Arcing time can be used for controlling the autoreclosing in cases protection function Start signal is
making the requests. In case if the request (start) activates during the Reclaim time the Arcing time
calculation starts and if fault persists autorecloser shall continue to next stage. If Arcing time
calculation starts but stops before the set time have been used then Reclaim time calculation
continues normally and when it is elapsed autorecloser shall return to either General Reclaim time or
into Ready mode and the shot is considered as successful. Arcing time counter is not resetting from
the request drop off during the Reclaim time and every time the request is activated (e.g. protection
function starts) the arcing time counter is deducted by the time request is on. This means that the time
set to Arcing time parameter means cumulative time of start allowed in Reclaim time before decision is
made that the shot is failed or succeeded.
In case the autoreclosing is used in the time coordinated network protected by IDMT time
characteristics and the relays are old mechanical types which have also current dependent release
time the operation of the protection selectivity has to be guaranteed by allowing all of the relays timing
devices reset completely during the dead time so that the correct time discrimination is maintained
after reclosing to the fault. Time required for mechanical IDMT relay to reset may be even 10 s in some
cases. When short dead times are required the relays should reset almost instantaneously so that the
current dependent time grading operates as expected. For these cases in the autorecloser is possible
to set certain discrimination time instead of arcing time, which starts simultaneously with reclaim time
and if during this discrimination time any new reclosing requests are made the recloser will halt and let
the protection devices operate based on their settings and does not interfere on the operation of the
protection functions or the breaker. This means also that further reclosing are not made before the
autorecloser is reset manually and the breaker shall remain open until it is manually closed.
Auto-recloser IO
Main outputs of the autorecloser function are Object open and Object close control signals. In addition
to these output controls the function will report the recloser status information to be used in the logics
or LED indications as well as applied operations. Setting parameters are static inputs for the function
which are changed only by user input in the setup phase of the function.
Inputs for the function are binary recloser request signals, blockings and controlling signals, controlled
object monitoring and status signals. The function registers its operation into 12 last time-stamped
registers and also generates general time stamped ON/OFF events to the common event buffer from
each of the two output signal as well as several operational event signals. Time stamp resolution is
1ms. Function provides also cumulative counters for each applied reclosing events and requests.
Autorecloser function can be divided into starter, shot selector state machine, sorter and shot blocks
which operate dynamically during the reclosing cycles based on the given settings and input signals
monitoring. Autorecloser behavior can be changed dynamically even during the cycle based on
programmed reclosing scheme and active requests.
AQ-F255
Instruction manual
Version: 2.00
231
© Arcteq Relays Ltd
