ABB REF615 G - LDC equation and parallel connection

loading state of the network. The control voltage U
p
is calculated according to the
equation
U U U U U
p s z ci rsv
= + + −
GUID-86D55536-6EF1-43CB-BA21-EF57280DEBB4 V1 EN (Equation 89)
U
p
Control voltage
U
s
Set voltage level Band center voltage
U
z
Line drop compensation term
U
ci
Circulating current compensation term
U
rsv
Voltage reduction parameter
U
p
can be directly read in the monitored data U_CTL.
The circulating current compensation term is calculated only in the parallel acting
operation modes "NRP" and "MCC".
Line Drop Compensation (LDC)
The line drop compensation feature is used to compensate the voltage drop along a
line or network fed by the transformer. The compensation setting parameters can
be calculated theoretically if the resistance and reactance of the line are known or
measured practically from the line drop.
I
L
X
L
R
L
U
B
U
L
Load
GUID-552C931B-4A1A-4361-8068-0A151CB99F30 V2 EN
Figure 398: Equivalent electrical circuit for calculating the LDC term
The compensation parameters Line drop V Ris (U
r
) and Line drop V React (U
x
), are
percentage values of U
n
according to the equations.
Section 9 1YHT530004D05 D
Control functions
734 615 series
Technical Manual