ABB RELION REX640 Technical Manual page 539

1MRS759142 F
The use of wattmetric protection gives a possibility to use the dedicated inverse
definite minimum time characteristics. This is applicable in large high-impedance
earthed networks with a large capacitive earth-fault current.
In a network employing a low-impedance earthed system, a medium-size neutral
point resistor is used. Such a resistor gives a resistive earth-fault current
component of about 200...400 A for an excessive earth fault. In such a system,
the directional residual power protection gives better possibilities for selectivity
enabled by the inverse time power characteristics.
4.2.7.9 Signals
WPWDE Input signals
Table 595: WPWDE Input signals
Name
IRES
URES
BLOCK
RCA_CTL
WPWDE Output signals
Table 596: WPWDE Output signals
Name
OPERATE
START
4.2.7.10 WPWDE Settings
Table 597: WPWDE Group settings (Basic)
Parameter Values (Range)
Directional mode
2=Forward
3=Reverse
Current start value 0.010...5.000
Voltage start value 0.010...1.000
Power start value 0.003...1.000
Reference power 0.050...1.000
Table continues on the next page
REX640
Technical Manual
Type
SIGNAL
SIGNAL
BOOLEAN
BOOLEAN
Type
BOOLEAN
BOOLEAN
Unit Step
xIn 0.001
xUn 0.001
xSn 0.001
xSn 0.001
Protection functions
Default Description
- Residual current
- Residual voltage
0=False Block signal for acti-
vating the blocking
mode
0=False Relay characteristic
angle control
Description
Operate
Start
Default
2=Forward
0.010
0.010
0.003
0.150
Description
Directional mode
Minimum operate
residual current for
deciding fault di-
rection
Start value for re-
sidual voltage
Start value for re-
sidual active power
Reference value of
residual power for
Wattmetric IDMT
curves
539