Siemens Reyrolle 7SR5 Manual page 278

Protection and Automation Functions
5.19 67 Directional Overcurrent/Earth Fault
[dw_7SR5_function67ApplicationAndSettingNotes1, 1, en_US]
Figure 5-31
Parameter: 67 > Minimum Voltage
•
Default setting: 1 V
Where the measured polarizing voltage is below this setting no directional control signal is given and
operation of protection elements set as directional will be inhibited. This prevents mal-operation under
fuse failure/MCB tripped conditions where noise voltages can be present.
Parameter: 67 > 2-out-of-3 Logic
•
Default setting: Disabled
When set to Enabled, the directional elements will only operate for the majority direction, e.g. if I
are detected as forward flowing currents and I
enable signals 67 FWD PhA and 67 FWD PhC will operate while phase the phase B directional enable
signal will be inhibited.
Parameter: 67G > Char Angle
•
Default setting: -15°
The 67G directional element provides forward and reverse outputs that can be used to control each
measured earth fault element.
The measured directional earth fault elements use the zero phase sequence (V
quantity and the zero phase sequence current (I
I (Operate)
I
0
278
Phase Fault Directional Characteristic
is detected as reverse current flow, then directional
b
) phasor is the operate quantity.
0
V (Reference)
V
0
Reyrolle 7SR5, Transformer Protection Device, Device Manual
C53000-G7040-C015-1, Edition 11.2019
and I
a c
) voltage as the reference
0