Secondary regulation shown in Fig. 1 operates at a global
level. After the transient conditions following a disturbance
have subsided, the secondary regulation will send ± set point
changes to the GTG and STG governors to bring the
frequency back to its nominal value, and to ensure correct
load sharing among the turbines. It will also send ± set point
changes to generator and transformers AVRs in order to
ensure correct voltage levels throughout the system.
Secondary regulation will also ensure reactive power sharing
where applicable.