Fast Tripping And Initiation Of Shot 1 Using Pickup Signals - ABB REF 610 Technical Reference Manual

REF 610
5.1.2.
140
Feeder Protection Relay
Technical Reference Manual - ANSI Version
As the set pickup value of element 51P in this example is higher than that of element
50P-1, as sometimes is the case, it is possible that the current will not exceed the set
pickup value of element 51P while the blocking of element 50P-1 is active. This will
lead to a pumping effect when the AR function is reset (the blocking of element 50P-
1 included), i.e. the AR sequence will pickup over and over again.
To avoid such a pumping effect, a cutout time is used. The cutout time, like the reset
time, will pickup when the set open time elapses and the AR function issues a
reclosing command to the circuit breaker. By setting the cutout time to be shorter
than the reset time (e.g. half of the reset time), the blocking of element 50P-1 (in this
case) will be reset before the AR function. Element 50P-1 will now be able to
continue the AR sequence and the pumping effect will thus be avoided.

Fast tripping and initiation of shot 1 using pickup signals

An alternative way to achieve fast tripping and shot initiation (typical for certain
countries, such as Finland), is to use pickup signals from protection elements for
shot initiation. The AR function of REF 610 can be initiated by the pickup signals
from elements 51P and 51N.
The pickup time of elements 51P and 51N is very short but can be extended with the settings
AR 51P Pickup Delay
When the set pickup delay elapses, the shot will be initiated and the AR function will trip the
circuit breaker by issuing the
Trip
51P
Pick up
Open CB Close CB
Command Command
51P Pickup
CB Closed
CB Open
Shot 1
51P TDLY
Fig. 5.1.2.-1 Fast initiation of shot 1 using pickup signals
and AR 51N Pickup Delay
Open CB Command
79
Shots 1, 2 and 3 initiation
t
Shots 1 initiation
0
51P Pick up
delay
Close CB
Command
51P Trip
51P Trip
Shot 2
51P TDLY 51P TDLY
1MRS 755535
of the AR function.
.
Open CB
Open CB Command
Close CB Command
Close CB
Command
51P Pickup
Open CB
Command
Shot 3 Definite Trip
51P TDLY
Open CB
Close CB