8.6.6 Monitored data
PID-3892-MONITOREDDATA v5
Table 248: SDEPSDE (67N) Monitored data
Name Type Values (Range) Unit Description
INCOSPHI REAL - A Magnitude of residual current along the
polarizing quantity 3I0cos(Fi-RCA)
IN REAL - A Measured magnitude of the residual
current 3I0
VN REAL - kV Measured magnitude of the residual
voltage 3V0
SN REAL - MVA Measured magnitude of residual power
3I03V0cos(Fi-RCA)
ANG FI-RCA REAL - deg Angle between 3V0 and 3I0 minus RCA (Fi-
RCA)
8.6.7 Operation principle
8.6.7.1 Function inputs
SEMOD171963-4 v4
The function is using phasors of the residual current and voltage. Group signals I3P and V3P
containing phasors of residual current and voltage are taken from pre-processor blocks.
The sensitive directional ground fault protection has the following sub-functions included:
Directional residual current protection measuring 3I
0
·cos φ
SEMOD171963-8 v7
φ is defined as the angle between the residual current 3I
0
and the reference voltage (|φ=ang(3I
0
)-
ang(V
ref
)|). The reference voltage (Vref) is the polarizing quantity which is used for directionality
and is defined as Vref = -3V
0
e
—jRCADir
, that is -3V
0
inversely rotated by the set characteristic angle
RCADir
.
RCADir
is normally set equal to 0 in a high impedance grounded network with a neutral
point resistor as the active current component is appearing out on the faulted feeder only.
RCADir
is set equal to -90° in an isolated network as all currents are mainly capacitive. The function
operates when 3I
0
·cos φ gets larger than the set value.
Section 8 1MRK 502 066-UUS B
Current protection
510
Technical manual
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