Signals - ABB RELION 620 Series Technical Manual

1MAC504801-IB E
4.3.2.6
620 series ANSI
Technical Manual
Table 272: Setting for a five-step df/dt< operation
Load-shedding steps
1
2
3
4
5
Once the frequency has stabilized, the shed load can be restored. The restoring operation
should be done stepwise, taking care that it does not lead the system back to the emergency
condition.
Table 273: Setting for a five-step restoring operation
Load-shedding steps
1
2
3
4
5

Signals

Table 274: 81LSH Input signals
Name Type
F SIGNAL
dF/dt SIGNAL
BLOCK BOOLEAN
BLK_REST BOOLEAN
MAN_RESTORE BOOLEAN
Table 275: 81LSH Output signals
Name Type
TRIP BOOLEAN
OPR_FRQ BOOLEAN
OPR_FRG BOOLEAN
PICKUP BOOLEAN
ST_FRQ BOOLEAN
Table continues on next page
Pickup value df/dt setting
-0.005 · Fn /s (-0.25 Hz/s)
-0.010 · Fn /s (-0.25 Hz/s)
-0.015 · Fn /s (-0.25 Hz/s)
-0.020 · Fn /s (-0.25 Hz/s)
-0.025 · Fn /s (-0.25 Hz/s)
Restoring pickup Val setting
0.990 · Fn (59.4 Hz)
0.990 · Fn (59.4 Hz)
0.990 · Fn (59.4 Hz)
0.990 · Fn (59.4 Hz)
0.990 · Fn (59.4 Hz)
Default Description
0 Measured frequency
0 Rate of change of frequency
0=False Block signal for activating the blocking mode
0=False Block restore
0=False Manual restore signal
Description
Trip of load shedding
Trip signal for under frequency
Trip signal for high df/dt
Pickup
Pick-Up signal for under frequency detection
Section 4
Protection functions
Trip Tm df/dt setting
8000 ms
2000 ms
1000 ms
500 ms
250 ms
Restore delay time setting
200000 ms
160000 ms
100000 ms
50000 ms
10000 ms
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