ABB Relion 620 Series - Page 478

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.
4.2.7.8 Signals
Table 461: WPWDE Input signals
Name Type Default Description
Io SIGNAL 0 Residual current
Uo SIGNAL 0 Residual voltage
BLOCK BOOLEAN 0=False Block signal for activating the
blocking mode
RCA_CTL BOOLEAN 0=False Relay characteristic angle control
Table 462: WPWDE Output signals
Name Type Description
OPERATE BOOLEAN Operate
START BOOLEAN Start
4.2.7.9 Settings
Table 463: WPWDE Group settings (Basic)
Parameter
Values (Range) Unit Step Default Description
Directional mode
2=Forward
3=Reverse
2=Forward Directional mode
Current start value 0.010...5.000 xIn 0.001 0.010 Minimum operate
residual current for
deciding fault di-
rection
Voltage start value 0.010...1.000 xUn 0.001 0.010 Start value for re-
sidual voltage
Power start value 0.003...1.000 xPn 0.001 0.003 Start value for re-
sidual active power
Reference power 0.050...1.000 xPn 0.001 0.150 Reference value of
residual power for
Wattmetric IDMT
curves
Characteristic an-
gle
-179...180 deg 1 -90 Characteristic an-
gle
Time multiplier 0.05...2.00 0.01 1.00 Time multiplier for
Wattmetric IDMT
curves
Table continues on the next page
Protection functions 1MRS757644 H
478 620 series
Technical Manual