Signals; Settings - ABB RELION 620 Series Technical Manual

Section 4
Protection functions
4.3.1.6
4.3.1.7
Table 267: 81 Group settings
Parameter Values (Range)
Trip mode 1=Freq<
2=Freq>
3=df/dt
4=Freq< + df/dt
5=Freq> + df/dt
6=Freq< OR df/dt
7=Freq> OR df/dt
Pickup value Freq> 0.900...1.200
Pickup value Freq< 0.800...1.100
Pickup value df/dt -0.200...0.200
Trip Tm Freq 80...200000
Trip Tm df/dt 120...200000
326
smaller power systems where the loss of a large generator requires quick remedial actions
to secure the power system integrity. In such situations, the load shedding actions are
required at a rather high frequency level. However, in combination with a large negative
frequency gradient, the underfrequency protection can be used at a high setting.

Signals

Table 265: 81 Input signals
Name Type
F SIGNAL
dF/dt SIGNAL
BLOCK BOOLEAN
Table 266: 81 Output signals
Name Type
TRIP BOOLEAN
OPR_OFRQ BOOLEAN
OPR_UFRQ BOOLEAN
OPR_FRG BOOLEAN
PICKUP BOOLEAN
ST_OFRQ BOOLEAN
ST_UFRQ BOOLEAN
ST_FRG BOOLEAN

Settings

Unit Step
xFn 0.001
xFn 0.001
xFn /s 0.005
ms 10
ms 10
Default Description
0 Measured frequency
0 Rate of change of frequency
0=False Block signal for activating the blocking mode
Description
Trip
Trip signal for overfrequency
Trip signal for underfrequency
Trip signal for frequency gradient
Pickup
Pickup signal for overfrequency
Pickup signal for underfrequency
Pickup signal for frequency gradient
Default Description
1=Freq< Frequency protection trip mode selection
1.050 Frequency pickup value overfrequency
0.950 Frequency pickup value underfrequency
0.010 Frequency pickup value rate of change
200 Trip delay time for frequency
400 Trip delay time for frequency rate of change
1MAC504801-IB E
620 series ANSI
Technical Manual