9440300990 7-7
DECS-250 Regulation
voltage for a specific point on the line. Line drop compensation is applied to both the real and reactive
portion of the generator line current. It is expressed as a percentage of the generator terminal voltage.
Equation 7-1
is used to calculate the Line Drop Value.
=
×
× cos
+ ×
× sin
Equation 7-1. Line Drop Value
LD
Value
= Line drop value (per unit)
V
avg
= Average voltage, metered value (per unit)
LD = Line Drop % / 100
I
avg
= Average Current, metered value (per unit)
I
bang
= Angle of phase B current (no compensation)
The LD
Value
is the per-unit value seen down the line from the synchronous machine. Equation 7-2 is used
to determine the voltage needed to adjust for line drop.
,
=
,
Equation 7-2. Voltage Needed to Adjust for Line Drop
Equation 7-3 is used to obtain primary units.
=
,
×
Equation 7-3. Obtain Primary Units
The new line drop adjusted setpoint is calculated using Equation 7-4.
=
+
Equation 7-4. Line Drop Adjusted Setpoint
Refer to Figure 7-5 for an illustration of the Line drop compensation settings.