Should it not be possible to find a setting, which satisfies both these
conditions, the neutral voltage (
3U0min) must be used for measurement in
addition to the neutral current.
Phase preference logic
GUID-C3BD8775-B46E-437E-B3B9-F082CFAB583E v1
The desired phase preference logic for cross-country faults is chosen with the aid of the
parameter
PhaseSelMode.
In solidly grounded systems, the
PhaseSelMode parameter is disabled by setting it to Solid
ground or Forward OR.
It is essential for all the relays in ungrounded systems and systems with Petersen coils to be
set to the same phase preference logic. The logic used in the system must be known before
one of the eight alternative schemes can be selected:
•
L1L3L2(L1) — cyclic
•
L3L1L2(L3) — cyclic
•
L1L3L2 — acyclic
•
L1L2L3 — acyclic
•
L3L2L1 — acyclic
•
L3L1L2 — acyclic
•
L2L1L3 — acyclic
•
L2L3L1 — acyclic
Undervoltage starters (Uweak)
GUID-2E537DE1-4FD1-476E-A15F-3F0354C6C425 v1
The undervoltage starters are used in conjunction with the switch-onto-fault function and the
transfer tripping schemes (POTT and PUTT NONDIR). The corresponding pick-up value is set in
relation to the rated voltage with the aid of the parameter
Uweak, which has a setting range of
0 to 2 U
N
in steps of 0.01.
5.1.6.3
Measurement
GUID-1C206723-EE56-4815-829C-56FD2084967D v1
All the settings for the impedance measuring zones are to be found in the Measurement sub-
menu.
Determining the distance zones
GUID-05267329-6581-44F6-A236-96D275BADFAC v1
Before it is possible to determine the reaches of the distance zones, the impedances and
phase-angles of the line sections during faults must be known. Typical settings for the various
zone reaches along the line are given below:
18000006-IEC19000408-1-en.vsdx
A
B
C
a
b
1
2
3
Z = 0.85 (a + k · b )
b
b
2
Z = 0.85 (a + k · b )
2
1
Z = 0.85 · a
1
Z = 1.2 · a
ÜR
IEC19000408 V1 EN-US
Figure 7:
Typical settings for the reaches of distance relay zones
1MRK 505 406-UEN B
Section 5
Bay protection functions
Bay protection functions REB500
41
Technical manual
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