Interruption Of Auto-Reclosing; Aids To Circuit Breaker Maintenance; Cbfail Alarm - ABB SPAA 341 C /E351 User Manual

Interruption of
auto-reclosing
Circuit breaker
supervision logic
Aids to circuit
breaker maintenance
An auto-reclose sequence (AR shots 1...5) can
be interrupted or is interrupted in the following
cases:
- the opening or closing of the circuit breaker
fails (CBPOS input does not change status)
- the CB status data changes from "open" to
"closed" during the dead time of the auto-
reclosure, for example, due to manual closing
of the circuit breaker
- the ARINH input is activated
- the circuit breaker is opened by remote control
(parameter V1)
When the auto-reclose module operates the
circuit breaker, it also checks that the state of the
CB position input changes properly during the
set pulse lenght. To be able to check the position
data the auto-reclose module needs information
about the position of the circuit breaker
(CBPOS). When required, the auto-reclose mod-
ule is able to operate without this information.
In such a case the control operations are not
supervised, i.e. whether they are successful or
not.
For the operation of the circuit breaker the
length of the open pulse and the close pulse of
the module is adjustable. These times are maxi-
mum times. If no CB position information is
available the control impulses are in accordance
with the setting. Open and close signals cannot
be active at the same time. If so, the open signal
interrupts the close signal. When CB position
information is available, the impulse is inter-
rupted, once the CB position has changed.
The purpose of the maintenance monitor is to
provide an alarm signal or, possibly, prevent
closing of the circuit breaker after a certain
number of CB operations. The operation of the
maintenance monitor is based on counting the
number of times the circuit breaker has opened.
As soon as the auto-reclose module notices a
circuit breaker trip the value of the maintenance
monitor decreases.
Different load on the circuit breaker influences
the maintenance monitor in a different way, for
instance, overcurrent may have a weighting
factor of 20 and manual CB opening a weight-
ing factor of 1, which means that the monitor
value is decreased by 20 or 1, respectively. The
auto-reclose module has five weighting factors:
opening initiated by AR1, by AR2, by AR3, by
AR4, and manual control. The weighting fac-
tors can be set in the range 0...50.
- the auto-reclose program is set out of use
- the auxiliary voltage supply to the relay is
interrupted or the internal self-supervision
system of the AR module detects a fault.
In all the cases mentioned above specified infor-
mation about the cause of the interruption can
be obtained over the serial communication sys-
tem.
Should the circuit-breaker position remain un-
changed during the control operation a circuit
breaker fail alarm will be issued (CBFAIL).
In addition, the following conditions are checked
before the circuit breaker is closed:
- the circuit breaker is open
- the AR initiation signals AR1...4 are not active
- the close inhibit input CINH is not energized
- the value of the circuit breaker maintenance
monitor must be greater than zero, if SGF2/
6=1.
- if the synchrocheck function is in use, the
input ARSYNC has to be energized
Once the conditions mentioned above are ful-
filled the circuit breaker is closed. The maxi-
mum waiting time for the conditions to be
fulfilled is 2 seconds. Should one or several
conditions prevent closing, an alarm signal
CBFAIL will be given in 2 seconds.
When the maintenance monitor reaches the
value zero, a permanent CBFAIL alarm signal is
issued. The maintenance monitor can be so
configured (SGF2/6) that the value zero pre-
vents CB closing and auto-reclose operations.
The alarm is reset by giving the maintenance
monitor a new value.
In addition, a pre-alarm level can be set for the
maintenance monitor. When the monitor
reaches this level or falls below it, a pulse-shaped
CBFAIL alarm signal is given when the CB is
opened. The pre-alarm function can be set out
of use by choosing the setting value zero (0) for
it.
The maintenance monitor can be set out of use
by setting all weighting factors at zero.
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