Compared with the base case, the higher-renewablepenetration
case has better frequency response. This is
because the dispatch increased headroom when wind generation
was added. This effect is nowhere near in proportion
to the amount of wind generation added, yet it helps
the system response. This case illustrates the possibility
that normal economic operation of the system may result
in improved system frequency performance as wind power
levels increase. The initial rate of change of frequency
(ROCOF) is essentially unchanged between the cases,
indicating that the reduction in system inertia that accompanies
displacement of some synchronous generation has
little impact