ABB REX 521 - Ai1; Condition Monitoring; CB Wear

122
1MRS751802-MUM
Protection Relay
Technical Reference Manual, Standard Configurations
REX 521
7.3.9. AI1
The analog measuring block is used for supervising current limits and for
determining the state of the motor (running/stopped) in H07.
Fig. 7.3.9.-1 Function block symbol of AI1
7.4. Condition monitoring
7.4.1. CB wear
In the circuit-breaker wear function block CB wear, calculating the electrical wear
of the circuit breaker is based on the current in each phase before opening. The
breaker wear is calculated for each phase separately and when the accumulated
breaker wear has reached the setting value, the function block will issue an alarm
signal.
The function block uses a 16-point setting table
(Main menu\Cond.Monit.\CB wear\ Control settings) for the
current and the corresponding breaker wear value. The calculation is based on linear
interpolation using the table. Typically, the breaker wear increases in proportion to
the square of the current. However, the interpolation table solution provides a close
match and facilitates the configuration.
Analog input, AI1
Limit selection Not in use
HW, HA, LW, LA
HW, HA
LW, LA
HW, LW
HA, LA
HW
HA
LW
LA
High alarm -10000.00000...10000.00000
Low alarm -10000.00000...10000.00000
HA start delay 1.0...300.0 s
HA reset delay 1.0...300.0 s
LA start delay 1.0...300.0 s
LA reset delay 1.0...300.0 s
AI1
LOW ALARM
HIGH ALARM