ABB REX 521 Technical Reference Manual, Standard Configurations

146
1MRS751802-MUM
Protection Relay
Technical Reference Manual, Standard Configurations
REX 521
Fig. 9.1.5.-1 Connection diagram for the standard configuration B01 with the breaker status indication, the
control and alarm signals.
9.2. Incoming feeder, Basic B01
9.2.1. Features
This application example describes an incoming feeder to a single busbar including:
• Overcurrent protection
• Non-directional earth fault protection
The network is resistance or solidly earthed. The three-phase current measurement
is established with current transformers. The neutral current is measured via a
current transformer located in the neutral earthing circuit on the LV side of the
power transformer.
CB
REX521
DC
ES
1
0
0
1
Blocking signal from
the residual voltage relay
to Io>
Breaker wear alarm
Circuit-breaker failure
protection
Blocking signal to the incoming feeder
(START 3I>>)
TRIP circuit breaker
CLOSE circuit breaker
CBstatusB

ABB REX 521 Specifications

General

Brand	ABB
Model	REX 521
Category	Other
Language	English