The fast load shedding calculations must be based on the
dynamic spinning reserve [2]. This is the spinning reserve that
is immediately available and is often much less that the
arithmetic difference between the actual loading of the GTG
and its maximum output capability at site conditions. Thus
even though there may be sufficient generation capacity on
paper, load shedding may still be required. Fig. 13 shows
what often happens when a GTG is subjected to a large load
step, in this case 18MW for a 90MW GTG. The GTG is
capable of accepting a step load of approximately 10% very
10
quickly which corresponds to its dynamic spinning reserve.
This quick response is shown in Fig. 13 just after the
application of the step load at time t = 0.