ABB Relion 670 series - Resistive Reach with Load Encroachment Characteristic

8 X1
Zm
8.11.3.2 Resistive reach with load encroachment characteristic
The procedure for calculating the settings for the load encroachment consist basically to
define the load angle LdAngle, the blinder RLdFwd in forward direction and blinder
RLdRev in reverse direction, as shown in figure
108.
R
X
RLdFwd
RLdRev
LdAngle
LdAngle
LdAngle
en05000226_ansi.vsd
LdAngle
ANSI05000226 V1 EN
Figure 170: Load encroachment characteristic
The load angle LdAngle is the same in forward and reverse direction, so it could be suitable
to begin to calculate the setting for that parameter. Set the parameter to the maximum
possible load angle at maximum active load. A value bigger than 20° must be used.
The blinder in forward direction, RLdFwd, can be calculated according to equation
103.
= ×
2
min
0.8
exp max
RLdFwd
P
V
where:
P exp max is the maximum exporting active power
V min is the minimum voltage for which the Pexp max occurs
0.8 is a security factor to ensure that the setting of RLdFwd can be lesser than the calculated minimal
resistive load.
Section 8 1MRK 506 369-UUS -
Impedance protection
354 Line distance protection REL670 2.2 ANSI
Application manual