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
M12391-91 v6
Operation of the automatic recloser can be set to Off and On by a setting parameter
or by external control. The setting parameter Operation = Off, or On sets the
function to Off or On. With the settings Operation = On and ExternalCtrl = On ,
the control is made by input signal 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 SETON output is set, and the auto recloser
becomes operative if other conditions such as circuit breaker is closed and circuit
breaker is ready are also fulfilled, the READY output is activated (high). Then the
auto recloser is ready to accept a start.
12.2.2.2 Start auto reclosing and conditions for start of a reclosing cycle
M12391-94 v5
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 START input. Starting signals
can be either, general 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, t1 3PhHS is used
and the closing is done without checking the 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:
1MRK 505 393-UEN B Section 12
Control
Line differential protection RED650 2.2 IEC 233
Application manual