  Due to the high solar irradiance or energy price, certain regions in the U.S.
may reach 100% PV penetration and experience degradation of frequency response
greater than the interconnection as a whole. Therefore, in this section, the
100% PV penetration region in each interconnection is simulated to study the
local high PV penetration effects. The study was performed by quantifying
RoCoF, frequency nadir, and settling frequency at different regional PV
penetration levels. The impact of high regional PV penetration on the
compliance of grid code on frequency response is also studied.
