7.1 Structural diagram of a turbogenerator

10.1
The structural diagram of a turbogenerator in load mode is shown in Fig. 4. A linearized system of equations [L1] is taken as the basis.

ΔE′q✱ =
K3
1+p·K3·T′do
 · ΔEfd✱ -
K3·K4
1+p·K3·T′do
 · Δδ
ΔMЭ✱ = K1 · Δδ + K2 · E′q✱
ΔUа✱ = K5 · Δδ + K6 · ΔE′q✱
Tj ·
dω✱
dt
 = Mизб✱
Torque is expressed in per-unit (p.u.) based on the three-phase power rating, and the d/dt operator is replaced by p. Symbol definitions are provided in Fig. 4.
Main assumptions: neglecting magnetic circuit saturation, stator active resistance, and the influence of damper windings; assuming operation into an infinite bus system.

7.1.1 Transfer function of Gะพв(p) element

We derive it from the relation: Ef = if · Rв + Lв ·p ·if      Rв and Lв - resistance and inductance of the excitation circuit.

if·Rв
Ef
 =

1

1+p·Lв/Rв
 =

1

p·Tв
In per-unit system (relative units):
if✱ ·ifб ·Rf✱ ·Rfб
Ef✱ · Ufб

=
 1

1+p·Lв/Rв·Lfб/Rfб