EX2: An interconnected 60 Hz power system consists of one area with three turbine-generator units rated 1000, 750 and
500 MVA respectively. The regulation constant of each unit is R = 0.05 pu
based on its own rating. Each unit is initially operating at one half of
its own rating, when the system load suddenly increase by
200 MW. Determine (a) the per unit area frequency
response characteristic (B) on 1000 MVA system base. (b)
the steady state drop in area frequency and ( C ) the
increase in turbine mechanical power output of each unit.
Assume APref of each turbine generator remain constant.
Neglect losses and the dependence of load on frequency.