Multimachine systems

1
Multi-machine systems

• Starrett Mini-Lecture 4

2
In multi-machine systems

• No Equal Area Criterion
• Visualize multiple springs masses that are
  interconnected by horizontal springs

3
Multi-Machine Diagram

• System of coupled, nonlinear differential
  equations
• Block diagram

4
Detailed generator models

• Include affects of varying flux linkages,
  generator internal voltages, the field voltage
• More differential equations!
• More variable transformations (Parks) circuit
  equations

5
Block diagrams
6
NOTE Before you can include models for
excitation systems, you need to include the
detailed machine models!
7
Excitation system

• Modulates the field voltage of the synchronous
  machines
• Supplies DC voltage
• DC Exc. DC generator
• AC Exc. AC generator (rectified)
• Static Exc. stationary DC supply

8
Elements of an excitation system (Kundur)

• Exciter - DC power supply for field
• Regulator - amplifies, stabilizes exciter
• Voltage transducer load compensator - senses
  terminal voltage, remote
• Power system stabilizer - additional signal for
  damping (speed, Pacc or f)
• Limiters and protection - limit voltages
  currents

9
Excitation System Components
10
How it all goes together