3. Protection functions
The IED offers phase-segregated (three phases)
high-impedance differential protection and non-
directional earth-fault protection for busbars,
motors and generators. REB611 also offers high-
impedance differential-based restricted earth-fault
protection for motors, generators, reactors and
power transformers.
Lockout
relay
86
Hi> 87
Hi> 87
Hi> 87
MCS 1I MCS 1I
3I>BF 51BF
Io>BF 51N
BF
Io>>> 50N
Io> 51N-1
3
3
3
3
REB611 (STANDARD CONF A)
GUID-E0FA94F1-428D-4BA3-82EF-F5DAB1CABDC7 V1 EN
Figure 1.
Protection function overview of standard configuration A in a single zone with bus-wire supervision
4. Application
The IED REB611 offers bus-differential protection
in a single zone with bus-wire supervision. It also
offers the possibility of bus-differential protection
over two zones using two REB611 IEDs.
The IED REB611 can be used in the protection of
a motor or generator using the combined
restricted earth-fault and residual earth-fault
protection functionalities. Due to the individuality
of the high-impedance protection functions, a
single REB611 can be used for restricted earth-
fault protection of both the high and low voltage
side of a power transformer.
The high-impedance principle for busbar
differential protection provides a secure and
dependable protection scheme against faults
within the measured zone. The high-impedance
principle has been used for many years for
differential protection due to the capability to
manage through-faults also with heavy current
transformer (CT) saturation.
The IED REB611’s high-impedance protection
functions contain built-in blocking functionality,
which is provided by the bus-wire supervision
functions to restrict faulty operations in case of
faults in the measurement circuits.
Busbar and Multipurpose Differential Protection and Control
1MRS757467 B
REB611
Product version: 1.0
ABB
5
Summary of Contents for Relion 611 series REB611
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