73
Table 5.1.4.11.-6 Auto-reclose function
Feature Value
Number of shots 0...3
CB Closing time 0.1...10 s
Pickup delay of element 51P 0...300 s
Pickup delay of 51N 0...300 s
Reset time 3...300 s
Cutout time 0.1...300 s
Dead time of shot 1 0.1...300 s
Dead time of shot 2 0.1...300 s
Dead time of shot 3 0.1...300 s
Operate time accuracy ±2% of the set time and ±25 ms
Table 5.1.4.11.-7 CBFAIL
Feature Value
Set operate time 0.10...60.0 s
Phase-current threshold for external
triggering of the CBFAIL
*
pick-up/drop-off 0.08/0.04 x I
n
(CT)
5.1.5. Trip-circuit supervision
The trip-circuit supervision (TCS) detects open circuits, both when the circuit
breaker is open and closed, and trip-circuit supply failure.
The trip-circuit supervision is based on a constant current injection principle: by
applying an external voltage, a constant current is forced to flow through the
external trip circuit. If the resistance of the trip circuit exceeds a certain limit, due to
oxidation or a bad contact, for instance, the trip-circuit supervision is activated and a
warning appears on the LCD together with a fault code. The warning signal from the
trip-circuit supervision can also be routed to SO2 by setting switch SGF1/8 to 1.
Under normal operating conditions, the applied external voltage is divided between
the relay’s internal circuit and the external trip circuit so that at least 20 V remains
over the relay’s internal circuit. If the external trip circuit’s resistance is too high or
the internal circuit’s too low, due to welded relay contacts, for instance, the voltage
over the relay’s internal circuit falls below 20 V (15...20 V), which activates the trip-
circuit supervision.
The operation condition is:
URRI
cxt sinj
−++
()
×≥R
eint
20 V ac/dc
(8)
U
c
= operating voltage over the supervised trip circuit
I
inj
= current flowing through the trip circuit, ~1.5 mA
R
ext
= external shunt resistor
R
int
= internal shunt resistor, 1 kΩ
R
s
= trip coil resistance
Feeder Protection Relay
Technical Reference Manual - ANSI Version
REF610REF610
1MRS755535
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