration conditions remains an issue. In this paper, the industry-provided full-detail interconnection models were further validated by synchrophasor frequency measurements and realistically-projected PV geographic distribution information were used to develop extra-high PV penetration scenarios and dynamic models for the three main U.S. interconnections, including Eastern Interconnection (EI), Western Electricity Coordinating Council (WECC), and Electric Reliability Council of Texas (ERCOT). Up to 65% instantaneous PV and 15% wind penetration were simulated and the frequency response change trend of each U.S. interconnection due to the increasing PV penetration level were examined. Most importantly, the practical solutions to address the declining frequency response were discussed. This paper will provide valuable guidance for policy makers, utility operators and academic researchers not only in the U.S. but also other countries in the world.