The transfer function of the voltage control loop under

the no-load condition:

22.4

Based on the transfer functions of the generator (Section 7.1.4,page 13.3), we

obtain the following block diagram of the control system...

Structural diagram of control system in no load mode

Note: Element designations on the diagram

(Mмех; БЧЗ; БН; зи; в;н;осв; оцр,u are kept in original Russian
In accordance with page 13.3 G5о in a  "no load mode" = 1967    
ΔUa*
ΔEf*
  = 
1967·0.15
1 +p·9.3
  
295
1 + p·9.3 ·

Kкн    - The voltage control loop gains at rated and no-load differs:

Under the rated mode Kкн=31.58 (page 22.3) At p=1  Kкн=31.58/2.4=13.16
In no-load mode:
Kкнo = 052·0.052·1967·0.15·12= 97.35   At p=1  Kкн=97.35/9.3=10.46

The Bode diagram (ЛАЧХ) of the loop will pass correspondingly lower

than in load mode.