Figure 486: Functional module diagram for monitoring circuit breaker status
Phase current check
This module compares the three phase currents to the setting
Acc stop current.
If the current in a phase exceeds the set level, information about the phase is
reported to the contact position indicator module.
Contact position indicator
The
OPENPOS
output is activated when the auxiliary input contact
POSCLOSE
is
FALSE, the
POSOPEN
input is TRUE and all the phase currents are below the setting
Acc stop current.
The
CLOSEPOS
output is activated when the auxiliary
POSOPEN
input is FALSE and
the
POSCLOSE
input is TRUE.
The
INVALIDPOS
output is activated when both the auxiliary contacts have the
same value, that is, both are in the same logical level, or if the auxiliary input contact
POSCLOSE
is FALSE and the
POSOPEN
input is TRUE and any of the phase currents
exceed the setting
Acc stop current
.
The status of the breaker is indicated by the binary outputs
OPENPOS
,
INVALIDPOS
and
CLOSEPOS
for open, invalid and closed position respectively.
7.1.4.2
Circuit breaker operation monitoring
The purpose of the circuit breaker operation monitoring subfunction is to indicate
if the circuit breaker has not been operated for a long time.
The operation of the circuit breaker operation monitoring can be described with a
module diagram. All the modules in the diagram are explained in the next sections.
Figure 487: Functional module diagram for calculating inactive days and alarm for
circuit breaker operation monitoring
Inactivity timer
The module calculates the number of days the circuit breaker has remained inactive,
that is, has stayed in the same open or closed state. The calculation is done by
monitoring the states of the
POSOPEN
and
POSCLOSE
auxiliary contacts.
The inactive days
INA_DAYS
is available in the monitored data view. It is also
possible to set the initial inactive days with the
Ini inactive days parameter.
1MRS757644 H
Condition monitoring functions
620 series
Technical Manual
911