OpModeZ2: This is to select the operating characteristic of zone 2 distance
element. This can be selected as Off/Mho offset/Quad non-dir.
Z2Fwd: This is to set the zone 2 forward positive sequence impedance reach in
ohm/p. It is recommended to set this to 125% of transformer impedance.
Z2Rev: This is to set the zone 2 reverse positive sequence impedance reach in
ohm/p. The recommended setting is 80% of shortest outgoing line in the reverse
direction in order to cover the bus faults.
RFFwZ2: This is to set the zone 2 forward fault resistive reach in ohm/p if
quadrilateral characteristic is selected. It should be set to give maximum coverage
of fault resistance and the load encroachment (R
Ldmax
).
RFRevZ2: This is to set the zone 2 reverse fault resistive reach in ohm/p if
quadrilateral characteristic is selected. It may be set identical to RFFwZ2.
tZ2: This is to set the zone 2 time delay to trip. The default setting is 0.5s. It should
be set to coordinate with clearance of adjacent circuit fault within reach by the
intended main protection or breaker fail protection.
Zone 3
OpModeZ3: This is to select the operating characteristic of the zone 3 distance
element. This can be selected as Off/Mho offset/Quad non-dir.
Z3Fwd: This is to set the zone 3 forward positive sequence impedance reach in
ohm/p. It should be set to overreach the remote terminal of the longest adjacent line
about 20% for all fault conditions.
Z3Rev: This is to set the zone 3 reverse positive sequence impedance reach in
ohm/p. This may be set identical to Z2Rev.
RFFwZ3: This is to set the zone 3 forward fault resistive reach in ohm/p if
quadrilateral characteristic is chosen. It should be set to give maximum coverage of
the fault resistance and load encroachment.
RFRevZ3: This is to set the zone 3 reverse fault resistive reach in ohm/p if
quadrilateral characteristic is chosen. It may be set identical to RFFwZ3.
tZ3: This is to set the zone 3 time delay to trip. Time delay is used to coordinate
with the slowest circuit backup protection or slowest local backup for faults within
zone 3 reach. The default setting is 1.5s.
7.3.4 Catenary Protection
GUID-F1E9801A-4413-4160-BAD5-17FBF6DFB639 v1
The ZGTPDIS function can also be utilized for catenary line protection. By using it
a simple, three-zone underimpedance protection with independent reach in forward
and reverse direction can be easily achieved. Consider the following:
Section 7 1MRK 506 375-UEN A
Impedance protection
154 Railway application RER670 2.2 IEC
Application manual
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