7.6.6 Monitored data
PID-3892-MONITOREDDATA v6
Table 106: SDEPSDE 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
UN REAL - kV Measured magnitude of
the residual voltage 3U0
SN REAL - MVA Measured magnitude of
residual power
3I03U0cos(Fi-RCA)
ANG FI-RCA
REAL - deg Angle between 3U0 and
3I0 minus RCA (Fi-RCA)
7.6.7 Operation principle
7.6.7.1 Function inputs
SEMOD171963-4 v5
The function is using phasors of the residual current and voltage. Group signals I3P
and U3P containing phasors of residual current and voltage which are taken from
pre-processor blocks.
The sensitive directional earth 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(U
ref
)|). The reference voltage (Uref) is the polarizing quantity
which is used for directionality and is defined as Uref = -3U
0
e
—jRCADir
, that is
-3U
0
inversely rotated by the set characteristic angle RCADir. RCADir is normally
set equal to 0 in a high impedance earthed 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.
1MRK 506 382-UEN A Section 7
Current protection
Line distance protection REL650 2.2 IEC 223
Technical manual
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