ABB RED650, Техническое руководство

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the possibility to detect high fault resistances, especially for phase-to-earth faults at
the remote line end. For example, for a given setting of the load angle
ArgLd , the
resistive blinder for the zone measurement can be set according to figure 53
affording higher fault resistance coverage without risk for unwanted operation due
to load encroachment. Separate resistive blinder settings are available in forward
and reverse direction.
The use of the load encroachment feature is essential for long heavily loaded lines,
where there might be a conflict between the necessary emergency load transfer and
necessary sensitivity of the distance protection. The function can also preferably be
used on heavy loaded, medium long lines. For short lines, the major concern is to
get sufficient fault resistance coverage. Load encroachment is not a major
problem. .
R
Z1
ArgLd
RLdFw
IEC09000248-3-en.vsdx
X
RLdRv
[1]
IEC09000248 V3 EN-US
Figure 53: Load encroachment phenomena and shaped load encroachment
characteristic
[1]
7.1.7.9 Simplified logic schemes
GUID-B43F2F0B-C8A2-4CFD-A9DD-51E167A90B56 v5
PHSL1, PHSL2,...PHSL3L1 are internal binary logical signals from the Phase-
selection element. They correspond directly to the six loops of the distance zones
and determine which loops should be released to operate.
FWL1, FWL2,...FWL3L1 and RVL1, RVL2,...RVL3L1 are the internal binary
signals from the Directional element. An FW signal is activated if the criteria for a
forward fault or load is fulfilled for its particular loop. The equivalent applies to the
reverse (RV) signals.
The internal input 'IN present' is activated if the residual current (3I0) exceeds 10%
of the maximum phase current magnitude and at the same time is above 5% of
[1] RLdRv=RLdRvFactor*RLdFw
1MRK 505 394-UEN A
Section 7
Impedance protection
Line differential protection RED650 2.2 IEC 133
Technical manual