Voltage
drop
(% of Vn)
Line length (p.u)
Line length = 1 p.u.
Actual load distribution
(Evenly distributed load)
S
1
S
2
·····
S
n
S
i
Actual voltage
drop
curve
Simplified
voltage
drop
curve used
in
algorithm
V
drop(real)
0
0
distance of equivalent
load tap = Equivalent load Dis
Ʃ
0
0.5
1.0
1.0
GUID-6325E875-F7DB-4D1B-978A-1E1583EB544C V1 EN
Figure 412: Description of the equivalent load distance
The exact value for Equivalent load Dis can be calculated based on the load flow and
voltage drop calculations using data from DMS-system and the following equation.
Equivalent load Dis =
=
V
V
d real
d tap d
( )
( , )1
GUID-348E8311-D555-4897-BF7E-077024585AAC V1 EN (Equation 142)
V
d(real)
The actual maximum voltage drop of the feeder
V
d(tap,d=1)
The fictional voltage drop, if the entire load would be tapped at the end (d=1) of the
feeder (not drawn in Figure 412). The calculation of this value requires data from the
DMS system.
Alternatively, the setting Equivalent load Dis can be determined by conducting a single-
phase ground-fault test (R
fault
= 0 Ω) at that point of the feeder where the maximum actual
voltage drop takes place. This point is typically located at the end of the main line. As a
result, the calculated value is stored in the recorded data Equivalent load Dis.
1MAC059074-MB A Section 5
Protection related functions
615 series ANSI 809
Technical Manual
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