When two generators of the same size are working in parallel, a change in
frequency (governor set points) of one of them changes both the system frequency
and power supplied by each generator.
To adjust power sharing without changing
the system frequency, we need to increase
the frequency (governor set points) of one
generator and simultaneously decrease the
frequency of the other generator.
To adjust the system frequency without
changing power sharing, we need to
simultaneously increase or decrease the
frequency (governor set points) of both
generators.