7
Initiation of auto-
reclosing
The protective stages to initiate or block the AR
functions are selected with SGF switches of the
protective relay modules. See sections "auto-
reclose initiation signals" in the userguides of
the protective relay modules.
The start of the AR shots are subject to the
following conditions:
1) An AR shot of a value smaller than that
indicated by the shot pointer cannot be started
2) An initiation signal (AR1...4) has to be active
and the corresponding setting has to be Start.
3) No initiation signal that inhibits (Block) the
shot must be active
4) Should a start delay have been set for the AR
shot (rf. Auto-reclose shot initiated by a start
signal of a protection relay module), the
initiation signal still has to be active when the
start delay elapses, to enable initiation of the
AR shot.
Example (see Figure 3):
The initiation signals AR1 and AR2 are as-
sumed to be activated when the value of the shot
pointer is 2 (AR shot 1 has just been made). AR
shot 2 would be the next one to start, but it is
blocked by AR1. The AR shots 3...5 have not
been configured to be initiated by either signal,
but the final trip function (6) has. So the next
operation will be final tripping.
An AR shot initiated by a trip signal of the
protection (SGF1/1...5 = 0) starts immediately.
The circuit breaker is then opened by a protec-
tion relay module.
A start delay can be set to delay the start of an AR
shot. Separate start delays can be set for each box
in the gray area in Figure 3.
When the AR shot is to be initiated by the start
signal of the protection (SGF1/1...5=1), the
circuit breaker is opened by the auto-reclose
module as soon as the start delay time of the
concerned AR shot has elapsed. The value zero
can also be selected for the start delay.
What is important for the start delay is that the
corresponding initiation signal remains active
throughout the time. Should the initiation sig-
nal reset the time delay starts from zero again.
The use of another initiation signal for blocking
the start of an AR shot does not influence the
time delay.
In the example in Fig. 4 input AR2 has a starting
function and AR1 an blocking function. In case
a) momentary activation of input AR1 does not
influence the start of the AR shot, nor the start
delay. The input AR1 used for blocking in case
b) remains active for a longer time than the start
delay of AR2. The AR shot is started 50 ms after
the blocking via AR1 is reset.
AR2
(Start)
Start delay time
Shot started
AR2
AR1
Start delay time
Shot started
AR1
(Block)
50 ms delay after
block signal reset
50 ms delay after
block signal reset
a)
b)
Fig. 4. Examples of AR initiation
An auto-reclose shot can be blocked by e.g. a
high-set overcurrent stage. If an activation of
initiation line AR1 is selected to block shot 1 it
means that shot 1 is blocked as long as the
initiation line AR1 is activated. However shot 2,
3, 4, 5 or the final trip function can be initiated.
The block function does not increase the value
of the shot pointer so if no shot or final trip can
be initiated the AR module will wait until the
block signal is reset or that the protection per-
forms definite tripping.
Auto-reclose shot
initiated by a trip
signal
Auto-reclose shot
initiated by a start
signal
Auto-reclose shot
blocked by an
initiation signal
Summary of Contents for SPAA 341 C /E351
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