Arcteq AQ-S215, Instruction Manual

Page: 153 / 289

1. An overcurrent is found in the protected line causing the I> protection to pick up. This
activates the AR1 R AR1 Request equested ed signal to begin to calculate the SSho hot1 Star t1 Start T t Time ime. This activates
the SSho hot 1 Running t 1 Running signal eventhough the auto-recloser function is not yet running.
2. The SSho hot1 Star t1 Start T t Time ime (500 ms) for has elapsed and the auto-recloser function starts running
(AR Running AR Running). This sends an "Open" command to the breaker.
3. The circuit breaker is opened and the I> stage's START signal is released and simultaneously
REQ1 trip signal for auto-reclosing is released. The auto-recloser function starts calculating
the SSho hot1 Dead T t1 Dead Time ime to close the breaker.
4. The fault is cleared during the SSho hot1 Dead T t1 Dead Time ime (200 ms). When this time is exceeded, the
auto-recloser 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. A
"Close" command is dropped after the breaker's "Closed" indication is received and the auto-
recloser function starts calculating the SSho hot1 R t1 Reclaim eclaim TTime ime.
6. The SSho hot1 R t1 Reclaim eclaim TTime ime (10 s) is exceeded, and so the AR Running AR Running, AR1 R AR1 Request equested ed and
SSho hot 1 Running t 1 Running 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 recloser cycle.
7. The AR R AR Reclaim eclaim time is exceeded and the function is set to "Ready" to wait for the next
request.
Auto-recloser in meshed or ring networks
A typical auto-recloser scheme cannot be applied directly to an overhead line network that has a
distributed generation (DG) component; this situation will become more common as renewable power
sources become more widespread. Instead, this requires a two-end auto-recloser scheme where the
two relays at both ends of the line function in a master–follower operation. The DG power plant must be
disconnected from the rest of the network before the breaker's "Close" command is applied; otherwise
the plant keeps the fault on during the auto-recloser's dead time and thus fails the reclosing.
Additionally, when the main grid is disconnected from the DG power plant, the closing of the breaker is
likely to cause phase shifting issues during the dead time.
Figure. 5.4.4 - 103. Auto-reclosing with distributed generation in the line.
This operation requires a link between the 110/20 kV substation's master relay and the 20 kV collector
substation's follower relay. When the auto-recloser function is initiated, the collector station's breaker is
opened and remains open until the auto-recloser sequence is over as there is no reason to close the
breaker until the auto-recloser cycle has successfully cleared the fault. When the sequence is
succesful, the collector substation's breaker is given permission to close after the reclaim time; the
breaker should be closed with the Synchrocheck function.
A AQ Q-S215 -S215
Instruction manual
Version: 2.04
152