ABB REL650 Applications Manual page 51

1MRK 506 334-UUS A
Application manual
The function of the zones for the distance protection A can be seen in figure 6.
Zone 4
Zone 3
Zone 2
Zone 1
A
REL 650
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ANSI11000109 V1 EN
Figure 6: Reach of the distance protection zones
Zone 1, with instantaneous operation, detects most short circuits faults on the protected
line. At the same time the selectivity must be assured. Therefore the most remote part of
the line is not covered by zone 1.
Zone 2, with a short delay, detects short circuits faults on part of the protected line not
covered by zone 1. The delay shall be sufficient to assure selectivity. This means that
faults cleared by instantaneous protection function at other objects connected to the
remote 138 kV busbar shall not cause unwanted trip at A.
Zone 3, together with zone 2, serves as remote back-up protection for short circuits faults
on the lines out from the remote 138 kV busbar. Zone 3 shall, if possible, cover the whole
length of these lines. The delay of zone 3 shall be sufficient to assure selectivity. This
means that faults cleared by delayed zone 2 protection function at other objects connected
to the remote 138 kV busbar shall not cause unwanted trip at A.
Zone 4 serves as back-up for short circuits faults on the 138 kV busbar in substation A.
Zone 4 has a delay to assure selectivity. The directional start signal for the zone can also
be used for additional functions related to distance protection: weak end infeed logic and
fault current reversal logic.
The calculations and choice of the settings are shown in the following instructions,
General settings, Zone 1– 4 settings. Zone 5 is not used.
REL650 setting examples
B
Z 1 = R 1 + jX 1
a
Z 0 = R 0 + jX0
REL 650
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