Civil Engineering Reference
In-Depth Information
FIGURE 14-6
Transient response of the system voltage under sudden load step.
V
= Rated output voltage
base
I
= Rated output current, and
base
Z
= Rated output voltage/Rated output current
base
14.4
Static Bus Impedance and Voltage Regulation
If the equivalent circuit model of
Figure 14-5
is derived under the steady
state static condition, the Z
is called the static bus impedance. The steady
state voltage rise on removal of the full load rated current is then
s
∆
V = I
·
base
Z
, and the voltage regulation is as follows:
s
V
V
base
∆
Voltage Regulation
=
⋅
100 percent
(14-7)
Under a load step transient, partial or full, as in the case of a loss of load
due to accidental opening of the load side breaker, the voltage oscillates until
the transient settles to the new steady state value. If the load current rises
in step as shown in
Figure 14-6
,
the voltage goes through oscillation before
settling down to a lower steady state value. The steady state change in the
bus voltage is then given by the following:
∆
V
=
∆
I
·
Z
S
