Control and Design of Microgrid Components - Power Systems ...

ω
ω
ω
o
Fo
ω
o
Fo
F
F
Unit
Power
Limits
Unit
Power
Limits
P=Pmax
P=0
P=Pmax
P=0
(a)
(b)
Figure 3.26 Steady State Characteristics for (a) P=0 Limit and (b) P=Pmax Limit.
Figure 3.26(b) shows the steady state characteristic for a unit that is operating in grid mode with
a setpoint Fo that has exceeded the limit P=Pmax. This characteristic enforces the slope when
unit output power is within limits, then the vertical bound of the limit becomes the characteristic
itself. This vertical line is located at the value F=Fmin. This characteristic enforces P=Pmax
while allows frequency to assume any value that the rest of the units in the system will demand.
This implies that frequency would decrease, as shown by the arrows on the vertical part of the
characteristic, on Figure 3.26(b)
ω
F
ω o
Unit
Power
Limits
F
F=Fmin
P=Pmax
F=Fmax
P=0
Figure 3.27 Steady State Characteristic Including Limits on the F-ω Plane with Feeder Flow
Control.
Figure 3.27 shows the steady state characteristic on the F-ω plane that enforces output power, P,
limits when feeder flow control is adopted. The fundamental trait of this characteristic is that it
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