Page 66 - Handbook of Electrical Engineering

GAS TURBINE DRIVEN GENERATORS 45

Figure 2.13 Basic control system block diagram of a gas turbine. The diagram represents the main elements
of the equation of motion.

f zi = frequency set-point of the i th governor in Hz
D i = governor droop in per unit of the i th governor
P i = electrical load of the i th generator in kW
G i = electrical power rating of the i th generator in kW

Transpose (2.62) to find P i ,
G i
P i = (f zi − f) (2.63)
D i f o
The total power demand P for n generators is,

i=n

P = P i (2.64)
i=1
i=n i=n
1 f zi G i f G i
= − (2.65)
f o D i f o D I
i=1 i=1
Which is of the simple form,

P = a − bf (2.66)

where
i=n
1 f zi G i
a = is a constant (2.67)
f o D i
i=1