Figure 12 shows the simulation result of frequency deviation
in Area 2. The largest deviation is in Without Charge Control,
followed by in Charge Control and in Charge Control with
LFC Signal, like the result of tie-line flow deviation. Charge
Control can not eliminate the error completely because it is a
proportional control based on error of frequency deviation. On
the other hand, Charge Control with LFC Signal is a
proportional-plus-integral control that tries to drive ACE to
zero. For the reasons stated above, Charge Control with LFC
Signal has a larger suppressant effect than that of Charge
Control.