ABB Relion 611 series REB611 Product Manual page 6

Busbar and Multipurpose Differential Protection and Control
REB611
Product version: 1.0
An additional stand-by (residual) earth-fault
protection is provided by the two non-directional
earth-fault stages. The stand-by earth-fault
protection can be used together with the high-
impedance protection functionality to protect
motors, generators and transformers against
residual earth-faults. The measurements are taken
from the earthing point of the protected object.
Zone A
3 3
Incoming / Outgoing
Feeder for Zone A
GUID-9D830E6D-F3C4-45D3-879E-FA6C6F140114 V1 EN
Figure 2. Bus-differential protection covering two zones with two REB611 IEDs
6
Bus coupler
3
3
REB611 REB611
The residual earth-fault protection can also be
used as bus-wire supervision, especially in new or
retrofitting applications, where an earth-fault
protection function is used for grounding the
measurement circuits where short-circuiting or
circuit breaks have occurred. The grounding can
be done by an external relay.
Zone B
3 3
Incoming / Outgoing
Feeder for Zone B
1MRS757467 B
ABB