Selecting Adaptive Sequence Length - ABB REF 610 Technical Reference Manual

1MRS 755535
5.1.3.
Feeder Protection Relay
Technical Reference Manual - ANSI Version
Shot initiation by a pickup signal applies only to shot 1, and to definite tripping, i.e.
when no more shots are allowed but the network fault has not been cleared. In this
case, the AR function will trip the circuit breaker on expiration of AR 51P Pickup
Delay and AR 51N Pickup Delay.
Note!
The signal Open CB Command must be routed to the output contact used for
tripping the circuit breaker.
Note!
At the factory default delay of 300 s for AR 51P Pickup Delay and AR 51N
Pickup Delay, the pickup signals will, in practise, not be used for shot initiation.
However, if elements 51P or 51N have been given an IDMT (mode) characteristic,
the factory default delay of 300 s will function as a trip time limiter. With small
currents, the operate time at IDMT (mode) characteristic may be relatively long.
However, since the pickup signals are always routed to the AR function, the circuit
breaker will be tripped and a shot initiated (provided that the signal Open CB
Command has been routed to the trip output contact) on expiration of the factory
default delay.
Note!
When using AR 51P Pickup Delay and AR 51N Pickup Delay for shot
initiation and the signal Open CB Command has been routed to the trip output
contact, elements 51P and 51N should not be used for blocking of shot 1.

Selecting adaptive sequence length

The auto-reclose sequence can be set to adapt to the fault current, either through
blocking of shot initiation or disable of the AR function.
In the examples below, three overcurrent elements (51P, 50P-1 and 50P-2) are used
and the number of shots of the AR sequence vary depending on which elements
trips.
Example 1
Pickup by checking that the switches have been properly set:
Settings Function
SG1/1=1 Blocking of initiation of shot 1 by the trip signal from element 50P-1
SG3/1=1 Disable of the AR function by the trip signal from element 50P-2
Number of shots = 3
If one or several phase currents
• exceed the set pickup value of element 51P but not of elements 50P-1 and 50P-2,
the AR sequence will include shot 1, 2 and 3.
• exceed the set pickup value of elements 51P and 50P-1 but not of element 50P-2,
the AR sequence will include shot 2 and 3.
• exceed the set pickup value of elements 51P, 50P-1 and 50P-2, no shots will be
performed (AR function disabled).
Note!
REF 610
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