ABB REL670 2.2 IEC - Consideration of Zero Sequence Mutual Coupling for Parallel Circuits

Table 23: Different groups of settings
Group Operation mode Zone 1 and Zone 2 Zone 3 and Reverse Zone
Group1 Case 1: Parallel
line switched off
and earthed at
both ends
0 1 0
1
1 0
3
m
N Nm
K
Z Z Z
K
Z Z
=
-
-
0 1
1
3
N
Z Z
K
Z
=
-
×
Group2
Case 2: Parallel
line switched off
and not earthed
or earthed at
only one end
0 1
1
3
N
Z Z
K
Z
=
-
×
0 1
1
3
N
Z Z
K
Z
=
-
×
Group3
Both lines in
service
0 1
1
3
N Nm
K
Z Z
K
Z
=
-
-
0
3
L L
N
L
K
Z Z
Z
=
-
For a discussion on other options of settings, refer to CIGRE SC34 report, WG-04
November 1991 “Application guide on protection of complex transmission
network configuration”.
8.4.3.7 Consideration of zero sequence mutual coupling for parallel circuits
GUID-D25BD616-CED9-4B82-8958-F90C4F819692 v1
For both zone 2 and zone 3 elements, the underreaching effect of zero sequence
mutual coupling for remote earth faults must also be considered in relation to the
primary reach setting criterion.
8.4.3.8 Load impedance limitation, without load encroachment function
SEMOD154469-91 v5
The following instruction is valid when the load encroachment function or blinder
function is not activated (BlinderMode=Off).The load encroachment function will
not be activated if RLdFw and RLdRv is set to a value higher than expected
minimal load impedance. If the load encroachment or blinder function is to be used
for all or some of the measuring zones, the load limitation for those zones
according to this chapter can be omitted. Check the maximum permissible resistive
reach for any zone to ensure that there is a sufficient setting margin between the
relay boundary and the minimum load impedance. The minimum load impedance
(Ω/phase) is calculated as:
Z
loadmin
U
2
S
-------=
EQUATION571 V1 EN-US (Equation 180)
Where:
U is the minimum phase-to-phase voltage in kV
S is the maximum apparent power in MVA.
1MRK 506 369-UEN B Section 8
Impedance protection
Line distance protection REL670 2.2 IEC 257
Application manual