  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.
