The operation of the subfunction can be described with a module diagram. All the
modules in the diagram are explained in the next sections.
Figure 782: Functional module diagram for circuit breaker gas pressure alarm
The gas pressure is monitored through the binary input signals
PRES_LO_IN
and
PRES_ALM_IN
.
Timer 1
When the
PRES_ALM_IN
binary input is activated, the
PRES_ALM
alarm is activated
after a time delay set with the
Pressure alarm time setting. The
PRES_ALM
alarm can
be blocked by activating the
BLOCK
input.
Timer 2
If the pressure drops further to a very low level, the
PRES_LO_IN
binary input
becomes high, activating the lockout alarm
PRES_LO
after a time delay set with
the
Pres lockout time setting. The
PRES_LO
alarm can be blocked by activating the
BLOCK
input.
7.1.6
Application
SSCBR includes different metering and monitoring subfunctions.
Circuit breaker status
Circuit breaker status monitors the position of the circuit breaker, that is, whether
the breaker is in an open, closed or intermediate position.
Circuit breaker operation monitoring
The purpose of the circuit breaker operation monitoring is to indicate that the
circuit breaker has not been operated for a long time. The function calculates the
number of days the circuit breaker has remained inactive, that is, has stayed in the
same open or closed state. There is also the possibility to set an initial inactive day.
Breaker contact travel time
High traveling times indicate the need for the maintenance of the circuit breaker
mechanism. Therefore, detecting excessive traveling time is needed. During the
opening cycle operation, the main contact starts opening. The auxiliary contact
A opens, the auxiliary contact B closes and the main contact reaches its opening
position. During the closing cycle, the first main contact starts closing. The auxiliary
contact B opens, the auxiliary contact A closes and the main contact reaches its
1MRS759142 F
Condition monitoring functions
REX640
Technical Manual
1369