1. ECE 576 POWER SYSTEM DYNAMICS AND STABILITY
Lecture 10
Synchronous Machine Controls – Turbine/Governor
Professor Pete Sauer
Department of Electrical and Computer Engineering
© 2000 University of Illinois Board of Trustees, All Rights Reserved

2. Speed and voltage control

3. Possible prime movers
gas engine
diesel engine
jet engine
water wheel
steam turbine

4. model shaft “squishiness” as a spring
Turbine models
model shaft “squishiness” as a spring
High-pressure turbine shaft dynamics

5. Steam chest time delay
High-pressure turbine shaft dynamics

6. For rigid shaft (no twist)

7. Speed governor model

8. Steam valve control
Steam valve limits
R = .05 (5% droop)

9. Example – no load to full load by governor action only (not be commanded power).
(5% drop in speed)

10. A complete dynamic model
Stator transients

11. d-axis rotor transients

12. q-axis rotor transients

13. Rotor shaft dynamics

14. Magnetic circuit algebraic equations (linear)

15. Excitation system (Exciter + Automatic Voltage Regulator)

16. Turbine/Governor

17. 3 stator
1 field
3 dampers
2 shaft
1 exciter
2 VR
1 turbine
1 governor 14
14th order model

18. Terminal constraints
How are Vd, Vq, Vo and Id, Iq, Io related?
Open circuit: Id = Iq = Io = 0
Short circuit: Vd = Vq = Vo = 0

19. Balanced 3 resistive load:
Substitute for Vd, Vq, Vo and eliminate Id, Iq, Io
using the 3 magnetic circuit algebraic equations

20. Infinite bus

21. Substitute for Vd, Vq, Vo and eliminate Id, Iq, Io
using the 3 magnetic circuit algebraic equations

22. Line impedance plus infinite bus
Note: These flux linkages are not independent states. They are in “series” with the synchronous machine flux linkages. They do not increase the order of the model.

23. An infinite bus
By definition, an infinite bus has:

24. How can we create one from our synchronous machine model?
Infinitely slow field
Infinitely slow 1q damper
No 1d damper
No 2q damper
Infinite inertia
No stator resistance
Negligible transient reactances