This type of sequence (i.e. the first shot clears the fault) represents 75...85 % of all faults that occur in
MV overhead line networks.
Figure. 5.4.4 - 195. Signal status graph of the transient earth fault auto-recloser cycle.
1. An earth fault is found in the protected line causing the I0Dir> protection to start
calculating the operating time for a trip.
2. The I0Dir> trips and gives the "Open" command to the breaker's open coil. The auto-
recloser function is initiated and the AR Running
AR Running, AR2 R
AR2 Request
equested
ed and SSho
hot 1 Running
t 1 Running signals
are activated.
3. The circuit breaker is opened and the I0Dir> TRIP signal is released and simultaneously the
REQ2 trip signal for the auto-recloser is released. The recloser starts calculating the SSho
hot1
t1
Dead T
Dead Time
ime to close the breaker.
4. The fault is cleared during SSho
hot1 Dead T
t1 Dead Time
ime calculation. When that time (200 ms) is
exceeded and the function sends a "Close" request to the object breaker: the conditions are
met and the breaker's "Close" command is sent to the breaker's close coil.
5. The circuit breaker is closed and since the fault was cleared, no pick-ups are detected. The
"Close" command is dropped after the breaker's "Closed" indication is received and the auto-
recloser function starts calculating SSho
hot1
t1 R
Reclaim T
eclaim Time
ime.
6. The SSho
hot1
t1 R
Reclaim T
eclaim Time
ime (10 s) is exceeded, and so the AR Running
AR Running, SSho
hot 2 Running
t 2 Running and
AR2 R
AR2 Request
equested
ed signals are terminated, and the AR R
AR Reclaim
eclaim calculation begins. The
difference between auto-reclosing and shot-specific reclaim times is that the function jumps
to the next available shot should the fault returns. If a fault returns after a successful cycle
and the function's AR Reclaim signal is active, the function jumps directly to the Final Trip
state and then enters the lock-out state. The user can control this behavior through the
function settings. Both reclaim times can be set to 0 s when they are not needed, and the
function skips all timers that are set to zero. The user can also set is so that AR Reclaim is not
used at all after a successful reclosing cycle.
7. The AR R
AR Reclaim
eclaim time is exceeded and the function is set to "Ready" to wait for the next
request.
A
AQ
Q-F215
-F215
Instruction manual
Version: 2.04
310