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1MRK 505 370-UEN D
"Prepare three-phase tripping" is then used to switch the tripping to three-phase. This signal
is generated by the auto recloser and connected to the trip function block and also connected
outside the IED through IO when a common auto recloser is provided for two sub-systems. An
alternative signal "Prepare 1-phase tripping" is also provided and can be used as an alternative
when the autorecloser is shared with another subsystem. This provides a fail safe connection
so that even a failure in the IED with the auto recloser will mean that the other sub-system will
start a three-phase trip.
A permanent fault will cause the line protection to trip again when it recloses in an attempt to
energize the line.
The auto reclosing function allows a number of parameters to be adjusted.
Examples:
•
number of auto reclosing shots
•
auto reclosing program
•
auto reclosing dead times for each shot
12.2.2.1
Auto reclosing operation Off and On
Operation of the automatic recloser can be set to Off and On by a setting parameter or by
external control. The setting parameter
With the settings
pulses to the inputs On and Off, for example, from a control system or by a control switch.
When the auto recloser is set On, the
operative if other conditions such as circuit breaker is closed and circuit breaker is ready are
also fulfilled, the
start.
12.2.2.2
Start auto reclosing and conditions for start of a reclosing cycle
The usual way to start an auto reclosing cycle, or sequence, is to start it at selective tripping by
line protection by applying a signal to the
trip signals or, only the conditions for differential, distance protection zone 1 and distance
protection aided trip. In some cases also directional earth fault protection aided trip can be
connected to start an auto reclose attempt. If general trip is used to start the auto recloser it
is important to block it from other functions that should not start an auto reclosing sequence.
In cases where one wants to differentiate three-phase auto reclosing dead time, for different
power system configuration or at tripping by different protection stages, one can also use the
STARTHS input (start high-speed reclosing). When initiating STARTHS , the auto reclosing dead
time for three-phase shot 1,
synchrocheck condition.
A number of conditions need to be fulfilled for the start to be accepted and a new auto
reclosing cycle to be started. They are linked to dedicated inputs. The inputs are:
CBREADY , circuit breaker ready for a reclosing cycle, for example, charged operating gear.
•
CBCLOSED to ensure that the circuit breaker was closed when the line fault occurred and
•
start was applied.
•
No signal at
been accepted, it is latched in and an internal signal "start" is set. It can be interrupted by
certain events, like an "inhibit" signal.
Busbar protection REB670
Application manual
Operation = Off , or On sets the function to Off or On.
Operation = On and ExternalCtrl = On , the control is made by input signal
SETON output is set, and the auto recloser becomes
READY output is activated (high). Then the auto recloser is ready to accept a
t1 3PhHS is used and the closing is done without checking the
INHIBIT input that is, no blocking or inhibit signal present. After the start has
START input. Starting signals can be either, general
Section 12
Control
M12391-91 v6
M12391-94 v5
267
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