ABB RELION REX640 Technical Manual page 894

Section 4
Protection functions
888
d
l
IN2
IN1
Z<
Parallel lines are mutually coupled
GUID-224B037C-3A58-4557-AE27-A65B6F5581B4 V1 EN
Figure 480: Operation principle of parallel line compensation functionality
The operation time delay is defined with the Gnd operate Dl Znx (x = 1...5) setting.
The timer can be disabled with the Gnd Op Dl mode Znx = "False" setting. This blocks
the OPERATE_Zx (x = 1...5) output of the phase-to-earth measuring elements.
Phase-to-phase impedance measuring elements
The phase-to-phase distance protection is suitable as a basic protection function
against two-phase short circuit faults in various networks, regardless of the treatment
of the neutral point. The short circuit fault protection is enabled with the Op Mod PP
loops Znx (x = 1...5) = "True" setting.
The reach of the phase-to-phase measuring elements is based on the loop impedance
R R
Z R j X
F F
= ⋅
+ + +
1 1
1
2 2
GUID-DFD24852-86F6-4726-93A4-B93DADC5AFAB V1 EN
1MRS759142 C
X
(Equation 222)
Technical Manual
R
REX640