ABB RELION REX640, Техническое руководство, Страница: 830 / 1960

FAULT_DIR gives the detected direction of the fault during fault situations, that is,
when the
START
output is active.
4.4.2.7 Application
The ability of a protection relay to provide direction information for faults is
referred to as its directional security. It is extremely important for the directional
protection function to identify the direction of the fault relative to the location of
the protection relay. The fault direction can be either downstream (forward fault) or
upstream of the protection relay (backward fault).
Different directional elements are used to determine the fault direction. One such
element is the negative-sequence voltage. As directional element, the negative-
sequence voltage can identify the direction of all unbalance faults. One of the
advantages of using negative-sequence elements is that the negative-sequence
component is insensitive to zero-sequence mutual coupling. The negative sequence
is also used where the source is not strong enough because with such a source the
value of the negative sequence near the protection relay has higher magnitude.
4.4.2.8 Signals
DNSPDOC Input signals
Table 746: DNSPDOC Input signals
Name Type Default Description
I3P SIGNAL - Three-phase currents
IRES SIGNAL - Residual current
U3P SIGNAL - Three-phase voltages
BLOCK BOOLEAN 0=False Block signal for acti-
vating the blocking
mode
DNSPDOC Output signals
Table 747: DNSPDOC Output signals
Name Type Description
OPERATE BOOLEAN Operate
START BOOLEAN Start
4.4.2.9 DNSPDOC Settings
Table 748: DNSPDOC Group settings (Basic)
Parameter Values (Range) Unit Step Default Description
Start value 0.05...5.00 xIn 0.01 0.05 Start value
Directional mode
1=Non-directional
2=Forward Directional mode
Table continues on the next page
Protection functions 1MRS759142 F
830 REX640
Technical Manual