In our model all 3 synchronous machine participate in the primary frequency
control. For both steam turbines IEEE governor model TGOV1 and
for the hydro turbine the IEEE governor model HYGOV were selected. In
order to limit the primary control reserves of each synchronous machines the
standard structures of the governors were modified. In Figure 4.1 and 4.2
the block diagrams of modified governor models are illustrated.
Consider the steam turbine governor model in Figure 4.1. The input1
on the slot 2 ! is the local frequency measurement and slot 3 !ref is the
constant nominal frequency. Consequently the sum of those two d! is local
frequency deviation. This frequency deviation signal goes to the gain-block
1/K with lim. The parameter R corresponds to the speed droop characteristic
S. The lower and upper bounds pmin and pmax are the limitation for the
primary reserve of the generator. The output of this gain-block o13 is the
primary frequency control response. This signal will be added to the secondary
frequency response, which will be explained in the next subsection,
and will be sent to the turbine controller over several blocks.
The hydro turbine governor HYGOV’s primary controller has operational
principle like TGOV1 - local frequency measurement and gain-block with
limits. Consider Figure 4.2. The major