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i
i
NOTE
The undetermined area for the device MLFB 6MD2321-1AA00-1AA0 is 10° and the respective angles
change accordingly.
The undetermined area for the device MLFB 6MD2322-1AA00-1AA0 is 20° and the respective angles
change accordingly.
For more information about ground-fault direction of solidly grounded system, see
and refer to the
Fault Parameter > Ground-Fault Detection > Neutral-point Treatment menu.
Ground-Fault Detection with Cos φ/Sin φ Measurement
The ground-fault detection with cos φ/sin φ measurement method is used to detect the ground fault based on
the active part of the current (resonant system) or reactive part of the current (isolated system). The ground-
fault detection with cos φ/sin φ measurement method is enabled when the I
dir
(user-settable parameter for
the resistive part of the ground current) parameter is configured to the values as in
dir
is set to 0,
the device detects the ground fault based on the vector method.
The ground-fault detection with cos φ/sin φ measurement method is only applicable for resonant-grounded
systems and isolated-grounded systems.
If the ground current ((I
N
>) and the resistive current exceed the set threshold (I
N
> and I
dir
respectively) and if
the time delay tI
N
> is greater than the set threshold, the device indicates a fault.
If I
dir
is set to 0 (vector method), irrespective of the selected ground-type connection, the total ground current
is compared with the set current I
N
> for fault detection.
For resonant-ground connections, if I
dir
is not 0 (ground-fault detection with cos φ/sin φ measurement
method), the active part of the ground current is compared with I
dir
in addition to the total ground current and
I
N
> for ground-fault detection.
For isolated-ground connections, if I
dir
is not 0 (ground-fault detection with cos φ/sin φ measurement
method), the reactive part of the ground current is compared with I
dir
in addition to the total ground current
and I
N
> for ground-fault detection.
For more information about I
dir
and refer to the Fault Parameters > Ground-Fault
Detection menu.
The following logic diagram illustrates the ground-fault detection with cos φ/sin φ measurement method.
[lo_sfcm-grndfltdet-cossine, 2, en_US]
Figure 4-14
Logic Diagram for Ground-Fault Detection with Cos φ/Sin φ Measurement Method
The following table displays the I
dir
range and the ground-fault detection with cos φ/sin φ measurement
method status:
4.1.20
Device Functions
4.1 Description
SICAM, Feeder Condition Monitor, Manual
45
E50417-H8940-C580-A4, Edition 03.2019
Содержание SICAM
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