Protection Functions - ABB RED615 Product Manual

Line Differential Protection and Control
RED615
Product version: 4.0

3. Protection functions

The IED offers two-stage phase-segregated line
differential protection, phase overcurrent
protection, negative phase-sequence overcurrent
protection and circuit-breaker failure protection.
Depending on the standard configuration chosen,
the basic functionality can be extended by
thermal overload protection, directional or non-
directional earth-fault protection, sensitive earth-
fault protection, phase discontinuity protection,
transient/intermittent earth-fault protection,
residual overvoltage protection and three-pole
multi-shot auto-reclose functions for overhead
line feeders. For standard configuration B
admittance-based, wattmetric-based or
harmonics-based earth-fault protection, is offered
as an option in addition to the directional earth-
fault protection.
GUID-B8CBF357-474F-4F61-BE28-D107515A09AA V4 EN
Figure 1. Protection function overview of standard configuration A
6
The line differential protection function includes a
stabilized low stage and an instantaneous high
stage. The stabilized low stage provides sensitive
differential protection and remains stable during,
for example, current transformer saturation
conditions. The low-stage operation can be
restrained using second harmonic detection if an
out-of-zone power transformer is to be energized.
The instantaneous high stage offers less sensitive
differential protection but enables fast operation
during high fault currents.
The operating time characteristic for the low
stage can be set to definite time or inverse
definite time mode. The direct inter-trip function
ensures that both ends are always simultaneously
tripped, independent of the fault current
contribution.
1MRS756500 F
ABB